5-aminolevulinic acid or its salts and methods for producing the same

Abstract

The objective is to provide 5-aminolevulinic acid or its salts, and a method for producing the same, which have fewer impurities and residual solvents and suppressed discoloration compared to conventional methods. [Solution] 5-aminolevulinic acid or a salt thereof, wherein, based on the peak area obtained by HPLC analysis, the ratio of the content of individual impurities to the content of 5-aminolevulinic acid or a salt thereof is 0.0007 or less, and the sum of the ratios of the content of individual impurities to the content of 5-aminolevulinic acid or a salt thereof is 0.0016 or less.

Description

[Technical Field]

[0001] This disclosure relates to 5-aminolevulinic acid or salts thereof and methods for producing the same. [Background technology]

[0002] 5-Aminolevulinic acid (hereinafter abbreviated as 5-ALA) is an amino acid that plays an important role in the body and is a useful substance in fields such as medicine, agriculture, and cosmetics.

[0003] Methods for producing 5-aminolevulinic acid or its salts include chemical synthesis and fermentation (for example, Patent Documents 1-5). Compared to chemical synthesis, the production of 5-aminolevulinic acid or its salts by fermentation has the advantage of having a lower environmental impact and being able to be produced in high yield by utilizing microorganisms with specific metabolic pathways.

[0004] When 5-aminolevulinic acid or its salts are crystallized with an organic solvent, the organic solvent may remain in the 5-aminolevulinic acid or its salt powder. According to the standards set by the Ministry of Health, Labour and Welfare under the Industrial Safety and Health Act, if the ethanol concentration in the product is 1000 ppm or higher, it falls under the category of "hazardous and harmful substances that must be labeled or notified (substances subject to mandatory labeling and provision of safety data sheets)." Since ensuring occupational safety is necessary when using 5-aminolevulinic acid products with labeling, this may affect the purchasing intentions of consumers.

[0005] The concentration of other impurities introduced during the manufacturing process of 5-aminolevulinic acid may also be a problem. According to the guidelines on impurities in the active pharmaceutical ingredients of new active ingredients stipulated in Pharmaceutical Affairs Bureau Notification No. 1216001, if the amount of individual impurities contained in the active pharmaceutical ingredient exceeds 0.05% by mass when the intake amount exceeds 2g / day, safety confirmation is required, which may hinder the drug application process. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent No. 2997979 [Patent Document 2] Japanese Patent No. 4520219 [Patent Document 3] Japanese Patent No. 4915723 [Patent Document 4] Japanese Patent No. 4989153 [Patent Document 5] Japanese Patent No. 5845203 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] As mentioned above, the production of 5-aminolevulinic acid or its salts involves problems with residual organic solvents remaining after the crystallization process (hereinafter also referred to as "residual organic solvents") and impurities introduced during the manufacturing process. In fact, the inventors examined the residual ethanol levels in five lots of 5-aminolevulinic acid or its salt powder (hereinafter also referred to as "market-distributed products") supplied by two companies, and found that several lots showed ethanol concentrations exceeding the standard value of 1000 ppm.

[0008] Furthermore, assuming that the structure of the impurities is similar to that of amino acids and therefore has a molar extinction coefficient equivalent to that of 5-aminolevulinic acid or its salts, which are used as standards in high-performance liquid chromatography (HPLC) measurements, we measured the peak area of ​​the impurities in other companies' products using an HPLC equipped with a UV-Vis absorbance detector. As a result, we identified lots containing a large amount of unknown impurities, the ratio of the peak area of ​​the impurities to that of 5-aminolevulinic acid or its salts exceeding 0.0005.

[0009] Here, a ratio of the peak area of ​​impurities to the peak area of ​​5-aminolevulinic acid exceeding 0.0005 is equivalent to the content of each impurity in the powder containing 5-aminolevulinic acid or its salt exceeding 0.05% by mass, indicating a deviation from the standard values ​​of the guidelines regarding impurities in the above-mentioned active pharmaceutical ingredient.

[0010] On the other hand, 5-aminolevulinic acid or its salts may discolor during storage. For example, if impurities remain, a reaction may occur between or between the 5-aminolevulinic acid or its salt and the remaining impurities, resulting in the formation of discolored substances, which may affect storage stability and product quality. Therefore, in order to improve storage stability and product quality, it is necessary to remove as many impurities as possible and obtain high-purity 5-aminolevulinic acid or its salts with suppressed discoloration.

[0011] However, there is no uniform method to suppress residual organic solvents, impurities, or discoloration in 5-aminolevulinic acid or its salts, as well as in various other compounds. Therefore, various methods have been investigated to suppress these, and finding 5-aminolevulinic acid or its salts that suppress these factors is extremely difficult.

[0012] Therefore, this disclosure aims to provide a powder of 5-aminolevulinic acid or its salt, and a method for producing the same, which has suppressed impurities, residual solvents, or discoloration compared to conventional methods. [Means for solving the problem]

[0013] The inventors of the present invention have discovered that by controlling the parameters during crystallization in the production of 5-aminolevulinic acid or its salts, it is possible to obtain 5-aminolevulinic acid or its salts with suppressed impurities, residual solvents, or discoloration compared to conventional methods, thereby completing the present invention.

[0014] In other words, this disclosure is as follows: 1. 5-aminolevulinic acid or a salt thereof that satisfies at least one of the following conditions (A1) and (A2), based on the peak area obtained by HPLC analysis. (A1) The ratio of the content of each impurity to the content of 5-aminolevulinic acid or its salt, as represented by the following formula (1), is 0.0007 or less. (A2) The sum of the ratios of the content of each impurity to the content of 5-aminolevulinic acid or its salt, as represented by the following formula (2), is 0.0016 or less. The ratio of the content of individual impurities to the content of 5-aminolevulinic acid or its salt = Peak area of ​​individual impurities quantifiable by HPLC / Peak area of ​​5-aminolevulinic acid or its salt ... Equation (1) The sum of the ratios of the content of individual impurities to the content of 5-aminolevulinic acid or its salt = Σ(peak area of ​​the amount of individual impurities quantifiable by HPLC / peak area of ​​5-aminolevulinic acid or its salt) ... Equation (2) 2. 5-aminolevulinic acid or its salt that satisfies (B1) and (B2) below. (B1) The light transmittance at a wavelength of 430 nm is 98.8% or higher. (B2) The light transmittance at a wavelength of 430 nm, as measured by a severe stability test under the following conditions, is 92.0% or higher. Conditions for the severe stability test: After storing the 5-aminolevulinic acid or its salt at a temperature of 70°C ± 2°C for 2 days, the transmittance of light at a wavelength of 430 nm is measured using a spectrophotometer. 3. The 5-aminolevulinic acid or salt thereof according to 1 or 2 above, wherein the residual organic solvent content in the 5-aminolevulinic acid or salt thereof is 1000 ppm or less. 4. The 5-aminolevulinic acid or salt thereof according to 1 or 2 above, wherein the arsenic content in the 5-aminolevulinic acid or salt thereof is less than 0.3 ppm. 5. The 5-aminolevulinic acid or salt thereof according to 1 or 2, wherein the 5-aminolevulinic acid or salt thereof is 5-aminolevulinic acid phosphate. 6. A method for producing 5-aminolevulinic acid or a salt thereof, comprising the steps [1] to [3] below. [1] A step to prepare a crystallization stock solution containing 5-aminolevulinic acid or a salt thereof, and then add water to the solution or concentrate the solution to prepare a crystallization stock solution with a concentration of 200 to 700 g / L in terms of 5-aminolevulinic acid monophosphate. [2] A step of raising the temperature of the crystallization stock obtained in [1] to 5-25°C. [3] A step 7 in which the first organic solvent is added to the crystallization stock solution obtained in [2] above to precipitate 5-aminolevulinic acid or a salt thereof, wherein the 5-aminolevulinic acid or a salt thereof satisfies at least one of the following (A1) and (A2) based on the peak area obtained by HPLC analysis, the method according to 6 above. (A1) The ratio of the content of each impurity to the content of 5-aminolevulinic acid or its salt, as represented by the following formula (1), is 0.0007 or less. (A2) The sum of the ratios of the content of each impurity to the content of 5-aminolevulinic acid or its salt, as represented by the following formula (2), is 0.0016 or less. The ratio of the content of individual impurities to the content of 5-aminolevulinic acid or its salt = Peak area of ​​individual impurities quantifiable by HPLC / Peak area of ​​5-aminolevulinic acid or its salt ... Equation (1) The sum of the ratios of the content of individual impurities to the content of 5-aminolevulinic acid or its salt = Σ(peak area of ​​the amount of individual impurities quantifiable by HPLC / peak area of ​​5-aminolevulinic acid or its salt) ... Equation (2) 8. The method according to 6 above, satisfying (B1) and (B2) below. (B1) The light transmittance at a wavelength of 430 nm is 98.8% or higher. (B2) The light transmittance at a wavelength of 430 nm, as measured by a severe stability test under the following conditions, is 92.0% or higher. Conditions for the severe stability test: After storing the 5-aminolevulinic acid or its salt at a temperature of 70°C ± 2°C for 2 days, the transmittance of light at a wavelength of 430 nm is measured using a spectrophotometer. 9. The method according to 6, wherein the content of residual organic solvent in the 5-aminolevulinic acid or its salt is 1000 ppm or less. 10. The method according to 6, wherein the arsenic content in the 5-aminolevulinic acid or its salt is less than 0.3 ppm. 11. The method according to 6, wherein the 5-aminolevulinic acid or salt thereof is 5-aminolevulinic acid phosphate. 12. The method according to 6, further comprising adding seed crystals to the crystallization stock solution in the manner described in [3] above, such that the content is 0.01 to 5.0% by mass. 13. The method according to [3] above, further comprising adding the seed crystal to the crystallization stock solution and then stirring for less than 360 minutes to mature the crystal. 14. The method according to 6, wherein the amount of the first organic solvent added in [3] is 0.50 v / v or less relative to the volume of the crystallization stock solution. 15. The method according to 12, further comprising the step of adding a second organic solvent to the crystallization stock solution after adding the seed crystal in [3]. 16. The method according to 15, wherein the rate of addition of the second organic solvent is 0.4 to 5.0 v / v / h relative to the volume of the crystallization stock solution. 17. The method according to 15, wherein the total amount of the first organic solvent and the second organic solvent added is 2 v / v or less relative to the volume of the crystallization stock solution. 18. The process includes separating and drying the precipitate obtained in [3] above to obtain a powder, The method according to 6, wherein the content of residual organic solvent in the powder is 1000 ppm or less. 19. The method according to any one of 6 to 18, wherein the first organic solvent in [3] is at least one selected from methanol, ethanol, isopropanol, n-propanol, acetone, and acetonitrile. 20. The method according to any one of 15 to 18, wherein the second organic solvent in [3] is at least one selected from methanol, ethanol, isopropanol, n-propanol, acetone, and acetonitrile. 21. The method according to 19, wherein the first organic solvent in [3] is ethanol. 22. The method according to 20, wherein the second organic solvent in [3] is ethanol. 23. A solution containing 5-aminolevulinic acid or its salt, glycine, alanine and PDPA, Na + A method for producing 5-aminolevulinic acid or a salt thereof, comprising treatment with a type of strongly acidic cation exchange resin. A method for producing 5-aminolevulinic acid or a salt thereof, comprising treating a solution containing 24,5-aminolevulinic acid or a salt thereof, glycine, alanine, and PDPA with at least one of a phosphate-type and an acetate-type strongly basic anion exchange resin. 25. A method for producing 5-aminolevulinic acid or a salt thereof, comprising the following x1) to x3) in any order. x1) Treat a solution containing 5-aminolevulinic acid or its salt, glycine, alanine, and PDPA with a strongly acidic cation exchange resin. x2) Treat a solution containing 5-aminolevulinic acid or its salt, glycine, alanine, and PDPA with a weakly acidic cation exchange resin. x3) ​​Treat a solution containing 5-aminolevulinic acid or its salt, glycine, alanine, and PDPA with a strongly basic anion exchange resin. 26. A method for producing 5-aminolevulinic acid or a salt thereof, comprising the following y1) to y4) in this order. y1) Solution A, containing 5-aminolevulinic acid or its salt, glycine, alanine, and PDPA, is treated with a strongly acidic cation exchange resin to obtain solution B. y2) Treat solution B with a weakly acidic cation exchange resin to obtain solution C. y3) The solution C is treated with a strongly basic anion exchange resin to obtain solution D. y4) Adjust the pH of solution D to obtain solution E. 27. The strongly acidic cation exchange resin is a polystyrene-based resin having a sulfonic acid group as a functional group, and its ionic type is Na + The method according to any one of the above 23, 25, and 26. 28. The method according to any one of 24 to 26, wherein the strongly basic anion exchange resin is a polystyrene-based resin having a dimethylethanolammonium group as a functional group, and its ionic type is at least one of the acetate type and the phosphoric acid type. 29. The method according to 26, wherein, in y1), the recovery conditions for obtaining solution B are initiated by a change in Brix and terminated by a change in pH. 30. The method according to 26, wherein, in y2) above, the recovery conditions for obtaining the solution C are initiated by a change in Brix and terminated by a change in Brix. 31. The method according to 26, wherein, in y3) above, the recovery conditions for obtaining the solution D are initiated by a change in Brix and terminated by a change in Brix. [Effects of the Invention]

[0015] The 5-aminolevulinic acid or its salts disclosed herein have fewer impurities and residual organic solvents compared to conventional products, and their discoloration is suppressed, resulting in superior storage stability and easier quality control and assurance. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 shows the results of measuring residual EtOH in the powder in Example 1-1. [Figure 2] Figure 2 shows the results of measuring residual EtOH in the powder in Examples 1-2. [Figure 3] Figure 3 shows the results of measuring residual EtOH in the powder in Examples 1-3. [Figure 4] Figure 4 shows the results of measuring residual EtOH in the powder in Example 2-6. [Figure 5] Figure 5 shows the results of powder X-ray diffraction measurements using 5-aminolevulinic acid phosphate powder. [Figure 6] Figure 6 is a flowchart showing the process in one embodiment of the manufacturing method of the present disclosure. [Figure 7]Figure 7 is a flowchart showing the process in one embodiment of the manufacturing method of the present disclosure. [Modes for carrying out the invention]

[0017] The following is a detailed description of this disclosure, but these are merely examples of desirable embodiments and are not limiting to these.

[0018] The "~" in a numerical range indicates a range that includes the numbers before and after it. For example, "0 mass%~100 mass%" means a range that is greater than or equal to 0 mass% and less than or equal to 100 mass%.

[0019] The 5-aminolevulinic acid and its salts of this disclosure will be described below based on embodiments, but the manufacturing methods of this disclosure are not limited thereto. The 5-aminolevulinic acid and its salts of this disclosure include the 5-aminolevulinic acid and its salts of the first and second embodiments described below.

[0020] 1,5-aminolevulinic acid or its salt In this disclosure, examples of salts of 5-aminolevulinic acid include salt forms such as phosphate, hydrochloride, and nitrate. Among these, phosphate is preferred from the viewpoint of use in food products, as it has excellent storage stability and low irritancy.

[0021] 5-aminolevulinic acid or its salts in this disclosure may be in powder form. Specifically, powders containing 5-aminolevulinic acid or its salts include crystalline powder containing 5-aminolevulinic acid or its salts, or amorphous powder obtained by freeze-drying, spray-drying, etc. The method for producing the powder is not particularly limited as long as powder can be obtained; for example, powder can be obtained by crystallization. The powder obtained by crystallization may be further purified by vacuum drying, air drying, heat drying, or by dissolving it again in an aqueous solution and performing general purification operations such as desalting, decolorization, crystallization, spray-drying, or freeze-drying, as needed. For this reason, in this disclosure, 5-aminolevulinic acid or its salts obtained by crystallization and 5-aminolevulinic acid or its salts precipitated from the crystallization stock solution may be crystalline, amorphous, or a mixture thereof.

[0022] [First Embodiment] <impurities> In the first embodiment of this disclosure, 5-aminolevulinic acid or a salt thereof is characterized by satisfying at least one of the following conditions (A1) and (A2) based on the peak area obtained by HPLC analysis. (A1) The ratio of the content of individual impurities that can be quantified by HPLC to the content of 5-aminolevulinic acid or its salt, as represented by the following formula (1), is 0.0007 or less. (A2) The sum of the ratios of the content of each individual impurity that can be quantified by HPLC to the content of 5-aminolevulinic acid or its salt, as represented by the following formula (2), is 0.0016 or less. The ratio of the content of individual impurities quantifiable by HPLC to the content of 5-aminolevulinic acid or its salt = Peak area of ​​individual impurities quantifiable by HPLC / Peak area of ​​5-aminolevulinic acid or its salt ... Equation (1) The sum of the ratios of the content of individual impurities to the content of 5-aminolevulinic acid or its salt = Σ(peak area of ​​the amount of each impurity quantifiable by HPLC / peak area of ​​5-aminolevulinic acid or its salt) ... Equation (2) In equation (2), Σ( ) represents the sum of the terms in parentheses.

[0023] In the first embodiment, the 5-aminolevulinic acid or salt thereof of the present disclosure can improve storage stability and product quality by having a ratio of the peak area of ​​individual impurities to the peak area of ​​5-aminolevulinic acid or salt thereof, represented by formula (1) above, of 0.0007 or less, based on the peak area obtained by HPLC analysis. In the first embodiment, the ratio is preferably 0.0006 or less, more preferably 0.0005 or less. In the second to sixth embodiments, the ratio is preferably 0.0015 or less, more preferably 0.0010 or less, even more preferably 0.0007 or less, and most preferably 0.0005 or less.

[0024] In the first embodiment, the 5-aminolevulinic acid or salt thereof of the present disclosure can improve storage stability and product quality by having a total ratio of the peak areas of individual impurities to the content of 5-aminolevulinic acid or salt thereof, represented by formula (2) above, based on the peak area obtained by HPLC analysis, of 0.0016 or less. In the first embodiment, the ratio is preferably 0.0015 or less, more preferably 0.0014 or less. In the second to sixth embodiments, the ratio is preferably 0.0022 or less, more preferably 0.0020 or less, even more preferably 0.0017 or less, and most preferably 0.0016 or less.

[0025] The 5-aminolevulinic acid or salt thereof of this disclosure can be freely combined, based on the peak area obtained by HPLC analysis, in terms of the ratio of the peak area of ​​each impurity to the peak area of ​​5-aminolevulinic acid or its salt represented by formula (1), and the sum of the ratios of the peak areas of each impurity to the content of 5-aminolevulinic acid or its salt represented by formula (2). Preferably, the ratio of the peak area of ​​each impurity to the peak area of ​​5-aminolevulinic acid or its salt is 0.0020 or less, and the sum of the ratios of the peak areas of each impurity to the content of 5-aminolevulinic acid or its salt is 0.0022 or less. More preferably, the ratio of the peak area of ​​each impurity to the peak area of ​​5-aminolevulinic acid or its salt is 0.0015 or less, and the sum of the ratios of the peak areas of each impurity to the content of 5-aminolevulinic acid or its salt is 0.0020 or less. More preferably, the ratio of the peak area of ​​each impurity to the peak area of ​​5-aminolevulinic acid or its salt is 0.0010 or less, and the sum of the ratios of the peak areas of each impurity to the content of 5-aminolevulinic acid or its salt is 0.0017 or less. Most preferably, the ratio of the peak area of ​​each impurity to the peak area of ​​5-aminolevulinic acid or its salt is 0.0007 or less, and the sum of the ratios of the peak areas of each impurity to the content of 5-aminolevulinic acid or its salt is 0.0016 or less.

[0026] More specifically, the methods for calculating the "ratio of the peak area of ​​individual impurities to the peak area of ​​5-aminolevulinic acid or its salt" and the "sum of the ratios of the peak areas of individual impurities to the peak area of ​​5-aminolevulinic acid or its salt" in this disclosure are described in the analytical examples and examples below.

[0027] In formulas (1) and (2) above, "impurities that can be quantified by HPLC" refers, in one embodiment, to impurities whose peak area in 5-aminolevulinic acid or its salt is greater than or equal to the limit of quantification by HPLC.

[0028] Furthermore, the "impurities quantifiable by HPLC" refers, in one embodiment, to impurities detected at RT2.2±0.2 to 42.1±0.2 in analysis using, for example, liquid chromatography (HPLC) with an ultraviolet-visible absorbance detector as described below. More specifically, these are impurities detected in HPLC with an ultraviolet-visible absorbance detector under the following conditions: separation column: InertSustain C18(UP) (5μm, 4.6×250mm, GL-Science), mobile phase: 0.1% trifluoroacetic acid / 15% acetonitrile, mobile phase flow rate: 1.0 mL / min, sample introduction volume: 50 μL, column temperature: 30°C, detection wavelength: 216 nm, preferably as described in (i), more preferably (ii), and even more preferably (iii). (i) RT2.2±0.2, RT2.4±0.2, RT2.8±0.2, RT3.3±0.2, RT3.4±0.2, RT3.5±0.2, RT3.9±0.2, RT4.0±0.2, RT4.1±0.2, RT4.2±0.2, RT4.3±0.2, RT4.4±0.2, RT4 .5±0.2, RT4.7±0.2, RT4.8±0.2, RT5.0±0.2, RT5.4±0.2, RT5.6±0.2, RT5.8±0.2, RT5.9±0.2, RT6.0±0.2, RT6.2±0.2, RT6.3±0.2, RT6.5±0.2, RT6.6±0.2, RT6.8±0.2, RT7.0±0.2, RT7.2±0.2, RT7.4±0.2, RT7.7±0.2, RT7.9±0.2, RT8.1±0.2, RT8.4±0.2, RT9.6±0.2, RT10.2±0.2, RT10.6±0.2, RT11.1±0.2, RT11 .7±0.2, RT13.3±0.2, RT14.9±0.2, RT15.3±0.2, RT16.7±0.2, RT20.2±0.2, R T22.1±0.2, RT22.6±0.2, RT22.8±0.2, RT23.2±0.2, RT30.1±0.2, RT42.1±0.2 (ii) RT2.2±0.2, RT2.4±0.2, RT3.4±0.2, RT3.9±0.2, RT4.0±0.2, RT4.1±0.2, RT4.2±0.2, RT4.3±0.2, RT4.4±0.2, RT4.5±0.2, RT4.8 ±0.2, RT5.0±0.2, RT5.8±0.2, RT6.0±0.2, RT6.2±0.2, RT6.3±0.2, RT6.5±0.2, RT6.6±0.2, RT6.8±0.2, RT7.0±0.2, RT7.2±0.2, RT7.4 ±0.2, RT7.7±0.2, RT7.9±0.2, RT8.1±0.2, RT8.4±0.2, RT9.6±0.2, RT10.2±0.2, RT10.6±0.2, RT11.1±0.2, RT11.7±0.2, RT13.3±0.2 , RT14.9±0.2, RT15.3±0.2, RT16.7±0.2, RT20.2±0.2, RT22.1±0.2, RT22.6±0.2, RT22.8±0.2, RT23.2±0.2, RT30.1±0.2, RT42.1±0.2 (iii) RT3.4±0.2, RT4.1±0.2, RT4.2±0.2, RT4.5±0.2, RT4.8±0.2, RT5.0±0.2, RT5.8±0.2, RT6.2±0.2, RT6.5±0.2, RT6.6±0.2, RT6.8±0.2, RT7.4±0.2, RT7.9±0.2, RT8.1±0.2, RT10.2±0.2, RT22.1±0.2, RT22.6±0.2, RT22.8±0.2, RT30.1±0.2, RT42.1±0.2 (The above RT refers to the holding time, and the unit of the number is "minutes".)

[0029] The ±0.2 in the value of "impurities that can be quantified by HPLC" refers to ±0.2 minutes, which is caused by measurement errors due to measurement conditions such as the measuring instrument and peak reading conditions, and is preferably ±0.1, more preferably ±0.01.

[0030] In this disclosure, "the ratio of the content of individual impurities to the content of 5-aminolevulinic acid or its salt" is synonymous with "the ratio of the peak area of ​​individual impurities to the peak area of ​​5-aminolevulinic acid or its salt."

[0031] In this disclosure, "the sum of the ratios of the content of individual impurities to the content of 5-aminolevulinic acid or its salt" is synonymous with "the sum of the ratios of the peak areas of individual impurities to the peak area of ​​5-aminolevulinic acid or its salt."

[0032] In this disclosure, “impurity” means any substance other than 5-aminolevulinic acid or its salts. Examples of impurities in this disclosure include culture-derived impurities, by-products of decomposition products of 5-aminolevulinic acid or its salts, and inorganic ions, inorganic acids, or inorganic metals.

[0033] Examples of impurities derived from the culture include carbon sources such as glucose and glycine, which are used in fermentation production, and nitrogen sources such as ammonia and ammonium chloride.

[0034] Many inorganic ions, inorganic acids, or inorganic metals originate from components present during fermentation production, but most are removed during the purification process of 5-aminolevulinic acid or its salts.

[0035] Examples of inorganic ions include inorganic cations such as sodium ions, potassium ions, calcium ions, and magnesium ions. Examples of inorganic anions include chloride ions, nitrate ions, and sulfate ions. Examples of inorganic metals include iron, arsenic, and lead.

[0036] The inorganic metal content in 5-aminolevulinic acid or its salts of this disclosure is not particularly limited, but a lower amount is preferable. For example, the inorganic metal content per 1 kg of powder is 10 mg or less (10 ppm or less), and the following are more preferable in order: 7 ppm or less, 5 ppm or less, 3 ppm or less, and 1 ppm or less.

[0037] Of the aforementioned inorganic metals, arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb), which are classified as Class 1 under the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) Guidelines for Elemental Impurities (ICH Q3D), are particularly toxic to humans and their use in pharmaceutical manufacturing is restricted or prohibited. The arsenic (As) content in 5-aminolevulinic acid or its salts in this disclosure is less than 0.3 ppm, and is more preferably 0.25 ppm or less, 0.2 ppm or less, 0.1 ppm or less, and 0.01 ppm or less.

[0038] <Residual organic solvents> In this disclosure, “residual organic solvent” means an organic solvent remaining in 5-aminolevulinic acid or its salt. Examples of organic solvents that may be contained in 5-aminolevulinic acid or its salt in this disclosure include organic solvents used for crystallization.

[0039] As the organic solvent, at least one selected from methanol, ethanol, isopropanol, n-propanol, acetone, and acetonitrile can be used, with ethanol being preferred. The organic solvent is difficult to remove from 5-aminolevulinic acid or its salts even in the separation and drying steps of the precipitate, so it is preferable to reduce the content of residual organic solvent as much as possible in the crystallization step. In this disclosure, the precipitate may be crystalline 5-aminolevulinic acid or a salt thereof, or it may be amorphous 5-aminolevulinic acid or a salt thereof.

[0040] In one embodiment, the 5-aminolevulinic acid or salt thereof of this disclosure preferably has a residual organic solvent content of 1000 ppm or less, and more preferably in the following order: 1000 ppm or less, 750 ppm or less, 500 ppm or less, 300 ppm or less, and 50 ppm or less.

[0041] <Coloring degree> Compounds such as 5-aminolevulinic acid phosphate, which are salts of 5-aminolevulinic acid, are colorless, and powdered 5-aminolevulinic acid phosphate is white or milky white. Preferably, the powder of 5-aminolevulinic acid or its salts in this disclosure is closer to white, and preferably the aqueous solution obtained by dissolving the powder in water is colorless and clear.

[0042] If 5-aminolevulinic acid or its salt contains impurities, a Maillard reaction or similar reaction occurs between the 5-aminolevulinic acid or its salt and the residual impurities, or between the residual impurities themselves, leading to the formation of colored substances, and thus the powder becomes colored.

[0043] One method for evaluating the degree of coloration of 5-aminolevulinic acid or its salts is to use a spectrophotometer, for example. More specifically, the degree of coloration of 5-aminolevulinic acid or its salts can be evaluated by measuring the transmittance of short-wavelength visible light in the wavelength range adjacent to the ultraviolet range (e.g., 430 nm) using a spectrophotometer.

[0044] [Second Embodiment] In a second embodiment of this disclosure, 5-aminolevulinic acid or a salt thereof is characterized by satisfying the following (B1) and (B2). (B1) The light transmittance at a wavelength of 430 nm, as measured by a spectrophotometer, is 98.8% or higher. (B2) The light transmittance at a wavelength of 430 nm, as measured by a severe stability test under the following conditions, is 92.0% or higher. Conditions for the severe stability test: After storing 5-aminolevulinic acid or its salt at a temperature of 70°C ± 2°C for 2 days, the transmittance of light at a wavelength of 430 nm is measured using a spectrophotometer.

[0045] The decrease in light transmittance at a wavelength of 430 nm, as measured by the spectrophotometer, is due to the yellow coloring component. In the second embodiment, the 5-aminolevulinic acid or its salt of this disclosure has a light transmittance of 98.8% or higher at a wavelength of 430 nm (B1), thereby reducing the yellow coloring component and suppressing coloration. The light transmittance at a wavelength of 430 nm is preferably, in order of preference, 98.8% or higher, 98.9% or higher, 99.0% or higher, 99.5% or higher, and 99.9% or higher.

[0046] As conditions for evaluating the degree of coloration of 5-aminolevulinic acid or its salts according to this disclosure, it is preferable to create an environment in which 5-aminolevulinic acid is prone to degradation, and to compare the state before and after degradation, as this clearly results in the presence or absence of coloration. An example of an environment in which 5-aminolevulinic acid or its salts are prone to degradation is to store 5-aminolevulinic acid or its salts under heating conditions of 70±2℃ for two days or more and conduct a severe stability test.

[0047] In the second embodiment, the 5-aminolevulinic acid or salt thereof of this disclosure has a light transmittance of 92.0% or higher at a wavelength of 430 nm, as measured by a severe stability test under the following conditions (B2), with the most preferred values ​​being 93.0% or higher, 97.0% or higher, 98.0% or higher, and 99.0% or higher. The light transmittance of 92.0% or higher indicates excellent stability. Conditions for the severe stability test: After storing 5-aminolevulinic acid or its salt at a temperature of 70°C ± 2°C for 2 days, the transmittance of light at a wavelength of 430 nm is measured using a spectrophotometer.

[0048] The spectrophotometer is not particularly limited as long as it can evaluate the degree of coloration. Examples include the Hitachi High-Tech Science U-5100, U-3900 / U-3900H, and UH5300; the Agilent Technologies Agilent Cary 60 UV-Vis spectrophotometer and Agilent Cary 3500 UV-Vis spectrophotometer; and the Thermo Fisher Scientific GENESYS 50 UV-Vis spectrophotometer, Biomate 160 UV-Vis spectrophotometer, and GENESYS 180 UV-Vis spectrophotometer.

[0049] <Diffraction angle by powder X-ray diffraction> The 5-aminolevulinic acid or its salts according to this disclosure may be crystalline or amorphous. Furthermore, the 5-aminolevulinic acid or its salts according to this disclosure can be applied regardless of whether they are crystalline or polymorphic. Therefore, the diffraction angle 2θ of the 5-aminolevulinic acid or its salts according to this disclosure by powder X-ray diffraction will differ depending on the resulting polymorph, but it is preferable that characteristic peaks are shown at diffraction angles 2θ of 7.9°±0.2°, 15.8°±0.2°, 18.9°±0.2°, 20.7°±0.2°, 21.1°±0.2°, 21.4°±0.2°, 22.9°±0.2°, 23.0°±0.2°, 27.8°±0.2°, and 33.2°±0.2°.

[0050] When the 5-aminolevulinic acid or salt thereof of this disclosure is 5-aminolevulinic acid phosphate, it is preferable that characteristic peaks are observed at diffraction angles 2θ of 7.9°±0.2°, 15.8°±0.2°, 18.9°±0.2°, 20.7°±0.2°, 21.1°±0.2°, 21.4°±0.2°, 22.9°±0.2°, 23.0°±0.2°, 27.8°±0.2°, and 33.2°±0.2° as determined by powder X-ray diffraction.

[0051] The ±0.2° in the characteristic peak value is a measurement error due to measurement conditions such as the measuring instrument and peak reading conditions, and is preferably ±0.1°, more preferably ±0.01°. Powder X-ray diffraction can be performed according to the method described in the measurement example below.

[0052] [Example of powder X-ray diffraction measurement] Equipment used: Powder X-ray diffraction device (XRD) Ultima IV (manufactured by Rigaku Corporation) Anode: Cu Wavelength: 1.5418Å

[0053] The 5-aminolevulinic acid or salt thereof of this disclosure preferably has a melting point of 129 to 131°C.

[0054] <Content of 5-aminolevulinic acid or its salt> In the 5-aminolevulinic acid or salt thereof of this disclosure, the content of 5-aminolevulinic acid or salt thereof per unit of solids is preferably 99.5% by mass or more, and more preferably in the following order: 99.6% by mass or more, 99.7% by mass or more, 99.8% by mass or more, and 99.9% by mass or more.

[0055] In this disclosure, the content and amount of 5-aminolevulinic acid or its salts are calculated using values ​​obtained by converting 5-aminolevulinic acid (hereinafter also referred to as the free form) or its salts to the amount of 5-aminolevulinic acid phosphate in the same mole. In this disclosure, "content of 5-aminolevulinic acid or its salts" is synonymous with "purity of 5-aminolevulinic acid or its salts."

[0056] <Application> Applications of 5-aminolevulinic acid or its salts as disclosed herein include, for example, vitamin B12 production, heme enzyme production, microbial culture and porphyrin production in the microbiology field; infectious disease treatment, sterilization, hemophilus diagnosis, derivative synthesis raw materials, hair removal, rheumatism treatment, cancer treatment, thrombosis treatment, intraoperative cancer diagnosis, animal cell culture, heme metabolism research, hair growth, heavy metal poisoning porphyria diagnosis and anemia prevention; and plant growth regulation and salt tolerance improvement in the agricultural field.

[0057] 2. Method for producing 2,5-aminolevulinic acid or its salt Hereinafter, the method for producing 5-aminolevulinic acid and its salts as disclosed herein will also be referred to as the manufacturing method of this disclosure. The manufacturing method of this disclosure will be described below based on embodiments, but the manufacturing method of this disclosure is not limited thereto. The manufacturing methods of the third to sixth embodiments described below are included in the manufacturing method of this disclosure.

[0058] The above-described embodiment of the manufacturing method of the present disclosure preferably includes the following steps [1] to [3]. Figures 6 and 7 are flowcharts showing the process in one embodiment of the manufacturing method of the present disclosure. [1] A step to prepare a crystallization stock solution by preparing a solution containing 5-aminolevulinic acid or a salt thereof, and adjusting the concentration of 5-aminolevulinic acid or a salt thereof to a specific range by adding water to the solution or concentrating the solution. [2] A step to adjust the temperature of the crystallization stock solution obtained in [1]. [3] The first organic solvent is added to the crystallization stock solution obtained in [2] to precipitate 5-aminolevulinic acid or a salt thereof.

[0059] 5-aminolevulinic acid is unstable at temperatures above 30°C and under neutral to basic conditions, and readily polymerizes to produce 2,5-pyrazinedipropanoic acid (hereinafter referred to as PDPA). In the manufacturing method of this disclosure, high-purity 5-aminolevulinic acid or its salt can be obtained by crystallization using an organic solvent.

[0060] The following describes each of the steps [1] to [3]. [1] A step to prepare a crystallization stock solution by preparing a solution containing 5-aminolevulinic acid or a salt thereof, and adjusting the concentration of 5-aminolevulinic acid or a salt thereof to a specific range by adding water to the solution or concentrating the solution. Step [1] is a step of preparing a crystallization stock solution from a solution containing 5-aminolevulinic acid or a salt thereof, in which the concentration of 5-aminolevulinic acid or a salt thereof is adjusted to a specific range.

[0061] In this disclosure, crystallization means precipitating 5-aminolevulinic acid or a salt thereof from a crystallization stock solution, and the precipitated powder may be crystalline, amorphous, or a mixture thereof.

[0062] One embodiment of the manufacturing method of this disclosure does not include the steps of chemical synthesis and extraction of 5-aminolevulinic acid, and it is preferable that 5-aminolevulinic acid or its salt is a product derived from fermentation production. In one embodiment, by not including the steps of chemical synthesis and extraction, the final powder can be mass-produced inexpensively and in an environmentally friendly manner.

[0063] In one embodiment of the manufacturing method of the present disclosure, step [1] preferably includes the following steps 0 to 10. Step 0: Separate the culture broth containing microorganisms or the solid matter containing microorganisms from the culture broth and recover the culture solution containing 5-aminolevulinic acid (hereinafter referred to as Solution A). Step 1: Solution A is treated with a strongly acidic cation exchange resin to separate 5-aminolevulinic acid from impurities and obtain solution B. Step 2: The solution B is treated with a weakly acidic cation exchange resin to obtain solution C. Step 3: The solution C is treated with a strongly basic anion exchange resin to obtain solution D. Step 4: Process the solution D, such as adjusting its pH, to obtain solution E. Step 5: A step of concentrating the solution E. Step 6: After crystallizing the concentrated liquid (first crystallization), a step is taken to obtain solution F by dissolving the obtained powder. This step is optional. Step 7: A step in which the solution F is decolorized using activated carbon to obtain a decolorized solution (solution G). This is an optional step. Step 8: Treating solution G with a chelate resin to obtain solution H. This is an optional step. Step 9: Pass the solution H through a microfiltration membrane and an ultrafiltration membrane to obtain a filtrate. This is an optional step. Step 10: A step of concentrating the filtrate to obtain a concentrate. This is an optional step. Step [1] includes both an embodiment in which the solution obtained in steps 0 to 10 (hereinafter referred to as "solution [1]") is used directly, and an embodiment in which the powder obtained after crystallization is redissolved and used as an 11th step. The following explains steps 0 through 10.

[0064] (Step 0) Step 0 involves separating the culture broth containing microorganisms, or the solid matter containing microorganisms, from the culture broth and recovering the culture medium (Solution A) containing 5-aminolevulinic acid. In Step 0, centrifugation or filtering is used to efficiently separate the culture broth from the microorganisms and solid matter. The recovered Solution A is a culture medium containing a high concentration of 5-aminolevulinic acid.

[0065] ((culture solution)) In this specification, "culture medium" includes microorganisms, culture media, etc. The culture medium is obtained by culturing microorganisms capable of producing 5-aminolevulinic acid in a culture medium containing components necessary for their growth. Examples of microorganisms capable of producing 5-aminolevulinic acid (hereinafter also referred to as 5-aminolevulinic acid-producing bacteria) include recombinant microorganisms into which genes necessary for the production of 5-aminolevulinic acid have been introduced.

[0066] Examples of the aforementioned microorganisms include bacteria such as Escherichia coli, Lactobacillus lactis, Corynebacterium glutamicum, Bacillus subtilis, and Pseudomonas putita, or yeasts such as Saccharomyces cerevisiae, Schizosaccharomyces pombe, and Pichia pastoris.

[0067] One method for genetically modifying the aforementioned microorganism to produce 5-aminolevulinic acid is the method described in Japanese Patent Publication No. 2005-333907, which allows for the fermentation production of 5-aminolevulinic acid using recombinant Corynebacterium glutamicum.

[0068] The culture medium may contain a carbon source, a nitrogen source, a phosphorus source, a sulfur source, other organic components, other inorganic components, etc. The types, combinations, and amounts of these components in the culture medium may be set as appropriate. The culture medium may further contain amino acids, nucleic acids, vitamins, etc.

[0069] The carbon source is not particularly limited as long as it can be assimilated by the transformant, and examples include carbohydrates such as glucose, fructose, sucrose, glycerin, molasses, starch, and starch hydrolysates; organic acids such as gluconic acid, pyruvic acid, lactic acid, and acetic acid; and amino acids such as glycine, glutamic acid, alanine, and aspartic acid.

[0070] Examples of the nitrogen sources include ammonia, various inorganic and organic ammonium salts such as ammonium chloride, ammonium sulfate, ammonium phosphate, ammonium nitrate, ammonium carbonate, and ammonium acetate; nitrogen-containing organic substances such as urea, peptone, NZ amine, meat extract, yeast extract, corn steep liquor, casein hydrolysate, fish meal or its digest, and various amino acids such as glycine and glutamic acid.

[0071] Examples of the inorganic components include potassium dihydrogen phosphate, potassium monohydrogen phosphate, magnesium sulfate, magnesium phosphate, sodium chloride, ferrous sulfate, manganese sulfate, zinc sulfate, and calcium carbonate.

[0072] The presence of glycine in the culture medium is preferable because it improves the productivity of 5-aminolevulinic acid or its salt. The glycine content in the culture medium is preferably 0.5 to 20% by mass. Glycine may be added to the culture medium at any time, such as at the start of cultivation or during cultivation, and the required amount may be added all at once or in divided portions.

[0073] Furthermore, in the manufacturing method disclosed herein, it is not necessary to specifically add 5-aminolevulinic acid, which is generally added to the culture medium, etc., in the manufacturing method using microorganisms, but it may be added as needed.

[0074] Various impurities added to the culture medium may be removed by a purification process. The solid components containing microorganisms can be separated from the culture medium, and the supernatant containing 5-aminolevulinic acid can be recovered. Methods for separating the solid components containing microorganisms from the culture medium include centrifugation and filtration.

[0075] (Solution A) The composition of solution A includes, for example, 5-aminolevulinic acid or a salt thereof. The concentration of 5-aminolevulinic acid or a salt thereof in solution A is not particularly limited, but from the viewpoint of purification efficiency, in one embodiment, it is usually preferably 0.01 g / L or more, more preferably 0.1 g / L or more, even more preferably 1 g / L or more, and most preferably 10 g / L or more, in terms of 5-aminolevulinic acid monophosphate. In another embodiment, the concentration is preferably 0.1 g / L to 100 g / L, more preferably 1 g / L to 70 g / L, and even more preferably 10 g / L to 60 g / L.

[0076] To bring the concentration of 5-aminolevulinic acid or its salt in solution A within the aforementioned range, the solution containing 5-aminolevulinic acid or its salt may be concentrated, or the solution may be diluted with water or the like. Any general method of concentration is acceptable, such as the heat concentration method or the vacuum concentration method. The solution A is preferably a culture medium derived from fermentation production using microorganisms or the supernatant obtained by removing solids from the culture medium.

[0077] Solution A may contain impurities. Examples of impurities that may be present in Solution A include alanine, glycine, and PDPA. The ratio of the content of each impurity to the content of 5-aminolevulinic acid or its salt in Solution A, i.e., (content of each impurity) / (content of 5-aminolevulinic acid or its salt), is preferably 0.0001 to 1, more preferably 0.0005 to 0.5, even more preferably 0.001 to 0.3, and most preferably 0.002 to 0.1 by mass.

[0078] (Step 1) The first step is to treat solution A obtained in step 0 with a strongly acidic cation exchange resin to obtain solution B. That is, in the first step, 5-aminolevulinic acid and the impurities described later are separated by treating solution A with a strongly acidic cation exchange resin.

[0079] The first step preferably includes, in more detail, the following steps (1-1) to (1-3). Step (1-1): The solution A is passed through a strongly acidic cation exchange resin to remove neutral impurities that do not have an electric charge and impurities that have a negative charge that do not bind to the strongly acidic cation exchange resin. Step (1-2): Wash the strongly acidic cation exchange resin with water. Step (1-3): Steps to elute acidic compounds, including 5-aminolevulinic acid or its salts, from a strongly acidic cation exchange resin. The following explains steps (1-1) to (1-3).

[0080] ((Step (1-1): A step in which solution A is passed through a strongly acidic cation exchange resin to remove at least a portion of neutral impurities that do not have an electric charge and impurities that have a negative charge that do not bind to the strongly acidic cation exchange resin.)) The pH of solution A for treatment with a strongly acidic cation exchange resin is preferably 1 to 7, more preferably 2 to 5, and most preferably 2.5 to 4.5. The concentration of 5-aminolevulinic acid or its salt in solution A for treatment with a strongly acidic cation exchange resin is preferably 0.1 g / L to 100 g / L, more preferably 1 g / L to 70 g / L, and even more preferably 10 g / L to 60 g / L, in terms of 5-aminolevulinic acid monophosphate.

[0081] If solution A does not have a pH within the aforementioned range or a concentration of 5-aminolevulinic acid or its salt, solution A may be pretreated. Examples of pretreatment include adjusting the pH, ultrafiltration of solution A, dilution with water, or concentration.

[0082] The strongly acidic cation exchange resin is not particularly limited, and examples include strongly acidic cation exchange resins having sulfonic acid groups in their exchange groups. Examples of the base material for the strongly acidic cation exchange resin include porous type, macroporous type, gel type, styrene type, acrylic type, etc.

[0083] Examples of strongly acidic cation exchange resins include, specifically, DOWEX® 88, DOWEX® 88MB, DOWEX® Monosphere® 88, TG-Gel (also known as XUS40232.01) from Dow Chemical, and Amberlite® (e.g., FPC16UPS Na, FPC88MB Na, FPC240H, CR3220 Ca, CR1310 Ca) from DuPont.Na, CR1360 Na, CR99K / 350, HPR1100Na, etc.), DOWEX (registered trademark) (e.g., HCR-S / S, HCR-S / S FF, HCR-W2, HGR-NG, Marathon C 10, Monosphere C 350, Monosphere C 400, MARATHON C, Marathon MSC, Marathon 1200, Marathon 1200), C100, C100E, C120E, C100×10, C100×16MBH, C145S, C150, C160, SGC650 from Purolite, Inc., Purolite® SST series (e.g., SSTC60, SSTC60H, SSTC80C, etc.) from Purolite, Inc., Diaion® SK series (e.g., SK1B, SK1BH, SK1BL, SK1BLH, SKL10, SKT10) from Mitsubishi Chemical Corporation L, SK104, SK110, SKT110, SKT110L, SK110L, SK112, SK112L, SK116, SKT20L, etc.), Mitsubishi Chemical Corporation's Diaion (registered trademark) PK series (e.g., PK208, PK208LH, PK212, PK212L, PK212LH, PK216, PK216L, PK216H, PK216LH, PK220, PK220L, PK228, PK228L, PK228LH, etc.), Mitsubishi Chemical Diaion® RCP series manufactured by Mitsubishi Chemical Corporation (e.g., RCP145H, RCP160M, etc.), Diaion® HPK25 manufactured by Mitsubishi Chemical Corporation, Diaion® UBK series manufactured by Mitsubishi Chemical Corporation (e.g., UBK16, UBK14, UBK12, UBK10, UBK10H, UBK10HUP, UBK08, UBK08A, UBK08H, UBK08HUP, UBK04, UBK02, UBKN1U, UBKN Examples include 1UMB, UBK522M, UBK530, UBK530J, UBK530K, UBK535, UBK535J, UBK535K, UBK535L, UBK550, UBK555, etc.), Mitsubishi Chemical Corporation's Rewrite JC series (e.g., JC600, JC603, etc.), LANXESS's Levatit® S1668, and LANXESS's Levatit® Monoplus series (e.g., S108, S108H, SP112, etc.).

[0084] As the strongly acidic cation exchange resin, it is preferable that the exchange group in the strongly acidic cation exchange resin has a sulfonic acid group. As the matrix of the strongly acidic cation exchange resin, a gel type is more preferable. Specifically, for example, MARATHON C, UBK04, and XUS40232.01 can be mentioned.

[0085] As the ionic form of the exchange group in the strongly acidic cation exchange resin, for example, H + type, Na + type, K + type, NH4 + type, etc. can be mentioned, and it is preferably the Na + type.

[0086] Examples of the neutral impurities include carbohydrates such as glucose, fructose, sucrose, molasses, starch, and starch hydrolysates.

[0087] Examples of the impurities with a negative charge include anions such as SO4 2- , Cl - , PO4 3- , etc., organic acids such as formic acid, acetic acid, propionic acid, and fatty acids, nucleic acids, amino acids, proteins, phospholipids, etc.

[0088] In step (1-1), the flow rate when passing solution A through the ion exchange resin is defined by the space velocity (the volume ratio of the solution passing through the column per hour when the resin volume of the ion exchange resin is taken as 1, hereinafter referred to as "SV").

[0089] As the flow-through conditions when treating solution A with the strongly acidic cation exchange resin, the flow rate is preferably SV0.1 to 5, more preferably SV0.2 to 4, and even more preferably SV0.5 to 2. As the flow-through conditions, the temperature is preferably 3 to 50°C, more preferably 8 to 40°C, even more preferably 10 to 40°C, and most preferably 15 to 35°C.

[0090] In this step (1-1), the positively charged compounds, including 5-aminolevulinic acid, in solution A are adsorbed onto the strongly acidic cation exchange resin.

[0091] ((Step (1-2)(1-1) involves eluting at least a portion of the remaining impurities from the strongly acidic cation exchange resin.)) Step (1-2) is a step in which neutral impurities and negatively charged impurities remaining in the strongly acidic cation exchange resin after solution A has been passed through it in step (1-1) are eluted from the strongly acidic cation exchange resin.

[0092] In order to elute any remaining impurities after step (1-1) from the strongly acidic cation exchange resin, the eluent preferably comprises at least one of water, ammonium hydroxide, sodium hydroxide, potassium hydroxide, etc., and more preferably comprises water and sodium hydroxide.

[0093] The concentrations of basic substances such as ammonium hydroxide, sodium hydroxide, and potassium hydroxide in the eluent are, in order of preference, 0.0000 mol / L or more, 0.0001 mol / L or more, 0.0005 mol / L or more, 0.001 mol / L or more, and 0.005 mol / L or more, followed by 1.0 mol / L or less, 0.7 mol / L or less, 0.5 mol / L or less, 0.1 mol / L, and 0.05 mol / L or less. These upper and lower limits can be combined arbitrarily. In another embodiment, it is preferable that the concentrations are 0.0000 to 1.0 mol / L, 0.0001 to 0.7 mol / L, 0.0005 to 0.5 mol / L, 0.001 to 0.1 mol / L, and 0.005 to 0.05 mol / L.

[0094] In another embodiment, from the viewpoint of efficiently removing impurities under mild conditions, a lower concentration of the basic substance is preferable, and there is no particular upper limit, but examples include 0.005 mol / L or less, preferably 0.001 mol / L or less, more preferably 0.0005 mol / L or less, even more preferably 0.0001 mol / L or less, and most preferably 0.0000 mol / L or less.

[0095] For washing the strongly acidic cation exchange resin with water, the flow rate is preferably SV0.1 to 5, more preferably SV0.2 to 4, and even more preferably SV0.5 to 2. The temperature is preferably 3 to 50°C, more preferably 8 to 40°C, even more preferably 15 to 40°C, and most preferably 20 to 35°C.

[0096] In this disclosure, the amount of solution that passes through the ion exchange resin is expressed as resin volume (the volume ratio of the solution when the resin volume of the ion exchange resin is set to 1, hereinafter referred to as "RV").

[0097] The amount of water used for rinsing in step (1-2) is preferably 0.1 to 20 RV, more preferably 0.5 to 10 RV, even more preferably 1 to 5 RV, and most preferably 2 to 4 RV, with the amount of strongly acidic cation exchange resin in step (1-2) being set to 1.

[0098] A more preferred embodiment involves passing water through the system first, followed by passing a basic aqueous solution such as ammonium hydroxide, sodium hydroxide, or potassium hydroxide through the system.

[0099] This step (1-2) washes away at least some of the impurities that remained in the strongly acidic cation exchange resin after step (1-1). Furthermore, by performing this step (1-2), it tends to be possible to reduce the content of alanine, glycine, and PDPA in the final 5-aminolevulinic acid or its salt, and to improve the content of 5-aminolevulinic acid or its salt.

[0100] ((Step (1-3) involves separately eluting the group of compounds containing 5-aminolevulinic acid or its salts, and the impurities remaining after Step (1-2), from a strongly acidic cation exchange tree.) Step (1-3) is the step of obtaining solution B by eluting 5-aminolevulinic acid or its salt from the strongly acidic cation exchange resin washed with water in step (1-2).

[0101] To separate the compounds containing 5-aminolevulinic acid or its salts from the remaining impurities (1-2) from the strongly acidic cation exchange resin, the eluent preferably contains at least one of water, ammonium hydroxide, sodium hydroxide, potassium hydroxide, etc., and more preferably sodium hydroxide.

[0102] The concentrations of basic substances such as ammonium hydroxide, sodium hydroxide, and potassium hydroxide in the eluent are preferably 0.01 mol / L or higher, followed by 0.05 mol / L or higher, 0.1 mol / L or higher, and 0.4 mol / L or higher, in that order of preference, and then 2.0 mol / L or lower, 1.5 mol / L or lower, 1.0 mol / L, and 0.6 mol / L or lower, in that order of preference. These upper and lower limits can be combined arbitrarily. In another embodiment, concentrations of 0.01 to 2.0 mol / L, 0.05 to 1.5 mol / L, 0.1 to 1.0 mol / L, and 0.4 to 0.6 mol / L are preferred.

[0103] The conditions for eluting 5-aminolevulinic acid or its salts bound to a strongly acidic cation exchange resin are preferably as follows: The eluate is preferably ammonium hydroxide, NaOH, KOH, etc., and more preferably a solution of an eluent such as NaOH. The flow rate is preferably SV0.1 to 5, more preferably SV0.2 to 4, and even more preferably SV0.5 to 2. The temperature is preferably 3 to 50°C, more preferably 8 to 40°C, even more preferably 15 to 40°C, and most preferably 20 to 35°C.

[0104] Furthermore, the amount of eluate is preferably 0.5 to 20 RV, more preferably 1 to 15 RV, even more preferably 2 to 12 RV, and most preferably 3 to 10 RV.

[0105] Solution B obtained in the first step preferably has a pH of 5 to 12, more preferably 6 to 10, and even more preferably 7 to 9. The concentration of 5-aminolevulinic acid or its salt in solution B is preferably 0.1 g / L to 100 g / L, more preferably 1 g / L to 70 g / L, even more preferably 3 g / L to 50 g / L, and most preferably 5 g / L to 20 g / L, in terms of 5-aminolevulinic acid monophosphate.

[0106] (Step 2) The second step involves treating solution B obtained in the first step with a weakly acidic cation exchange resin to obtain solution C. Solution B obtained in the first step contains positively charged impurities, particularly Na derived from the eluent. + It contains a large amount of [unclear] and is basic.

[0107] Under basic conditions, compounds containing 5-aminolevulinic acid do not carry a positive charge and therefore pass through without adsorption. Consequently, even under basic conditions, positively charged impurities, particularly inorganic cations such as sodium ions, potassium ions, calcium ions, and magnesium ions, are adsorbed onto the weakly acidic cation exchange resin and removed.

[0108] When treating solution B with a weakly acidic cation exchange resin, the flow rate is preferably SV0.1 to 10, more preferably SV0.5 to 8, even more preferably SV3 to 6, and most preferably SV4 to 5. The temperature is preferably 1 to 50°C, more preferably 5 to 40°C, even more preferably 10 to 35°C, and most preferably 20 to 30°C.

[0109] Examples of weakly acidic cation exchange resins include those having a carboxylic acid group as an exchange group, and whose resin matrix is ​​porous, macroporous, gel, styrene, or acrylic.

[0110] Examples of weakly acidic cation exchange resins include DuPont's Amberlite® (e.g., FPC76J, FPC3500, etc.), Purolite's C104, C106, C107E, C115E, Purolite's Purolite® SSTC104, Mitsubishi Chemical Corporation's Diaion® WK series (e.g., WK10, WK100, WK10S, WK11, WK40, WK60, WK60L, etc.), Mitsubishi Chemical Corporation's Diaion® WT01S, and Lanxess's Levatit® CNP80WS.

[0111] The ionic form of the exchange group in a weakly acidic cation exchange resin is not particularly limited, for example, H + Type, Na + Type, K + Type, NH4 + Examples include H + It is preferable that it be a type.

[0112] In the second step, in addition to solution B, deionized water can be used as the liquid to pass through when treating solution B with the ion exchange resin. Deionized water is used to elute substances that do not adsorb to the ion exchange resin and to improve the recovery rate of 5-aminolevulinic acid or its salt.

[0113] (Step 3) The third step involves treating solution C obtained in the second step with a strongly basic anion exchange resin to obtain solution D. Solution C obtained in the second step is a weakly acidic solution.

[0114] Solution C contains a group of similar compounds including 5-aminolevulinic acid and negatively charged impurities. By treating it with a strongly basic anion exchange resin, the negatively charged impurities and colored components are adsorbed, while 5-aminolevulinic acid or its salts pass through without being adsorbed, thus removing the negatively charged impurities.

[0115] When treating solution C with a strongly basic anion exchange resin, the flow rate is preferably SV0.1 to 10, more preferably SV0.1 to 5, even more preferably SV0.5 to 2, and most preferably SV0.8 to 1.2. The temperature is preferably 1 to 50°C, more preferably 5 to 40°C, even more preferably 5 to 35°C, and most preferably 12 to 30°C.

[0116] Examples of strongly basic anion exchange resins include those having either a quaternary ammonium compound of type I, which has a trimethylammonium group or a triethylammonium group as an exchange group, or a quaternary ammonium compound of type II, which has a dimethylethanolammonium group, and the resin matrix being porous, macroporous, gel, styrene, or acrylic.

[0117] Examples of strongly basic anion exchange resins include, specifically, Dow Chemical's 1×2, 1×4, 1×8, 22, MSA-2, and DuPont's Amberlite (registered trademark) (e.g., HPR4700 Cl, HPR4700 OH, FPA400J Cl, IRA404J Cl, FPA420 OH, FPA900UPS Cl, HPR4580 Cl, SCAV4 Cl, FPA410J Cl, IRA411 Cl, FPA22UPS Cl, HPR4780 Cl, IRA400J Cl, IRA402BL Cl, IRA900J Cl, HPR4002 Cl, IRA410J Cl, IRA910CT Cl, HPR4010 Cl, HPR4100 Cl, HPR9200 Cl, HPR550 Cl, HPR550OH etc.), Purolite A400, A600, SGA550, A200, A300, A500, A501P, A502PS, A503, A510, A520E, A850, A860, A870, PFA520E, Purolite® SST series (e.g., SSTA63, SSTA64), Mitsubishi Chemical Corporation Diaion® PA series (e.g., PA306S, PA308, PA308L, P (A312, PA312L, PA312LOH, PA312LTU, PA312LTUMB, PA316, PA316L, PA318L, PA318LOH, PA408, PA412, PA412M, PA418, PA418L, PA418LL, PAF308L, HPA25L, HPA25M, HPA512L, HPA716, etc.), Mitsubishi Chemical Corporation's Diaion (registered trademark) NSA100, UMA130J, Mitsubishi Chemical Corporation's Diaion (Registered Trademark) SA series (e.g., SA10A, SA10AL, SA10ALLP, SA10AOH, SA10AP, SA10DL, SA11A, SA11AL, SA12A, SA12AL, SA12ALL, SA20A, SA20ALL, SA20ALLP, SA20AP, SA20AP2, SAF11AL, SANUPB, SAT10L, SAT20L, etc.), Mitsubishi Chemical Corporation's Diaion (Registered Trademark) UBA series (e.g., UB Examples include A100, UBA100OH, UBA100OHUP, UBA120, UBA120A, UBA120OH, UBA120OHUP, UBA150, UBA200, etc., Mitsubishi Chemical's Rewrite JA series (e.g., JA100, JA200, JA400, JA420, JA450, etc.), and Lanxess's LevaChit® MonoPlus series (e.g., M500, M800, MP800, M600, MP600, etc.).

[0118] The ionic form of the quaternary ammonium exchange group in a strongly basic anion exchange resin is not particularly limited, and for example, hydroxide ion (OH) - (type), chloride ion (Cl - (Type), sulfuric acid type (SO4 2- (type), phosphate type (PO4 3- type), nitric acid type (NO3 -Examples include either the form (type) or a state in which an organic acid used as an eluent later is bound, such as acetate ion (CH3COO - It is preferable that it be of the type.

[0119] In the third step, it is preferable that the recovery conditions for obtaining solution D are initiated by a change in Brix and terminated by a change in Brix. As for the rate of change in Brix, a Brix of 0.2% or more after starting to pass solution C through can be used as an indicator for starting recovery, and a Brix of 1.0% or less can be used as an indicator for ending recovery. In this specification, the indicators at the start and end of recovery can be any indicator that allows for the estimation of the rate of change in the concentration of 5-aminolevulinic acid, such as the rate of change in electrical conductivity, the rate of change in pH, or the rate of change in Brix, with the rate of change in Brix being preferred as the indicator.

[0120] The pH of solution D is preferably 0.5 to 10, more preferably 1 to 7, even more preferably 2 to 6, and most preferably 2.5 to 5. The concentration of 5-aminolevulinic acid or its salt in solution D is preferably 0.1 to 100 g / L, more preferably 1 to 70 g / L, even more preferably 5 to 50 g / L, and most preferably 30 to 45 g / L, in terms of 5-aminolevulinic acid monophosphate.

[0121] In the third step, in addition to solution C, deionized water can be used as the liquid to pass through when treating solution C with the ion exchange resin. Deionized water is used to elute substances that do not adsorb to the ion exchange resin and to improve the recovery rate of 5-aminolevulinic acid or its salt. In this step, the solutions that can be used to pass solution C through the cation exchange resin are preferably solution C and deionized water.

[0122] (Step 4) The fourth step is to perform treatments such as adjusting the pH of solution D to obtain solution E. If the solution D obtained in the third step does not have the pH or the concentration of 5-aminolevulinic acid or its salt, the fourth step may be performed after the third step to adjust the pH of solution D to obtain solution E.

[0123] In the fourth step, examples of solutions used to adjust the pH of solution D include solutions such as phosphoric acid, hydrochloric acid, sulfuric acid, acetic acid, or nitric acid.

[0124] Furthermore, if solution E contains impurities that hinder crystallization, the solution may be passed through or added to a column packed with ion exchange resin, synthetic adsorption resin, activated carbon, etc., and the impurities and salts may be removed by filtration or other means.

[0125] The pH of solution E is preferably 1 to 7, more preferably 2 to 6, even more preferably 2.5 to 5, and most preferably 2.5 to 3.5. Examples of pH adjusting agents for adjusting this pH include hydrochloric acid, sulfuric acid, phosphoric acid, phosphorous acid, nitric acid, nitrite, acetic acid, potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, and ammonia, with phosphoric acid and hydrochloric acid being preferred, and phosphoric acid being the most preferred. These pH adjusting agents may be used in mixtures of two or more types. The concentration of 5-aminolevulinic acid or its salt in solution E is preferably 0.1 to 100 g / L, more preferably 1 to 70 g / L, even more preferably 5 to 50 g / L, and most preferably 30 to 45 g / L, in terms of 5-aminolevulinic acid monophosphate.

[0126] (Step 5) The fifth step is to concentrate the solution E obtained in the fourth step using a general concentration method such as a heating concentration method or a vacuum concentration method. The content of 5-aminolevulinic acid or its salt in the concentrated solution is preferably 10 to 800 g / L, more preferably 50 to 600 g / L, even more preferably 300 to 700 g / L, and most preferably 500 to 650 g / L, in terms of 5-aminolevulinic acid monophosphate.

[0127] (filtration) One filtration method is to perform microfiltration of solution E or the concentrated solution using a membrane with a diameter of 0.2 to 1.2 μm. Specifically, one method is to treat solution E or a solution obtained by passing solution E through a column packed with ion exchange resin, synthetic adsorption resin, activated carbon, etc., or by adding such resin, with a membrane filter.

[0128] (Step 6) The sixth step is an optional step, and in one embodiment, it is a step in which the concentrated liquid is crystallized (hereinafter also abbreviated as the "first crystallization step") and the obtained powder is dissolved to obtain solution F. In one embodiment, the first crystallization step preferably includes the following (α1) to (α5). (α1) Steps to prepare the crystallization stock solution. (α2)(α1) Step of adjusting the temperature of the crystallization stock solution obtained in (α2)(α1) (α3)(α2) Add the first organic solvent to the crystallization stock solution obtained in (α3)(α2) to precipitate 5-aminolevulinic acid or a salt thereof. (α4) Step of adding the second organic solvent to the crystallization stock solution. (α5) Steps to separate precipitates (α1) to (α5) are explained below.

[0129] (α1) Preparation of crystallization stock solution The solution D or solution E obtained in the above steps can be used to obtain a crystallization stock solution containing 5-aminolevulinic acid or its salt by common concentration methods such as diluting an aqueous solution of 5-aminolevulinic acid or its salt with water, heating and concentrating, membrane concentration, or vacuum concentration. A crystallization stock solution refers to a solution used for crystallizing 5-aminolevulinic acid or its salt.

[0130] The concentration of 5-aminolevulinic acid or its salt in the crystallization stock solution is preferably 900 g / L or less, 700 g / L or less, 650 g / L or less, and 600 g / L or less, in terms of 5-aminolevulinic acid monophosphate, and preferably 200 g / L or more, 300 g / L or more, 400 g / L or more, and 500 g / L or more. These upper and lower limits can be arbitrarily combined. In another embodiment, the concentration of 5-aminolevulinic acid or its salt in the crystallization stock solution is preferably 200 to 900 g / L, more preferably 300 to 900 g / L, even more preferably 400 to 900 g / L, and most preferably 500 to 650 g / L, in terms of 5-aminolevulinic acid phosphate. By setting the concentration of 5-aminolevulinic acid or its salt in the crystallization stock solution within the above range, residual organic solvents can be reduced and product quality can be improved.

[0131] To achieve the above concentration of 5-aminolevulinic acid or its salt in an aqueous solution, it may be dissolved using ion-exchanged purified water or the like. Alternatively, the aqueous solution containing 5-aminolevulinic acid or its salt can be concentrated and prepared using a general concentration method such as heating or vacuum concentration.

[0132] (α2)(α1) Step of adjusting the temperature of the crystallization stock solution obtained in (α2)(α1) Step (α2) is a step in which the temperature of the crystallization stock solution obtained in step (α1) is adjusted to a specific range. The temperature of the crystallization stock solution is preferably 30°C or lower, 25°C or lower, or 20°C or lower, and preferably 5°C or higher. These upper and lower limits can be arbitrarily combined. In another embodiment, the temperature of the crystallization stock solution is preferably 5 to 30°C, more preferably 5 to 25°C, even more preferably 5 to 20°C, and most preferably 10 to 20°C. By setting the temperature of the crystallization stock solution within the above range, residual organic solvent can be further reduced and product quality can be improved. Examples of methods for adjusting the temperature of the crystallization stock solution include a constant temperature bath and a jacketed tank.

[0133] (α3)(α2) Add the first organic solvent to the crystallization stock solution obtained in (α3)(α2) to precipitate 5-aminolevulinic acid or a salt thereof. Step (α3) is a step in which the temperature of the crystallization stock solution adjusted in step (α2) is adjusted by adding the first organic solvent to precipitate 5-aminolevulinic acid or a salt thereof.

[0134] In step (α3), the amount of first' organic solvent added is preferably 2.0 v / v or less, more preferably 1.0 v / v or less, even more preferably 0.80 v / v or less, and most preferably 0.60 v / v or less, relative to the volume of the crystallization stock solution. The lower limit of the amount of first' organic solvent added is not particularly limited, but is preferably 0.01 v / v or more, more preferably 0.10 v / v or more, even more preferably 0.20 v / v or more, and most preferably 0.30 v / v or more, relative to the volume of the crystallization stock solution. These upper and lower limits can be combined arbitrarily. In another embodiment, the amount of first' organic solvent added is 0.01 to 2.0 v / v, 0.10 to 1.0 v / v, 0.20 to 0.80 v / v, and 0.30 to 0.60 v / v, relative to the volume of the crystallization stock solution.

[0135] In the step of adding the first organic solvent, the crystallization temperature is not particularly limited, but it is preferably the same temperature as in step (α2). In step (α3), the rate at which the organic solvent is added is not particularly limited, as long as there is no precipitation of solids due to a decrease in local solubility.

[0136] (1st organic solvent) In step (α3), the first organic solvent is preferably at least one organic solvent selected from the group consisting of methanol, ethanol, acetone, 1-propanol, 2-propanol, ethyl acetate, 1-butanol, 2-butanol, heptane, isopropyl acetate, methyl ethyl ketone, propyl acetate, and tetrahydrofuran. Among these, at least one organic solvent selected from the group consisting of methanol, ethanol, acetone, 1-propanol, and 2-propanol is more preferred, and methanol or ethanol is most preferred. Furthermore, these organic solvents may be used individually or in combination of multiple types.

[0137] In step (α3), the first' organic solvent may be added as a mixture with an organic solvent, a mixture with water, or a mixture of an organic solvent and water. The concentration of the first' organic solvent in the mixture is preferably 30% by volume or more, more preferably 50% by volume or more, even more preferably 80% by volume or more, and most preferably 100% by volume. These upper and lower limits can be combined arbitrarily. In another embodiment, the concentration of the first' organic solvent in the mixture is preferably 30 to 100% by volume, more preferably 50 to 100% by volume, and even more preferably 80 to 100% by volume.

[0138] (seed crystal) In step (α3), seed crystals may be added to the crystallization stock before 5-aminolevulinic acid or its salt precipitates. The timing of adding the seed crystals to the crystallization stock is not particularly limited, but from the viewpoint of purification efficiency, for example, it is preferably within 0 to 12 hours, more preferably within 0 to 8 hours, even more preferably within 0 to 4 hours, and most preferably immediately after the end of the addition of the first organic solvent, from the start of the addition of the first organic solvent.

[0139] The amount of seed crystal added to the crystallization stock solution is preferably 0.01 to 5.0% by mass, more preferably 0.01 to 3.0% by mass, even more preferably 0.01 to 0.5% by mass, and most preferably 0.03 to 0.5% by mass, relative to 5-aminolevulinic acid or its salt in the crystallization stock solution. By setting the amount of seed crystal added within the above range, residual organic solvent can be further reduced, and product quality can be improved.

[0140] After adding the seed crystal, it is preferable that the entire crystallization stock solution containing the seed crystal is stirred in a nearly uniform state, and that it be allowed to mature so that the added seed crystal can grow. The main purpose of maturation is to grow and increase the size of the crystal, but the precipitation of new crystals may occur simultaneously with the growth of the crystal.

[0141] The crystal maturation time, measured starting from the completion of seed crystal addition, is preferably less than 360 minutes and 240 minutes or less, and preferably 1 minute or more and 10 minutes or more. These upper and lower limits can be combined arbitrarily. In another embodiment, the crystal maturation time, measured starting from the completion of seed crystal addition, is preferably 1 to 359 minutes, more preferably 1 to 240 minutes, even more preferably 10 to 359 minutes, and most preferably 10 to 240 minutes. By setting the crystal maturation time within the above range, residual organic solvents can be further reduced and product quality can be improved.

[0142] The temperature at which the seed crystal is added to the crystallization stock solution is not particularly limited as long as the seed crystal does not dissolve, but it is preferably 30°C or lower, 25°C or lower, 20°C or lower, and preferably 5°C or higher. These upper and lower limits can be combined arbitrarily. In another embodiment, the temperature at which the above seed crystal is added to the crystallization stock solution is preferably 5 to 30°C, more preferably 5 to 25°C, and even more preferably 15 to 20°C.

[0143] (α4) Step of adding the second organic solvent to the crystallization stock solution. The first crystallization step preferably includes a step (α4) in which, after adding the seed crystal to the crystallization stock solution in step (α3), a second' organic solvent is further added to the crystallization stock solution. The timing of adding the second' organic solvent to the crystallization stock solution is not particularly limited, but from the viewpoint of purification efficiency, for example, immediately after the crystal maturation is completed is preferred.

[0144] The amount of the second organic solvent added is preferably 3.0 v / v or less, more preferably 2.6 v / v or less, even more preferably 2.4 v / v or less, and most preferably 2.0 v / v or less, relative to the volume of the crystallization stock solution. The lower limit of the amount of the second organic solvent added is not particularly limited, but it is preferably 0.1 v / v or more, relative to the volume of the crystallization stock solution. These upper and lower limits can be combined arbitrarily. In another embodiment, the amount of the second organic solvent added is preferably 0.1 to 3.0 v / v, more preferably 0.1 to 2.7 v / v, even more preferably 0.1 to 2.5 v / v, and most preferably 0.1 to 2.4 v / v, relative to the volume of the crystallization stock solution.

[0145] The total amount of the first' organic solvent and the second' organic solvent added to the crystallization stock solution is preferably 3.0 v / v or less, more preferably 2.5 v / v or less, even more preferably 2.2 v / v or less, and most preferably 2.0 v / v or less, relative to the volume of the crystallization stock solution. The amount of the first' organic solvent and the second' organic solvent added is not particularly limited to the lower limit, but is preferably 0.1 v / v or more, relative to the volume of the crystallization stock solution. These upper and lower limits can be combined arbitrarily. In another embodiment, the amount of the first' organic solvent and the second' organic solvent added is preferably 0.1 to 4.0 v / v, more preferably 0.1 to 3.5 v / v, even more preferably 0.1 to 3.2 v / v, and most preferably 0.1 to 3.0 v / v, relative to the volume of the crystallization stock solution.

[0146] In step (α4), the crystallization temperature is not particularly limited, but it is preferably the same temperature as in step [α2]. The rate at which the second organic solvent is added to the crystallization stock solution is not particularly limited as long as there is no precipitation of solids due to a decrease in local solubility, but it is preferably 5.0 v / v / h or less, 2.0 v / v / h or less, 1.5 v / v / h or less, and 1.0 v / v / h or less relative to the volume of the crystallization stock solution. The rate at which the second organic solvent is added to the crystallization stock solution is not particularly limited in terms of the lower limit, but it is preferably 0.1 v / v or more, 0.2 v / v or more, 0.3 v / v or more, 0.4 v / v or more, and 0.5 v / v or more relative to the volume of the crystallization stock solution. These upper and lower limits can be combined arbitrarily. In another embodiment, the rate at which the second organic solvent is added to the crystallization stock solution is preferably 0.1 to 5.0 v / v / h, more preferably 0.2 to 2.0 v / v / h, even more preferably 0.3 to 1.5 v / v / h, and most preferably 0.5 to 1.3 v / v / h, relative to the volume of the crystallization stock solution.

[0147] In step (α4), the second' organic solvent may be added as a mixture with an organic solvent, a mixture with water, or a mixture of an organic solvent and water. The concentration of the second' organic solvent in the mixture is preferably 30% by volume or more, more preferably 50% by volume or more, even more preferably 80% by volume or more, and most preferably 100% by volume. These upper and lower limits can be combined arbitrarily. In another embodiment, the concentration of the second' organic solvent in the mixture is preferably 30 to 100% by volume, more preferably 50 to 100% by volume, and even more preferably 80 to 100% by volume.

[0148] (α5) Steps to separate precipitates The first crystallization step preferably includes a step of separating the precipitate from the crystallization stock solution. A method for removing the organic solvent from the precipitate obtained by the above crystallization is, for example, to separate the precipitate from the slurry and then wash and dry it.

[0149] (Method for separating precipitates from slurry and washing them) The method for separating and washing precipitates from the slurry is not particularly limited as long as the precipitates and mother liquor (ML) can be separated, but examples include filtration, pressure filtration, suction filtration, and centrifugation. In the case of centrifugation, it is preferable to wash the precipitates from the viewpoint of removing impurities. As a method for washing the precipitates, for example, they can be washed using an organic solvent added during crystallization or an aqueous solution containing an organic solvent.

[0150] The amount of solution used for the above washing is preferably 0.5 to 2 v / w, more preferably 1.0 to 1.9 v / w, and even more preferably 1.2 to 1.8 v / w, in volume ratio to the weight of the precipitate of 5-aminolevulinic acid or its salt.

[0151] (Drying) The drying method is not particularly limited as long as it can remove the organic solvent, prevent the decomposition of 5-aminolevulinic acid or its salt, and preserve the form of the precipitate (crystalline or amorphous). For example, vacuum drying, fluidized bed drying, and forced-air drying can be applied.

[0152] The separated and dried precipitate is dissolved with ion-exchanged purified water or the like to obtain a solution (Solution F) of 5-aminolevulinic acid or its salt. The content of 5-aminolevulinic acid or its salt in the solution is preferably 10 to 800 g / L, more preferably 50 to 600 g / L, even more preferably 100 to 500 g / L, and most preferably 300 to 500 g / L, in terms of 5-aminolevulinic acid monophosphate.

[0153] (Step 7) Step 7 is an optional step, and in one embodiment, it is a step of obtaining a decolorized solution (solution G) from solution F using activated carbon. In one embodiment, activated carbon may be added to decolorize the solution E or the concentrated solution or the solution F to obtain solution G. Examples of activated carbon include Carborafin (registered trademark), Kyoryoku Shirasagi (hereinafter, Shirasagi is a registered trademark), Purified Shirasagi, Special Shirasagi, Shirasagi A, Shirasagi C, Shirasagi ANOX-1, Shirasagi FAC-10, Shirasagi WP-H, Shirasagi DO-2, Shirasagi DO-5, Granular Shirasagi G2c, Granular Shirasagi WH2c, Granular Shirasagi W2c, Granular Shirasagi WH5c, Granular Shirasagi W5c, Granular Shirasagi LGK-100, Granular Shirasagi LGK-400, Granular Shirasagi KL, Granular Shirasagi LH2c, Spherical Shirasagi X8100H, Spherical Shirasagi XS8100H, and Granular Shirasagi G. 2x, Granular White Heron G5x, Granular White Heron S2x, Granular White Heron WH2x, Granular White Heron X2M, Granular White Heron C2c, Granular White Heron C2x, Spherical White Heron X7000H, Spherical White Heron X7100H, Spherical White Heron XS7100H, Spherical White Heron Examples include Spherical Shirasagi LGK-700, Spherical Shirasagi DX7-3, Shirasagi M, Shirasagi P, Granular Shirasagi GM2X, Seitz AKSJ, and Taiko (hereinafter, Taiko is a registered trademark) S, Taiko K, Taiko P, Taiko W, Taiko A, and Taiko Y manufactured by Futamura Chemical Co., Ltd., with Taiko S being preferred.

[0154] (Step 8) Step 8 is, in one embodiment, a step of treating solution G with a chelate resin to obtain solution H. Alternatively, in one embodiment, solution E or concentrated solution or solution F or decolorized solution (solution G) may be passed through the chelate resin to obtain solution H. Examples of chelate resins include those having a sulfone group, iminodiacetic acid or aminomethylphosphonic acid as an exchange group, and whose resin matrix is ​​porous, macroporous, gel, styrene, or acrylic.

[0155] Examples of chelating resins include DuPont's C467, Purolite's MTS9500, and LANXESS's Lewatit® CNP80, CNP80WS, MDSTP208, MDSTP260, TP207, TP208, TP209XL, and TP260.

[0156] (Step 9) Step 9 is an optional step, and in one embodiment, it is a step of passing the solution H through a microfiltration membrane and an ultrafiltration membrane to obtain a filtrate. In one embodiment, ultrafiltration may be performed by passing the solution D, solution E, or solution F obtained in the above step through an ultrafiltration membrane (hereinafter also referred to as "UF membrane") (MWCO=6000) capable of removing substances with a molecular weight of 6000 or more, to remove, for example, endotoxins, proteins, high molecular weight peptides, toxins, etc. from the decolorized filtrate. Furthermore, microfiltration can be performed before or after this step using a membrane with a diameter of 0.2 to 1.2 μm. Specifically, for example, a method of processing with a membrane filter can be mentioned.

[0157] (Step 10) Step 10 is an optional step, and in one embodiment, it is a step of concentrating the filtrate obtained in step 9 to obtain a concentrate. For solution D, solution E, solution F, or solution G obtained in the above step, a crystallization stock solution containing 5-aminolevulinic acid or its salt can be obtained by general concentration methods such as diluting an aqueous solution of 5-aminolevulinic acid or its salt with water, heating and concentrating, membrane concentration, or vacuum concentration.

[0158] The concentration of 5-aminolevulinic acid or its salt in the crystallization stock solution is preferably 700 g / L or less, 650 g / L or less, and 600 g / L or less, in terms of 5-aminolevulinic acid monophosphate, and preferably 200 g / L or more, 260 g / L or more, 300 g / L or more, 400 g / L or more, and 500 g / L or more. These upper and lower limits can be arbitrarily combined. In another embodiment, the concentration of 5-aminolevulinic acid or its salt in the crystallization stock solution is preferably 200 to 700 g / L, more preferably 260 to 650 g / L, 260 to 600 g / L, 300 to 700 g / L, even more preferably 400 to 700 g / L, and most preferably 500 to 650 g / L, in terms of 5-aminolevulinic acid monophosphate. By setting the concentration of 5-aminolevulinic acid or its salt in the crystallization stock solution within the aforementioned range, residual organic solvents can be reduced, thereby improving product quality.

[0159] To achieve the above concentration of 5-aminolevulinic acid or its salt in an aqueous solution, it may be dissolved using ion-exchanged purified water or the like. Alternatively, the aqueous solution containing 5-aminolevulinic acid or its salt can be concentrated and prepared using a general concentration method such as heating or vacuum concentration.

[0160] [2] A step to adjust the temperature of the crystallization stock solution obtained in [1]. Step [2] is a step of adjusting the temperature of the crystallization stock solution obtained in step [1] to a specific range. The temperature of the crystallization stock solution is preferably 30°C or lower, 25°C or lower, or 20°C or lower, and preferably 5°C or higher. These upper and lower limits can be combined arbitrarily. In another embodiment, the temperature of the crystallization stock solution is preferably 5 to 30°C, more preferably 5 to 25°C, even more preferably 5 to 20°C, and most preferably 10 to 20°C. By setting the temperature of the crystallization stock solution within the above range, residual organic solvent can be further reduced and product quality can be improved. Examples of methods for adjusting the temperature of the crystallization stock solution include a constant temperature bath and a jacketed tank.

[0161] [3] The first organic solvent is added to the crystallization stock solution obtained in [2] to precipitate 5-aminolevulinic acid or a salt thereof. Step [3] is a step in which a first organic solvent is added to the crystallization stock solution whose temperature was adjusted in step [2] to precipitate 5-aminolevulinic acid or a salt thereof.

[0162] In step [3], the amount of the first organic solvent added is 0.55 v / v or less, preferably 0.50 v / v or less, more preferably 0.45 v / v or less, and even more preferably 0.40 v / v or less, relative to the volume of the crystallization stock solution. The lower limit of the amount of the first organic solvent added is not particularly limited, but is 0.01 v / v or more, relative to the volume of the crystallization stock solution. These upper and lower limits can be combined arbitrarily. In another embodiment, the amount of the first organic solvent added is 0.01 to 0.55 v / v, 0.01 to 0.50 v / v, 0.01 to 0.45 v / v, or 0.01 to 0.40 v / v, relative to the volume of the crystallization stock solution.

[0163] In the step of adding the first organic solvent, the crystallization temperature is not particularly limited, but it is preferably the same temperature as in step [2]. In step [3], the rate at which the organic solvent is added is not particularly limited, as long as there is no precipitation of solids due to a decrease in local solubility.

[0164] (First organic solvent) In step [3], the first organic solvent is preferably at least one organic solvent selected from the group consisting of methanol, ethanol, acetone, 1-propanol, 2-propanol, ethyl acetate, 1-butanol, 2-butanol, heptane, isopropyl acetate, methyl ethyl ketone, propyl acetate, and tetrahydrofuran. Among these, at least one organic solvent selected from the group consisting of methanol, ethanol, acetone, 1-propanol, and 2-propanol is more preferred, and most preferably ethanol. These organic solvents may be used individually or in combination of multiple types.

[0165] In step [3], the first organic solvent may be added as a mixture with an organic solvent, a mixture with water, or a mixture of an organic solvent and water. The concentration of the first organic solvent in the mixture is preferably 30% by volume or more, more preferably 50% by volume or more, even more preferably 80% by volume or more, and most preferably 100% by volume. These upper and lower limits can be combined arbitrarily. In another embodiment, the concentration of the first organic solvent in the mixture is preferably 30 to 100% by volume, more preferably 50 to 100% by volume, and even more preferably 80 to 100% by volume.

[0166] (seed crystal) In step [3], seed crystals may be added to the crystallization stock before the precipitate of 5-aminolevulinic acid or its salt precipitates. The timing of adding the seed crystals to the crystallization stock is not particularly limited, but from the viewpoint of purification efficiency, for example, it is preferably within 0 to 12 hours, more preferably within 0 to 8 hours, even more preferably within 0 to 4 hours, and most preferably immediately after the end of the addition of the first organic solvent, from the start of the addition of the first organic solvent.

[0167] The amount of seed crystal added to the crystallization stock solution is preferably 0.01 to 5.0% by mass, more preferably 0.01 to 3.0% by mass, even more preferably 0.01 to 0.5% by mass, and most preferably 0.05 to 0.5% by mass, relative to 5-aminolevulinic acid or its salt in the crystallization stock solution. By setting the amount of seed crystal added within the above range, residual organic solvent can be further reduced, and product quality can be improved.

[0168] After adding the seed crystal, it is preferable that the entire crystallization stock solution containing the seed crystal is stirred in a nearly uniform state, and that it be allowed to mature so that the added seed crystal can grow. The main purpose of maturation is to grow and increase the size of the crystal, but the precipitation of new crystals may occur simultaneously with the growth of the crystal.

[0169] The crystal maturation time, measured starting from the completion of seed crystal addition, is preferably less than 360 minutes and 240 minutes or less, and preferably 1 minute or more and 10 minutes or more. These upper and lower limits can be combined arbitrarily. In another embodiment, the crystal maturation time, measured starting from the completion of seed crystal addition, is preferably 1 to 359 minutes, more preferably 1 to 240 minutes, even more preferably 10 to 359 minutes, and most preferably 10 to 240 minutes. By setting the crystal maturation time within the above range, residual organic solvents can be further reduced and product quality can be improved.

[0170] The temperature at which the seed crystal is added to the crystallization stock solution is not particularly limited as long as the seed crystal does not dissolve, but it is preferably 30°C or lower, 25°C or lower, 20°C or lower, and preferably 5°C or higher. These upper and lower limits can be combined arbitrarily. In another embodiment, the temperature at which the above seed crystal is added to the crystallization stock solution is preferably 5 to 30°C, more preferably 5 to 25°C, and even more preferably 15 to 20°C.

[0171] [4] Step of adding the second organic solvent to the crystallization stock solution. The manufacturing method of the present disclosure preferably includes a step [4] in which, after adding the seed crystal to the crystallization stock solution in step [3], a second organic solvent is further added to the crystallization stock solution. The timing of adding the second organic solvent to the crystallization stock solution is not particularly limited, but from the viewpoint of purification efficiency, for example, immediately after the crystal maturation is completed is preferred.

[0172] The amount of the second organic solvent added is preferably 3.0 v / v or less, more preferably 2.6 v / v or less, even more preferably 2.4 v / v or less, and most preferably 2.0 v / v or less, relative to the volume of the crystallization stock solution. The lower limit of the amount of the second organic solvent added is not particularly limited, but it is preferably 0.1 v / v or more, relative to the volume of the crystallization stock solution. These upper and lower limits can be combined arbitrarily. In another embodiment, the amount of the second organic solvent added is preferably 0.1 to 3.0 v / v, more preferably 0.1 to 2.5 v / v, even more preferably 0.1 to 2.2 v / v, and most preferably 0.1 to 2.0 v / v, relative to the volume of the crystallization stock solution.

[0173] The total amount of the first and second organic solvents added to the crystallization stock solution is preferably 3.0 v / v or less, more preferably 2.5 v / v or less, even more preferably 2.2 v / v or less, and most preferably 2.0 v / v or less, relative to the volume of the crystallization stock solution. The amount of the first and second organic solvents added is not particularly limited to the lower limit, but is preferably 0.1 v / v or more, relative to the volume of the crystallization stock solution. These upper and lower limits can be combined arbitrarily. In another embodiment, the amount of the first and second organic solvents added is preferably 0.1 to 3.0 v / v, more preferably 0.1 to 2.5 v / v, even more preferably 0.1 to 2.2 v / v, and most preferably 0.1 to 2.0 v / v, relative to the volume of the crystallization stock solution.

[0174] In step [4], the crystallization temperature is not particularly limited, but is preferably the same as in step [2]. The rate at which the second organic solvent is added to the crystallization stock is not particularly limited as long as there is no precipitation of solids due to a decrease in local solubility, but is preferably 5.0 v / v / h or less, 2.0 v / v / h or less, 1.5 v / v / h or less, and 1.0 v / v / h or less with respect to the volume of the crystallization stock. The rate at which the second organic solvent is added to the crystallization stock is not particularly limited in terms of the lower limit, but is preferably 0.1 v / v or more with respect to the volume of the crystallization stock. These upper and lower limits can be combined arbitrarily. In another embodiment, the rate at which the second organic solvent is added to the crystallization stock is preferably 0.4 to 5.0 v / v / h, more preferably 0.4 to 2.0 v / v / h, even more preferably 0.4 to 1.5 v / v / h, and most preferably 0.4 to 1.0 v / v / h with respect to the volume of the crystallization stock.

[0175] In step [4], the second organic solvent may be added as a mixture with an organic solvent, a mixture with water, or a mixture of an organic solvent and water. The concentration of the second organic solvent in the mixture is preferably 30% by volume or more, more preferably 50% by volume or more, even more preferably 80% by volume or more, and most preferably 100% by volume. These upper and lower limits can be combined arbitrarily. In another embodiment, the concentration of the second organic solvent in the mixture is preferably 30 to 100% by volume, more preferably 50 to 100% by volume, and even more preferably 80 to 100% by volume.

[0176] [5] Steps to separate precipitates In the manufacturing method of the present disclosure, it is preferable to further include a step of separating the precipitate from the crystallization stock solution. A method for removing the organic solvent from the precipitate obtained by the above crystallization is, for example, a method of separating the precipitate from the slurry and washing and drying it.

[0177] (Method for separating precipitates from slurry and washing them) The method for separating precipitates from slurry is not particularly limited as long as the precipitates and mother liquor (ML) can be separated, but examples include filtration, pressure filtration, suction filtration, and centrifugation. In the case of centrifugation, it is preferable to wash the precipitates from the viewpoint of removing impurities. As a method for washing the precipitates, for example, they can be washed using an organic solvent added during crystallization or an aqueous solution containing an organic solvent.

[0178] The amount of solution used for the above washing is preferably 0.5 to 2 v / w, more preferably 0.9 to 1.1 v / w, and even more preferably 0.9 to 1.0 v / w, as a volume ratio to the weight of the 5-aminolevulinic acid precipitate.

[0179] (Drying) The drying method is not particularly limited as long as it can remove the organic solvent, prevent the decomposition of 5-aminolevulinic acid or its salt, and preserve the form of the precipitate (crystalline or amorphous). For example, vacuum drying, fluidized bed drying, and forced-air drying can be applied.

[0180] The drying temperature is not particularly limited as long as it can remove adhering moisture and solvent, but is preferably 50°C or lower, more preferably 40°C or lower, and most preferably 30°C or lower. The lower limit of the drying temperature is not particularly limited, but is preferably 4°C or higher. These upper and lower limits can be combined arbitrarily. In another embodiment, the drying temperature is preferably 4 to 50°C, more preferably 4 to 40°C, and even more preferably 4 to 30°C. The drying time is not particularly limited as long as it can remove adhering moisture and solvent, but is preferably 48 hours or less, 24 hours or less, 10 hours or less, or 5 hours or less. The lower limit is not particularly limited, but is 1 hour or more. These upper and lower limits can be combined arbitrarily. In another embodiment, the drying time is preferably 1 to 48 hours, more preferably 1 to 24 hours, even more preferably 1 to 10 hours, and most preferably 1 to 5 hours. In the case of vacuum drying, the pressure is not particularly limited, but from the viewpoint of purification efficiency, it is preferably 0.1 hPa or higher, 1 hPa or higher, or 10 hPa or higher. The pressure for vacuum drying is not particularly limited to an upper limit, but is preferably 150 hPa or less, 100 hPa or less, or 80 hPa or less. These upper and lower limits can be combined arbitrarily. In another embodiment, the pressure for vacuum drying is preferably 0.1 to 150 hPa, more preferably 1 to 100 hPa, and even more preferably 10 to 80 hPa.

[0181] [Third to Sixth Embodiments] A third embodiment of this disclosure provides a solution containing 5-aminolevulinic acid or a salt thereof, glycine, and alanine, with Na + This is a method for producing 5-aminolevulinic acid or a salt thereof, which includes treatment with a type of strongly acidic cation exchange resin.

[0182] A fourth embodiment of the present disclosure is a method for producing 5-aminolevulinic acid or a salt thereof, comprising treating a solution containing 5-aminolevulinic acid or a salt thereof, glycine, and alanine with at least one of a phosphoric acid type and an acetate type strongly basic anion exchange resin.

[0183] A fifth embodiment of this disclosure is a method for producing 5-aminolevulinic acid or a salt thereof, comprising the following x1) to x3) in any order: x1) Treating a solution containing 5-aminolevulinic acid or a salt thereof, glycine, and alanine with a strongly acidic cation exchange resin. x2) Treating a solution containing 5-aminolevulinic acid or a salt thereof, glycine, and alanine with a weakly acidic cation exchange resin. x3) Treating a solution containing 5-aminolevulinic acid or a salt thereof, glycine, and alanine with a strongly basic anion exchange resin.

[0184] A sixth embodiment of this disclosure is a method for producing 5-aminolevulinic acid or a salt thereof, comprising the following steps y1) to y4) in this order: y1) A solution A containing 5-aminolevulinic acid or a salt thereof, glycine, and alanine is treated with a strongly acidic cation exchange resin to obtain solution B. y2) Solution B is treated with a weakly acidic cation exchange resin to obtain solution C. y3) Solution C is treated with a strongly basic anion exchange resin to obtain solution D. y4) The pH of solution D is adjusted to obtain solution E.

[0185] In the third to sixth embodiments, the solution containing 5-aminolevulinic acid or its salt, glycine, alanine, and PDPA is the solution A described above in step 0. The concentration of 5-aminolevulinic acid or its salt in the solution is not particularly limited, but from the viewpoint of purification efficiency, in one embodiment, it is preferably 0.1 g / L to 100 g / L, more preferably 1 g / L to 70 g / L, and even more preferably 10 g / L to 60 g / L in terms of 5-aminolevulinic acid monophosphate. The glycine content ratio in the solution, (glycine content) / (5-aminolevulinic acid or its salt content), is preferably 0.0001 to 1, more preferably 0.0005 to 0.5, even more preferably 0.001 to 0.3, and most preferably 0.05 to 0.15 by mass. The alanine content ratio in the solution, (alanine content) / (5-aminolevulinic acid or its salt content), is preferably 0.0001 to 1, more preferably 0.0005 to 0.5, even more preferably 0.001 to 0.3, and most preferably 0.005 to 0.05, on a mass basis. The PDPA content ratio in the solution, (PDPA content) / (5-aminolevulinic acid or its salt content), is preferably 0.0001 to 1, more preferably 0.0005 to 0.5, even more preferably 0.001 to 0.3, and most preferably 0.002 to 0.1, on a mass basis.

[0186] In the third, fifth, and sixth embodiments, the strongly acidic cation exchange resin is the same as the strongly acidic cation exchange resin described in the first step. In the fifth and sixth embodiments, the weakly acidic cation exchange resin is the same as the weakly acidic cation exchange resin described in the second step. In the fourth to sixth embodiments, the strongly basic anion exchange resin is the same as the strongly basic anion exchange resin described in the third step.

[0187] One embodiment of x1) in the fifth embodiment is the same embodiment as the first step. One embodiment of x2) in the fifth embodiment is the same embodiment as the second step. One embodiment of x3) in the fifth embodiment is the same embodiment as the third step.

[0188] One aspect of y1) in the sixth embodiment is the same as the aspect of the first step. One aspect of y2) in the sixth embodiment is the same as the aspect of the second step. One aspect of y3) in the sixth embodiment is the same as the aspect of the third step. One aspect of y4) in the sixth embodiment is the same as the aspect of the fourth step.

[0189] In the sixth embodiment, in y1), the recovery conditions for obtaining solution B are preferably initiated by a change in Brix value and terminated by a change in pH. In this specification, Brix value is a measure that indicates the mass percentage of the concentration of soluble solids in a liquid, mainly 5-aminolevulinic acid or its salt, and refers to the number of grams of 5-aminolevulinic acid or its salt contained in 100 grams of liquid. The unit of Brix value is usually expressed in degrees (°Brix), but it can also be expressed as a mass percentage (mass%). For example, a Brix value of 10°Brix (or 10 mass%) means that the liquid contains a concentration of 10 mass% of 5-aminolevulinic acid or its salt. As a measurement method, the refractive index of the liquid is measured using a refractometer, and the Brix value is calculated based on this. When using a refractometer, it is calibrated with a standard solution, the sample solution is dropped onto the prism surface and the refractive index is read, and temperature correction is performed as necessary.

[0190] In this specification, "initiated by a change in Brix value" means that the recovery process is started when a certain change occurs in the Brix value under the recovery conditions for obtaining the solution. Specifically, it means the operation of starting the recovery of the solution triggered by the point at which the sugar content (Brix value) of the liquid begins to change as the process progresses. Furthermore, "terminated by a change in pH" means that the recovery process is terminated when the pH value reaches a certain range under the recovery conditions for obtaining the solution. Specifically, it means the operation of stopping the recovery process when the pH value of the liquid reaches a target range or a specific condition during the recovery process. By combining changes in Brix value and pH, it is possible to set more precise recovery conditions and optimize the process.

[0191] Specifically, in y1), the Brix value and pH of the solution are measured, and the recovery of solution B is started when the Brix value is preferably 2.0 to 6.0% by mass, more preferably 4.0 to 6.0% by mass, and the recovery of solution B is stopped when the pH is preferably 11.0 to 13.0, more preferably 12.0 to 13.0, thereby enabling efficient separation of solution B.

[0192] After the preparation of solution B in the sixth embodiment is completed, in the next step y2), solution B is further treated with a weakly acidic cation exchange resin. This is to further remove impurities remaining in solution B and improve the purity of 5-aminolevulinic acid. Since the weakly acidic cation exchange resin has different exchange sites than the strongly acidic resin, it exhibits different adsorption and separation characteristics for impurities.

[0193] In y2) above, it is preferable that the recovery conditions for obtaining solution C are initiated by a change in Brix and terminated by a change in Brix. Specifically, the recovery of solution C is started when the Brix value of the solution is preferably 2.0% by mass, and the recovery of solution C is terminated when 4.5 ± 1.5 RV of deionized water relative to the volume of the weakly acidic cation exchange resin is passed through the solution when the Brix value of solution C is preferably 1.0% by mass. This enables effective removal of impurities.

[0194] Next, in y3), solution C is treated with a strongly basic anion exchange resin. This removes anionic impurities from solution C and restores the ionic equilibrium of 5-aminolevulinic acid or its salt. The strongly basic anion exchange resin has high selectivity and can efficiently remove even residual trace amounts of impurities.

[0195] In y3) above, it is preferable that the recovery conditions for obtaining solution D are initiated by a change in Brix and terminated by a change in Brix. Specifically, the recovery of solution D is started when the Brix value of the solution is preferably 0.2% by mass, and the recovery of solution D is terminated when 1.25 ± 0.625 RV of deionized water relative to the volume of the strongly basic anion exchange resin is passed through the solution when the Brix value of the solution is preferably 1.0% by mass. This enables effective removal of anionic impurities.

[0196] Finally, in y4), the pH of solution D is adjusted to obtain solution E. At this stage, it is preferable to adjust the pH to a specific range (preferably 2.5 to 3.5) in order to ensure appropriate storage conditions for 5-aminolevulinic acid or its salt. This final adjustment ensures product stability and maintains consistency in product quality.

[0197] [Seventh Embodiment] 33. A method for producing 5-aminolevulinic acid or a salt thereof, comprising the steps of [1]' to [3]' described below, in the case of [1] above. Before steps [2] to [5], a step similar to (step 6) in the second embodiment described above may be performed.

[0198] As described above, the following configurations are disclosed in this specification. 1. 5-aminolevulinic acid or a salt thereof that satisfies at least one of the following conditions (A1) and (A2), based on the peak area obtained by HPLC analysis. (A1) The ratio of the content of each impurity to the content of the 5-aminolevulinic acid or its salt represented by the following formula (1) is 0.0007 or less. (A2) The total ratio of the content of each impurity to the content of the 5-aminolevulinic acid or its salt represented by the following formula (2) is 0.0016 or less. Ratio of the content of each impurity to the content of 5-aminolevulinic acid or its salt = Peak area of each impurity quantifiable by HPLC / Peak area of 5-aminolevulinic acid or its salt... Formula (1) Total ratio of the content of each impurity to the content of 5-aminolevulinic acid or its salt = Σ(Peak area of each impurity amount quantifiable by HPLC / Peak area of 5-aminolevulinic acid or its salt)... Formula (2) 2. 5-Aminolevulinic acid or its salt satisfying the following (B1) and (B2). (B1) The light transmittance at a wavelength of 430 nm is 98.8% or more. (B2) The light transmittance at a wavelength of 430 nm measured by a severe stability test under the following conditions is 92.0% or more. Conditions of the severe stability test: After storing the 5-aminolevulinic acid or its salt at a temperature of 70°C ± 2°C for 2 days, measure the light transmittance at a wavelength of 430 nm with a spectrophotometer. 3. The 5-aminolevulinic acid or its salt according to 1 or 2 above, wherein the content of the residual organic solvent contained in the 5-aminolevulinic acid or its salt is 1000 ppm or less. 4. The 5-aminolevulinic acid or its salt according to any one of 1 to 3 above, wherein the content of arsenic contained in the 5-aminolevulinic acid or its salt is less than 0.3 ppm. 5. The 5-aminolevulinic acid or its salt according to any one of 1 to 4 above, wherein the 5-aminolevulinic acid or its salt is 5-aminolevulinic acid phosphate. 6. A method for producing 5-aminolevulinic acid or its salt, comprising the following steps [1] to [3]. [1] A step of preparing a solution containing 5-aminolevulinic acid or its salt, and preparing a crystallization stock solution having a concentration of 200 to 700 g / L in terms of 5-aminolevulinic acid monophosphate by adding water to the solution or concentrating the solution. [2] Step of adjusting the temperature of the crystallization stock solution obtained in [1] to 5 - 25°C. [3] Step of adding a first organic solvent to the crystallization stock solution obtained in [2] to precipitate 5 - aminolevulinic acid or its salt. 7. The method according to 6 above, wherein the 5 - aminolevulinic acid or its salt satisfies at least one of the following (A1) and (A2) based on the peak area by HPLC analysis. (A1) The ratio of the content of each impurity to the content of the 5 - aminolevulinic acid or its salt represented by the following formula (1) is 0.0007 or less. (A2) The total of the ratios of the content of each impurity to the content of the 5 - aminolevulinic acid or its salt represented by the following formula (2) is 0.0016 or less. Ratio of the content of each impurity to the content of 5 - aminolevulinic acid or its salt = Peak area of each impurity quantifiable by HPLC / Peak area of 5 - aminolevulinic acid or its salt... Formula (1) Total of the ratios of the content of each impurity to the content of 5 - aminolevulinic acid or its salt = Σ(Peak area of each impurity amount quantifiable by HPLC / Peak area of 5 - aminolevulinic acid or its salt)... Formula (2) 8. The method according to 6 above, which satisfies the following (B1) and (B2). (B1) The light transmittance at a wavelength of 430 nm is 98.8% or more. (B2) The light transmittance at a wavelength of 430 nm measured by a severe stability test under the following conditions is 92.0% or more. Conditions of the severe stability test: After storing the 5 - aminolevulinic acid or its salt at a temperature of 70°C ± 2°C for 2 days, measure the light transmittance at a wavelength of 430 nm with a spectrophotometer. 9. The method according to any one of 6 - 8 above, wherein the content of the residual organic solvent contained in the 5 - aminolevulinic acid or its salt is 1000 ppm or less. 10. The method according to any one of 6 - 9 above, wherein the content of arsenic contained in the 5 - aminolevulinic acid or its salt is less than 0.3 ppm. 11. The method according to any one of 6 to 10 above, wherein the 5-aminolevulinic acid or salt thereof is 5-aminolevulinic acid phosphate. 12. The method according to any one of 6 to 11, further comprising adding seed crystals to the crystallization stock solution in the manner described in [3] above, such that the content is 0.01 to 5.0% by mass. 13. The method according to [3] above, further comprising adding the seed crystal to the crystallization stock solution and then stirring for less than 360 minutes to mature the crystal. 14. The method according to any one of 6 to 13 above, wherein the amount of the first organic solvent added in [3] is 0.50 v / v or less relative to the volume of the crystallization stock solution. 15. The method according to any one of 12 to 14, wherein, in [3] above, a second organic solvent is added to the crystallization stock solution after the seed crystal has been added. 16. The method according to 15, wherein the rate of addition of the second organic solvent is 0.4 to 5.0 v / v / h relative to the volume of the crystallization stock solution. 17. The method according to 15 or 16, wherein the total amount of the first organic solvent and the second organic solvent added is 2 v / v or less relative to the volume of the crystallization stock solution. 18. The process includes separating and drying the precipitate obtained in [3] above to obtain a powder, The method according to any one of 6 to 17, wherein the content of residual organic solvent in the powder is 1000 ppm or less. 19. The method according to any one of 6 to 18, wherein the first organic solvent in [3] is at least one selected from methanol, ethanol, isopropanol, n-propanol, acetone, and acetonitrile. 20. The method according to any one of 15 to 19, wherein the second organic solvent in [3] is at least one selected from methanol, ethanol, isopropanol, n-propanol, acetone, and acetonitrile. 21. The method according to 19 or 20, wherein the first organic solvent in [3] is ethanol. 22. The method according to 20 or 21, wherein the second organic solvent in [3] is ethanol. A solution containing 23,5-aminolevulinic acid or its salt, glycine, alanine, and PDPA, Na + A method for producing 5-aminolevulinic acid or a salt thereof, comprising treatment with a type of strongly acidic cation exchange resin. A method for producing 5-aminolevulinic acid or a salt thereof, comprising treating a solution containing 24,5-aminolevulinic acid or a salt thereof, glycine, alanine, and PDPA with at least one of a phosphate-type and an acetate-type strongly basic anion exchange resin. 25. A method for producing 5-aminolevulinic acid or a salt thereof, comprising the following x1) to x3) in any order. x1) Treat a solution containing 5-aminolevulinic acid or its salt, glycine, alanine, and PDPA with a strongly acidic cation exchange resin. x2) Treat a solution containing 5-aminolevulinic acid or its salt, glycine, alanine, and PDPA with a weakly acidic cation exchange resin. x3) ​​Treat a solution containing 5-aminolevulinic acid or its salt, glycine, alanine, and PDPA with a strongly basic anion exchange resin. 26. A method for producing 5-aminolevulinic acid or a salt thereof, comprising the following y1) to y4) in this order. y1) Solution A, containing 5-aminolevulinic acid or its salt, glycine, alanine, and PDPA, is treated with a strongly acidic cation exchange resin to obtain solution B. y2) Treat solution B with a weakly acidic cation exchange resin to obtain solution C. y3) The solution C is treated with a strongly basic anion exchange resin to obtain solution D. y4) Adjust the pH of solution D to obtain solution E. 27. The method according to any one of 23 to 26, wherein the strongly acidic cation exchange resin is a polystyrene-based resin having a sulfonic acid group as a functional group, and its ionic type is Na+. 28. The method according to any one of 24 to 27, wherein the strongly basic anion exchange resin is a polystyrene-based resin having a dimethylethanolammonium group as a functional group, and its ionic type is at least one of the acetate type and the phosphoric acid type. 29. The method according to any one of 26 to 28, wherein, in y1), the recovery conditions for obtaining the solution B are initiated by a change in Brix and terminated by a change in pH. 30. The method according to any one of 26 to 29, wherein, in y2) above, the recovery conditions for obtaining the solution C are initiated by a change in Brix and terminated by a change in Brix. 31. The method according to any one of 26 to 30, wherein, in y3) above, the recovery conditions for obtaining the solution D are initiated by a change in Brix and terminated by a change in Brix. 32. The 5-aminolevulinic acid or salt thereof according to any one of 1 to 5 above, wherein the 5-aminolevulinic acid or salt thereof is in powder form. 33. A method for producing 5-aminolevulinic acid or a salt thereof, comprising the steps of [1]' to [3]' below when preparing a solution containing 5-aminolevulinic acid or a salt thereof as described in [1] above. [1] A step of preparing a crystallization stock solution containing 5-aminolevulinic acid or a salt thereof, and adding water to the solution or concentrating the solution to prepare a crystallization stock solution with a concentration of 200 to 900 g / L in terms of 5-aminolevulinic acid monophosphate. [2] A step of raising the temperature of the crystallization stock obtained in [1] above to 5 to 25°C. [3] A step of adding the first organic solvent to the crystallization stock solution obtained in [2] above to precipitate 5-aminolevulinic acid or a salt thereof. 34. The method according to 33, wherein the 5-aminolevulinic acid or a salt thereof satisfies at least one of the following conditions (A1) and (A2) based on the peak area obtained by HPLC analysis. (A1) The ratio of the content of each impurity to the content of 5-aminolevulinic acid or its salt, as represented by the following formula (1), is 0.0007 or less. (A2) The sum of the ratios of the content of each impurity to the content of 5-aminolevulinic acid or its salt, as represented by the following formula (2), is 0.0016 or less. Ratio of the content of individual impurities to the content of 5-aminolevulinic acid or its salt = Peak area of ​​individual impurities quantifiable by HPLC / Peak area of ​​5-aminolevulinic acid or its salt ... Equation (1) Sum of the ratios of the content of individual impurities to the content of 5-aminolevulinic acid or its salt = Σ (Peak area of ​​the amount of individual impurities quantifiable by HPLC / Peak area of ​​5-aminolevulinic acid or its salt) ... Equation (2) 35. The method according to 33 above, satisfying (B1) and (B2) below. (B1) The light transmittance at a wavelength of 430 nm is 98.8% or higher. (B2) The light transmittance at a wavelength of 430 nm, as measured by a severe stability test under the following conditions, is 92.0% or higher. Conditions for the severe stability test: After storing the 5-aminolevulinic acid or its salt at a temperature of 70°C ± 2°C for 2 days, the transmittance of light at a wavelength of 430 nm is measured using a spectrophotometer. 36. The method according to any one of 33 to 35, wherein the content of residual organic solvent in the 5-aminolevulinic acid or its salt is 1000 ppm or less. 37. The method according to any one of 33 to 36, wherein the arsenic content in the 5-aminolevulinic acid or its salt is less than 0.3 ppm. 38. The method according to 33, wherein the 5-aminolevulinic acid or salt thereof is 5-aminolevulinic acid phosphate. 39. The method according to any one of 33 to 38, further comprising adding seed crystals to the crystallization stock solution in the manner described in [3]' above, such that the content is 0.01 to 5.0% by mass. 40. The method according to 39, wherein, in [3]', the seed crystal is added to the crystallization stock solution and then stirred for less than 360 minutes to mature the crystal. 41. The method according to any one of 33 to 40, wherein, in [3]', the amount of the 1' organic solvent added is 2.0 v / v or less relative to the volume of the crystallization stock solution. 42. The method according to any one of 39 to 41, including a step of adding a second organic solvent to the crystallization stock solution after adding the seed crystal in [3]'. 43. The method according to 42, wherein the addition rate of the second organic solvent is 0.1 to 5.0 v / v / h with respect to the volume of the crystallization stock solution. 44. The method according to 42 or 43, wherein the total addition amount of the first organic solvent and the second organic solvent is 3.0 v / v or less with respect to the volume of the crystallization stock solution. 45. Including separating and drying the precipitate obtained in [3]' to obtain a powder, The method according to any one of 33 to 44, wherein the content of the residual organic solvent in the powder is 1000 ppm or less. 46. The method according to any one of 33 to 45, wherein the first organic solvent in [3]' is at least one selected from methanol, ethanol, isopropanol, normal propanol, acetone, and acetonitrile. 47. The method according to any one of 33 to 46, wherein the second organic solvent in [3]' is at least one selected from methanol, ethanol, isopropanol, normal propanol, acetone, and acetonitrile. 48. The method according to 46 or 47, wherein the first organic solvent in [3]' is methanol or ethanol. 49. The method according to 47 or 48, wherein the second organic solvent in [3]' is methanol or ethanol.

Examples

[0199] Hereinafter, the present disclosure will be described using examples, but the present disclosure is not limited to these examples. Unless otherwise specified, % indicates mass %, and ppm indicates mass ppm.

[0200] [Procedures of various analysis methods] [Gas chromatography (GC)] Ethanol concentration measurement 〈Analysis Example 1: Measurement of ethanol concentration in 5-aminolevulinic acid phosphate powder〉 Sample solutions were prepared using ion-exchanged purified water to achieve concentrations of 0.008 g / L, 0.016 g / L, 0.040 g / L, 0.080 g / L, and 0.160 g / L of ethanol standard solutions and 5-aminolevulinic acid monophosphate 50 g / L. Analysis was performed under the following conditions, and the ethanol peak (retention time: 1.6 minutes) was detected. The ethanol was then quantified using the 5-point scale method based on the peak area values ​​of the standard.

[0201] GC analysis conditions Equipment used: GC-2014 (manufactured by Shimadzu Corporation) Hydrogen generator: HE-260 (manufactured by Shimadzu Corporation) Autosampler: AOC-20s (manufactured by Shimadzu Corporation) Separation column: DB-WAX (30m x 0.530mm x 1.0μm, Agilent) Carrier gas: Helium Carrier gas flow rate: 25.0 mL / min Sample introduction volume: 1.0 μL Column temperature: 35.0℃ Evaporation chamber temperature: 200℃ Detector temperature: 230.0℃ Detector: Flame ionization detector (FID)

[0202] (Calculation of ethanol concentration in 5-aminolevulinic acid phosphate powder) The residual ethanol content of the 5-aminolevulinic acid phosphate powder was calculated based on the calibration curve Y=AX+B obtained from the aforementioned ethanol standard solutions of 0.008 to 0.160 g / L.

[0203] The slope of the calibration curve, calculated with the ethanol standard solution concentration on the X axis and the peak area values ​​detected from each ethanol standard solution on the Y axis, was defined as A, the intercept as B, the peak area value of ethanol in the sample solution as C, the weighed value of 5-aminolevulinic acid phosphate powder as W1 (g), the volume of the 5-aminolevulinic acid hydrochloride solution as L1 (L), and the concentration of ethanol in the sample solution was calculated using the following formula (I).

[0204] Ethanol content (ppm) = (CB) / A / W1 × L1 × 1,000,000… Equation (I)

[0205] [Liquid chromatography (HPLC)] titer The procedure described below will also be referred to as "HPLC for titer analysis" below. <Analysis Example 1: Concentration Measurement of 5-Aminolevulinic Acid Phosphate> A 0.1 g / L standard solution of 5-aminolevulinic acid phosphate was prepared by dissolving 5-aminolevulinic acid hydrochloride manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. in distilled water. A sample solution was also prepared with distilled water to achieve a 5-aminolevulinic acid phosphate concentration of 0.1 g / L. Analysis was performed under the following conditions to detect the 5-aminolevulinic acid phosphate peak (retention time: 22 minutes). The amount of 5-aminolevulinic acid phosphate was quantified using the one-check method based on the peak area of ​​the standard sample. Similarly, peaks of glycine (retention time: 9 minutes) and alanine (retention time: 13 minutes), which may be present as impurities in the sample solution, were detected. The amounts of glycine and alanine were quantified using the one-check method based on the peak areas of the standard sample.

[0206] (Analytical conditions for 5-aminolevulinic acid phosphate) The analysis of 5-aminolevulinic acid phosphate, glycine, and alanine was performed using HPLC with a fluorescence detector under the following conditions. Separation column: YMC Triart-C18, 3μm, 3.0×150nm, manufactured by YMC. Mobile phase: An aqueous solution prepared by dissolving 70% by volume of potassium hydrogen phosphate (3.325 g) and sodium lauryl sulfate (1.45 g) in 3.5 L of ion-exchanged purified water, adjusting the pH to 2.5 with phosphoric acid, and then adding MeOH to the solution to a volume of 30%. Mobile phase flow rate: 0.5mL / min Reaction solution: Dissolve boric acid (54.0g), sodium hydroxide (32.4g), and Briji-35 (22%, 4.1mL) in 2.7L of ion-exchanged purified water, then add o-phthalaldehyde (0.6g) and N-acetylcysteine ​​(4.6g) to create an aqueous solution. Reaction solution flow rate: 0.2 mL / min Sample introduction volume: 5 μL Column temperature: 40℃ Detector: Fluorescence detector (excitation wavelength: 360 nm, fluorescence wavelength: 440 nm)

[0207] (Calculation of 5-aminolevulinic acid phosphate concentration) The weighing value of the 5-aminolevulinic acid hydrochloride standard (for biochemistry, standard content 98.0+%, Fujifilm Wako Pure Chemical Industries, Ltd.) was denoted as W2, the volume of the 5-aminolevulinic acid hydrochloride solution prepared with ion-exchanged purified water as the solvent as L2, the purity of the 5-aminolevulinic acid hydrochloride as P, the peak area value of the 5-aminolevulinic acid hydrochloride solution as D, and the peak area value of 5-aminolevulinic acid phosphate in the sample solution as E. The concentration of 5-aminolevulinic acid phosphate in the sample solution was calculated using the following formula (II).

[0208] Furthermore, the molecular weight of 5-aminolevulinic acid phosphate was set to 229.125 g / mol, and the molecular weight of 5-aminolevulinic acid hydrochloride was set to 167.59 g / mol, to correct for the salt form of 5-aminolevulinic acid.

[0209] The concentration of 5-aminolevulinic acid phosphate in the sample solution (g / L) = W² / L² × P × 229.125 ÷ 167.59 × (E / D) ... Equation (II) (Calculation of glycine concentration) The weighed value of glycine standard (reagent grade, specified content 99.0+%, Fujifilm Wako Pure Chemical Corporation) is W Gly The volume of the glycine solution with ion-exchanged purified water as the solvent is L Gly The peak area value of the glycine solution is D Gly The peak area value of glycine in the sample solution is E Gly The concentration of glycine in the sample solution was calculated using the following formula (XXXa).

[0210] Glycine concentration in sample solution (g / L) = W Gly / L Gly ×(E Gly / D Gly )...Formula (XXXa) (Calculation of alanine concentration) The weighed value of alanine standard (reagent grade, specification content 99.0+%, Fujifilm Wako Pure Chemical Corporation) is W Ala The volume of the alanine solution with ion-exchanged purified water as the solvent is L Ala The peak area value of the alanine solution is D Ala The peak area value of alanine in the sample solution is E Ala The concentration of alanine in the sample solution was calculated using the following formula (XXXb).

[0211] Alanine concentration in sample solution (g / L) = W Ala / L Ala ×(E Ala / D Ala )...Formula (XXXb)

[0212] [Liquid Chromatography (HPLC)] PDPA <Analysis Example 1: Measurement of PDPA content in 5-aminolevulinic acid phosphate powder> The commercially available 5-aminolevulinic acid phosphate and the sample solution were diluted with a 0.05 mol / L aqueous HCl solution to a concentration of 5-aminolevulinic acid phosphate of 1 g / L. Analysis was performed under the following conditions, and the PDPA peak (retention time: 9 minutes) was detected. The impurity content was quantified from the peak area value using the one-check curve method.

[0213] (Analytical conditions for 5-aminolevulinic acid phosphate) The analysis of 5-aminolevulinic acid phosphate was performed using HPLC with a UV-Vis absorbance detector under the following conditions. Separation column: Inertsil ODS-3V (5μm, 4.6×150mm, GL-Science) Mobile phase A: Dissolve 6.0 g of sodium 1-heptanesulfonate in 5 L of ion-exchanged purified water and adjust the pH to 2.0 with phosphoric acid (85.0%, reagent grade, Fujifilm Wako Pure Chemical Industries, Ltd.). Mobile phase B: Acetonitrile (Isocratic grade for liquid chromatography, Supelco). Mobile phase flow rate: 1.0mL / min Sample introduction volume: 20 μL Column temperature: 25℃ Detector: Ultraviolet absorption detector (SPD-40, manufactured by Shimadzu Corporation) Detection wavelength: 210nm The system was operated with the mobile phase gradient shown in Table 1X.

[0214] [Table 1X]

[0215] Limit of Quantification: Based on the PDPA peak area obtained by HPLC analysis, the limit of quantification for PDPA was determined to be 10 ppm relative to the liquid volume.

[0216] (Calculation of PDPA content in 5-aminolevulinic acid phosphate) PDPA reagent (NIPPON RIKA CO., LTD) was dissolved in 0.05 M HCl to prepare a PDPA standard solution with a PDPA concentration of 0.01 g / L.

[0217] The area value of PDPA detected in each sample solution by HPLC was defined as A1, and the area value of the PDPA standard solution with a PDPA concentration of 0.01 g / L was defined as A2. The PDPA concentration (g / L) in each sample solution was then quantified using the following formula (X1).

[0218] PDPA concentration (g / L)=A1 / A2×0.01…Equation (X1)

[0219] (Calculation of PDPA concentration relative to 5-aminolevulinic acid phosphate concentration)

[0220] The concentration of 5-aminolevulinic acid phosphate (g / L) in each sample solution quantified according to the procedure shown in Analysis Example 1 above was defined as A3, and the concentration of PDPA (g / L) in each sample solution quantified according to the procedure shown in (Analysis Conditions for 5-aminolevulinic acid phosphate) above was defined as A4. The relative concentration of PDPA to the concentration of 5-aminolevulinic acid phosphate in each sample solution was calculated using the following formula (X2).

[0221] PDPA relative concentration (ppm) = A4 / A3 × 1,000,000… Equation (X2)

[0222] [Liquid Chromatography (HPLC)] Impurities <Analysis Example 1: Measurement of impurity content in 5-aminolevulinic acid phosphate powder> The commercially available 5-aminolevulinic acid phosphate and the sample solutions were diluted with a mobile phase (0.1% trifluoroacetic acid / 15% acetonitrile) to a concentration of 5 g / L. Analysis was performed under the following conditions, and the peak of 5-aminolevulinic acid phosphate (retention time: 3 minutes) was detected. Each sample solution was diluted 100-fold and used as a standard solution. The impurity content was quantified using the one-check curve method based on the peak area value of 5-aminolevulinic acid phosphate in the standard solution.

[0223] (Analytical conditions for 5-aminolevulinic acid phosphate) The analysis of 5-aminolevulinic acid phosphate was performed using HPLC with a UV-Vis absorbance detector under the following conditions. Separation column: InertSustain C18(UP) (5μm, 4.6×250mm, GL-Science) Mobile phase: 0.1% trifluoroacetic acid / 15% acetonitrile Mobile phase flow rate: 1.0mL / min Sample introduction volume: 50 μL Column temperature: 30℃ Detector: Ultraviolet absorption detector (SPD-20A, manufactured by Shimadzu Corporation) Detection wavelength: 216nm Limit of Quantitative Analysis: Based on the peak area obtained by HPLC analysis, the ratio of the impurity content to the content of 5-aminolevulinic acid or its salt is 0.0005. Detection limit: Based on the peak area obtained by HPLC analysis, the ratio of the impurity content to the content of 5-aminolevulinic acid or its salt must be 0.0002. Peaks below the detection limit (0.0002) are not treated as impurities and are not included in the table of results for the analysis of impurity content.

[0224] (Calculation of impurity content in 5-aminolevulinic acid phosphate) The peak area of ​​5-aminolevulinic acid phosphate in the standard solution of each sample was denoted as F, and the peak area of ​​each individual impurity quantifiable by HPLC in the sample solution was denoted as G. The ratio of the content of each individual impurity quantifiable by HPLC in the sample solution was calculated using the following formula (III).

[0225] The ratio of the content of individual impurities to the content of 5-aminolevulinic acid or its salt = Peak area of ​​individual impurities quantifiable by HPLC in the sample solution / (Peak area of ​​5-aminolevulinic acid or its salt in the standard solution) = G / F ... Equation (III)

[0226] Let N be the total number of impurities detected in the sample. The sum of the ratios I of the content of each individual impurity to the content of 5-aminolevulinic acid or its salt was calculated using the following formula (IV). In formula (IV), H is the ratio of the content of each individual impurity to the content of 5-aminolevulinic acid or its salt.

[0227]

number

[0228] [Analysis of the content of 5-aminolevulinic acid or its salts by potentiometric titration] 0.3 g of potassium bituminate, dried at 105°C for 4 hours, was weighed into a 100 mL glass beaker. Then, 50 mL of acetic acid was added along with a stirrer bar, and the mixture was stirred to dissolve the potassium bituminate. The mixture containing only 50 mL of acetic acid with the stirrer bar added was used as the Factor Blank.

[0229] 0.22 g of 5-aminolevulinic acid phosphate powder was weighed into a 100 mL glass beaker. 5 mL of formic acid was added along with a stirrer bar, and the mixture was stirred to dissolve the 5-aminolevulinic acid phosphate powder. 50 mL of acetic acid was then added, and the mixture was stirred again. The solution containing only 5 mL of formic acid with 50 mL of acetic acid was designated as the "Blank" solution.

[0230] Potentiometric titration was performed on FactorBlank, potassium bitalate, Blank, and 5-aminolevulinic acid phosphate powder samples using an automatic potentiometric titrator (AT-710, Kyoto Electronics Manufacturing Co., Ltd.) and a main control unit (MCU-710, Kyoto Electronics Manufacturing Co., Ltd.).

[0231] The titrant was a 0.1 M perchloric acid-acetic acid solution, and the sample was stirred during titration. The FactorBlank titration volume was D FactorBlank The titration volume of potassium bitalate is D Factor The weighed value of potassium bitarate is W Factor The molar mass of potassium bithalate was set to 204.23 g / mol, the titrator to 0.1 mol / L, and the concentration of the perchloric acid acetic acid solution to 0.1 mol / L. The factor value f was calculated using the following formula (V).

[0232] f = 1000 × W Factor / {204.23×0.1×(D Factor -D FactorBlank )}...Formula (V)

[0233] The titration volume of the blank is D Blank The titration volume of 5-aminolevulinic acid phosphate powder is D Sample F represents the Factor value, and W represents the weighing value of 5-aminolevulinic acid phosphate powder. Sample The molar mass of 5-aminolevulinic acid phosphate powder was set to 229.1 g / mol, the titration solution to 0.1 mol / L of perchloric acid acetic acid solution to 0.1 mol / L, and the content of 5-aminolevulinic acid phosphate in the 5-aminolevulinic acid phosphate powder was calculated using the following formula (VI).

[0234] 5-aminolevulinic acid phosphate content (%) = {(D Sample -D Blank ) × 229.1 × 0.1 × f × 100} / {W Sample ×1000}...Equation (VI)

[0235] [Light transmittance at a wavelength of 430nm] Procedure for measuring color 1 g of 5-aminolevulinic acid phosphate was accurately weighed, and a sample solution was prepared with ion-exchange purified water to a concentration of 100 g / L (C=10). The solution was then filtered using a syringe filter (Merck Millipore, MillEX-LH, PTFE membrane, pore diameter: 0.45 μm). The filtered sample was injected into a quartz cell, and the absorbance at a wavelength of 430 nm was measured using a double-beam spectrophotometer (HITACHI, U-3900H). Ion-exchange purified water was used as the reference for the spectrophotometer.

[0236] (Concentration calculation from weighed values ​​of 5-aminolevulinic acid phosphate powder) The weighed value of 5-aminolevulinic acid phosphate powder was set to W3 (approximately 1 g), the volume of the 5-aminolevulinic acid hydrochloride solution was L3, and the concentration of 5-aminolevulinic acid phosphate, C (g / L), was calculated using the following formula (i).

[0237] C = W3 / L3 × 1000 ... Equation (i)

[0238] (Calculation of light absorbance at a wavelength of 430 nm from 5-aminolevulinic acid phosphate powder) The concentration of 5-aminolevulinic acid phosphate is C, the absorbance is Abs, and the absorbance of Blank (ion-exchanged purified water) is Abs. Blank The concentration of 5-aminolevulinic acid phosphate in the sample solution was calculated using the following formula (ii).

[0239] Abs 100g / L =Abs / C × 100…Equation (ii)

[0240] (Calculation of light transmittance at a wavelength of 430 nm from the absorbance of 5-aminolevulinic acid phosphate powder) The concentration of 5-aminolevulinic acid phosphate is C, the absorbance is Abs, and the absorbance of Blank (ion-exchanged purified water) is Abs. Blank The concentration of 5-aminolevulinic acid phosphate in the sample solution was calculated using the following formula (iii).

[0241]

number

[0242] [Inductively coupled plasma mass spectrometry (ICP-MS)] Arsenic <Analysis Example 1: Measurement of Residual Metal Concentration in 5-Aminolevulinic Acid Phosphate Solution> The concentrations of each metal element in 5-aminolevulinic acid phosphate solution were quantified using the intensity of each metal element in the solution and a calibration curve created from metal element standard solutions. Residual metal concentration analysis was performed three times on each sample (n=3), and the concentration of each metal element in each sample was quantified, with the average value calculated.

[0243] ICP-MS analysis conditions Equipment used: Agilent 7900 (manufactured by Agilent Technologies) Autosampler: G8410A (manufactured by Agilent Technologies) Limit of Quantitative Analysis: Based on the concentration of 5-aminolevulinic acid phosphate determined by HPLC analysis, the content of each residual metal is 0.25 ppm.

[0244] Description of standard materials General-purpose mixed standard solution (XSTC-13B) (manufactured by SpexCetiprep) Contains 10 mg / L of arsenic (As).

[0245] (Calculation of residual metal concentration in 5-aminolevulinic acid phosphate solution) The residual metal concentrations in the 5-aminolevulinic acid phosphate solution were calculated from a calibration curve obtained from metal standard solutions and from the ICP-MS intensities of each metal element detected in the 5-aminolevulinic acid phosphate solution.

[0246] In this disclosure, ICP-MS intensity refers to counts per second (counts per second).

[0247] Preparation of diluent To prepare the diluent, 66 mL of nitric acid and 10 mL of hydrochloric acid were added to 500 mL of ion-exchanged purified water, and then 1000 mL of ion-exchanged purified water was added.

[0248] Preparation of metal standard solutions (Calibration curve solutions such as Ag / Al / As) Calibration solution 1 (BLANK): Diluent only (As concentration 0 μg / mL) Calibration solution 2: 0.5 mL of general-purpose mixed standard solution was measured, and 9.5 mL of diluent was added to make a total volume of 10 mL. (As concentration 500 μg / L) Calibration solution 3: 0.25 mL of general-purpose mixed standard solution was measured, and 9.75 mL of diluent was added to make a total volume of 10 mL. (As concentration 250 μg / L) Calibration solution 4: 0.1 mL of general-purpose mixed standard solution was measured, and 9.9 mL of diluent was added to make a total volume of 10 mL. (As concentration 100 μg / L) Calibration solution 5: 1.0 mL of calibration solution 4 was measured and 9.0 mL of diluent was added to make a total volume of 10 mL. (As concentration 10 μg / L) Calibration solution 6: 0.5 mL of calibration solution 4 was measured and 9.5 mL of diluent was added to make a total volume of 10 mL. (As concentration 5 μg / L)

[0249] Preparation of sample solution 3.0 mL of 5-aminolevulinic acid phosphate solution was taken, and 0.21 mL of nitric acid and 5.79 mL of diluent were added to prepare a 9 mL sample solution.

[0250] Calibration curve solutions with metal concentrations of 0, 5.0, 10, 100.0, 250.0, and 500.0 μg / L were measured by ICP-MS to create the calibration curve Y = AX + B.

[0251] The sample solution was measured using ICP-MS, and the intensity Ix1 (arb.unit) of each metal in the sample solution was used as Yx1 on the calibration curve. The measured concentration Xx1 (ppb) of each metal element was then calculated. The concentration Inx1 of each metal element in the blank was similarly measured, and the concentration of each metal element in the blank (noise intensity, ppb) was calculated from the intensity. The calculated concentrations of each metal element for n=3 samples were averaged.

[0252] The concentrations of each metal element were calculated using the following formula (X). In formula (X), f is the concentration of each element (1 μg / mL) when the general-purpose mixed standard solution is diluted 10 times.

[0253] 1. Metal element concentration Cmet x 1 (ng / mL) = [Measured concentration X x 1 (ppb) × f - Concentration in sample blank In x 1 (ppb)] × [Amount of sample solution prepared for ICP-MS (9mL) / Original sample volume (3mL)] ... Equation (X)

[0254] The concentrations (ppm) of each metal element relative to the phosphate concentration of 5-aminolevulinic acid in the sample were calculated using the single-element concentration Cmetx1 (ng / mL) calculated according to equation (X2), and the phosphate concentration of 5-aminolevulinic acid in the 5-aminolevulinic acid phosphate solution Calv (g / L).

[0255] 1 Metal element concentration Cmet1 (ng / mL) / Calv (g / L)...Formula (X2)

[0256] [Test Example 1: Production of a powder with a high content of 5-aminolevulinic acid phosphate] [Preparation Example 1] Preparation Example 1 is an example. [1] Preparation of crystallization stock solution (Step 0) Using the method described in Japanese Patent Publication No. 2005-333907, recombinant Corynebacterium glutamicum was used to ferment and produce 5-aminolevulinic acid. Subsequently, sulfuric acid was added to adjust the pH to 2.88, inactivating the 5-aminolevulinic acid-producing bacteria, and 60.0 L of culture solution containing 45.4 g / L of 5-aminolevulinic acid was obtained.

[0257] Cross-flow filter (0.1 μm filter, film area 0.35 m²) 2 Using a PALL-made device, inactivated bacterial cells (biomass) were separated from the culture medium, and 150.1 L of a solution (referred to as Solution A) containing 17.3 g / L of 5-aminolevulinic acid was obtained.

[0258] As Preparation Example 1, the prepared solution A was subjected to ion exchange chromatography in the following first, second, and third steps.

[0259] (Step 1) In the first step, Na +Using 24.935 L of UBK-04 [DIAION (trademark), manufactured by Mitsubishi Chemical Corporation], a type of strongly acidic cation exchange resin, solution A was passed through and adsorbed onto UBK04 under conditions of 25°C or below and SV 0.682 RV / h. Subsequently, UBK04 was washed with 37.4 L of ion-exchanged purified water.

[0260] A 0.5±0.1 mol / L solution of NaOH was passed through UBK04 to elute the adsorbed components. While measuring the Brix and pH at the UBK04 outlet during elution, the solution passed through UBK04 (referred to as solution B) was passed through the WK40L column in the second step when the Brix reached 5.0±1.0%. Subsequently, the flow to the WK40L column was terminated when the pH at the UBK04 outlet reached 12.0.

[0261] (Step 2) Next, H + Using WK40L [DIAION (trademark), manufactured by Mitsubishi Chemical Corporation], a weakly acidic cation exchange resin of type 1, 3.74 L of solution B was passed through the WK40 under the condition of SV 4.545 RV / h.

[0262] While measuring the Brix at the outlet of the WK40 resin column, the liquid passing through the WK40 resin column was collected when the Brix reached 2.0%. When solution B was depleted, water was added using ion-exchanged purified water, and when the Brix returned to 1.0% and the total volume of liquid passed through the column reached 16.3 L, the liquid passing through the WK40 resin column was collected and designated as solution C.

[0263] (Step 3) Furthermore, using 5.44 L of the acetic acid-type strongly basic anion exchange resin PA412 [DIAION (trademark), manufactured by Mitsubishi Chemical Corporation], the above solution C, adjusted to 12±3°C, was passed through a PA412 resin column under the condition of SV 1.042 RV / h. While measuring the Brix at the outlet of the PA412 resin column, the recovery of the PA412 pass-through liquid was started when the Brix reached 0.2 mass%.

[0264] When solution C was depleted, water was pumped in ion-exchanged purified water until the Brix level returned to 1.0% and the cumulative volume of liquid passed through the column reached 6.6 L. At this point, 59.0 L of the PA412-passed liquid was collected in a container that had been cooled to 13°C and stirred, and this solution was designated as solution D. During collection, solution D was cooled to 13.0°C.

[0265] (Step 4) Solution D was heated to below 25°C while phosphoric acid (H3PO4, 75% by mass) was added to adjust the pH to 2.5-3.0, and 5-aminolevulinic acid was converted to 5-aminolevulinic acid phosphate (this was designated as solution E). Solution D after pH adjustment was concentrated at below 40°C, and 3.48 L of concentrated solution containing 627.7 g / L of 5-aminolevulinic acid was recovered and used as the concentrated solution (crystallization stock).

[0266] The crystallization stock solution was introduced into the crystallization tank, and its temperature was adjusted to 17°C. Primary methanol (MeOH) at a rate of 0.8 v / v / h relative to the volume of the crystallization stock solution was added to the crystallization tank, and the crystallization stock solution and primary MeOH were mixed by stirring. While maintaining the solution temperature at 17°C, 0.33 g of seed crystals were added, and the mixture was aged for 2 hours with stirring. As seed crystals, 5-aminolevulinic acid phosphate powder having the spectral pattern obtained by powder X-ray diffraction in Example 1 of Japanese Patent Publication No. 4989153 (Patent Document 4) was used.

[0267] At the point when concentration was complete, 2.4 v / v of MeOH was added to the volume of the crystallization stock solution at a rate of 0.8 v / v / h, and the crystallization stock solution and secondary MeOH were mixed by stirring. While maintaining the solution temperature at 17 ± 3°C, stirring was continued for 2 hours after the completion of secondary MeOH addition to obtain a slurry of 5-aminolevulinic acid phosphate crystals.

[0268] The crystalline slurry was centrifuged to separate the 5-aminolevulinic acid crystals, and then the wet crystals were washed at room temperature with 100% MeOH at a concentration of 1.0 v / w relative to the weight of the wet crystals, yielding 1952.5 g of wet crystals.

[0269] [Comparative Example 1-1] <Comparative study of Example 1 in Patent Publication No. 4989153 (Patent Document 4)> 4.67 g (27.92 mmol, 100.14% content, Hamari Pharmaceutical Co., Ltd.) of 5-aminolevulinic acid hydrochloride and 3.576 g (31.33 mmol) of 85% by mass phosphoric acid were dissolved in 14 g of distilled water, and 2.970 g (29.35 mmol) of triethylamine was added dropwise while stirring at 0-5°C.

[0270] After the dropwise addition was complete, the mixture was stirred at room temperature for 30 minutes, and then 14.75 g of ethanol was added. At this stage, 1.01 mg of 5-aminolevulinic acid phosphate crystals (obtained in Example 3 below) was added, and gentle stirring was continued. Colorless, transparent crystals slowly began to precipitate.

[0271] After stirring for approximately 30 minutes, 59.07 g of ethanol was added, and stirring was continued for 2 hours to completely precipitate the crystals. The crystals were collected by suction filtration (using three sheets of ADVANTEC filter paper, 5C, φ55 mm) and dried under reduced pressure at room temperature for 16 hours. 5.015 g of 5-aminolevulinic acid phosphate powder was obtained.

[0272] [Comparative Example 1-2] <Comparative study of Example 2 in Japanese Patent Publication No. 2007-238577> 40 g of 5-aminolevulinic acid hydrochloride (239 mmol, 100.14% content, Hamari Pharmaceutical Co., Ltd.) and 18 mL of 85% phosphoric acid (263 mmol) were dissolved in 120 mL of purified water, and 25.4 g of triethylamine (251 mmol) was added dropwise while stirring under an ice bath.

[0273] After the dropwise addition was complete, the mixture was stirred at room temperature for 10 minutes, and then 1.6 L of ethanol was added and stirred. The precipitated sediment was collected by suction filtration (using 5C, φ55 mm, ADVANTEC* 3 sheets of filter paper) and dried under reduced pressure at room temperature for 16 hours. 50.62 g (224 mmol) of 5-aminolevulinic acid phosphate powder was obtained.

[0274] [Comparative Examples 1-3] <Comparative study of Example 1 in Patent Publication No. 5845203 (Patent Document 5)> A 20 mL column was packed with strongly acidic cation exchange resin (UBK08, manufactured by Nippon Rensui Co., Ltd.). The cation exchange resin was used after being converted from sodium ion type to hydrogen ion type by passing 1N hydrochloric acid (4RV) through it. The flow rate was 0.0115 L / h and the SV was 0.568 RV / h.

[0275] After passing 4 g of 5-aminolevulinic acid hydrochloride (content 100.14%, Hamari Pharmaceutical Co., Ltd.) dissolved in 200 mL of ion-exchanged purified water through the column, ion-exchanged purified water (2RV) was passed through. Next, 0.5 N aqueous ammonia (8RV) was slowly passed through, and 92 mL of eluate was obtained while cooling in a 6°C constant temperature bath.

[0276] The system in which 13.8 mL of 15% phosphoric acid aqueous solution was added to the beaker used to collect the eluate will be referred to as Comparative Example 1-3a. The system in which 12.8 mL of 15% phosphoric acid aqueous solution was added will be referred to as Comparative Example 1-3b. The 15% phosphoric acid aqueous solution was stirred with a magnetic stirrer and allowed to stand while the eluate was collected.

[0277] After passing activated carbon (SG280P, 0.0035 g, 0.07% relative to 5-aminolevulinic acid phosphate) through the solution, it was concentrated to a volume of 9 mL (Comparative Example 1-3a) or 8 mL (Comparative Example 1-3b) using an evaporator.

[0278] The concentrate was cooled in a 6°C constant temperature bath while 16 mL of ethanol was added, and after vigorously stirring with a stirrer, it was left to stand overnight at 4°C. The precipitated solid was collected by suction filtration using Omnipore® Membrane Filters (0.45 μm JH, Millipore) and washed with 100 mL of ethanol.

[0279] The obtained solid was dried under reduced pressure at room temperature for 24 hours to obtain 5.6179 g (Comparative Example 1-3a) or 6.6169 g (Comparative Example 1-3b) of 5-aminolevulinic acid phosphate powder.

[0280] <Analysis of residual ethanol in powder obtained through comparative study> Table 1A shows the results of measuring the residual ethanol in the powders obtained in Comparative Examples 1-1 to 1-3.

[0281] [Table 1A]

[0282] As shown in Table 1A, residual ethanol exceeding 1000 ppm was detected in all samples.

[0283] <Impurity analysis of powder obtained in the comparative example> The impurity content in the powders obtained in Comparative Examples 1-1 to 1-3 was determined by HPLC analysis based on the above formula (III). The results are shown in Table 1B.

[0284] In Table 1B, the values ​​represent the ratio of the content of each individual impurity to the content of 5-aminolevulinic acid phosphate. In Table 1B, RT stands for Retention time, and ND stands for Not Detected.

[0285] [Table 1B]

[0286] As shown in Table 1B, in all samples, one or more impurities were detected in which the ratio of the individual impurities to the content of 5-aminolevulinic acid or its salt exceeded 0.0005. Furthermore, in some samples, the sum of the ratios of the individual impurities to the content of 5-aminolevulinic acid or its salt exceeded 0.0015.

[0287] <Impurity analysis of the powder used as raw material in the comparative example> The impurity content in the 5-aminolevulinic acid phosphate powder used as raw material for Comparative Examples 1-1 to 1-3 was determined by HPLC analysis based on the above formula (III). The results are shown in Table 1C.

[0288] In Table 1C, the values ​​represent the ratio of the content of each individual impurity to the content of 5-aminolevulinic acid phosphate. In Table 1C, RT stands for Retention time, and ND stands for Not Detected.

[0289] [Table 1C]

[0290] As shown in Table 1C, the number of impurities detected in the 5-aminolevulinic acid phosphate powder used as raw material for Comparative Examples 1-1 to 1-3, and the sum of the ratios of the content of each impurity to the content of 5-aminolevulinic acid or its salt (0.0064), were significantly lower compared to Comparative Examples 1-1 to 1-3.

[0291] Most of the impurities detected in the powders of Comparative Examples 1-1 to 1-3 are presumed to have been introduced from chemicals added during the manufacturing process of 5-aminolevulinic acid crystals, or to have been generated by the denaturation of 5-aminolevulinic acid due to thermal load such as the reduced-pressure heating and concentration process. Therefore, the manufacturing method of this disclosure is useful because it removes as many impurities as possible from powders containing 5-aminolevulinic acid or its salts.

[0292] [Example 1-1] <Investigation of the amounts of the first organic solvent and the second organic solvent to be added> [1] Preparation of crystallization stock solution 5-aminolevulinic acid phosphate powder obtained under the same conditions as in Preparation Example 1 above was dissolved in ion-exchanged purified water to prepare 15.0 L of a 333 g / L 5-aminolevulinic acid phosphate solution.

[0293] The concentration of the 5-aminolevulinic acid phosphate solution was measured using HPLC for titer analysis. + Using 6.0 L of the molded chelate resin Lewatit® TP260 (manufactured by LANXESS), a 5-aminolevulinic acid phosphate solution was passed through the TP260, and the liquid that passed through the resin column was collected when the Brix reached 1.0% by mass.

[0294] Subsequently, when the 5-aminolevulinic acid phosphate solution was depleted, water was pumped in deproteinized ion-exchanged purified water, and the collection of the phosphate passing through the resin column was terminated when the Brix value returned to 1.0% by mass. Molecules with a molecular weight of 6,000 or more, such as proteins, that may be present in the collected phosphate passing through the resin column were removed by ultrafiltration.

[0295] The ultrafiltration permeate was introduced into a round-bottom flask, and the flask containing the ultrafiltration permeate was heated in a constant temperature bath maintained at 60°C while being concentrated for 10 hours using an evaporator with an internal pressure of 65 hPa. The concentration of 5-aminolevulinic acid phosphate after concentration was 500 g / L, and this solution will be referred to as the crystallization stock solution below.

[0296] [2] A step to adjust the temperature of the crystallization stock solution obtained in [1]. The crystallization stock solution was introduced into the crystallization tank, and the temperature of the crystallization stock solution was controlled to 20°C.

[0297] [3] The first organic solvent is added to the crystallization stock solution obtained in [2] to precipitate 5-aminolevulinic acid or a salt thereof. In the crystallization process, ethanol (EtOH), the poor solvent for 5-aminolevulinic acid phosphate, was divided into primary (first organic solvent) and secondary (second organic solvent) components and added to the crystallization stock solution. The total amount of primary and secondary ethanol (EtOH) added was set to 2.0 v / v relative to the volume of the crystallization stock solution. Primary EtOH was added to the crystallization tank at amounts of 0.4, 0.6, 0.8, and 1.0 v / v relative to the volume of the crystallization stock solution, and the crystallization stock solution and primary EtOH were mixed by stirring.

[0298] At the point of concentration completion (before addition of primary EtOH), 0.07% by mass of 5-aminolevulinic acid phosphate powder (seed crystal) was added to the mixture of the crystallization stock solution and primary EtOH, and the mixture was stirred and aged for 10 minutes while maintaining the temperature of the crystallization stock solution at 20°C.

[0299] [4] Step of adding the second organic solvent to the crystallization stock solution. At the completion of concentration, (2.0 - primary EtOH addition amount)v / v of secondary EtOH was added to the volume of the crystallization stock solution at a rate of 0.5v / v / h, and the mixture and secondary EtOH were mixed by stirring. Stirring was continued for 2 hours after the completion of secondary EtOH addition, and 5-aminolevulinic acid phosphate was crystallized from the mixture. This solution will be referred to as the crystallization slurry below.

[0300] [5] Steps to separate the crystals After separating the wet crystals and mother liquor of 5-aminolevulinic acid phosphate from the crystallization slurry by centrifugation, EtOH was added to the wet crystals of 5-aminolevulinic acid phosphate in the centrifuge to wash them, and the wet crystals of 5-aminolevulinic acid phosphate were collected in a round-bottom flask.

[0301] Wet crystals of 5-aminolevulinic acid phosphate were placed in a box-type dryer (AVO-310V, AS ONE). The wet crystals of 5-aminolevulinic acid phosphate were dried under vacuum conditions, with the internal temperature of the box-type dryer set to 30°C and the pressure gauge attached to the dryer reading below -0.1 MPa. The residual solvent content in the 5-aminolevulinic acid phosphate powder was analyzed by gas chromatography (GC). The results are shown in Table 1 and Figure 1.

[0302] [Table 1]

[0303] As shown in Table 1 and Figure 1, under conditions where the primary EtOH addition amount was 0.4 v / v, the residual EtOH in the 5-aminolevulinic acid phosphate powder was less than 1000 ppm.

[0304] [Examples 1-2] <Investigation of crystallization temperature> A crystallization stock solution of 5-aminolevulinic acid phosphate was prepared using the same procedure as in [Example 1-1] up to concentration. 5-aminolevulinic acid phosphate powder was then prepared using solution temperatures (crystallization temperatures) of 5, 10, 15, 25, or 30°C, and the residual solvent value in the 5-aminolevulinic acid phosphate powder was analyzed by gas chromatography.

[0305] Furthermore, since the seed crystal dissolves at crystallization temperatures of 25°C and 30°C, the primary EtOH addition amount was changed to 0.4 v / v at 5-20°C, 0.5 v / v at 25°C, and 0.7 v / v at 30°C. The results are shown in Table 2 and Figure 2.

[0306] [Table 2]

[0307] As shown in Table 2 and Figure 2, crystallization under conditions of a crystallization temperature of 15-25°C resulted in a residual EtOH content of less than 1000 ppm in the 5-aminolevulinic acid phosphate powder.

[0308] [Examples 1-3] <Investigation of secondary EtOH addition rate> A crystallization stock solution of 5-aminolevulinic acid phosphate was prepared using the same procedure as in [Example 1-1] up to concentration. 5-aminolevulinic acid phosphate powder was then prepared using secondary EtOH addition rates of 0.1, 0.3, 0.5, 0.7, and 1.0 v / v / h during crystallization, and the residual solvent value in the 5-aminolevulinic acid phosphate powder was analyzed by gas chromatography. The results are shown in Table 3 and Figure 3.

[0309] [Table 3]

[0310] As shown in Table 3 and Figure 3, crystallization under conditions where the secondary EtOH addition rate was 0.5 v / v / h or higher resulted in a residual EtOH content of less than 1000 ppm in the 5-aminolevulinic acid phosphate powder.

[0311] [Examples 1-4] <Investigation of crystallization temperature when the concentration of the crystallization stock solution is 600 g / L 1> A crystallization stock solution of 5-aminolevulinic acid phosphate was prepared using the same procedure as in [Example 1-1] up to concentration. The concentration of the crystallization stock solution was increased from 500 g / L to 600 g / L, and the crystallization temperature was set to 10, 20, or 30°C to prepare 5-aminolevulinic acid phosphate powder. The residual solvent value in the 5-aminolevulinic acid phosphate powder was analyzed by gas chromatography.

[0312] When the crystallization stock solution concentration is 600 g / L, and the crystallization temperature is 30°C, the seed crystal does not dissolve with a primary EtOH addition rate of 0.3 v / v. Therefore, the primary EtOH addition rate was set to 0.3 v / v at 10°C and 20°C as well. The results are shown in Table 4.

[0313] [Table 4]

[0314] As shown in Table 4, the residual EtOH in the 5-aminolevulinic acid phosphate powder was less than 1000 ppm when the crystallization temperature was 10°C and 20°C.

[0315] [Examples 1-5] <Investigation of crystallization temperature when the concentration of the crystallization stock solution is 600 g / L 2> A crystallization stock solution of 5-aminolevulinic acid phosphate was prepared using the same procedure as in [Example 1-1] up to concentration. The crystallization stock solution concentration was set to 600 g / L, and the crystallization temperatures were set to 5°C and 25°C to prepare 5-aminolevulinic acid phosphate powder. The residual solvent value in the 5-aminolevulinic acid phosphate powder was analyzed by gas chromatography.

[0316] At 25°C, it was confirmed that the seed crystal did not dissolve under conditions of a primary EtOH addition rate of 0.1 v / v or higher, and the primary EtOH addition rate was also set to 0.1 v / v at 5°C. The results are shown in Table 5.

[0317] [Table 5]

[0318] As shown in Table 5, under both conditions where crystallization was performed at crystallization temperatures of 5°C and 25°C, the residual EtOH in the 5-aminolevulinic acid phosphate powder was less than 1000 ppm.

[0319] [Examples 1-6] <Investigation of crystallization temperature when the concentration of the crystallization stock solution is 650 g / L> A crystallization stock solution of 5-aminolevulinic acid phosphate was prepared using the same procedure as in [Example 1-1] up to concentration. The crystallization stock solution concentration was set to 650 g / L, and the crystallization temperatures were set to 5°C and 25°C to prepare 5-aminolevulinic acid phosphate powder. The residual solvent value in the 5-aminolevulinic acid phosphate powder was analyzed by gas chromatography. The results are shown in Table 6.

[0320] [Table 6]

[0321] As shown in Table 6, under conditions where crystallization was performed at a crystallization temperature of 5°C, the residual EtOH in the 5-aminolevulinic acid phosphate powder was less than 1000 ppm.

[0322] [Examples 1-7] <Investigation of seed crystal addition amount> A crystallization stock solution of 5-aminolevulinic acid phosphate was prepared using the same procedure as in [Example 1-1] up to concentration. Seed crystals were added at 0, 0.07, 0.21, or 0.5% by mass during crystallization to prepare 5-aminolevulinic acid phosphate powder, and the residual solvent value in the 5-aminolevulinic acid phosphate powder was analyzed by gas chromatography. The results are shown in Table 7.

[0323] [Table 7]

[0324] As shown in Table 7, even without the addition of seed crystals, the residual EtOH in the 5-aminolevulinic acid phosphate powder was less than 1000 ppm.

[0325] [Example 2-1] <Study on the concentration of the crystallization stock solution after decolorization with activated carbon, when the concentration of the crystallization stock solution is 535, 560, or 585 g / L> [1] Preparation of crystallization stock solution 5-aminolevulinic acid phosphate powder was prepared using the same method as in Preparation Example 1. The 5-aminolevulinic acid phosphate powder was dissolved in ion-exchanged purified water to prepare two sets of 9.985 L each of 5-aminolevulinic acid phosphate solution with a concentration of approximately 380 g / L. The concentration of the 5-aminolevulinic acid phosphate solution was measured by titer analysis using HPLC.

[0326] Two sets of 137g activated carbon (Taiko S) were added, and the solution was decolorized for 3 hours while maintaining a temperature of 15°C. Afterward, the activated carbon was removed from the 5-aminolevulinic acid phosphate solution, and the decolorized filtrate was collected and mixed to form one set. + A 9.0 L container of Lewatit® TP260 chelate resin (manufactured by LANXESS) was used. While measuring the Brix at the outlet of the resin column, the decolorized filtrate was passed through the TP260, and the filtrate was collected from the point when the Brix reached 1.0 mass%.

[0327] Subsequently, when the 5-aminolevulinic acid phosphate solution was depleted, water was added using ion-exchanged purified water, and the collection of the phosphate through the resin column was terminated when the Brix returned to 1.0% by mass. Molecules with a molecular weight of 6,000 or more, such as proteins, that may be present in the collected phosphate through the resin column were removed using an ultrafiltration membrane, and the ultrafiltration phosphate was obtained.

[0328] The ultrafiltration phosphate was introduced into a round-bottom flask, and the flask containing the ultrafiltration phosphate was heated in a constant temperature bath maintained at 65°C while being concentrated for 18 hours using an evaporator with an internal pressure of 70 hPa. Through concentration, 5-aminolevulinic acid phosphate concentrations of 535 g / L were adjusted to 330 mL, 560 g / L to 316 mL, or 585 g / L to 302 mL, respectively. This solution will be referred to as the crystallization stock solution below.

[0329] [2] A step to adjust the temperature of the crystallization stock solution obtained in [1]. The crystallization stock solution was introduced into the crystallization tank, and the temperature of the crystallization stock solution was controlled to 15°C.

[0330] [3] The first organic solvent is added to the crystallization stock solution obtained in [2] to precipitate 5-aminolevulinic acid or a salt thereof. Primary EtOH was added to the crystallization tank at a ratio of 0.3 v / v relative to the volume of the crystallization stock solution, and the crystallization stock solution and primary EtOH were mixed by stirring. 0.125 g of 5-aminolevulinic acid phosphate crystalline powder was added to the crystallization stock solution as a seed crystal, and the crystallization stock solution was aged for 10 minutes while stirring, with the temperature of the crystallization stock solution maintained at 15°C.

[0331] [4] Step of adding the second organic solvent to the crystallization stock solution. At the point of concentration completion (before primary EtOH addition), 1.7 v / v of EtOH was added to the volume of the crystallization stock solution at a rate of 0.7 v / v / h, and the crystallization stock solution and secondary EtOH were mixed by stirring. Stirring was continued for 2 hours after the completion of secondary EtOH addition, and 5-aminolevulinic acid phosphate was crystallized from the mixture to obtain a crystalline slurry.

[0332] [5] Steps to separate the crystals After separating the wet crystals of 5-aminolevulinic acid phosphate from the crystalline slurry by centrifugation, 100% EtOH at a concentration of 1.0 v / w relative to the weight of the wet crystals was added to the wet crystals of 5-aminolevulinic acid phosphate in the centrifugation to wash them, and the wet crystals of 5-aminolevulinic acid phosphate were collected in a round-bottom flask.

[0333] A round-bottom flask containing wet crystals of 5-aminolevulinic acid phosphate was heated in a constant temperature bath maintained at 30°C, while the wet crystals were dried at room temperature for 5 hours using an evaporator with an internal pressure of 53 hPa. The residual solvent content in the 5-aminolevulinic acid phosphate powder was analyzed by gas chromatography. The results are shown in Table 8.

[0334] [Table 8]

[0335] As shown in Table 8, when crystallization was performed with a crystallization stock solution concentration of 535-585 g / L (calculated as 5-aminolevulinic acid monophosphate), the residual EtOH in the 5-aminolevulinic acid phosphate powder was less than 1000 ppm.

[0336] The impurity content in the 5-aminolevulinic acid phosphate powder prepared in Example 2-1 was determined by HPLC analysis based on the above formula (III). The results are shown in Table 9.

[0337] In Table 9, the values ​​represent the "ratio of the content of individual impurities to the content of 5-aminolevulinic acid phosphate." In Table 9, RT stands for Retention time, and ND stands for Not Detected.

[0338] [Table 9]

[0339] As shown in Table 9, at all crystallization stock solution concentrations, the ratio of the content of individual impurities to the content of 5-aminolevulinic acid phosphate in the 5-aminolevulinic acid phosphate powder was 0.0005 or less, and the sum of the ratios of the content of individual impurities to the content of 5-aminolevulinic acid phosphate was 0.0015 or less. On the other hand, impurities with a ratio exceeding 0.0005 to the content of 5-aminolevulinic acid phosphate were detected in commercially available products.

[0340] [Example 2-2] <Investigation of crystallization temperature when the concentration of the crystallization stock solution after decolorization with activated carbon is 535 or 585 g / L> Before concentration and after centrifugation, a crystallization stock solution of 5-aminolevulinic acid phosphate was prepared using the same procedure as in [Example 2-1]. 5-aminolevulinic acid phosphate powder was then prepared at crystallization temperatures of 5, 15, or 25°C, and the residual solvent content in the 5-aminolevulinic acid phosphate powder was analyzed by gas chromatography. The results are shown in Table 10.

[0341] [Table 10]

[0342] As shown in Table 10, under all conditions, the residual EtOH value in the 5-aminolevulinic acid phosphate powder was less than 1000 ppm.

[0343] The impurity content in the 5-aminolevulinic acid phosphate powder prepared in Example 2-2 was determined by HPLC analysis based on the above formula (III). The results are shown in Table 11.

[0344] In Table 11, the values ​​represent the "ratio of the content of individual impurities to the content of 5-aminolevulinic acid phosphate." In Table 11, RT stands for Retention time, and ND stands for Not Detected.

[0345] [Table 11]

[0346] As shown in Table 11, under conditions where the crystallization temperature was 15°C or higher, at both crystallization stock solution concentrations of 535 and 585 g / L (calculated as 5-aminolevulinic acid monophosphate), no impurities exceeding a ratio of 0.0005 to the content of 5-aminolevulinic acid phosphate were detected in the 5-aminolevulinic acid phosphate powder, and the sum of the ratios of the content of individual impurities to the content of 5-aminolevulinic acid phosphate was 0.0015 or less.

[0347] When the crystallization temperature was 5°C, at a concentration of 535 g / L in terms of 5-aminolevulinic acid monophosphate, the ratio of the content of individual impurities to the content of 5-aminolevulinic acid phosphate in the 5-aminolevulinic acid phosphate powder was 0.0005 or less, and the sum of the ratios of the content of individual impurities to the content of 5-aminolevulinic acid was 0.0015 or less. On the other hand, impurities with a ratio exceeding 0.0005 to the content of 5-aminolevulinic acid phosphate were detected in commercially available products.

[0348] [Examples 2-3] <Study on the rate of secondary EtOH addition when the concentration of the crystallization stock solution after decolorization with activated carbon is set to 560 g / L> Before concentration and after centrifugation, a crystallization stock solution of 5-aminolevulinic acid phosphate was prepared using the same procedure as in [Example 2-1]. 5-aminolevulinic acid phosphate powder was prepared by adding secondary EtOH at rates of 0.4, 0.7, and 1.0 v / v / h during crystallization, and the residual solvent value in the 5-aminolevulinic acid phosphate powder was analyzed by gas chromatography. The results are shown in Table 12.

[0349] [Table 12]

[0350] As shown in Table 12, under all conditions, the residual EtOH value in the 5-aminolevulinic acid phosphate powder was less than 1000 ppm.

[0351] [Examples 2-4] <Investigation of crystallization concentration when the concentration of the crystallization stock solution after decolorization with activated carbon is set to 520 g / L or 560 g / L> Before concentration and after centrifugation, a crystallization stock solution of 5-aminolevulinic acid phosphate was prepared using the same procedure as in [Example 2-1]. The crystallization stock solution was then crystallized at a concentration of 520 g / L or 600 g / L in terms of 5-aminolevulinic acid monophosphate to produce 5-aminolevulinic acid phosphate powder, and the residual solvent value in the 5-aminolevulinic acid phosphate powder was analyzed by gas chromatography. The results are shown in Table 13.

[0352] [Table 13]

[0353] As shown in Table 13, under all conditions, the residual EtOH value in the 5-aminolevulinic acid phosphate powder was less than 1000 ppm.

[0354] The impurity content in the 5-aminolevulinic acid phosphate powder prepared in Examples 2-4 was determined by HPLC analysis based on formula (III) above. The results are shown in Table 14.

[0355] In Table 14, the values ​​represent the "ratio of the content of individual impurities to the content of 5-aminolevulinic acid phosphate." In Table 14, RT stands for Retention time, and ND stands for Not Detected.

[0356] [Table 14]

[0357] As shown in Table 14, at all crystallization stock solution concentrations, the ratio of the content of individual impurities to the content of 5-aminolevulinic acid phosphate in the 5-aminolevulinic acid phosphate powder was 0.0005 or less, and the sum of the ratios of the content of individual impurities to the content of 5-aminolevulinic acid was 0.0015 or less. On the other hand, impurities with a ratio exceeding 0.0005 to the content of 5-aminolevulinic acid phosphate were detected in commercially available products.

[0358] [Examples 2-5] <Investigation of the amount of primary EtOH to add when the concentration of the crystallization stock solution after decolorization with activated carbon is 560 g / L> Before concentration and after centrifugation, a crystallization stock solution of 5-aminolevulinic acid phosphate was prepared using the same procedure as in [Example 2-1]. The amount of primary EtOH added was increased from 0.3 v / v to 0.35 v / v to prepare 5-aminolevulinic acid phosphate powder, and the residual solvent value in the 5-aminolevulinic acid phosphate powder was analyzed by gas chromatography. The results are shown in Table 15.

[0359] [Table 15]

[0360] As shown in Table 15, under all conditions, the residual EtOH value in the 5-aminolevulinic acid phosphate powder was less than 1000 ppm.

[0361] [Examples 2-6] <Investigation of maturation time after seed crystal addition when the concentration of the crystallization stock solution after decolorization with activated carbon is 560 g / L> Before concentration and after centrifugation, a crystallization stock solution of 5-aminolevulinic acid phosphate was prepared using the same procedure as in [Example 2-1]. 5-aminolevulinic acid phosphate powder was then prepared by adjusting the maturation time from seed crystal addition to 10, 120, 180, 240, or 360 minutes, and the residual solvent value in the 5-aminolevulinic acid phosphate powder was analyzed by gas chromatography. The results are shown in Table 16 and Figure 4.

[0362] [Table 16]

[0363] As shown in Table 16 and Figure 4, the residual EtOH value in the 5-aminolevulinic acid phosphate powder increased with increasing maturation time from seed crystal addition. When the maturation time was 240 minutes or less, the residual EtOH value in the 5-aminolevulinic acid phosphate powder was less than 1000 ppm.

[0364] [Impurity analysis in Company A's Product 2 and Company B's Product 2] [Example Test 1-1] The impurity content in Company A's Product 2 and Company B's Product 2 was determined by HPLC analysis based on the above formula (III). The results are shown in Table 17.

[0365] In Table 17, the values ​​represent the "ratio of the content of individual impurities to the content of 5-aminolevulinic acid phosphate." In Table 17, RT stands for Retention time, and ND stands for Not Detected.

[0366] [Table 17]

[0367] As shown in Table 17, impurities were detected in all marketed products where the ratio of the individual impurity content to the 5-aminolevulinic acid phosphate content exceeded 0.0005.

[0368] [Example 3] [1] Preparation of crystallization stock solution 5-aminolevulinic acid phosphate powder was prepared using the same method as in Preparation Example 1. The 5-aminolevulinic acid phosphate powder was dissolved in ion-exchanged purified water to prepare 2220 mL of a 5-aminolevulinic acid phosphate solution with a concentration of 441.3 g / L (equivalent to 5-aminolevulinic acid monophosphate). The concentration of the 5-aminolevulinic acid phosphate solution was measured by titer analysis using HPLC.

[0369] 10g of activated carbon (Taiko S) was added, and the solution was decolorized for 30 minutes while maintaining a temperature of 15°C. The activated carbon was then removed from the 5-aminolevulinic acid phosphate solution, and the decolorized filtrate was collected. + 1.0 L of the molded chelate resin Lewatit® TP260 (manufactured by LANXESS) was used. Under conditions of room temperature and SV 4.5 RV / h, the decolorized filtrate was passed through TP260 while measuring the Brix at the outlet of the resin column, and the liquid that passed through TP260 was collected when the Brix reached 1.0 mass%.

[0370] When the decolorized filtrate was depleted, water was added using ion-exchanged purified water, and the collection of the filtrate through the resin column was terminated when the Brix returned to 1.0% by mass. Molecules with a molecular weight of 6,000 or more, such as proteins, that may be present in the collected filtrate through the resin column were removed using an ultrafiltration membrane, and the filtrate obtained from the ultrafiltration was obtained.

[0371] The ultrafiltration phosphate was introduced into a round-bottom flask, and the flask containing the ultrafiltration phosphate was heated in a constant temperature bath maintained at 60°C while being concentrated for 21.6 hours using an evaporator with an internal pressure of 65 hPa. A 1500 mL solution containing 560 g / L of 5-aminolevulinic acid phosphate (856.8 g of 5-aminolevulinic acid phosphate) was prepared through concentration, and this solution was divided into four 375 mL portions (each containing 563.2 g / L of 5-aminolevulinic acid phosphate). These solutions will be referred to as crystallization stock solutions 1 to 4 below.

[0372] [2] A step to adjust the temperature of the crystallization stock solution obtained in [1]. Four crystallization stocks (1-4) were introduced into the crystallization tank, and the temperature of the crystallization stocks was controlled to 15°C.

[0373] [3] The first organic solvent is added to the crystallization stock solution obtained in [2] to precipitate 5-aminolevulinic acid or a salt thereof. Primary EtOH at a rate of 0.3 v / v relative to the volume of the crystallization stock solution was added to the crystallization tank at a rate of 0.7 v / h, and the crystallization stock solution and primary EtOH were mixed by stirring. 0.1252 g (0.06 mass%) of 5-aminolevulinic acid phosphate powder was added to the crystallization stock solution as a seed crystal, and the crystallization stock solution was heated to 15°C and matured for 10 minutes with stirring. As the seed crystal, 5-aminolevulinic acid phosphate powder having the powder X-ray diffraction spectral pattern obtained in Example 1 of Japanese Patent Publication No. 4989153 (Patent Document 4) was used.

[0374] [4] Step of adding the second organic solvent to the crystallization stock solution. At the point of concentration completion (before primary EtOH addition), 1.7 v / v of EtOH was added to the volume of the crystallization stock solution at a rate of 0.7 v / v / h, and the crystallization stock solution and secondary EtOH were mixed by stirring. Stirring was continued for 2 hours after the completion of secondary EtOH addition, and 5-aminolevulinic acid phosphate was crystallized from the mixture to obtain a crystalline slurry.

[0375] [5] Steps to separate the crystals The crystalline slurry was centrifuged to separate the 5-aminolevulinic acid crystals into solid and liquid phases. The wet crystals were then washed at room temperature with 100% EtOH at a concentration of 1.0 v / w relative to the weight of the wet crystals to obtain the wet crystals.

[0376] [6] Steps to separate the crystals The obtained wet crystals were divided into individual round-bottom flasks and dried at room temperature for 5 hours in an evaporator with an internal pressure of 53 hPa while being heated in a constant temperature bath controlled at 30°C. All four divided crystals were condensed to obtain 658.02 g of 5-aminolevulinic acid phosphate powder, and the residual solvent content in the powder was analyzed by gas chromatography. The results are shown in Table 2A.

[0377] [Table 2A]

[0378] As shown in Table 2A, the residual EtOH in the 5-aminolevulinic acid phosphate powder was less than 1000 ppm.

[0379] The impurity content in the 5-aminolevulinic acid phosphate powder obtained in Example 3 was determined by HPLC analysis based on the above formula (III). The results are shown in Table 2B.

[0380] The values ​​shown in Table 2B represent the "ratio of the content of individual impurities to the content of 5-aminolevulinic acid phosphate." In Table 2B, RT stands for Retention time, and ND stands for Not Detected.

[0381] [Table 2B]

[0382] As shown in Table 2B, at all crystallization stock solution concentrations, the ratio of the content of individual impurities to the content of 5-aminolevulinic acid phosphate mixed in the 5-aminolevulinic acid phosphate powder was 0.0005 or less, and the sum of the ratios of the content of individual impurities to the content of 5-aminolevulinic acid was 0.0015 or less.

[0383] On the other hand, impurities were detected in market-circulated products where the ratio of the amount of each impurity to the amount of 5-aminolevulinic acid phosphate exceeded 0.0005.

[0384] A severe stability test was performed on the 5-aminolevulinic acid phosphate powder obtained in Example 3, and the color was evaluated before and after the test. The results are shown in Table 2C.

[0385] [Table 2C]

[0386] As shown in Table 2C, all of the samples in Example 3 and the commercially available product showed a decrease in light transmittance at a wavelength of 430 nm, which is yellow in the harsh stability test. However, the light transmittance at a wavelength of 430 nm was lower for Example 3 compared to the commercially available product.

[0387] [Analysis of the content of 5-aminolevulinic acid or its salt in various examples] The content of 5-aminolevulinic acid phosphate in Example 3 and Comparative Examples 1-1 to 1-3 was measured by potentiometric titration. The results are shown in Table 3A.

[0388] [Table 3A]

[0389] As shown in Table 3A, the content of 5-aminolevulinic acid phosphate in Example 3 was 100.1%, while the content of 5-aminolevulinic acid phosphate in Comparative Examples 1-1 to 1-3 ranged from 100.4% to 120.9%.

[0390] Due to the principle of potentiometric titration, it reacts with impurities other than 5-aminolevulinic acid phosphate. In Example 3, the sum of the ratios of the individual impurities to the content of 5-aminolevulinic acid or its salt was detected at only 0.0000 by HPLC (below the detection limit). Therefore, based on the two measurements by potentiometric titration and HPLC, it can be considered that the content of 5-aminolevulinic acid phosphate is approximately 100%.

[0391] On the other hand, HPLC analysis clearly shows that the samples in Comparative Examples 1-1 to 1-3 contain a large amount of impurities. Even in Comparative Example 1-2, which had a moisture content of 100.4%, HPLC analysis revealed that it contained impurities with a total ratio of 0.0017 of the individual impurities to the content of 5-aminolevulinic acid or its salt. Therefore, the 100.4% content should be considered as a result of some impurities being detected in addition to 5-aminolevulinic acid.

[0392] Furthermore, potentiometric titration cannot detect impurities whose content ratio is less than 0.02 compared to individual impurities detectable by HPLC (ultraviolet absorption spectroscopy). To more accurately indicate purity, it is necessary to refer to HPLC in addition to potentiometric titration, and impurities with a content ratio of 0.0005 or higher were confirmed in all lots of the commercially available product.

[0393] Based on the above, Example 3, which showed a content of nearly 100% through two measurements using potentiometric titration and HPLC, can be said to be superior to both the commercially available product and the competitor's patented product in terms of 5-aminolevulinic acid phosphate content.

[0394] Table 3B shows the PDPA content at each step of Example 3. The culture medium contained 39.2 g of PDPA, but the amount of PDPA was reduced to 0.021 g by the time the crystals obtained by crystallization (first crystallization) were dried into a dry powder. The largest amounts of PDPA were removed in steps (1-1) and (1-2) of UBK04, demonstrating that PDPA can be removed from the 5-aminolevulinic acid phosphate fermentation solution by using a strongly acidic cation exchange resin.

[0395] [Table 3B]

[0396] [6] Table 3C and Figure 5 show the results of powder X-ray diffraction measurements using the 5-aminolevulinic acid phosphate powder obtained in the crystal separation process. In the table, "2θ" represents the diffraction angle (2θ°), and "relative intensity" represents the relative intensity ratio (I / I0). A relative intensity ratio of 5 or greater is indicated. It was confirmed that the 5-aminolevulinic acid phosphate powder was a crystalline powder.

[0397] [Table 3C]

[0398] Table 3D shows the results of measuring the residual metal concentration in Product 1 from Company C and in Example 3, both commercially available 5-aminolevulinic acid phosphate powders, using ICP-MS. The unit is parts per million (ppm) relative to the 5-aminolevulinic acid phosphate concentration. LOQ in Table 3D stands for Limit of Quantification.

[0399] [Table 3D]

[0400] As shown in Table 3D, the As content of Company C's Product 1, a commercially available 5-aminolevulinic acid phosphate powder, was 0.3 ppm, while the As content of the 5-aminolevulinic acid phosphate powder prepared using the procedure shown in Example 3 was 0.25 ppm or less.

[0401] [Preparation Example 2: Preparation of 5-aminolevulinic acid culture medium] Following the method described in Japanese Patent Publication No. 2005-333907, recombinant Corynebacterium glutamicum was used to ferment and produce 5-aminolevulinic acid, and then sulfuric acid was added to adjust the pH to 3.0 ± 0.2. Subsequently, the culture solution was maintained at 20 ± 10°C for more than 5 hours to inactivate the 5-aminolevulinic acid-producing bacteria, and 57.3 kL of culture solution containing 41.0 g / L of 5-aminolevulinic acid was obtained.

[0402] Inactivated bacterial cells were separated from the culture medium using a cross-flow filter (0.1 μm filter), and 71.0 kL of solution A (supernatant) containing 15.2 g / L of 5-aminolevulinic acid phosphate was obtained.

[0403] Solution A, prepared in Preparation Example 2, was used in the following [Comparative Example 2] and [Comparative Example 3]. [Comparative Example 2: Production of 5-aminolevulinic acid phosphate powder obtained using only strongly acidic cation exchange resin]

[0404] Na + 0.108 L of UBK04 [DIAION (trademark), manufactured by Mitsubishi Chemical Corporation], a type 100% strongly acidic cation exchange resin, was packed into a column. 0.6633 L of solution A (5-aminolevulinic acid concentration after dispensing: 15.1 g / L) was passed through and adsorbed onto UBK04 at near room temperature and SV 0.682 RV / h. Subsequently, UBK04 was washed with 0.162 L of ion-exchanged purified water.

[0405] Next, 0.5 ± 0.1 mol / L of NaOH was passed through UBK04 to eluate the adsorbed components. While measuring the Brix and pH at the UBK04 outlet during elution, the UBK04 eluate (solution B) was collected from the point when the Brix reached 5.0 ± 1.0 mass% until the pH reached 12.0. During collection, solution D was cooled to 13.0°C.

[0406] The UBK04 eluate was heated to 25°C and phosphoric acid (H3PO4, 75%) was added to adjust the pH to 2.74, converting 5-aminolevulinic acid to 5-aminolevulinic acid phosphate. The pH-adjusted solution was concentrated at 40°C, and 0.018 L of concentrated solution containing 364.4 g / L of 5-aminolevulinic acid (in terms of 5-aminolevulinic acid monophosphate) was recovered.

[0407] 0.084 g (1.2 mass%) of activated carbon (SW-50, Taiko) was added to the concentrated solution, and decolorization was performed for 180 min while controlling the solution temperature to a target of 15.0°C. The concentrated solution was removed by suction filtration using 0.084 g of a filtration aid (BC200, Arbocel) to remove the activated carbon. The 5-aminolevulinic acid phosphate remaining in the suction filtration bottle was recovered with ion-exchanged purified water to obtain 0.529 L of decolorized filtrate (solution G).

[0408] The decolorized filtrate was concentrated at a temperature below 40°C, and 0.0147 L of concentrated solution containing 389.9 g / L of 5-aminolevulinic acid (5-aminolevulinic acid monophosphate equivalent) was recovered and used as the crystallization stock solution.

[0409] Primary EtOH (99.5% purity) at a rate of 0.3 v / v relative to the volume of the crystallization stock solution was added to the crystallization tank at a rate of 0.8124 v / v / h, and the crystallization stock solution and primary EtOH were mixed by stirring. 0.00503 g (0.07 mass%) of 5-aminolevulinic acid phosphate crystalline powder was added to the crystallization stock solution as a seed crystal, and the crystallization stock solution was aged for 10 minutes while stirring, with the temperature of the crystallization stock solution maintained at 15°C.

[0410] At the point of concentration completion (before primary EtOH addition), 1.7 v / v of EtOH was added to the volume of the crystallization stock solution at a rate of 0.8124 v / v / h, and the crystallization stock solution and secondary EtOH (99.5% purity) were mixed by stirring. Stirring was continued for 19 hours after the completion of secondary EtOH addition, and 5-aminolevulinic acid phosphate was crystallized from the mixture to obtain a crystalline slurry.

[0411] 11.44 g of 5-aminolevulinic acid phosphate wet crystals were recovered by suction filtration (using four sheets of 5C, ADVANTEC filter paper), and 11.44 mL of EtOH (99.5% purity) was poured in all at once and stirred for about 1 minute to wash the 5-aminolevulinic acid phosphate wet crystals.

[0412] The wet crystals of 5-aminolevulinic acid phosphate were dried under reduced pressure for 5 hours in an evaporator with an internal pressure of 53 hPa, and 10.14 g of 5-aminolevulinic acid phosphate powder was recovered. Table 3E shows the content of 5-aminolevulinic acid (phosphate equivalent), Gly, Ala, and PDPA in the process solution and the dried powder from crystallization (first crystallization) in Comparative Example 2. ALVP, Gly, and Ala contained in the eluate (solution B) were quantified by titer analysis HPLC. The PDPA content was quantified by PDPA content analysis HPLC.

[0413] [Table 3E]

[0414] As shown in Table 3E, both Gly and Ala were removed by the time of the UBK04 eluate. Regarding PDPA, similar to Table 3B, the PDPA contained in solution A was removed by the time of the UBK04 eluate (solution B). In other words, Gly, Ala, and PDPA contained in the 5-aminolevulinic acid culture solution can be removed using a strongly acidic cation exchange resin.

[0415] [Comparative Example 3: Production of 5-aminolevulinic acid phosphate powder obtained using only a strongly acidic cation exchange resin and a strongly basic anion exchange resin]

[0416] Na +Using 0.108 L of UBK04 [DIAION (trademark), manufactured by Mitsubishi Chemical Corporation], a type of strongly acidic cation exchange resin, 0.6897 L of solution A (the 5-aminolevulinic acid concentration after dispensing was 14.5 g / L in terms of 5-aminolevulinic acid monophosphate) was passed through and adsorbed onto UBK04 under conditions of 25°C or below and SV 0.682 RV / h.

[0417] A 0.5±0.1 mol / L solution of NaOH was passed through UBK04 to eluate the adsorbed components. While measuring the Brix and pH at the UBK04 outlet during elution, the UBK04 eluate (eluate B) was collected from the point when the Brix reached 5.0±1.0 mass% until the pH reached 12.0.

[0418] UBK04 liquid passed through CH3COO ― Using 0.024 L of the type 1 strong basic anion exchange resin PA412 [DIAION (trademark), manufactured by Mitsubishi Chemical Corporation], the UBK04 perfusion solution, adjusted to 12±3°C, was passed through the PA412 resin column under the condition of SV 1.042 RV / h. While measuring the Brix at the outlet of the PA412 resin column, the PA412 perfusion solution (solution D) was collected when the Brix reached 0.2 mass%. During collection, solution D was cooled to 13.0°C.

[0419] When the UBK04 perfusion solution (Solution B) was depleted, the system was purged with ion-exchanged purified water until the Brix level reached 0.0 mass%, and the PA412 perfusion solution (Solution D) was recovered.

[0420] While maintaining a temperature below 25°C, phosphoric acid (H3PO4, 75%) was added to adjust the pH to 2.65, converting 5-aminolevulinic acid to 5-aminolevulinic acid phosphate. The pH-adjusted solution was concentrated at a temperature below 40°C, and a concentrated solution of 0.0106 L (equivalent to 384 g / L of 5-aminolevulinic acid monophosphate) was recovered.

[0421] 0.0489 g of activated carbon (SW-50, Taiko) was added to the concentrated solution, and decolorization was performed for 180 min while maintaining a temperature of 15.0°C. The concentrated solution was then filtered by suction using 0.0489 g of a filtration aid (BC200, Arbocel) to remove the activated carbon. The 5-aminolevulinic acid phosphate remaining in the suction filter bottle was recovered with ion-exchanged purified water to obtain 0.560 L of decolorized filtrate (solution G).

[0422] The decolorized filtrate was concentrated at a temperature of 40°C or below to 0.0073 L so that the 5-aminolevulinic acid phosphate concentration reached 500 g / L, and this was used as the crystallization stock solution.

[0423] Primary EtOH at a rate of 0.7 v / v / h relative to the volume of the stock solution was added to the crystallization tank, and the crystallization stock solution and primary EtOH were mixed by stirring. 0.00258 g (0.07 mass%) of 5-aminolevulinic acid phosphate crystalline powder was added to the crystallization stock solution as a seed crystal, and the crystallization stock solution was aged for 10 minutes while stirring, with the temperature of the crystallization stock solution maintained at 15°C.

[0424] At the point of concentration completion (before primary EtOH addition), 1.7 v / v of EtOH was added to the volume of the crystallization stock solution at a rate of 0.7 v / v / h, and the crystallization stock solution and secondary EtOH were mixed by stirring. Stirring was continued for 15 hours after the completion of secondary EtOH addition, and 5-aminolevulinic acid phosphate was crystallized from the mixture to obtain a crystalline slurry.

[0425] 7.44 g of 5-aminolevulinic acid phosphate wet crystals were collected by suction filtration (using four sheets of 5C, ADVANTEC filter paper), and 7.44 mL of ethanol was poured in all at once and stirred for about 1 minute to wash the 5-aminolevulinic acid phosphate wet crystals.

[0426] Wet crystals of 5-aminolevulinic acid phosphate were dried under reduced pressure for 5 hours in an evaporator with an internal pressure of 53 hPa, and 6.89 g of 5-aminolevulinic acid phosphate powder was recovered.

[0427] The solubility of the 5-aminolevulinic acid phosphate powder obtained in Comparative Examples 2 and 3 was analyzed. The results are shown in Table 19A.

[0428] [Table 19A]

[0429] As shown in Table 19A, when impurities were removed from a 5-aminolevulinic acid solution produced by fermentation using a strongly acidic cation exchange resin, a weakly acidic cation exchange resin, and a strongly basic anion exchange resin, the transmittance of the obtained 5-aminolevulinic acid phosphate powder at a wavelength of 430 nm was 99.8%. On the other hand, the transmittance when using only a strongly acidic cation exchange resin was 0.0%, and the transmittance when using both a strongly acidic cation exchange resin and a strongly basic anion exchange resin was 6.1%.

[0430] Based on the above, it was shown that the removal of impurities using a combination of a strongly acidic cation exchange resin, a weakly acidic cation exchange resin, and a strongly basic anion exchange resin is more useful in decolorizing 5-aminolevulinic acid solutions produced by fermentation compared to using only 1-2 of the ion exchange resins.

[0431] The residual solvent values ​​in the 5-aminolevulinic acid phosphate powder obtained in Comparative Examples 2 and 3 were analyzed by gas chromatography (GC). The results are shown in Table 19B.

[0432] [Table 19B]

[0433] As shown in Table 19B, when impurities were removed from a 5-aminolevulinic acid solution produced by fermentation using a strongly acidic cation exchange resin, a weakly acidic cation exchange resin, and a strongly basic anion exchange resin, the residual EtOH in the obtained 5-aminolevulinic acid phosphate powder was 498 ppm. On the other hand, the residual EtOH when using only a strongly acidic cation exchange resin was 20108 ppm, and the residual EtOH when using both a strongly acidic cation exchange resin and a strongly basic anion exchange resin was 15649 ppm.

[0434] Based on the above, it was shown that a manufacturing method combining a strongly acidic cation exchange resin, a weakly acidic cation exchange resin, and a strongly basic anion exchange resin is useful in reducing the residual solvent concentration in 5-aminolevulinic acid phosphate powder compared to using only one or two types of ion exchange resins.

[0435] [Preparation Example 3: Preparation of 5-aminolevulinic acid culture medium] Following the method described in Japanese Patent Publication No. 2005-333907, recombinant Corynebacterium glutamicum was used to ferment and produce 5-aminolevulinic acid, and then sulfuric acid was added to adjust the pH to 3.0 ± 0.2. Subsequently, the culture broth was maintained at 20 ± 10°C for more than 5 hours to inactivate the 5-aminolevulinic acid-producing bacteria, and 2.38 L of culture solution containing 50.5 g / L of 5-aminolevulinic acid was obtained.

[0436] The culture medium prepared in Preparation Example 3 was used in [Reference Example 1-1] and [Reference Example 1-2] below.

[0437] [Reference example 1-1:H + [Amino acid removal efficiency in 5-aminolevulinic acid solution when using a type of strongly acidic cation exchange resin]

[0438] H + A 1.6L container of MARATHON C [DOWEX (trademark), manufactured by DuPont], a type of strong acid cation exchange resin, was used, and the MARATHON C was heated to 35°C. Under conditions of SV0.9RV / h, 2.38L of culture medium (5-aminolevulinic acid concentration equivalent to 50.5g / L of phosphate) was passed through and adsorbed. Subsequently, the MARATHON C was washed with ion-exchange purified water.

[0439] A 0.5 ± 0.1 mol / L solution of NaOH was passed through MARATHON C to elute the adsorbed components. While measuring the Brix and pH at the outlet of MARATHON C during elution, the MARATHON C eluate was collected from the point when Brix reached 1.0 mass% until the pH reached 12.0.

[0440] H +Using 0.3 L of WK40L [DIAION (trademark), manufactured by Mitsubishi Chemical Corporation], a weakly acidic cation exchange resin of type 4, the above solution B was passed through WK40L under the condition of SV 4.545 RV / h.

[0441] While measuring the Brix at the outlet of the WK40L resin column, the liquid passing through the WK40L resin column (solution C) was collected from the point when the Brix rose to 0.1 mass%. When the liquid passing through the MARATHON C (solution B) was depleted, water was pumped in with ion-exchanged purified water, and the liquid passing through the WK40L column (solution C) was collected until the Brix decreased to 1.0 mass%.

[0442] CH3COO ― Using 380 mL of the type 0.1 strong basic anion exchange resin PA412 [DIAION (trademark), manufactured by Mitsubishi Chemical Corporation], 2.49 L of WK 40 L resin column perfusion solution (solution C) was passed through the PA412 resin column at room temperature under conditions of SV 1.0 RV / h. While measuring the Brix at the outlet of the PA412 resin column, the PA412 perfusion solution (solution D) was collected when the Brix reached 0.2 mass%.

[0443] When the WK40L resin column filtration solution (Solution C) was depleted, the PA412 filtration solution (Solution D) was recovered by flushing with ion-exchanged purified water until the Brix reached 1.0 mass%. The pH of Solution D was 4.96.

[0444] 30.0 mL of phosphoric acid (H3PO4, 75%) was added to adjust the pH to 2.77, converting 5-aminolevulinic acid to 5-aminolevulinic acid phosphate, and a 2.63 L PA412 permeate (Solution E) containing 30.5 g / L of 5-aminolevulinic acid phosphate was obtained.

[0445] [Reference Example 1-2: Na + [Amino acid removal efficiency in 5-aminolevulinic acid solution when using a type of strongly acidic cation exchange resin]

[0446] Na +Using 1.5 L of MARATHON C [DOWEX (trademark), manufactured by DuPont], a type of strong acidic cation exchange resin, the MARATHON C was heated to 35°C. Under conditions of SV 0.9 RV / h, 2.38 L of culture medium (5-aminolevulinic acid concentration of 50.5 g / L) was passed through and adsorbed. Subsequently, the MARATHON C was washed with ion-exchange purified water.

[0447] A 0.5±0.1 mol / L solution of NaOH was passed through MARATHON C to elute the adsorbed components. While measuring the Brix and pH at the outlet of MARATHON C during elution, the MARATHON C eluate (Solution B) was collected from the point when the Brix reached 1.0±1.0 mass% until the pH reached 12.0.

[0448] The ALVP, Gly, and Ala contained in the culture medium used as raw materials for Comparative Example 3 and Reference Example 1-1, as well as in the MARATHON C eluate (Solution B), were quantified by titer analysis using HPLC.

[0449] H + Using 0.3 L of WK40L [DIAION (trademark), manufactured by Mitsubishi Chemical Corporation], a weakly acidic cation exchange resin of type 5, solution B was passed through WK40L under the condition of SV 4.5 RV / h.

[0450] While measuring the Brix at the outlet of the WK40L resin column, the liquid (solution C) passing through the WK40L resin column was collected from the point when the Brix rose to 0.1 mass%. When the liquid passing through MARATHON C was depleted, water was pumped in with ion-exchanged purified water, and the liquid (solution C) passing through the WK40L column was collected until the Brix decreased to 1.0 mass%.

[0451] CH3COO ― Using a 380 mL container of the type 0.5 strong basic anion exchange resin PA412 [DIAION (trademark), manufactured by Mitsubishi Chemical Corporation], 2.18 L of WK 40 L resin column filtration solution (solution C) was passed through the PA412 resin column under the condition of SV 1.0 RV / h. While measuring the Brix at the outlet of the PA412 resin column, the PA412 filtration solution (solution D) was collected when the Brix reached 0.2 mass%.

[0452] Once the PA412 filtration solution was depleted, the PA412 filtration solution (solution D) was recovered by flushing with ion-exchanged purified water until the Brix reached 1.0 mass%. The pH of solution D was 5.07.

[0453] 28.0 mL of phosphoric acid (H3PO4, 75%) was added to adjust the pH to 2.73, converting 5-aminolevulinic acid to 5-aminolevulinic acid phosphate, and a 2.33 L PA412 permeate (solution E) containing 31.8 g / L of 5-aminolevulinic acid phosphate was obtained.

[0454] Tables 20 and 21 are H + Type and Na + This shows the degree of Gly and Ala removal when using a type of strongly acidic cation exchange resin.

[0455] [Table 20]

[0456] [Table 21]

[0457] As shown in Table 21, the strongly acidic cation exchange resin is Na + In the case of type H, most of the Gly and Ala contained in the culture medium was removed from WK40L (solution C). On the other hand, as shown in Table 20, the strongly acidic cation exchange resin H + If it is of the type, Ala remains in WK40L (solution C), and Na + Although it did not show the same removal efficiency as other types, it was found to be effective against ALVP and Gly.

[0458] From the above, Na + It was confirmed that using a type of strongly acidic cation exchange resin allows for more efficient removal of impurities such as Gly and Ala during the fermentation process.

[0459] The solubility of the pH-adjusted PA412 perfusion solution (Solution E) obtained in Reference Examples 1-1 and 1-2 was analyzed. The results are shown in Table 22.

[0460] [Table 22]

[0461] As shown in Table 22, H + Compared to using a type of strongly acidic cation exchange resin, Na + Using a type of strongly acidic cation exchange resin, further CH3COO ― The solubility of the PA412 solution (solution E) after pH adjustment was significantly improved when passed through a strongly basic anion exchange resin of the type Na. + When using a type 1 strong acid cation exchange resin, the transmittance at a wavelength of 430 nm of the pH-adjusted PA412-passed solution (solution E) was 66.2%. In contrast, H + When a type of strong acid cation exchange resin was used, the figure was 53.3%.

[0462] Based on the above, the strongly acidic cation exchange resin is Na + By making it a type, H + This method allows for the removal of color-causing impurities from the process solution compared to the mold method. As a result, it was shown that the residual color in the subsequent strongly basic anion exchange resin pass-through solution (solution E) can be reduced.

[0463] [Preparation Example 4: Preparation of 5-aminolevulinic acid culture medium] Following the method described in Japanese Patent Publication No. 2005-333907, recombinant Corynebacterium glutamicum was used to ferment and produce 5-aminolevulinic acid, and then sulfuric acid was added to adjust the pH to 3.0 ± 0.2. Subsequently, the culture solution was maintained at 20 ± 10°C for more than 5 hours to inactivate the 5-aminolevulinic acid-producing bacteria, and 15.5 L of culture solution (Solution A) containing 31.0 g / L of 5-aminolevulinic acid in phosphate terms was obtained.

[0464] H +A 6.9L container of MARATHON C [DOWEX (trademark), manufactured by DuPont], a type of strong acid cation exchange resin, was used, and the MARATHON C was heated to 35°C. Under conditions of SV0.9RV / h, 15.5L of culture medium (5-aminolevulinic acid concentration equivalent to 31.0 g / L of phosphate) was passed through and adsorbed. Subsequently, the MARATHON C was washed with ion-exchange purified water.

[0465] 0.5 mol / L NaOH was passed through MARATHON C to eluate the adsorbed components. While measuring the Brix and pH at the outlet of MARATHON C during elution, the eluate from MARATHON C (eluate B) was collected from the point when Brix reached 2.5 mass% until the pH reached 12.7.

[0466] H + Using 1.4 L of WK40L [DIAION (trademark), manufactured by Mitsubishi Chemical Corporation], a weakly acidic cation exchange resin of type 5, solution B was passed through WK40L under the condition of SV 4.5 RV / h.

[0467] While measuring the Brix at the outlet of the WK40L resin column, the liquid passing through the WK40L resin column was collected from the point when the Brix rose to 0.1 mass%. When the liquid passing through the MARATHON C (solution B) was depleted, water was added using ion-exchanged purified water, and the liquid passing through the WK40L column (solution C) was collected until the Brix decreased to 0.8 mass%.

[0468] The WK40L column permeate (Solution C) prepared in Preparation Example 4 was used in the following [Reference Example 2-1], [Reference Example 2-2], and [Reference Example 2-3].

[0469] [Reference Example 2-1:Cl ― [Efficiency of removing residual amino acids from 5-aminolevulinic acid solution using a type of strongly basic anion exchange resin] Cl ―Using a 440 mL container of the type 0.5 strong basic anion exchange resin PA412 [DIAION (trademark), manufactured by Mitsubishi Chemical Corporation], 2.3 L of WK 40 L resin column perfusion solution (solution C) was passed through the PA412 resin column under the condition of SV 1.0 RV / h. While measuring the Brix at the outlet of the PA412 resin column, the PA412 perfusion solution (solution D) was collected when the Brix reached 0.2 mass%.

[0470] When the WK40L resin column filtration solution (Solution C) was depleted, the column was replenished with ion-exchanged purified water until the Brix reached 1.0% by mass, and 2.24 L of PA412 filtration solution (Solution D) containing 31.2 g / L of 5-aminolevulinic acid in phosphate equivalent was recovered.

[0471] 25 mL of phosphoric acid (H3PO4, 75%) was added to adjust the pH to 2.09, converting 5-aminolevulinic acid to 5-aminolevulinic acid phosphate (Solution E). Concentration was performed under reduced pressure, and 0.436 L of a concentrated solution containing 160 g / L of 5-aminolevulinic acid phosphate was recovered and used as the concentrate. During concentration, the 5-aminolevulinic acid phosphate solution was heated at 53°C for a total of 12 hours.

[0472] The concentrated solution was filtered using a membrane filter (Omnipore, Merck) with a pore size of 0.45 μm.

[0473] Reduced-pressure concentration was performed, and 0.090 L of concentrate containing an estimated 786 g / L of 5-aminolevulinic acid phosphate was recovered and used as the crystallization stock solution. During concentration, the 5-aminolevulinic acid phosphate solution was heated at 40°C for a total of 19 hours.

[0474] The crystallization stock solution was introduced into the crystallization tank, and its temperature was controlled to 17±3℃. 0.02g (0.03 mass%) of seed crystals was added, and the mixture was allowed to mature for 2 hours while stirring.

[0475] 3.0 v / v of methanol (MeOH) was added to the volume of the crystallization stock solution into the crystallization tank at a rate of 0.8 v / v / h, and the crystallization stock solution and MeOH were mixed by stirring. After aging for 2 hours while stirring, a slurry of 5-aminolevulinic acid phosphate crystals was obtained.

[0476] The crystal slurry was centrifuged to filter out 5-aminolevulinic acid crystals. The mother liquor of the slurry was called ML, and 0.3 L of it was recovered. 100% MeOH at 100 v / w% based on the weight of the wet crystals at room temperature was added to the 5-aminolevulinic acid wet crystals and stirred for about 1 minute to wash the wet crystals. Again, the crystal slurry was centrifuged to obtain 40.5 g of washed 5-aminolevulinic acid wet crystals.

[0477] The wet crystals of 5-aminolevulinic acid phosphate were recovered into an eggplant flask. While heating the eggplant flask containing the wet crystals of 5-aminolevulinic acid phosphate in a constant temperature bath adjusted to 27 ± 3°C, the wet crystals of 5-aminolevulinic acid phosphate crystals were dried for 15 ± 10 hours using an evaporator with an internal pressure of Full vaccum.

[0478] [Reference Example 2-2: Amino acid removal efficiency in a 5-aminolevulinic acid solution when using a CH3COO ― type strongly basic anion exchange resin] CH3COO ― 440 mL of the strongly basic anion exchange resin PA412 [DIAION (trademark), manufactured by Mitsubishi Chemical Corporation] of the CH3COO type was used, and 2.3 L of the WK40L resin column passing solution (Solution C) was passed through the PA412 resin column under the condition of SV 1.0 RV / h. While measuring the Brix at the outlet of the PA412 resin column, the PA412 passing solution (Solution D) was started to be recovered when the Brix reached 1.0 mass%.

[0479] When the WK40L resin column passing solution (Solution C) was depleted, water flushing was performed with ion-exchanged purified water until the Brix reached 1.0 mass%, and 2.280 L of the PA412 passing solution (Solution D) containing 31.1 g / L of 5-aminolevulinic acid in terms of phosphate was recovered.

[0480] 25.4 mL of phosphoric acid (H3PO4, 75%) was added to adjust the pH to 2.74, converting 5-aminolevulinic acid to 5-aminolevulinic acid phosphate (Solution E). Concentration was carried out at a temperature below 53°C, and 0.443 L of the concentrate containing 160 g / L of 5-aminolevulinic acid phosphate was recovered and used as the concentrate. During concentration, the 5-aminolevulinic acid phosphate solution was heated at 53°C for a total of 12 hours.

[0481] The concentrated solution was filtered using a membrane filter (Omnipore, Merck) with a pore size of 0.45 μm.

[0482] Concentration was carried out at a temperature below 40°C, and 0.091 L of concentrated solution containing 779 g / L of 5-aminolevulinic acid phosphate was recovered and used as the crystallization stock solution. During the concentration process, the 5-aminolevulinic acid phosphate solution was heated at 40°C for a total of 19 hours.

[0483] The crystallization stock solution was introduced into the crystallization tank, and its temperature was controlled to 17±3℃. 0.02g (0.03 mass%) of seed crystals was added, and the mixture was allowed to mature for 2 hours while stirring.

[0484] Methanol (MeOH) at a rate of 0.8 v / v / h relative to the volume of the crystallization stock solution was added to the crystallization tank, and the crystallization stock solution and MeOH were mixed by stirring. After maturation for 2 hours while stirring, a slurry of 5-aminolevulinic acid phosphate crystals was obtained.

[0485] The crystalline slurry was centrifuged to separate the 5-aminolevulinic acid crystals. The mother liquor of the slurry was called ML, and 0.3 L was collected. The wet crystals were washed by adding 100% MeOH at room temperature and 100 v / w% relative to the weight of the wet crystals, and stirring for about 1 minute. The crystalline slurry was centrifuged again to obtain 56.5 g of washed 5-aminolevulinic acid wet crystals.

[0486] The wet crystals of 5-aminolevulinic acid phosphate were collected in a round-bottom flask. The round-bottom flask containing the wet crystals of 5-aminolevulinic acid phosphate was heated in a constant temperature bath maintained at 27±3℃, and the wet crystals of 5-aminolevulinic acid phosphate were dried for 15±10 hours in an evaporator with full vacuum pressure.

[0487] [Reference Example 2-3: PO4] 3― [Efficiency of removing residual amino acids from 5-aminolevulinic acid solution using a type of strongly basic anion exchange resin] PO4 3― Using a 440 mL container of the type 1 strong basic anion exchange resin PA412 [DIAION (trademark), manufactured by Mitsubishi Chemical Corporation], 2.3 L of WK 40 L resin column effluent was passed through the PA412 resin column under the condition of SV 1.0 RV / h. Brix at the outlet of the PA412 resin column was measured, and the PA412 effluent was collected when Brix reached 0.2 mass%.

[0488] Once the PA412 phosphate was depleted, the mixture was flushed with ion-exchanged purified water until the Brix reached 1.0% by mass, and 2.240 L of PA412 phosphate containing 32.9 g / L of 5-aminolevulinic acid (in phosphate equivalent) was recovered.

[0489] 15.5 mL of phosphoric acid (H3PO4, 75%) was added to adjust the pH to 2.75, converting 5-aminolevulinic acid to 5-aminolevulinic acid phosphate. Concentration was carried out at a temperature below 53°C, and 0.460 L of concentrated solution containing 160 g / L of 5-aminolevulinic acid phosphate was recovered and used as the concentrate. During concentration, the 5-aminolevulinic acid phosphate solution was heated at 53°C for a total of 12 hours.

[0490] The concentrated solution was filtered using a membrane filter (Omnipore, Merck) with a pore size of 0.45 μm.

[0491] Concentration was carried out at temperatures below 40°C, and 0.095 L of concentrated solution containing an estimated 746 g / L of 5-aminolevulinic acid phosphate was recovered and used as the crystallization stock solution. During concentration, the 5-aminolevulinic acid phosphate solution was heated at 40°C for a total of 19 hours.

[0492] The crystallization stock solution was introduced into the crystallization tank, and its temperature was controlled to 17±3℃. 0.02g (0.03 mass%) of seed crystals was added, and the mixture was allowed to mature for 2 hours while stirring.

[0493] Methanol (MeOH) at a rate of 0.8 v / v / h relative to the volume of the crystallization stock solution was added to the crystallization tank, and the crystallization stock solution and MeOH were mixed by stirring. After maturation for 2 hours while stirring, a slurry of 5-aminolevulinic acid phosphate crystals was obtained.

[0494] The crystalline slurry was centrifuged to separate the 5-aminolevulinic acid crystals. The mother liquor of the slurry was called ML, and 0.3 L was collected. The wet crystals were washed by adding 100% MeOH at room temperature and 100 v / w% relative to the weight of the wet crystals, and stirring for about 1 minute. The crystalline slurry was centrifuged again to obtain 58.4 g of washed 5-aminolevulinic acid wet crystals.

[0495] The wet crystals of 5-aminolevulinic acid phosphate were collected in a round-bottom flask. The round-bottom flask containing the wet crystals of 5-aminolevulinic acid phosphate was heated in a constant temperature bath maintained at 27±3℃, and the wet crystals of 5-aminolevulinic acid phosphate were dried for 15±10 hours in an evaporator with full vacuum pressure.

[0496] The solubility of the PA412 filtration solution, whose pH was adjusted to 2.75 as obtained in Reference Examples 2-1, 2-2, and 2-3, was analyzed. The results are shown in Table 23.

[0497] [Table 23]

[0498] As shown in Table 23, the ionic form of PA412 is CH3COO ― In this case, the transmittance of the PA412-transmitted solution (solution E) at a wavelength of 430 nm was 33.5%. On the other hand, the ionic form of PA412 is Cl ―When it was so, the transmittance of the PA412 passing solution (Solution E) at a wavelength of 430 nm was 33.5%. Furthermore, when the ionic form of PA412 was PO4 3― When it was so, the transmittance of the PA412 passing solution (Solution E) at a wavelength of 430 nm was 3.9%.

[0499] From the above, by setting the ionic form of the strongly basic anion exchange resin to CH3COO ― It was shown that the color and taste remaining in the passing solution (Solution E) of the strongly basic anion exchange resin can be reduced as compared with the strongly basic anion exchange resin of Cl ― ―

[0500] The dissolution amount of 5-aminolevulinic acid phosphate in the ML obtained in Reference Examples 2-1 to Reference Examples 2-3 was measured by HPLC for titer analysis. The results are shown in Table 24.

[0501]

Table 24

[0502] As shown in Table 24, when the ionic form of PA412 was CH3COO ― the dissolution amount of 5-aminolevulinic acid phosphate in ML was 7.1 g, and when the ionic form of PA412 was PO4 ― it was 6.3 g. On the other hand, when the ionic form of PA412 was Cl ― the dissolution amount of 5-aminolevulinic acid phosphate in ML was 35.9 g.

[0503] From the above, by setting the ionic form of the strongly basic anion exchange resin to CH3COO ― or PO4 - It was shown that the dissolution of 5-aminolevulinic acid phosphate in ML can be reduced and the yield can be improved as compared with the strongly basic anion exchange resin of Cl ― ―

[0504] [Preparation Example 5: Preparation of 5-aminolevulinic acid fermentation broth] Following the method described in Japanese Patent Publication No. 2005-333907, recombinant Corynebacterium glutamicum was used to ferment and produce 5-aminolevulinic acid, and then sulfuric acid was added to adjust the pH to 3.0 ± 0.2. Subsequently, the culture broth was maintained at 20 ± 10°C for more than 5 hours to inactivate the 5-aminolevulinic acid-producing bacteria, and 39.0 L of culture solution containing 47.4 / L of 5-aminolevulinic acid was obtained.

[0505] Inactivated microbial cells were separated from the fermentation broth using a cross-flow filter (0.1 μm filter), and 16.7 L of solution A (supernatant) containing 18.7 g / L of 5-aminolevulinic acid phosphate was obtained.

[0506] Solution A, prepared in Preparation Example 4, was used in [Example 4] below. [Example 4: Preparation of 5-aminolevulinic acid phosphate crystals by a single crystallization method]

[0507] Na + Using 4.940 L of XUS40232.01 [Dowex (trademark), manufactured by DuPont], a type of strongly acidic cation exchange resin, 16.7 L of solution A was passed through and adsorbed onto the XUS40232.01 under conditions of SV 0.68 RV / h.

[0508] 0.6 mol / L NaOH was passed through XUS40232.01 to eluate the adsorbed components. While measuring the Brix and pH at the outlet of XUS40232.01 during elution, the XUS40232.01 eluate (eluate B) was collected from the point when the Brix reached 5.0 mass% or higher until the pH reached 12.0 or higher.

[0509] H + Using 0.41 L of WK40L [DIAION (trademark), manufactured by Mitsubishi Chemical Corporation], a weakly acidic cation exchange resin of type XUS40232.01, the eluate (eluate B) was passed through WK40L under conditions of SV8.23RV / h.

[0510] While measuring the Brix at the outlet of the WK40L resin column, the eluent (eluent C) was collected from the point when the Brix rose to 2.0 mass%. When eluent (eluent B) was depleted, water pumping with ion-exchanged purified water was started. From the point when the Brix decreased to below 1.0 mass% until water pumping with 1.85 L (4.5 times the resin volume) of ion-exchanged purified water was started, the eluent (eluent C) from the WK40L column was collected. The eluent (eluent C) being collected was cooled to 12.0°C.

[0511] CH3COO ― Using 1.30 L of the type 1 strong basic anion exchange resin PA412M [DIAION (trademark), manufactured by Mitsubishi Chemical Corporation], when 5.94 L of WK40L resin column eluent (eluent C) had accumulated, it was passed through the PA412M resin column under conditions of 12°C and SV0.80 RV / h. While measuring the Brix at the outlet of the PA412M resin column, the PA412 eluent (eluent D) was collected when the Brix reached 0.2 mass%.

[0512] When the WK40L resin column eluent (eluent C) was depleted, the PA412M eluent (solution D) was recovered by flushing with ion-exchanged purified water until the Brix reached 1.0% by mass. The PA412M eluent (solution D) was cooled to 12.0°C during recovery. During cooling and recovery, phosphoric acid (H3PO4, 75%) was added to solution D as needed to adjust the pH to a range of 3.00 ± 0.25.

[0513] After the entire volume of solution D was recovered, phosphoric acid (H3PO4, 75%) was added as needed to adjust the pH to 2.75 ± 0.25, converting 5-aminolevulinic acid to 5-aminolevulinic acid phosphate. A 6.63 L solution of pH-adjusted PA412M permeate (solution E) containing 37.7 g / L of 5-aminolevulinic acid phosphate was obtained. The total volume of phosphoric acid added was 90.0 mL.

[0514] After adjusting the pH at a temperature below 45°C, the PA412M filtration solution (Solution E) was concentrated, and 0.351 L of concentrated solution containing 492.7 g / L of 5-aminolevulinic acid (phosphate equivalent) was recovered and used as the primary concentrate.

[0515] 17.20 g (10% by mass) of activated carbon (SW-50, Taiko) was added to the primary concentrate, and decolorization was performed for 180 min while maintaining a temperature of 15.0°C. The concentrate was filtered by suction using 1.72 g of a filtration aid (BC200, Arbocel) to remove the activated carbon. The 5-aminolevulinic acid phosphate remaining in the suction filter bottle was recovered with ion-exchanged purified water to obtain 0.923 L of decolorized filtrate (solution G).

[0516] 0.176 L of H+ type chelate resin Lewatit® TP260 (manufactured by LANXESS) was used. The solution was passed through TP260 under conditions of SV 4.5 RV / h. While measuring the Brix at the outlet of the resin column, the decolorized filtrate was passed through TP260, and the solution that passed through the resin column (solution H) was collected when the Brix reached 1.0 mass%.

[0517] Subsequently, when the 5-aminolevulinic acid phosphate solution was depleted, water was added using ion-exchanged purified water, and the collection of the phosphate through the resin column was terminated when the Brix returned to 1.0% by mass. Molecules with a molecular weight of 6,000 or more, such as proteins, that may be present in the collected phosphate through the resin column were removed using an ultrafiltration membrane, and the ultrafiltration phosphate was obtained. The volume of the ultrafiltration phosphate was 1.462 L, and it contained 106.6 g / L of 5-aminolevulinic acid (phosphate equivalent).

[0518] Impurities in the ultrafiltration lattice were removed using a filter (0 μm pore, pore diameter: 0.2 μm).

[0519] The ultrafiltration purine was concentrated at a temperature below 40°C, and 0.255 L of concentrated solution containing 603 g / L of 5-aminolevulinic acid (phosphate equivalent) was recovered and used as the secondary concentrate.

[0520] While maintaining the temperature of the secondary concentrate at 15°C, primary EtOH (99.5% purity) at a rate of 0.7 v / v / h relative to the volume of the secondary concentrate was added to the crystallization tank, and the crystallization stock solution and primary EtOH were mixed by stirring. 0.090 g (0.059 mass%) of 5-aminolevulinic acid phosphate crystalline powder was added to the crystallization stock solution as a seed crystal, and the mixture was stirred and allowed to mature for 10 minutes.

[0521] At the point of concentration completion (before primary EtOH addition), 1.7 v / v of EtOH was added to the volume of the crystallization stock solution at a rate of 0.7 v / v / h, and the crystallization stock solution and secondary EtOH (99.5% purity) were mixed by stirring. Stirring was continued for 2 hours after the completion of secondary EtOH addition, and 5-aminolevulinic acid phosphate was crystallized from the mixture to obtain a crystalline slurry.

[0522] After separating the wet crystals of 5-aminolevulinic acid phosphate from the crystal slurry by centrifugation, 140 mL (100% by mass) of 100% EtOH was added relative to the weight of the wet crystals to wash the 5-aminolevulinic acid phosphate wet crystals. After further solid-liquid separation by centrifugation, the 5-aminolevulinic acid phosphate wet crystals were collected in a round-bottom flask.

[0523] A round-bottom flask containing wet crystals of 5-aminolevulinic acid phosphate was heated in a constant temperature bath controlled at 30°C, while attached to an evaporator with an internal pressure of 53 hPa. The flask was rotated at a very low speed of 5-10 rpm, allowing the wet crystals of 5-aminolevulinic acid phosphate to dry over time.

[0524] The residual solvent in the 5-aminolevulinic acid phosphate crystals prepared in Example 4 was analyzed by gas chromatography. The results of the residual solvent analysis are shown in Table 25.

[0525] [Table 25]

[0526] As shown in Table 25, even when 5-aminolevulinic acid phosphate was prepared using a single crystallization process, the residual ethanol in the 5-aminolevulinic acid phosphate crystals remained below 1000 ppm. Therefore, it was demonstrated that the single crystallization process does not adversely affect the residual ethanol in the 5-aminolevulinic acid phosphate crystals.

[0527] The impurity concentration in the 5-aminolevulinic acid phosphate crystals prepared in Example 4 was analyzed by HPLC. The results of the impurity analysis are shown in Table 26.

[0528] [Table 26]

[0529] As shown in Table 26, when 5-aminolevulinic acid phosphate was prepared using the single-step crystallization process, no impurity peaks exceeding the detection limit (area value 0.0002) were detected, similar to Example 3 using the two-step crystallization process. Therefore, it was demonstrated that impurities can be reduced regardless of the number of crystallization steps using the crystallization process of the present invention.

[0530] As shown in Table 26, when 5-aminolevulinic acid phosphate was prepared using a process that omitted steps 6 through 10, no impurity peaks exceeding the detection limit (area value 0.0002) were detected in the 5-aminolevulinic acid phosphate crystals, similar to the case when 5-aminolevulinic acid phosphate crystals were prepared using a process that did not omit steps 6 through 10 (Example 3). Therefore, it was shown that omitting steps 6 through 10 does not adversely affect the impurity concentration in the 5-aminolevulinic acid phosphate crystals.

[0531] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications are possible without departing from the spirit and scope of the invention. This application is based on Japanese Patent Application No. 2024-144553, filed on 26 August 2024, which is incorporated by reference in its entirety. All references incorporated herein are incorporated as a whole.

Claims

1. 5-aminolevulinic acid or a salt thereof that satisfies at least one of the following conditions (A1) and (A2), based on the peak area obtained by HPLC analysis. (A1) The ratio of the content of each impurity to the content of 5-aminolevulinic acid or its salt, as represented by the following formula (1), is 0.0007 or less. (A2) The sum of the ratios of the content of each impurity to the content of 5-aminolevulinic acid or its salt, as represented by the following formula (2), is 0.0016 or less. The ratio of the content of individual impurities to the content of 5-aminolevulinic acid or its salt = Peak area of ​​individual impurities quantifiable by HPLC / Peak area of ​​5-aminolevulinic acid or its salt ... Equation (1) The sum of the ratios of the content of individual impurities to the content of 5-aminolevulinic acid or its salt = Σ (peak area of ​​the amount of each impurity quantifiable by HPLC / peak area of ​​5-aminolevulinic acid or its salt) ... Equation (2)

2. 5-aminolevulinic acid or a salt thereof that satisfies the following conditions (B1) and (B2). (B1) The light transmittance at a wavelength of 430 nm is 98.8% or higher. (B2) The light transmittance at a wavelength of 430 nm, as measured by a severe stability test under the following conditions, is 92.0% or higher. Conditions for the severe stability test: After storing the 5-aminolevulinic acid or its salt at a temperature of 70°C ± 2°C for two days, the transmittance of light at a wavelength of 430 nm is measured using a spectrophotometer.

3. The 5-aminolevulinic acid or salt thereof according to claim 1 or 2, wherein the content of residual organic solvent in the 5-aminolevulinic acid or salt thereof is 1000 ppm or less.

4. The 5-aminolevulinic acid or salt thereof according to claim 1 or 2, wherein the arsenic content in the 5-aminolevulinic acid or salt thereof is less than 0.3 ppm.

5. The 5-aminolevulinic acid or salt thereof according to claim 1 or 2, wherein the 5-aminolevulinic acid or salt thereof is 5-aminolevulinic acid phosphate.

Images