A method for separating and purifying mevastatin from mevastatin mother liquor

Abstract

The present invention provides a method for separating and purifying mevastatin from a mevastatin mother liquor. The method primarily comprises the steps of gradient hydrolysis ring-opening and salt formation, stripping and impurity removal, extraction and purification, and condensation ring-closure. The gradient hydrolysis ring-opening step controls the generation of impurities, and this, combined with the stripping and impurity removal step, synergistically improves the yield and purity of mevastatin. The mevastatin separation and purification method provided by the present invention ultimately yields mevastatin with a purity exceeding 90% and a yield exceeding 80%.

Description

Technical Field

[0001] The invention belongs to the field of medicinal chemistry, and particularly relates to a method for separating and purifying mevastatin from mevastatin mother liquor. Background Art

[0002] Lovastatin is an inhibitor of hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase, the rate-limiting enzyme in liver cholesterol synthesis, and has a positive effect on lowering cholesterol in the body. Its standard name is (S)-2-methylbutanoyl-(1S,7S,8S,8aR)-1,2,3,7,8,8a-hexahydro-7-methyl-8-{2-[(2R,4R)-4-hydroxy-6-oxo-2H-tetrahydropyranose]-[( ...

[0003]

[0004] The structure of 1-naphthyl]-ethyl}-1-naphthyl ester is as follows:

[0005] Mevastatin is effective for treating hypercholesterolemia, treating mild, moderate, and severe hyperlipidemia, as well as familial and non-familial hyperlipidemia, but is less effective in lowering plasma triglycerides. It is a secondary metabolite of fungi and an HMG-CoA reductase inhibitor, competitively inhibiting HMG-CoA reductase and thus having a positive effect on lowering cholesterol in the body. Its derivative, pravastatin, has even stronger cholesterol-lowering properties, and is therefore used as a raw material in the production of pravastatin.

[0006] The existing method for recovering mevastatin mother liquor comprises hydrolysis, ring opening, conversion to an aqueous phase, passing the product through a D317 resin column, and then discontinuously eluting the resin column with ethanol solutions of varying concentrations. The eluate is extracted and concentrated, and then condensed and ring-closed for crystallization. The content of the product was determined by HPLC to be 75%, and the average recovery rate of the mevastatin mother liquor was 66.5%.

[0007] During the process of implementing the technical solutions described in the examples of this application, the present inventors discovered that the aforementioned technology presents at least the following technical problems: The primary step in the entire process involves a macroporous resin column, which is inherently expensive, requires complex equipment, requires strict process parameter control, results in a long production cycle, and results in high overall costs. More importantly, the high-temperature ring-opening reaction of mevastatin under alkaline conditions introduces a significant number of degradation impurities, resulting in reduced purity of the finished product. Furthermore, significant mevastatin loss occurs during the macroporous resin adsorption and desorption processes, resulting in a reduced yield of the finished product.

[0008] Therefore, it is necessary to develop a separation and purification method that can not only improve the separation and purification efficiency of mevastatin but also control the generation of impurities through the process. Summary of the Invention

[0009] In view of the above-mentioned shortcomings of the existing technology, the purpose of the present invention is to provide a method for separating and purifying mevastatin from a mevastatin mother liquor. The method can effectively reduce the impurities generated by degradation in the ring-opening reaction system through a gradient ring-opening hydrolysis reaction and a back-extraction impurity removal method, thereby achieving a short cycle and high product yield and purity.

[0010] In order to achieve the above object, the technical solution adopted by the present invention is:

[0011] A method for separating and purifying mevastatin from a mevastatin mother liquor comprises the following steps:

[0012] (1) concentrating the mevastatin mother liquor to remove the organic solvent to obtain a mevastatin concentrate;

[0013] (2) subjecting the concentrated solution obtained in step (1) to a gradient hydrolysis ring-opening reaction to convert it into a mevastatin hydrolyzate;

[0014] (3) adding a stripping solvent to the hydrolyzate obtained in step (2) at a pH of 5-7 to remove oil, thereby obtaining a clear aqueous phase solution of mevastatin;

[0015] (4) extracting the lower clear aqueous phase solution obtained in step (3) with an extraction solvent at a pH of 2-3 to obtain a mevastatin supernatant organic phase solution;

[0016] (5) subjecting the supernatant organic phase solution obtained in step (4) to a condensation ring-closure reaction to obtain a cyclized solution;

[0017] (6) Concentrating and crystallizing the cyclized solution obtained in step (5) to obtain mevastatin.

[0018] Wherein, the mevastatin content in the mevastatin concentrated mother solution in step (1) is ≥40000 mg / L, and the purity is ≥15%.

[0019] The gradient hydrolysis ring-opening reaction in step (2) is to add an alkaline aqueous solution to the concentrated solution, react at 85-95° C. for 2-5 hours, then add an organic acid to adjust the pH to 8.5-11, and react at 40-60° C. for 1-4 hours.

[0020] The alkaline aqueous solution is selected from at least one of sodium bicarbonate solution, sodium carbonate solution and sodium hydroxide solution, wherein the volume ratio of mevastatin concentrate to the alkaline aqueous solution is 1:1.5-6.

[0021] The organic acid is preferably oxalic acid or acetic acid.

[0022] The mevastatin content in the mevastatin hydrolyzate is 8000-22000 mg / L.

[0023] Wherein, the stripping solvent in step (3) is ethyl acetate or butyl acetate.

[0024] Furthermore, the mevastatin hydrolyzate obtained in step (2) is mixed with a water-insoluble stripping solvent such as ethyl acetate or butyl acetate, and the pH value is adjusted to 5 to 7 with acid while stirring. The mixture is allowed to stand for 1 to 6 hours to separate layers, thereby obtaining an aqueous phase containing 8000 to 22000 mg / L of mevastatin acid and an organic phase containing 150 to 300 mg / L of mevastatin acid.

[0025] Wherein, the extraction solvent in step (4) is toluene or isopropyl phenyl ether.

[0026] Furthermore, the lower clear aqueous phase solution of mevastatin obtained in step (3) is mixed with a water-insoluble extraction solvent such as toluene and phenylisopropyl ether, and the pH value is adjusted to 2 to 5 with an inorganic acid such as phosphoric acid or hydrochloric acid under stirring. The mixture is allowed to stand for 1 to 6 hours to separate the layers, thereby obtaining an organic phase containing 4000 to 30000 mg / L of mevastatin acid and an aqueous phase containing 100 to 250 mg / L of mevastatin acid.

[0027] The ring-closure reaction in step (5) is carried out at 90-95° C. for 8-16 hours.

[0028] Furthermore, the mevastatin supernatant organic phase solution obtained in step (4) is heated to 90-95° C. and maintained at this temperature for cyclization for 8-16 hours until the concentration ratio of mevastatin acid to mevastatin in the organic phase is less than 5%, and the cyclization is stopped.

[0029] The cyclized liquid obtained in step (5) is vacuum concentrated to 80,000-100,000 mg / L at 50-65° C., cooled to 5-15° C. for crystallization for 2-6 hours, and filtered. The filtrate is the mother liquor, and the filter cake is the recovered mevastatin powder.

[0030] Furthermore, the mevastatin mother liquor in step (1) is a crystallization mother liquor obtained by subjecting the mevastatin fermentation broth to a series of treatments and then using an organic solvent for crystallization. The mother liquor is concentrated at a temperature of 50 to 70° C. and a pressure of -0.07 to -0.1 MPa. Mevastatin and mevastatin acid are relatively stable at this temperature and will not degrade. The mevastatin content in the concentrated mother liquor is ≥40,000 mg / L and the purity is ≥15%. The higher the mevastatin content and purity in the mother liquor, the easier the subsequent processing is, and the generation of impurities is reduced.

[0031] In the above step (2), the ratio of alkali to water is (4-10) g / 100 ml, and the ratio of mevastatin ester mother liquor concentrate to alkali water is 1 ml: (1.5-6) ​​ml. The first gradient of the gradient hydrolysis ring-opening reaction is to mix the mevastatin mother liquor and alkali water, heat it to 85-95 ° C, and keep it at a constant temperature for 2-5 hours. Its purpose is to quickly open the mevastatin in the mevastatin ester mother liquor and convert it into mevastatin salt under strong alkaline and high temperature conditions; secondly, under strong alkaline and high temperature conditions, promote the hydrolysis of high molecular weight impurities, thereby converting them into mevastatin salts, thereby improving their yield. If too much alkali is added, the hydrolysis and saponification will be thorough and the purity of the hydrolyzate will be too low; if too little alkali is added, the hydrolysis will be difficult to proceed, the hydrolysis time will be long, the hydrolysis will not be thorough, and the hydrolysis ring-opening yield will be low. Therefore, it is necessary to reasonably control the amount of alkali added to take into account the purity and yield of mevastatin.

[0032] The second gradient of the gradient hydrolysis ring-opening reaction is to adjust the pH value and reduce the reaction temperature to avoid high temperature and alkaline degradation to produce more impurities. The pH of the aqueous solution of the mevastatin ester mother liquor is adjusted to 8.5-11 using an acidic material, and the temperature is controlled at 40-60°C for 1-4 hours to form a mevastatin hydrolyzate. If the pH value of the mevastatin hydrolyzate is greater than 11, a large amount of greasy base is transferred into the aqueous phase, resulting in an increase in the impurity content. If the pH value of the mevastatin hydrolyzate is less than 8, the solubility of the mevastatin salt is reduced, thereby reducing the yield. This step transfers 95% of the mevastatin in the mother liquor into alkaline water through alkaline hydrolysis phase transfer, removing a large amount of greasy alkali-insoluble impurities.

[0033] In the reaction of step (3) above, the mevastatin hydrolyzate is extracted and deoiled with ethyl acetate or butyl acetate at a pH of 5 to 7, so that the impurities in the mevastatin hydrolyzate enter the ethyl acetate or butyl acetate, while the mevastatin sodium salt remains in the aqueous phase. The impurities are then separated by standing and stratifying. The main purpose is to remove some high molecular weight impurities, which are easily soluble in ethyl acetate or butyl acetate and are oily after dissolving in ethyl acetate or butyl acetate, so it is called deoiling. After extraction, the aqueous phase contains 8000 to 22000 mg / L of mevastatin acid and the organic phase contains 50 to 300 mg / L of mevastatin acid.

[0034] In the above step (3), the volume ratio of mevastatin hydrolyzate to ethyl acetate or butyl acetate is 1:0.5-2.5.

[0035] The lower clear aqueous phase of mevastatin in step (4) is adjusted to a pH of 2 to 5 using phosphoric acid and hydrochloric acid, and then stirred and mixed with a water-insoluble extraction solvent such as toluene or phenylisopropyl ether, so that impurities in the aqueous solution of mevastatin sodium salt enter the water; the mevastatin sodium salt is converted into mevastatin acid, which enters the toluene or phenylisopropyl ether, thereby separating the mevastatin acid from the impurities. The mixture is allowed to stand for 1 to 6 hours and separated, thereby obtaining an organic phase containing 4,000 to 30,000 mg / L of mevastatin acid and an aqueous phase containing 100 to 250 mg / L of mevastatin acid.

[0036] In the above step (4), the volume ratio of the mevastatin lower aqueous phase solution to toluene or phenylisopropyl ether is 1:0.5-2.5.

[0037] In the above step (5), the mevastatin acid in the supernatant organic phase is cyclized to form mevastatin at a temperature of 90-95° C. When the content of mevastatin acid and mevastatin in the organic phase is determined by HPLC (area normalization method), if the content ratio is less than 5%, the cyclization is stopped. The cyclization time is 8-16 hours.

[0038] Mevastatin in the mevastatin mother liquor is recovered through the above steps, and the purity of the recovered mevastatin powder is ≥90%, and the yield is 80% to 90%.

[0039] The method for separating and purifying mevastatin from mevastatin mother liquor provided by the present invention is a new process with industrial production value. Compared with the existing technology, it has the following advantages and positive effects:

[0040] 1) During the implementation of the present invention, a gradient hydrolysis ring-opening reaction was creatively invented, which controlled the generation of impurities through the process, and then combined with the stripping and oil removal step to synergistically work, thereby effectively improving the yield and purity of mevastatin.

[0041] 2) The process of the present invention greatly reduces the production cycle while ensuring the yield and purity of the finished product.

[0042] 3) The method for separating and purifying mevastatin provided by the present invention can obtain mevastatin with a purity of more than 90% and a yield of more than 80%. DETAILED DESCRIPTION

[0043] Mevastatin content detection method:

[0044] The following examples all adopt the following method to detect the content of mevastatin:

[0045] The HPLC analysis method was established using a Thermo Ultimate 3000 high-performance liquid chromatograph from the United States with a UV detector; the chromatographic column was: Agilent Zorbax SB-C18 (150 mm×1.6 mm, 5 μm); the injection volume was 10 μl; the mobile phase was: acetonitrile-0.1% phosphoric acid (gradient elution); the flow rate was: 2.0 ml / min; and the column temperature was: 30°C.

[0046] Using the external standard method, the retention time of mevastatin was found to be 5.817 min.

[0047] Example 1

[0048] 3 L of mevastatin mother liquor was concentrated to a volume of 1 L at a temperature of 50° C. and a vacuum condition of -0.98 MPa. The mevastatin content was 56742 mg / L and the purity was 17.56%.

[0049] Weigh 150g of sodium carbonate and dissolve it in 3L of tap water. Add 1L of the concentrate and heat at 85°C with stirring for 5 hours to hydrolyze. Cool to 40°C, adjust the pH to 8.5 with oxalic acid, and maintain the temperature at 40°C for 4 hours to obtain 3.5L of mevastatin hydrolyzate. The mevastatin potency in the mevastatin hydrolyzate was 15430mg / L, with a theoretical yield of 95.18%.

[0050] 8.75 L of ethyl acetate was added to the mevastatin hydrolyzate, stirred, and oxalic acid was added to adjust the pH to 5. The stratification was allowed to stand for 6 hours, yielding 3.35 L of a lower aqueous phase of mevastatin solution and 9.00 L of an ethyl acetate layer. The titer of the mevastatin salt in the lower aqueous phase was 15210 mg / L, while that in the ethyl acetate layer was 245 mg / L, resulting in a stripping yield of 94.35%.

[0051] 1.7 L of toluene was added to the mevastatin lower aqueous phase solution, and the mixture was stirred. Hydrochloric acid was then added while stirring to adjust the pH to 4.5. The solution was allowed to stand for 1 hour to separate into separate layers, yielding 1.61 L of a mevastatin supernatant organic phase solution and 3.2 L of an aqueous layer. The mevastatin acid titer in the mevastatin supernatant organic phase solution was 29,790 mg / L, while that in the aqueous layer was 186 mg / L, for an extraction yield of 94.13%.

[0052] The supernatant organic phase solution of mevastatin was heated to 90°C and maintained at 90°C for 10 hours for cyclization. The concentration ratio of mevastatin acid to mevastatin was detected to be 0.04. The solution was concentrated in vacuo at 50°C to 80,000 mg / L, cooled to 5°C, crystallized for 2 hours, filtered, and the filter cake was top washed with 10 ml of toluene and dried at 60°C to obtain 52.56 g of mevastatin recovered powder with a purity of 91.76%. The total recovery rate of mevastatin in the mother liquor was 85.0%.

[0053] Example 2

[0054] 3 L of mevastatin mother liquor was concentrated to a volume of 1.2 L at a temperature of 60° C. and a vacuum condition of -0.85 MPa, with a mevastatin content of 43896 mg / L and a purity of 15.12%.

[0055] Weigh 180g of sodium bicarbonate and dissolve it in 2.7L of tap water. Add 1.2L of the concentrate and heat at 90°C with stirring for 4 hours to hydrolyze. Cool to 45°C, adjust the pH to 9.0 with oxalic acid, and maintain the temperature at 45°C for 3 hours to obtain 3.0L of mevastatin hydrolyzate. The mevastatin potency in the mevastatin hydrolyzate was 16910mg / L, with a theoretical yield of 96.31%.

[0056] 6 L of ethyl acetate was added to the mevastatin hydrolyzate, stirred, and oxalic acid was added to adjust the pH to 5.5. The stratification was allowed to stand for 5 hours, yielding 2.75 L of a lower aqueous phase of mevastatin and 6.20 L of an ethyl acetate layer. The titer of the mevastatin salt in the lower aqueous phase was 17534 mg / L, while that in the ethyl acetate layer was 271 mg / L, resulting in a stripping yield of 95.05%.

[0057] 2.75 L of toluene was added to the mevastatin lower aqueous phase solution, and the mixture was stirred. Hydrochloric acid was then added while stirring to adjust the pH to 4.0. The solution was allowed to stand for 1 hour to separate into separate layers, yielding 2.66 L of a mevastatin supernatant organic phase solution and 2.69 L of an aqueous layer. The mevastatin acid titer in the mevastatin supernatant organic phase solution was 17,368 mg / L, while that in the aqueous layer was 215 mg / L, for an extraction yield of 95.81%.

[0058] The supernatant organic phase solution of mevastatin was heated to 92°C and maintained at 92°C for 12 hours for cyclization. The concentration ratio of mevastatin acid to mevastatin was detected to be 0.04. The solution was concentrated in vacuo at 55°C to 100,000 mg / L, cooled to 10°C, crystallized for 4 hours, filtered, and the filter cake was top washed with 10 ml of toluene and dried at 60°C to obtain 49.91 g of mevastatin recovered powder with a purity of 90.98%. The total yield of mevastatin in the mother liquor was 86.2%.

[0059] Example 3

[0060] 3 L of mevastatin mother liquor was concentrated to a volume of 0.9 L at 70° C. and vacuum conditions of -0.80 MPa, with a mevastatin content of 60826 mg / L and a purity of 17.28%.

[0061] Weigh 165g of sodium hydroxide and dissolve it in 4.2L of tap water. Add 0.9L of the concentrate and heat at 95°C with stirring for 3 hours to hydrolyze. Cool to 50°C, adjust the pH to 10.0 with acetic acid, and maintain the temperature at 50°C for 2 hours to obtain 4.5L of mevastatin hydrolyzate. The mevastatin potency in the mevastatin hydrolyzate was 11665mg / L, with a theoretical yield of 95.89%.

[0062] 6.75 L of butyl acetate was added to the mevastatin hydrolyzate, stirred, and acetic acid was added to adjust the pH to 6. The mixture was allowed to stand for 4 hours to separate into separate layers, yielding 4.30 L of a lower aqueous phase of mevastatin solution and 7.00 L of a butyl acetate layer. The titer of the mevastatin salt in the lower aqueous phase was 11,733 mg / L, while that in the butyl acetate layer was 190 mg / L, resulting in a stripping yield of 96.11%.

[0063] 6.45 L of phenisopropyl ether was added to the lower aqueous phase of mevastatin solution. After stirring, phosphoric acid was added while stirring to adjust the pH to 3.0. The solution was allowed to stand for 4 hours to separate into layers, yielding 6.10 L of a supernatant organic phase solution of mevastatin and 4.5 L of an aqueous layer. The mevastatin acid titer in the supernatant organic phase was 7949 mg / L, while that in the aqueous layer was 112 mg / L, for an extraction yield of 96.11%.

[0064] The supernatant organic phase solution of mevastatin was heated to 95°C and maintained at 95°C for cyclization for 14 hours. The concentration ratio of mevastatin acid to mevastatin was detected to be 0.03. The solution was concentrated in vacuo at 60°C to 90,000 mg / L, cooled to 15°C, crystallized for 6 hours, filtered, and the filter cake was top washed with 10 ml of benzyl isopropyl ether and dried at 60°C to obtain 49.40 g of mevastatin recovered powder with a purity of 91.32%. The total yield of mevastatin in the mother liquor was 82.4%.

[0065] Example 4

[0066] 3 L of mevastatin mother liquor was concentrated to a volume of 1.3 L at a temperature of 55° C. and a vacuum condition of -0.70 MPa. The mevastatin content was 53689 mg / L and the purity was 18.01%.

[0067] Weigh 312g of sodium carbonate and dissolve it in 7.8L of tap water. Add 1.3L of the concentrate and heat at 85°C with stirring for 2 hours to hydrolyze. Cool to 55°C, adjust the pH to 11.0 with acetic acid, and maintain the temperature at 55°C for 1 hour to obtain 8.0L of mevastatin hydrolyzate. The mevastatin potency in the mevastatin hydrolyzate was 8475mg / L, with a theoretical yield of 97.14%.

[0068] 8 L of butyl acetate was added to the mevastatin hydrolyzate, stirred, and acetic acid was added to adjust the pH to 6.5. The layers were allowed to stand for 3 hours to yield 7.6 L of a lower aqueous phase of mevastatin and 8.5 L of a butyl acetate layer. The titer of the mevastatin salt in the lower aqueous phase was 8565 mg / L, while that in the ethyl acetate layer was 154 mg / L, resulting in a stripping yield of 96.01%.

[0069] 15.2 L of phenisopropyl ether was added to the mevastatin supernatant aqueous phase solution. After stirring, phosphoric acid was added while stirring to adjust the pH to 2.0. The solution was allowed to stand for 5 hours to separate into layers, yielding 15 L of a mevastatin supernatant organic phase solution and 7.9 L of an aqueous layer. The mevastatin acid titer in the mevastatin supernatant organic phase solution was 4171 mg / L, and the mevastatin acid titer in the aqueous layer was 160 mg / L, for an extraction yield of 96.12%.

[0070] The supernatant organic phase solution of mevastatin was heated to 94°C and maintained at 94°C for 16 hours for cyclization. The concentration ratio of mevastatin acid to mevastatin was detected to be 0.02. The solution was concentrated in vacuo at 65°C to 85,000 mg / L, cooled to 7°C, crystallized for 3 hours, filtered, and the filter cake was top washed with 10 ml of phenylisopropyl ether and dried at 60°C to obtain 48.49 g of mevastatin recovered powder with a purity of 91.01%. The total yield of mevastatin in the mother liquor was 82.2%.

[0071] Example 5

[0072] 3 L of mevastatin mother liquor was concentrated to a volume of 1.1 L at a temperature of 65° C. and a vacuum condition of -0.75 MPa, with a mevastatin content of 48591 mg / L and a purity of 19.37%.

[0073] Weigh 200g of sodium carbonate and dissolve it in 2L of tap water. Add 1.1L of the concentrate and heat at 91°C with stirring for 4.5 hours to hydrolyze. Cool to 60°C, adjust the pH to 10.5 with oxalic acid, and maintain the temperature at 60°C for 1.5 hours to obtain 2.4L of mevastatin hydrolyzate. The mevastatin potency in the mevastatin hydrolyzate was 21246mg / L, with a theoretical yield of 95.40%.

[0074] 1.2 L of ethyl acetate was added to the mevastatin hydrolyzate, stirred, and oxalic acid was added to adjust the pH to 7.0. The layers were allowed to stand for 2 hours to yield 2.3 L of a lower aqueous phase containing mevastatin and 1.3 L of a butyl acetate layer. The titer of the mevastatin salt in the lower aqueous phase was 21057 mg / L, while that in the ethyl acetate layer was 247 mg / L, resulting in a stripping yield of 94.98%.

[0075] 5.75 L of toluene was added to the mevastatin lower aqueous phase solution, and the mixture was stirred. Hydrochloric acid was then added while stirring to adjust the pH to 5.0. The mixture was allowed to stand for 6 hours to separate into separate layers, yielding 5.5 L of a mevastatin supernatant organic phase solution and 2.5 L of an aqueous layer. The mevastatin acid titer in the mevastatin supernatant organic phase solution was 8380 mg / L, while that in the aqueous layer was 198 mg / L, for an extraction yield of 95.17%.

[0076] The supernatant organic phase solution of mevastatin was heated to 91°C and maintained at 91°C for 15 hours for cyclization. The concentration ratio of mevastatin acid to mevastatin was detected to be 0.03. The solution was concentrated in vacuo at 52°C to 95,000 mg / L, cooled to 12°C, crystallized for 5 hours, filtered, and the filter cake was top washed with 10 ml of toluene and dried at 60°C to obtain 52.32 g of mevastatin recovered powder with a purity of 91.03%. The total yield of mevastatin in the mother liquor was 89.1%.

[0077] Example 6

[0078] 3 L of mevastatin mother liquor was concentrated to a volume of 0.8 L at a temperature of 68° C. and a vacuum condition of -0.95 MPa, with a mevastatin content of 68281 mg / L and a purity of 21.65%.

[0079] Weigh 120g of sodium hydroxide and dissolve it in 2.4L of tap water. Add 0.8L of the concentrate and heat at 88°C with stirring for 3.5 hours to hydrolyze. Cool to 48°C, adjust the pH to 9.5 with acetic acid, and maintain the temperature at 48°C for 2.5 hours to obtain 2.6L of mevastatin hydrolyzate. The mevastatin potency in the mevastatin hydrolyzate was 20,360mg / L, with a theoretical yield of 96.91%.

[0080] 3.9 L of butyl acetate was added to the mevastatin hydrolyzate, stirred, and acetic acid was added to adjust the pH to 6.0. The layers were allowed to stand for 1 hour to yield 2.45 L of a lower aqueous phase of mevastatin solution and 4.0 L of a butyl acetate layer. The titer of the mevastatin salt in the lower aqueous phase was 20,760 mg / L, while that in the butyl acetate layer was 157 mg / L, resulting in a stripping yield of 96.08%.

[0081] 3.68 L of phenisopropyl ether was added to the mevastatin supernatant aqueous phase solution. After stirring, phosphoric acid was added while stirring to adjust the pH to 3.5. The solution was allowed to stand for 4.5 hours to separate into separate layers, yielding 3.90 L of a mevastatin supernatant organic phase solution and 2.2 L of an aqueous layer. The mevastatin acid titer in the mevastatin supernatant organic phase solution was 12492 mg / L, and in the aqueous layer was 156 mg / L, for an extraction yield of 95.79%.

[0082] The supernatant organic phase solution of mevastatin was heated to 93°C and maintained at 93°C for cyclization for 8 hours. The concentration ratio of mevastatin acid to mevastatin was detected to be 0.03. The solution was concentrated in vacuo at 63°C to 100,000 mg / L, cooled to 10°C, crystallized for 3 hours, filtered, and the filter cake was top washed with 10 ml of toluene and dried at 60°C to obtain 51.70 g of mevastatin recovered powder with a purity of 92.13%. The total yield of mevastatin in the mother liquor was 87.2%.

[0083] Comparative Example 1

[0084] 3 L of mevastatin mother liquor was concentrated to a volume of 1 L at a temperature of 50° C. and a vacuum condition of -0.98 MPa. The mevastatin content was 55708 mg / L and the purity was 16.98%.

[0085] Weigh 150g of sodium carbonate and dissolve it in 3L of tap water. Add 1L of the concentrate and heat at 85°C with stirring for 5 hours to hydrolyze. Cool to 40°C, adjust the pH to 8.5 with oxalic acid, and maintain the temperature at 40°C for 4 hours to obtain 3.6L of mevastatin hydrolyzate. The mevastatin potency in the mevastatin hydrolyzate was 14698mg / L, with a theoretical yield of 94.98%.

[0086] 1.7 L of toluene was added to the mevastatin hydrolyzate, and the mixture was stirred. Hydrochloric acid was then added while stirring to adjust the pH to 4.5. The solution was allowed to stand for 1 hour to separate into separate layers, yielding 1.5 L of a supernatant organic phase solution of mevastatin and 3.7 L of an aqueous layer. The mevastatin acid titer in the supernatant organic phase was 31913 mg / L, while that in the aqueous layer was 454 mg / L, for an extraction yield of 90.47%.

[0087] The supernatant organic phase solution of mevastatin was heated to 90°C and maintained at 90°C for cyclization for 10 hours. The concentration ratio of mevastatin acid to mevastatin was detected to be 0.04. The solution was concentrated in vacuo at 50°C to 80,000 mg / L, cooled to 5°C, crystallized for 2 hours, filtered, and the filter cake was top washed with 10 ml of toluene and dried at 60°C to obtain 50.69 g of mevastatin recovered powder with a purity of 78.13%. The total recovery rate of mevastatin in the mother liquor was 71.1%.

[0088] Based on Example 1, the ethyl acetate stripping process was omitted, and the purity of the recovered mevastatin powder obtained was 78.13%, and the total recovery rate was 71.1%. By comparison, it can be seen that the omission of the ethyl acetate stripping process resulted in a decrease in the purity and total recovery rate of the recovered powder.

[0089] Comparative Example 2

[0090] 3 L of mevastatin mother liquor was concentrated to a volume of 1 L at a temperature of 50° C. and a vacuum condition of -0.98 MPa. The mevastatin content was 56015 mg / L and the purity was 17.01%.

[0091] To 1 L of mevastatin concentrate, add 3 L of tap water, raise the temperature to 85°C, adjust the pH to 8.5 with saturated sodium carbonate solution, stir and hydrolyze for 5 hours, then cool to 40°C to obtain 3.8 L of mevastatin hydrolyzate. The mevastatin potency in the mevastatin hydrolyzate was 12202 mg / L, with a theoretical yield of 82.78%.

[0092] 1.7 L of toluene was added to the mevastatin hydrolyzate, and the mixture was stirred. Hydrochloric acid was then added while stirring to adjust the pH to 4.5. The solution was allowed to stand for 1 hour to separate into separate layers, yielding 1.55 L of a supernatant organic phase solution of mevastatin and 3.9 L of an aqueous layer. The mevastatin acid titer in the supernatant organic phase was 26,675 mg / L, while that in the aqueous layer was 712 mg / L, for an extraction yield of 89.17%.

[0093] The supernatant organic phase solution of mevastatin was heated to 90°C and maintained at 90°C for cyclization for 10 hours. The concentration ratio of mevastatin acid to mevastatin was detected to be 0.04. The solution was concentrated in vacuo at 50°C to 80,000 mg / L, cooled to 5°C, crystallized for 2 hours, filtered, and the filter cake was top washed with 10 ml of toluene and dried at 60°C to obtain 40.66 g of mevastatin recovered powder with a purity of 71.91%. The total recovery rate of mevastatin in the mother liquor was 52.2%.

[0094] Based on Example 1, a conventional hydrolysis ring-opening method was used, and the ethyl acetate stripping process was omitted. The purity of the recovered mevastatin powder obtained was 71.91%, and the total recovery was 52.2%. By comparison, it can be seen that the use of conventional hydrolysis ring-opening and the omission of ethyl acetate stripping will result in a decrease in the purity and total yield of the recovered powder.

[0095] Comparative Example 3

[0096] 3 L of mevastatin mother liquor was concentrated to a volume of 1 L at a temperature of 50° C. and a vacuum condition of -0.98 MPa. The mevastatin content was 58447 mg / L and the purity was 18.02%.

[0097] To 1 L of mevastatin concentrate, add 3 L of tap water, raise the temperature to 85°C, adjust the pH to 8.5 with saturated sodium carbonate solution, stir and hydrolyze for 5 hours, then cool to 40°C to obtain 3.7 L of mevastatin hydrolyzate. The mevastatin potency in the mevastatin hydrolyzate was 13138 mg / L, with a theoretical yield of 83.17%.

[0098] 8.75 L of ethyl acetate was added to the mevastatin hydrolyzate, stirred, and oxalic acid was added to adjust the pH to 5. The stratification was allowed to stand for 6 hours, yielding 3.90 L of a lower aqueous phase of mevastatin and 8.40 L of an ethyl acetate layer. The titer of the mevastatin salt in the lower aqueous phase was 11892 mg / L, while that in the ethyl acetate layer was 238 mg / L, resulting in a stripping yield of 95.41%.

[0099] 1.7 L of toluene was added to the mevastatin lower aqueous phase solution, and the mixture was stirred. Hydrochloric acid was then added while stirring to adjust the pH to 4.5. The solution was allowed to stand for 1 hour to separate into separate layers, yielding 1.65 L of a mevastatin supernatant organic phase solution and 3.85 L of an aqueous layer. The mevastatin acid titer in the mevastatin supernatant organic phase solution was 25581 mg / L, while that in the aqueous layer was 786 mg / L, for an extraction yield of 91.01%.

[0100] The supernatant organic phase solution of mevastatin was heated to 90°C and maintained at 90°C for cyclization for 10 hours. The concentration ratio of mevastatin acid to mevastatin was detected to be 0.04. The solution was concentrated in vacuo at 50°C to 80,000 mg / L, cooled to 5°C, crystallized for 2 hours, filtered, and the filter cake was top washed with 10 ml of toluene and dried at 60°C to obtain 41.07 g of mevastatin recovered powder with a purity of 85.19%. The total recovery rate of mevastatin in the mother liquor was 63.1%.

[0101] Based on Example 1, a conventional hydrolysis ring-opening method and ethyl acetate stripping were used to obtain a mevastatin recovered powder with a purity of 85.19% and a total recovery of 63.1%. By comparison, it can be seen that the use of conventional hydrolysis ring-opening and the omission of ethyl acetate stripping will result in a decrease in the purity and total yield of the recovered powder.

[0102] Comparative Example 4

[0103] 3 L of mevastatin mother liquor was concentrated to a volume of 1 L at a temperature of 50° C. and a vacuum condition of -0.98 MPa. The mevastatin content was 57916 mg / L and the purity was 17.62%.

[0104] To 1 L of mevastatin concentrate, add 3 L of tap water, heat to 85°C, adjust the pH to 8.5 with saturated sodium carbonate solution, stir and hydrolyze for 5 hours, then cool to 40°C to obtain 3.6 L of mevastatin hydrolyzate. The mevastatin potency in the mevastatin hydrolyzate was 13,308 mg / L, with a theoretical yield of 82.72%.

[0105] The mevastatin hydrolyzate is passed through a D 317 resin column, and then the resin column is discontinuously eluted with an ethanol solution. The eluate is concentrated to remove the ethanol, thereby obtaining a concentrated solution.

[0106] To the concentrate, 1.7 L of toluene was added and the mixture was stirred. Hydrochloric acid was then added while stirring to adjust the pH to 4.5. The mixture was allowed to stand for 1 hour to separate into separate layers, yielding 1.65 L of a supernatant organic phase solution of mevastatin. The mevastatin acid titer of the supernatant organic phase solution was 18298 mg / L, for a yield of 63.02%.

[0107] The supernatant organic phase solution of mevastatin was heated to 90°C and maintained at 90°C for cyclization for 10 hours. The concentration ratio of mevastatin acid to mevastatin was detected to be 0.04. The solution was concentrated in vacuo at 50°C to 80,000 mg / L, cooled to 5°C, crystallized for 2 hours, filtered, and the filter cake was top washed with 10 ml of toluene and dried at 60°C to obtain 31.17 g of mevastatin recovered powder with a purity of 92.02%. The total recovery rate of mevastatin in the mother liquor was 49.52%.

[0108] Based on Example 1, a conventional hydrolysis ring-opening method was used, and impurities were removed using a macroporous resin. The purity of the recovered mevastatin powder obtained was 92.02%, and the total recovery was 49.52%. By comparison, it can be seen that the total yield was reduced by using conventional hydrolysis ring-opening and using a macroporous resin to remove impurities.

[0109] Table 1 Comparison of the quality of mevastatin recovered powder obtained in Examples 1-4 and Comparative Examples 1-4

[0110] Examples and Comparative Examples purity Total yield Examples 1-6 ≥90％ 80％～90％ Comparative Example 1 78.13％ 71.1％ Comparative Example 2 71.91％ 52.2％ Comparative Example 3 85.19％ 63.1％ Comparative Example 4 92.02％ 49.52％

[0111] As shown in Table 1, the method for separating and purifying mevastatin from a mevastatin mother liquor provided by the present invention has high purity and total yield of the recovered mevastatin powder, thereby improving its quality.

[0112] The preferred embodiments of the present invention are described above, but it should be pointed out that those skilled in the art can make several improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for separating and purifying mevastatin from a mevastatin mother liquor, comprising the steps of: (1) concentrating the mevastatin mother liquor to remove the organic solvent to obtain a mevastatin concentrate; (2) subjecting the concentrated solution obtained in step (1) to a gradient hydrolysis ring-opening reaction to convert it into a mevastatin hydrolyzate, wherein: The gradient hydrolysis ring-opening reaction is to add an alkaline aqueous solution to the concentrated solution, react at 85-95°C for 2-5 hours, then add an organic acid to adjust the pH to 8.5-11, and react at 40-60°C for 1-4 hours; (3) adding ethyl acetate or butyl acetate as a stripping solvent to the hydrolyzate obtained in step (2) at a pH of 5-7 to remove oil, thereby obtaining a clear aqueous phase solution of mevastatin; (4) extracting the lower clear aqueous phase solution obtained in step (3) with an extraction solvent at a pH of 2-3 to obtain a mevastatin supernatant organic phase solution; (5) subjecting the supernatant organic phase solution obtained in step (4) to a condensation ring-closure reaction to obtain a cyclized solution; (6) Concentrating and crystallizing the cyclized solution obtained in step (5) to obtain mevastatin.

2. The method according to claim 1, characterized in that The mevastatin content in the mevastatin concentrate of step (1) is ≥40000 mg / L.

3. The method according to claim 1, characterized in that The alkaline aqueous solution is selected from at least one of sodium bicarbonate solution, sodium carbonate solution and sodium hydroxide solution, wherein the volume ratio of mevastatin concentrate to the alkaline aqueous solution is 1:1.5-6.

4. The method according to claim 1, characterized in that The organic acid is oxalic acid or acetic acid.

5. The method according to claim 1, characterized in that The mevastatin content in the mevastatin hydrolyzate is 8000-22000 mg / L.

6. The method according to claim 1, characterized in that The extraction solvent in step (4) is toluene or isopropyl benzene ether.

7. The method according to claim 1, characterized in that The ring-closure reaction in step (5) is carried out at 90-95° C. for 8-16 hours.

8. The method according to claim 1, characterized in that The ring-closing reaction in step (5) is carried out until the concentration ratio of mevastatin acid to mevastatin in the organic phase is less than 5%.

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