A method for removing starch impurities in a beta-cyclodextrin production process

Abstract

The application discloses a method for removing starch impurities in a beta-cyclodextrin production process. After the removal of the auxiliary, insoluble substances, macromolecular starch impurities, and other macromolecular substances such as proteins and pigments are removed through an ultrafiltration membrane. The clear phase is collected to obtain a clear phase passing through the ultrafiltration membrane. The clear phase is a small-molecule starch impurity. The concentrated phase is collected, cooled and crystallized, and the solid is separated by centrifugation to obtain the product. The method can effectively remove most of the starch impurities in the product. After the removal of the auxiliary, the hot feed liquid can directly pass through the ultrafiltration membrane and the nanofiltration membrane. The membrane can be repeatedly used, the cost is reduced, and meanwhile, other substances are not introduced. The process operation is simple.

Description

Technical Field

[0001] This invention relates to the technical field of pharmaceutical and chemical engineering, and in particular to a method for removing starchy impurities during the production of β-cyclodextrin. Background Technology

[0002] β-Cyclodextrin, a novel pharmaceutical excipient, is a cyclic compound composed of seven glucose residues linked by β-1,4-glycosidic bonds and produced by the extraction of starch through microbial enzymatic action. With a molecular weight of 1134.98, its cyclic structure exhibits external hydrophilicity and internal hydrophobicity, allowing it to encapsulate substances of a certain molecular weight, thereby improving drug solubility and bioavailability. Furthermore, it can enhance drug stability and prevent drug oxidation and decomposition.

[0003] Currently, the purification process for β-cyclodextrin production mostly requires two steps, which is complex and results in significant product loss that needs to be recovered.

[0004] Currently, the only mention of a purification method in the "Preparation Process of β-Cyclodextrin" (Chinese Patent CN104762345B) involves cooling to 65°C after de-oxidation, adding activated carbon and saccharifying enzymes for impurity removal, followed by enzyme inactivation. However, this method results in residual starchy impurities after conversion, increasing the difficulty of activated carbon adsorption, and the presence of activated carbon may also affect the degradation of saccharifying enzymes. Furthermore, filtering activated carbon may lead to a significant loss of β-cyclodextrin product, and the need for enzyme inactivation increases thermal costs. Summary of the Invention

[0005] Based on the shortcomings of the prior art, the technical problem solved by the present invention is to provide a method for removing starchy impurities in the production process of β-cyclodextrin with good processing effect. This method can effectively remove most of the starchy impurities in the production process of β-cyclodextrin. After descaling, the hot feed liquid can be directly passed through ultrafiltration membrane and nanofiltration membrane. The membrane can be reused, reducing costs, and no other substances are introduced. The process is simple to operate.

[0006] To address the aforementioned technical problems, this invention provides a method for removing starchy impurities during the production of β-cyclodextrin, comprising the following steps:

[0007] (1) Adding β-cyclodextrin invertase to starch liquefaction liquid generates β-cyclodextrin and other starch impurities;

[0008] (2) Heat the material after conversion to remove the additives;

[0009] (3) After the removal of the auxiliary agent is completed, add the recycled crystallization mother liquor from step (4) of the previous batch, ultrafilter, and collect the clear phase;

[0010] (4) Obtain the clear phase through the nanofiltration membrane. The clear phase consists of small-molecule starch impurities. Collect the concentrated phase, cool it to 40-45℃ to crystallize, and centrifuge to separate the solids to obtain the product and the crystallization mother liquor, which can be reused in the next batch of step (2).

[0011] As a preferred embodiment of the above technical solution, the method for removing starchy impurities during the production of β-cyclodextrin provided by the present invention further includes some or all of the following technical features:

[0012] As an improvement to the above technical solution, step (1) is specifically as follows: The process of adding β-cyclodextrin invertase to starch liquefaction liquid to generate β-cyclodextrin and other starch impurities in step (1) is generally as follows: β-cyclodextrin invertase is added to starch liquefaction liquid, and the starch can be from any selected plant species. β-cyclodextrin invertase is Bacillus macerationus, Bacillus megaterium, etc. The selected β-cyclodextrin invertase and the required parameters of starch liquefaction liquid are described in known literature. Usually, starch liquefaction liquid is a solution or slurry aqueous solution with a mass concentration of about 35%, and then gelatinization and liquefaction are carried out by enzymes or acids. The preferred enzyme for this liquefaction is α-amylase. Next, the selected β-cyclodextrin invertase is added to starch liquefaction liquid, and the pH value, temperature and treatment time are adjusted to be suitable for the selected enzyme. Generally, the pH value is between about 4.5 and 6.5, the temperature range is between about ambient temperature and 75°C, the reaction time is about 10 hours to 7 days, and cyclohexane is added during the conversion process to improve the yield.

[0013] As an improvement to the above technical solution, the heating temperature in step (2) is 95-100℃.

[0014] As an improvement to the above technical solution, the ultrafiltration process in step (3) uses an ultrafiltration membrane with a permeable molecular weight of 2500-3500 Da.

[0015] As an improvement to the above technical solution, the ultrafiltration process in step (3) uses a ceramic membrane.

[0016] As an improvement to the above technical solution, the nanofiltration membrane used in step (4) has a permeable molecular weight of 500-1000 Da.

[0017] As an improvement to the above technical solution, the nanofiltration membrane material is polyamide.

[0018] As an improvement to the above technical solution, the nanofiltration process in step (4) operates at a pressure of 1.5-2.5 MPa and has a pore size of 1-2 nm. Preferably, the operating pressure is 2 MPa and the pore size is approximately 1 nm.

[0019] The key control points for obtaining high-purity β-cyclodextrin in this invention are:

[0020] 1. After the conversion is completed, heat the material to 95-100℃ to remove the additives;

[0021] 2. After the removal of the auxiliary agent is completed, a portion of the recycled crystallization mother liquor is added and passed through an ultrafiltration membrane. The ultrafiltration membrane is made of ceramic material and has a permeation molecular weight of 3000 Da. It mainly removes insoluble matter, large molecular starch impurities, as well as other large molecular substances such as proteins and pigments, and collects the clear phase.

[0022] 3. A clear phase nanofiltration membrane was obtained, made of polyamide, operating at a pressure of 2 MPa, with a pore size of approximately 1 nm and a permeable molecular weight of 800 Da. The clear phase consisted of small-molecule starch impurities. The concentrated phase was collected, cooled to 40-45℃ for crystallization, and the solids were separated by centrifugation to obtain the product.

[0023] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0024] This invention can effectively remove most of the starchy impurities in the product. After descaling, the hot liquid can be directly passed through ultrafiltration and nanofiltration membranes. The membranes can be reused, reducing costs, and no other substances are introduced. The process is simple to operate.

[0025] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, the following detailed description is provided in conjunction with preferred embodiments. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below.

[0027] Figure 1 This is a purity test chart of the β-cyclodextrin product prepared in Example 1 of this invention;

[0028] Figure 2 This is a purity test chart of the β-cyclodextrin product prepared in Example 2 of this invention;

[0029] Figure 3 This is a purity test chart of the β-cyclodextrin product prepared in Example 3 of this invention;

[0030] Figure 4 This is a purity test chart of the β-cyclodextrin product prepared in Example 4 of this invention;

[0031] Figure 5 This is a purity test chart of the β-cyclodextrin product prepared in Comparative Example 1 of this invention;

[0032] Figure 6This is a flowchart of the method for removing starchy impurities during the production of β-cyclodextrin according to the present invention. Detailed Implementation

[0033] The following detailed description of specific embodiments of the present invention is part of this specification. The principles of the present invention are illustrated through examples, and other aspects, features and advantages of the present invention will become apparent from this detailed description.

[0034] Production of conversion liquid

[0035] The process of adding β-cyclodextrin invertase to starch liquefaction liquid to generate β-cyclodextrin and other starch impurities is generally as follows: β-cyclodextrin invertase is added to the starch liquefaction liquid, where the starch can be derived from any selected plant species. β-cyclodextrin invertases include Bacillus macerationus and Bacillus megaterium. The selected β-cyclodextrin invertase and the required parameters for the starch liquefaction liquid are described in known literature. Typically, the starch liquefaction liquid is a solution or slurry-like aqueous solution with a mass concentration of approximately 20-35%, which is then gelatinized and liquefied by enzymes or acids. The preferred enzyme for this liquefaction is α-amylase. Next, the selected β-cyclodextrin invertase is added to the starch liquefaction liquid, and the pH, temperature, and treatment time are adjusted to suit the selected enzyme. Generally, the pH is between approximately 4.5 and 6.5, the temperature range is from approximately ambient temperature to 75°C, and the reaction time is approximately 10 hours to 7 days. During the conversion process, adjuvants such as cyclohexane are added to improve the yield.

[0036] Example 1

[0037] A starch slurry with a mass concentration of 20% was prepared using starch and water. The pH of the starch slurry was adjusted to 5.6, and 4 units of thermoresistant α-amylase per gram of starch were added and mixed thoroughly. The mixture was then heated to 100°C and spray-cooked, followed by incubation at 99°C for 40 minutes to obtain a liquefied solution. The solution was then cooled to 60°C, and 5 units of β-cyclodextrin invertase per gram of starch and 6% cyclohexane per gram of dry starch were added. The mixture was allowed to react completely for 20 hours.

[0038] After the liquefied liquid was converted by β-cyclodextrin invertase to obtain 90L of conversion solution mainly composed of β-cyclodextrin and other starchy impurities, the solution was heated to 98℃ to remove the auxiliary agent cyclohexane. The solution after removal was then mixed with 18L of pre-crystallization mother liquor and passed through an ultrafiltration membrane (molecular weight 3000 Da), yielding 103L of clear phase. This clear phase was then passed through a nanofiltration membrane (molecular weight 800 Da) under conditions of 2MPa and 1nm pore size, collecting 90L of concentrated phase. The concentrated phase was then cooled to 40℃ for crystallization. The resulting crystallization mother liquor contained low-molecular-weight impurities and could be reused in the solution after removal. The final crystals had a turbidity of 1.56 NTU at 10000 ppm, and the peak area for purity testing was 2095.33 (sample number BXS250910-1-03-1). The calculated purity was 100.24%, meeting the Chinese Pharmacopoeia standard, and the product quality was qualified.

[0039] The product testing method is the standard method of the Chinese Pharmacopoeia.

[0040] Example 2

[0041] A starch slurry with a mass concentration of 20% was prepared using starch and water. The pH of the starch slurry was adjusted to 5.6, and 4 units of thermoresistant α-amylase per gram of starch were added and mixed thoroughly. The mixture was then heated to 100°C and spray-cooked, followed by incubation at 99°C for 40 minutes to obtain a liquefied solution. The solution was then cooled to 60°C, and 5 units of β-cyclodextrin invertase per gram of starch and 6% cyclohexane per gram of dry starch were added. The mixture was allowed to react completely for 20 hours.

[0042] After the liquefied liquid was converted by β-cyclodextrin invertase to obtain 85L of conversion solution mainly composed of β-cyclodextrin and other starchy impurities, the solution was heated to 99℃ to remove the auxiliary agent cyclohexane. The solution after removal was then mixed with 17L of crystallization mother liquor and passed through an ultrafiltration membrane. A molecular weight of 2500 Da was passed through, yielding 98L of clear phase. This clear phase was then passed through a nanofiltration membrane, with a molecular weight of 500 Da passing through at 2MPa and a pore size of 1nm. 85L of concentrated phase was collected. The concentrated phase was then cooled to 40℃ for crystallization. The resulting crystallization mother liquor contained low-molecular-weight impurities and could be reused in the solution after removal. The final crystals had a turbidity of 0.45 NTU at 10000 ppm, and the peak area for purity testing was 1957.47 (sample number BXS250910-1-03-2). The calculated purity was 99.48%, meeting the Chinese Pharmacopoeia standard, and the product quality was qualified.

[0043] Example 3

[0044] A starch slurry with a mass concentration of 20% was prepared using starch and water. The pH of the starch slurry was adjusted to 5.6, and 4 units of thermoresistant α-amylase per gram of starch were added and mixed thoroughly. The mixture was then heated to 100°C and spray-cooked, followed by incubation at 99°C for 40 minutes to obtain a liquefied solution. The solution was then cooled to 60°C, and 5 units of β-cyclodextrin invertase per gram of starch and 6% cyclohexane per gram of dry starch were added. The mixture was allowed to react completely for 20 hours.

[0045] After the liquefied liquid was converted by β-cyclodextrin invertase to obtain 80L of conversion solution mainly composed of β-cyclodextrin and other starchy impurities, the solution was heated to 97℃ to remove the auxiliary agent cyclohexane. The solution after removal was then mixed with 16L of a reserved crystallization mother liquor and passed through an ultrafiltration membrane. A molecular weight of 3500 Da was passed through, yielding 94L of clear phase. This clear phase was then passed through a nanofiltration membrane, with a molecular weight of 1000 Da passing through at 2MPa and a pore size of 1nm. 80L of concentrated phase was collected. The concentrated phase was then cooled to 40℃ for crystallization. The resulting crystallization mother liquor contained low-molecular-weight impurities and could be reused in the solution after removal. The final crystals had a turbidity of 0.79 NTU at 10000 ppm, and a peak area of ​​2125.80 (sample number BXS250910-1-04-1). The calculated purity was 100.86%, meeting the Chinese Pharmacopoeia standard, and the product quality was qualified.

[0046] Example 4

[0047] A starch slurry with a mass concentration of 20% was prepared using starch and water. The pH of the starch slurry was adjusted to 5.6, and 4 units of thermoresistant α-amylase per gram of starch were added and mixed thoroughly. The mixture was then heated to 100°C and spray-cooked, followed by incubation at 99°C for 40 minutes to obtain a liquefied solution. The solution was then cooled to 60°C, and 5 units of β-cyclodextrin invertase per gram of starch and 6% cyclohexane per gram of dry starch were added. The mixture was allowed to react completely for 20 hours.

[0048] After the liquefied liquid was converted by β-cyclodextrin invertase to obtain 95L of conversion solution containing β-cyclodextrin and other starchy impurities, the solution was heated to 100℃ to remove the auxiliary agent cyclohexane. The solution after removal was then mixed with 19L of crystallization mother liquor and passed through an ultrafiltration membrane (110L of clear phase with a molecular weight of 3500 Da). This clear phase was then passed through a nanofiltration membrane (95L of concentrated phase with a molecular weight of 500 Da, 2MPa, 1nm pore size). The concentrated phase was then cooled to 40℃ for crystallization. The resulting crystallization mother liquor contained low-molecular-weight impurities and could be reused in the solution after removal. The final crystals had a turbidity of 0.58 NTU at 10000 ppm, and the peak area for purity testing was 2044.91 (sample number BXS250910-1-04-2). The calculated purity was 100.05%, meeting the Chinese Pharmacopoeia standard, and the product quality was qualified.

[0049] Comparative Example 1

[0050] A starch slurry with a mass concentration of 20% was prepared using starch and water. The pH of the starch slurry was adjusted to 5.6, and 4 units of thermoresistant α-amylase per gram of starch were added and mixed thoroughly. The mixture was then heated to 100°C and spray-cooked, followed by incubation at 99°C for 40 minutes to obtain a liquefied solution. The solution was then cooled to 60°C, and 5 units of β-cyclodextrin invertase per gram of starch and 6% cyclohexane per gram of dry starch were added. The mixture was allowed to react completely for 20 hours.

[0051] After the liquefied liquid was converted by β-cyclodextrin invertase to obtain a feed solution with β-cyclodextrin and other starchy impurities as the main components, 90L of the feed solution was heated for de-acidification. After de-acidification, activated carbon was added, and the solution was kept at this temperature for 1 hour before being filtered through a plate and frame filter. The resulting hot filtrate was cooled to 40℃ for crystallization. The final crystals had a turbidity of 12.53 NTU at 10,000 ppm and a purity of 98.24% (sample number BXS250909-1-03-2, peak area 3575.99), and the product quality was substandard.

[0052] Table 1. Test results of products from the examples and control examples

[0053]

[0054] All the raw materials listed in this invention, as well as the upper and lower limits and ranges of the raw materials and the upper and lower limits and ranges of the process parameters (such as temperature, time, etc.), can realize this invention. Examples are not listed one by one here.

[0055] The above description is merely a preferred embodiment of the present invention, and should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for removing starch impurities in a process for the production of β-cyclodextrin, characterized in that, It includes the following steps: (1) Adding β-cyclodextrin invertase to starch liquefaction liquid generates β-cyclodextrin and other starch impurities; (2) Heat the material after conversion to remove the additives; the heating temperature is 95-100℃. (3) After the removal of the auxiliary agent in step (2) is completed, add the recycled crystallization mother liquor from step (4) of the previous batch, ultrafilter, and collect the clear phase; the ultrafiltration process uses a ceramic membrane; the ultrafiltration process uses an ultrafiltration membrane with a permeable molecular weight of 2500-3500 Da; (4) The clear phase nanofiltration membrane obtained in step (3) is collected, the concentrated phase is crystallized, and the solids are separated by centrifugation to obtain the product. The separated liquid is the crystallization mother liquor, which is used in the next batch of step (2). The nanofiltration membrane material is polyamide, the nanofiltration membrane used in the nanofiltration process has a permeable molecular weight of 500-1000 Da, the nanofiltration process operating pressure is 1.5-2.5 MPa, and the pore size is 1-2 nm.

2. The process for removal of starch impurities in the production of β-cyclodextrin as claimed in claim 1 wherein: The β-cyclodextrin invertase is selected from Bacillus macerationus and Bacillus megaterium; the starch liquefaction solution is a solution or slurry-like aqueous solution with a mass concentration of about 35%, which is then gelatinized and liquefied by enzymes or acids. The enzyme used for this liquefaction is bacterial α-amylase; the process of adding β-cyclodextrin invertase to the starch liquefaction solution to generate β-cyclodextrin involves adding auxiliary agents, a pH value between 4.5 and 5.8, a temperature range between ambient temperature and 75°C, and a reaction time of 10 hours to 7 days.

3. The process for removal of starch impurities in the production of β-cyclodextrin as claimed in claim 2, wherein: The auxiliary agent is cyclohexane.

4. The process for removal of starch impurities in the production of β-cyclodextrin as claimed in claim 1 wherein: In step (4).

5. The process for removal of starch impurities in the production of β-cyclodextrin as claimed in claim 1 wherein: In step (4), the crystallization process involves cooling the temperature to 40-45℃ for crystallization.

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