Daptomycin drying method

Abstract

The invention relates to the field of daptomycin production, in particular to a drying method of daptomycin. According to the method, firstly, an evacuation channel in a daptomycin crystal is opened by adopting an ultrasonic vacuum drying method, and a solvent contained in a crystal solid is quickly volatilized under a vacuum drying condition, so that the vacuum drying efficiency is improved. The method has the advantages that the raw materials are recycled, then the nitrogen is introduced for boiling drying, the drying process is carried out under the oxygen isolation condition, moisture can be quickly dried, impurity growth can be effectively controlled, and the method is low in energy consumption, high in efficiency and high in industrial implementation performance.

Description

Technical Field

[0001] The present invention relates to the field of medicine, and in particular to an optimization method for daptomycin solid drying treatment, which realizes a daptomycin drying process with high efficiency, low solvent residue and moisture control by combining ultrasonic vacuum drying and nitrogen boiling drying technology. Background Art

[0002] Daptomycin is a cyclic lipopeptide antibiotic with a new structure consisting of thirteen amino acids extracted from the fermentation broth of Streptomyces. It was discovered by Eli Lilly in the 1980s and successfully developed by Cubist Pharmaceuticals in 1997. It mainly acts on drug-resistant bacteria, such as vancomycin-resistant enterococci (VRE), glycopeptide antibiotic-sensitive Staphylococcus aureus (GISA), methicillin-resistant Staphylococcus aureus (MRSA), penicillin-resistant Streptococcus pneumoniae (PRSP) and coagulase-positive Staphylococcus aureus (CNS), etc., and shows good activity.

[0003]

[0004] Daptomycin has a complex structure and poor stability. It is easy to be transformed into daptomycin impurities under wet and hot conditions. It is difficult to directly synthesize it chemically. At present, daptomycin is a fermentation product. A large amount of byproducts such as pigments and impurities will be produced during the fermentation process of daptomycin. The daptomycin in the fermentation liquid is also easy to be transformed into daptomycin impurities during the extraction process. Therefore, it is necessary to obtain a higher purity final product through a subsequent purification process. The commonly used subsequent purification process for daptomycin fermentation liquid includes: the fermentation liquid is filtered through a ceramic membrane or static adsorption or solvent extraction, macroporous resin gradient adsorption analysis, ion exchange resin gradient adsorption analysis, nanofiltration concentration, reverse phase high pressure preparation, etc., to obtain the final product, and the liquid chromatography method is tested. The prior art can prepare daptomycin with a chromatographic purity greater than 98% (daptomycin impurity content is less than 2%). Although the daptomycin impurity content in this final product is less than 2%, the final product still contains water and residual organic solvents, which are not used as impurities when calculating the purity of daptomycin. Excessive residual water in daptomycin is not conducive to the stability of the product (evolving into daptomycin impurities), and excessive residual organic solvents may also cause harm to human health. Therefore, it is necessary to control the residual water and organic solvents in daptomycin within a small range.

[0005] Daptomycin wet solid is a daptomycin intermediate product obtained by obtaining a fermentation liquid through a fermentation process, separating the solution containing daptomycin through solid-liquid separation, column chromatography, membrane concentration, etc., and then crystallizing and filtering the solution through organic solvents such as isopropanol and ethyl acetate to obtain a water and / or solvent mass content of more than 50%. Since the daptomycin wet solid contains too much water and organic solvent, it must be dried using a drying technology. The current drying technology can reduce the mass content of water and organic solvent of daptomycin to less than 5%. There are many literature reports on the method of drying daptomycin. The known processes include: using a freeze-drying process, using a spray drying process, and using a conventional vacuum drying process. Some of the above existing processes have high energy consumption and are difficult to be industrialized on a large scale; some drying conditions are harsh and take a long time, making it difficult to ensure that daptomycin is less decomposed during the drying process, and it is difficult to obtain a high-purity final product. For example, the patent document with publication number CN113004373A introduces that the drying method of daptomycin is a freeze-drying process, which requires long-term freezing to allow the solvent and water to sublime, so the process has high energy consumption. At the same time, since the freezing process requires the daptomycin to be dried to be dispersed and spread in the freeze-drying equipment, and the freeze-drying equipment usually has limited space and limited capacity, large-scale freeze-drying is impossible; the patent document with publication number CN110548130A introduces that the drying method of daptomycin is spray drying, and the drying conditions are high-temperature conditions (during spray drying, the inlet air temperature is controlled to be 220-180°C, and the outlet air temperature is controlled to be 115-105°C). Daptomycin is easily transformed into daptomycin impurities under hot and humid conditions, so this process is not conducive to the stability of daptomycin; at the same time, spray drying uses a nozzle, and the wet daptomycin to be dried with a viscous characteristic will cause the nozzle to be gradually blocked.

[0006] The patent document with publication number CN114344447A discloses a daptomycin for injection and a preparation method thereof, comprising the following steps: (a) filtering the daptomycin fermentation broth, introducing the filtrate into an ion exchange resin for enrichment and adsorption, washing with pure water, eluting with a NaCl aqueous solution, desorbing with a NaCl aqueous solution, collecting the desorbed liquid, and concentrating by ultrafiltration to obtain a concentrated filtrate A; (b) introducing the concentrated filtrate A into a macroporous adsorption resin for enrichment and adsorption, washing with pure water, eluting with an ethanol aqueous solution, desorbing with an ethanol aqueous solution, collecting the desorbed liquid, and concentrating by ultrafiltration to obtain a concentrated filtrate B; (c) introducing the concentrated filtrate B into a polymer resin for adsorption, washing with pure water, and desorbing with a NaCl aqueous solution; The sodium acetate aqueous solution is eluted, the sodium acetate aqueous solution is desorbed, the desorbed liquid is collected, and the ultrafiltration is concentrated to obtain a concentrated filtrate C; (d) the concentrated filtrate C is introduced into a C18 resin for adsorption, washed with an ethanol aqueous solution, and desorbed with an ethanol aqueous solution, the desorbed liquid is collected, and the ultrafiltration is concentrated to remove endotoxins to obtain a concentrated filtrate D; (e) a salt solution is added to the concentrated filtrate D for crystallization, and then daptomycin powder is obtained after suction filtration, leaching, and drying, the daptomycin powder is dissolved, and the daptomycin aqueous solution is desalted with a strong acid cation resin to obtain a desalted liquid; (f) the desalted liquid is sterilized and filtered after adjusting the pH value, and then filled and freeze-dried to obtain the daptomycin for injection. The moisture content of the daptomycin is 0.4%-0.6%. The "freeze-drying" method still used in step (f) of this technology controls the moisture content of daptomycin to 0.4%-0.6%, which is similar to the method used in CN113004373A, has high energy consumption, and is difficult to produce in large quantities. Moreover, when the water content of daptomycin is controlled to be below 5%, the stability of daptomycin can be guaranteed. Therefore, it is particularly important to develop a daptomycin drying method which uses a wet product of daptomycin with a high water content and a high total amount of residual organic solvent after fermentation as a raw material, and which is efficient, low in energy consumption, can be mass-produced, and has mild drying conditions to control the water content to below 5%. Summary of the invention

[0007] In view of the problems existing in the above-mentioned background technology, the object of the present invention is to provide a method for optimizing the drying process of daptomycin, which effectively reduces solvent residue, accurately controls the moisture content of the product, reduces energy consumption, and improves drying efficiency and product quality by combining ultrasonic vacuum drying with nitrogen boiling drying.

[0008] In order to achieve the above object, the present invention provides a method for drying daptomycin, which comprises the following steps:

[0009] (1) subjecting a wet solid daptomycin product having a total mass content of solvent and / or water of more than 50% to ultrasonic vacuum drying to obtain a solid daptomycin intermediate;

[0010] (2) The daptomycin solid intermediate that has been subjected to ultrasonic vacuum drying is subjected to boiling drying in a dry nitrogen boiling drying device to obtain a daptomycin final product.

[0011] The present invention first adopts an ultrasonic vacuum drying method to open the evacuation channel in the daptomycin crystal, and under the condition of vacuum drying, the solvent in the daptomycin wet product solid is rapidly volatilized, thereby improving the vacuum drying efficiency. Then, nitrogen boiling drying is introduced, and the drying process is carried out under oxygen isolation conditions, so that moisture can be quickly dried and impurity growth can be effectively controlled. This technical solution must first perform ultrasonic vacuum drying and then perform nitrogen boiling drying; if nitrogen boiling drying is performed first, the daptomycin solid wet product will be syrupy and stick to the sieve plate of the nitrogen boiling drying equipment, and it is impossible to dry evenly and quickly.

[0012] In step (1), ultrasonic vacuum drying is performed in an ultrasonic vacuum drying oven, and the daptomycin wet solid is a crude product containing daptomycin obtained by crystallizing the fermentation broth through an organic solvent such as isopropanol, ethyl acetate, acetone or methanol, wherein the total mass content of the solvent and / or water is more than 50%. The present invention aims to dry the daptomycin wet solid in a short time to control the moisture content to between 2.9% and 4.6%.

[0013] Ultrasonic vacuum drying refers to drying the wet solid daptomycin in an ultrasonic environment and a vacuum environment.

[0014] Furthermore, in step (1), drying is performed in a vacuum environment, the vacuum degree is set to -0.085 MPa to -0.07 MPa, and the temperature is controlled below 28°C.

[0015] Vacuum degree is too high, which is unfavorable for the flow of the gas evaporated, and the evaporated organic solvent and water are easily attached to the wet solid surface of daptomycin, resulting in solid surface saccharification, preventing the organic solvent and water volatilization inside the solid, resulting in a long drying time. The volatilization of moisture and organic solvent can take away part of the heat, and if the drying process is not heated, the temperature of the daptomycin solid will be continuously reduced, which is unfavorable for the continued evaporation of moisture and organic solvent, so the drying temperature is controlled at more than 20 DEG C, but daptomycin is easily derived into daptomycin impurities under hot and humid conditions, so the temperature is controlled at less than 28 DEG C. That is, preferably the temperature is controlled within the range of 20-28 DEG C, thereby reducing the amount of daptomycin derived into daptomycin impurities on the one hand, and maintaining higher drying efficiency on the other hand.

[0016] The term "saccharification" means that when there is a large amount of organic solvent or water on the solid surface of daptomycin, the surface will dissolve to form a viscous substance like syrup or honey.

[0017] Furthermore, in step (1), ultrasonic vacuum drying uses ultrasonic intermittent drying, the power is set between 200-300W, the ultrasonic time is controlled at 10-20 minutes each time, and the interval between two ultrasonic times is 5-10 minutes.

[0018] Furthermore, step (1) is dried until the residual solvent reaches 1500-3000 ppm, and this stage is terminated. This stage usually takes 2.5-4 hours.

[0019] The term "intermittent drying" means that after each ultrasonic drying for a period of time (one ultrasonic drying), the ultrasonic drying is stopped for a period of time before the next ultrasonic drying is carried out.

[0020] Ultrasound plays a vibrating role, which is conducive to product dispersion. The wet product of daptomycin crystallization is dispersed under the "vacuum" environment with the volatilization of organic solvents and water under the action of ultrasound, avoiding the operation of unpacking and crushing. Intermittent ultrasound is to prevent excessive local vibration caused by continuous ultrasound and cause local temperature to be too high, because the hot and humid conditions caused by excessive local temperature will promote the generation of daptomycin impurities. Ultrasound treatment within this power range and time range can make daptomycin solid vibrate and disperse. Excessive power wastes energy. The ultrasonic time can disperse the product. Too long will easily lead to temperature increase, so that the impurities in daptomycin grow. Step (1) is dried to the end when the solvent residue reaches 1500-3000ppm. After experimental verification, when the solvent residue is within this range, the daptomycin solid intermediate forms a light yellow powder ( Figure 1 ), the powdered daptomycin solid intermediate can be dried by nitrogen boiling. If the residual solvent is too high, the daptomycin solid intermediate will be saccharified into lumps ( Figure 2 ), it is impossible to further dry it by nitrogen boiling drying; the residual solvent can be determined by gas chromatography.

[0021] In step (2), dry nitrogen is used as the medium, the drying temperature is controlled between 25-30°C, and the air volume is set to 40-100m 3 / h. Perform fluidized bed drying, and the drying time is controlled within 30-60 minutes. Further, after the drying is completed, ensure that the moisture content of daptomycin is controlled between 2.9% and 4.6%.

[0022] Nitrogen has the function of isolating oxygen, and at the same time, as an airflow, it takes away moisture and residual solvents in the product. The crystallized daptomycin wet solid is in the form of a viscous syrup, and direct nitrogen drying cannot blow the product into a "boiling" state, resulting in uneven drying of the daptomycin wet solid, and the purpose of controlling the moisture content of daptomycin between 2.9% and 4.6% cannot be achieved. Therefore, the present invention first uses vacuum drying to dry the daptomycin wet solid into a powdered solid (at this time, the moisture content is higher than 4.6%), and then performs nitrogen boiling drying. The temperature between 25-30°C can prevent daptomycin from decomposing into daptomycin impurities, and at the same time has a relatively high drying efficiency; the air volume is set to 40-100m 3 / h can improve the drying efficiency, so that the nitrogen boiling drying time is controlled within 30-60 minutes to achieve the purpose of controlling the moisture content of daptomycin to between 2.9% and 4.6%.

[0023] In step (1), the temperature is controlled to be below 28°C, because under negative pressure conditions, the boiling points of the solvent and water will decrease, and providing a temperature below 28°C can ensure the evaporation of the solvent and water, while taking into account that daptomycin is not decomposed into impurities too quickly. In step (2), the temperature is controlled to be below 30°C, because the boiling drying time is shorter than the vacuum drying time, and it can be appropriately increased by 2°C to ensure the rapid evaporation of the solvent and water, while taking into account that daptomycin is not decomposed into impurities too quickly.

[0024] The term "fluidized bed drying" means: using airflow to dry the material. Specifically, the wet material is placed on a sieve plate, and a drying medium (usually gas) is blown in from below through the sieve holes to blow the material into a boiling state to achieve the purpose of accelerating drying. Nitrogen fluidized bed drying equipment is a commonly used equipment that can be used for mixing, granulation, and drying. This technology uses its drying function to dry the solid intermediate of daptomycin, and does not use the mixing and granulation functions of the nitrogen fluidized bed drying equipment.

[0025] The conjunction "and / or" indicates that the two connected words are in an "and" relationship, or the two connected words are in an "or" relationship, for example, solvent and / or water means "solvent and water", solvent, or water.

[0026] Compared with the prior art, the present invention has at least the following beneficial effects:

[0027] 1. The drying process is efficient, and the drying is completed in 3-5 hours. The wet daptomycin product with a total content of water and / or organic solvent of more than 50% is dried to a daptomycin moisture content in the range of 2.9%-4.6%, and the residual solvent content is also low at this time; at the same time, batch production can be achieved, and each batch of drying can achieve 40kg of daptomycin wet solid as the drying object.

[0028] 2. The residual solvent content of daptomycin is low, and the residual solvent content is less than 1000ppm.

[0029] 3. The moisture content of daptomycin is controlled to 2.9%-4.6%, which ensures that daptomycin has better stability.

[0030] 4. The drying process of the present invention is carried out at a relatively low temperature (below 30° C.), ensuring that daptomycin is less decomposed during the drying process.

[0031] 5. The method of the present invention uses a low temperature and a short drying time, so the energy consumption is low and it has strong industrial feasibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Daptomycin is in powder form.

[0033] Figure 2 It is a saccharified daptomycin.

[0034] Specific implementation examples

[0035] To further illustrate the present invention, a daptomycin drying method provided by the present invention is described in detail below with reference to examples.

[0036] Embodiment 1:

[0037] 500 grams of daptomycin wet solid (total mass content of isopropanol and water is 54%) obtained by filtering after crystallization with isopropanol was evenly spread on the tray of ultrasonic vacuum drying oven. The temperature was set to 20°C. The ultrasonic generator was turned on, the power was set to 250W, and the intermittent working mode was adopted. Each ultrasonic operation was 15 minutes, and then stopped for 5 minutes to prevent overheating. The vacuum valve of the vacuum drying oven was opened, and the vacuum degree was maintained between -0.075MPa and -0.07MPa. The residual solvent was determined by gas chromatography, and the residual solvent was detected to reach 2340ppm, and this stage was terminated to obtain the solid intermediate of daptomycin. The drying time was 3.5 hours in total.

[0038] The daptomycin solid intermediate after ultrasonic vacuum drying was quickly transferred to the nitrogen boiling drying equipment. The nitrogen flow rate was set to 60m 3 / h, the temperature is 27°C, and the equipment is started. During the drying process, nitrogen is continuously introduced to ensure the purity of the drying environment. After 45 minutes of drying, the sample is taken and the moisture content is 2.9% by Karl Fischer water method. The drying is terminated to obtain 224g of daptomycin solid. The residual isopropanol is 980ppm by gas chromatography.

[0039] Embodiment 2:

[0040] 4kg of daptomycin wet solid (total mass content of isopropanol and water is 58%) obtained by filtering after crystallization with isopropanol was evenly spread on the tray of ultrasonic vacuum drying oven. The temperature was set to 26°C. The ultrasonic generator was turned on, and the ultrasonic power was set to 280W. The intermittent working mode was adopted, and each ultrasonic operation was 10 minutes, followed by a 5-minute break. The vacuum valve of the vacuum drying oven was opened, and the vacuum degree was maintained between -0.075MPa and -0.07MPa, and the residual solvent was monitored. When it dropped to 1800ppm, drying was stopped to obtain a solid intermediate of daptomycin. The drying time was 3.8 hours in total.

[0041] The daptomycin solid intermediate after ultrasonic vacuum drying was quickly transferred to the nitrogen boiling drying equipment. The nitrogen flow rate was set to 80m 3 / h, the temperature is 28°C, and the equipment is started. During the drying process, nitrogen is continuously introduced to ensure the purity of the drying environment. After 50 minutes of drying, a sample is taken and the moisture content is 4.5% by Karl Fischer moisture method. The drying is terminated to obtain 1.58 kg of daptomycin solid. The residual isopropanol is determined by gas chromatography to be 778 ppm.

[0042] Embodiment 3:

[0043] The wet solid product of daptomycin (the total mass content of ethyl acetate and water is 61%) obtained by filtering after crystallization of 40kg ethyl acetate is evenly spread on the tray of ultrasonic vacuum drying oven. The temperature is strictly controlled at 28°C. The ultrasonic generator is turned on, the ultrasonic power is set to 300W, and the intermittent working mode is adopted. Each ultrasonication is 20 minutes, and then 5 minutes are stopped. The vacuum valve of the vacuum drying oven is opened, and the vacuum degree is maintained between -0.075MPa and -0.07MPa, and the residual solvent is monitored. When the residual solvent monitoring display reaches 1500ppm, the drying is terminated to obtain the solid intermediate of daptomycin. The drying time is 3.1 hours in total.

[0044] The daptomycin solid intermediate after ultrasonic vacuum drying was transferred to a nitrogen boiling drying device, and the nitrogen flow rate was set to 100m 3 / h, the temperature was maintained at 25°C, and the equipment was started. Nitrogen was continuously introduced during the drying process to ensure the purity of the drying environment. After 55 minutes of drying, the sample was taken and the moisture content was 3.2% using the Karl Fischer moisture method. The drying was terminated to obtain 13.66 kg of daptomycin solid. The residual isopropanol was determined to be 840 ppm by gas chromatography.

[0045] Example 4

[0046] Except that the ultrasonic vacuum drying was terminated when the residual solvent content reached 3000 ppm during the ultrasonic vacuum drying, the other aspects were the same as those of Example 1. The ultrasonic vacuum drying took a total of 2.5 hours.

[0047] The nitrogen boiling drying process is basically the same as that in Example 1. After 35 minutes of drying, the sample is taken and the moisture content is 4.6% by Karl Fischer moisture method, and the drying is terminated. The residual isopropanol is 990 ppm by gas chromatography.

[0048] Comparative Example 1

[0049] This comparative example was subjected to ultrasonic vacuum drying without nitrogen boiling drying:

[0050] 500 grams of daptomycin wet solid (isopropanol and water content of 56%) obtained by filtering after crystallization with isopropanol was evenly spread on the tray of ultrasonic vacuum drying oven. The temperature was set to 20°C. The ultrasonic generator was turned on, the power was set to 250W, and the intermittent working mode was adopted. Each ultrasonic operation lasted for 15 minutes, and then stopped for 5 minutes to prevent overheating. The vacuum valve of the vacuum drying oven was opened, and the vacuum degree was maintained between -0.080MPa and -0.07MPa, and the residual solvent was monitored. The residual solvent was determined by gas chromatography, and the residual solvent was detected to reach 2540ppm. The moisture content was determined to be 6.7%, and it had been dried for 3.5 hours.

[0051] Continue ultrasonic vacuum drying, and monitor the residual solvent amount and moisture content every hour during the drying process. The moisture content decreases slowly during this process (because the lattice is closed, the solvent and moisture in the crystal cannot be released). After drying for 5 hours, the final residual solvent amount is 2450ppm, and the final moisture content is 6.5%, which cannot reach below 5%.

[0052] The purity of daptomycin solid was verified by liquid chromatography, and the results are shown in Table 1:

[0053] Table 1 Daptomycin solid purity verification results

[0054]

[0055]

[0056] As can be seen from Table 1, the daptomycin impurity content in daptomycin before and after drying is very low, that is, the purity of daptomycin solid is very high, meeting the requirements of pharmaceutical preparation standards; at the same time, compared with before drying, the increase in daptomycin impurities after drying is very small, indicating that the drying method of the present invention will not significantly promote the decomposition of daptomycin. It can be seen that the drying method of the present invention can improve the drying efficiency and reduce the drying energy consumption without substantially increasing the daptomycin impurities.

[0057] Although the invention has been described herein with reference to illustrative embodiments thereof, it should be understood that numerous other modifications and implementations can be devised by those skilled in the art that will fall within the scope and spirit of the principles disclosed herein.

Claims

1. A method for drying daptomycin, characterized in that: The method comprises the following steps: (1) subjecting a wet solid daptomycin product having a total mass content of solvent and / or water of more than 50% to ultrasonic vacuum drying to obtain a solid daptomycin intermediate; (2) boiling and drying the daptomycin solid intermediate in a nitrogen boiling drying device to obtain a daptomycin final product.

2. The method for drying daptomycin according to claim 1, characterized in that: In step (1), drying is performed until the residual solvent content reaches 1500-3000 ppm.

3. The drying method of daptomycin according to claim 2, characterized in that: In step (1), ultrasonic vacuum drying is carried out in an ultrasonic vacuum drying oven, using ultrasonic intermittent drying. The vacuum degree is set to -0.085MPa to -0.07MPa, and the temperature is controlled below 28°C. The ultrasonic power is 200-300W, each ultrasonic time is 10-20 minutes, and the interval between two ultrasonic times is 5-10 minutes.

4. The method for drying daptomycin according to claim 3, characterized in that: In step (1), the temperature of ultrasonic vacuum drying is controlled within the range of 20-28°C.

5. The method for drying daptomycin according to claim 4, characterized in that: In step (1), drying is performed for 2.5-4 hours.

6. The method for drying daptomycin according to claim 5, characterized in that: In step (2), dry nitrogen is used as the medium, the drying temperature is controlled between 25-30°C, and the air volume is set to 40-100m 3 / h, drying time is controlled within 30-60 minutes.

7. The method for drying daptomycin according to claim 6, characterized in that: The ultrasonic power in step (1) is 250-300W, and the air volume in step (2) is set to 60-100m 3 / h.

8. The method for drying daptomycin according to claim 2 or 3, characterized in that: In step (2), dry nitrogen is used as the medium, the drying temperature is controlled between 25-30°C, and the air volume is set to 40-100m 3 / h, and dried to a moisture content of daptomycin of 2.9%-4.6%.

9. The method for drying daptomycin according to claim 8, characterized in that: The solvent is isopropanol, ethyl acetate, acetone or methanol.

10. The method for drying daptomycin according to claim 9, characterized in that: The total mass content of the solvent and / or water in the daptomycin wet solid product is 54%-61%.

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