Method for preparing drug sustained release microspheres by adding cosolvent

Abstract

The invention relates to a method for preparing drug sustained release microspheres by adding a cosolvent and microspheres prepared by using the method. According to the method disclosed by the invention, the preparation process of the microspheres can be effectively optimized by adding the cosolvent into the oil phase, and the active pharmaceutical ingredients with good water solubility can be fully dissolved in the organic solvent, so that the use of the internal water phase is reduced in the preparation process of the microspheres, the prepared microspheres are full and uniform in appearance, the surface layers and the interiors of the microspheres are free from large holes, and the service life of the microspheres is prolonged. The burst release phenomenon of the medicine is effectively reduced, and meanwhile, the slow release time of the medicine is greatly prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of microsphere preparation, in particular to a drug microsphere and a preparation method thereof. BACKGROUND

[0002] Goserelin is an analogue of gonadotropin-releasing hormone (GnRHa), which is an artificial chemical synthesis extremely similar to the structure of natural GnRH. It is mainly used in the treatment of hormone-responsive cancers such as prostate cancer and breast cancer, and estrogen-dependent diseases such as endometriosis, uterine fibroids, female infertility, precocious puberty, and prevention of premature ovulation in in vitro fertilization. These drugs are all gonadotropin-releasing hormone (GnRH) receptor agonist drugs, which can reduce the secretion of testosterone and estradiol by reducing gonadotropin. GnRH is a gonadotropin-releasing hormone synthesized and released by hypothalamic GnRH neurons, which stimulates the anterior pituitary to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which constitutes the basic steps of the hypothalamic-pituitary-ovarian axis.

[0003] The commonly used goserelin drugs in China include leuprolide, goserelin, triptorelin, etc., among which leuprolide acetate is the most commonly used. Leuprolide can effectively inhibit the function of the pituitary-gonadal system, and has stronger resistance to proteolytic enzymes and stronger affinity to pituitary GnRH receptors than GnRH. The activity of promoting luteinizing hormone (LH) release is about 20 times that of GnRH, and the inhibitory effect on the pituitary-gonadal function is also stronger than that of GnRH. In the early stage of medication, FSH, LH, estrogen or androgen may appear a short-term increase, and then due to the decrease in pituitary responsiveness, the secretion of FSH, LH and estrogen or androgen is inhibited, thereby having a therapeutic effect on sex hormone-dependent diseases (such as prostate cancer, endometriosis, etc.).

[0004] At present, the long-acting sustained-release injection products of leuprolide and triptorelin on the market in China are all microsphere preparations, with an onset time of 1 month, 3 months and 6 months, and a more optimal duration of treatment effect.

[0005] The microspheres prepared by the complex emulsion method (w / o / w) is one of the most common means of industrial production, especially suitable for the preparation of microspheres of polypeptide drugs such as leuprolide, which is easily soluble in water. However, due to the introduction of the inner water phase in the preparation process, the preparation steps are usually more complex and cumbersome than the single emulsion method (o / w), and the process control is more difficult. In order to make the active pharmaceutical ingredients fully dissolved in the inner water phase, heating is usually required during the preparation process, which greatly increases the risk of polypeptide impurities during the preparation process. In addition, the introduction of the inner water phase usually causes the inevitable appearance of holes of different sizes on the surface of the microspheres, thereby increasing the burst release of the microspheres in the body at the initial stage of drug use, and the high blood drug concentration makes the toxic and side effects of the drug easy to appear and greatly shortens the drug release period. SUMMARY

[0006] The inventors found in the research that by using an improved o / w emulsification technology, the addition of a cosolvent in the oil phase can effectively optimize the preparation process of the microspheres, so that the water-soluble active pharmaceutical ingredients such as leuprolide acetate, triptorelin acetate and goserelin acetate can be fully dissolved in the organic solvent, thereby reducing the use of the inner water phase in the preparation process of the microspheres, and the prepared microspheres are full and uniform in appearance, and there are no large holes on the surface and inside of the microspheres, effectively reducing the burst release of the drug, and greatly prolonging the drug release time. The microsphere preparation contains active pharmaceutical ingredients and biocompatible polymer materials, which can overcome the problems of complex process, large burst release and short release period of leuprolide microsphere preparation caused by complex emulsion method. Through this improved o / w emulsification technology, the present application can prepare a stable release that can maintain the drug for 1.5 to 4 months. The method needs to control the following steps:

[0007] 1. Control the mass percentage of cosolvent and biocompatible polymer material. In the preparation process of the microspheres, the active pharmaceutical ingredients and the cosolvent are pretreated to obtain a solid powder mixture, which is then added to the oil phase to make the active pharmaceutical ingredients fully dissolved in the oil phase, and then the o / w one-step emulsion method is used to prepare the microspheres, which can increase the encapsulation efficiency of the microspheres, and the active pharmaceutical ingredients can be uniformly distributed in the microspheres, which is beneficial to the sustained release effect of the microspheres.

[0008] 2. Control the mass percentage of active pharmaceutical ingredients and biocompatible polymer material. In the preparation process of the microspheres, the mass percentage of the active pharmaceutical ingredients and the biocompatible polymer material is controlled, so that enough active pharmaceutical ingredients are loaded in the microspheres to achieve a sustained release effect of 1.5-4 months, and at the same time, the appearance of the microspheres is not affected, and the appearance of broken spheres and irregular spheres is not caused.

[0009] 3. Controlling the mass percentage of the biocompatible polymer material and the oil phase. Controlling the mass percentage of the biocompatible polymer material and the oil phase in the preparation process of the microspheres, so that the biocompatible polymer material in the oil phase cannot be too low to cause the subsequent emulsion droplets to easily appear demulsification and stratification, and too high to cause the viscosity of the oil phase to be too high, causing insufficient encapsulation rate, and the prepared microspheres to be poor in sphericity and irregular in shape.

[0010] In order to achieve the above object, the technical scheme of the present application is as follows:

[0011] A) dissolving and dispersing the biocompatible polymer material, the active pharmaceutical ingredient and the cosolvent in the organic solvent to obtain an oil phase;

[0012] B) dissolving the surfactant in water to obtain an external water phase;

[0013] C) adding the prepared oil phase into the above-mentioned external water phase to mix and emulsify, obtaining a mixed emulsion;

[0014] D) solidifying, drying and sieving the mixed emulsion to obtain the sustained-release microspheres containing the active pharmaceutical ingredient.

[0015] Preferably, the active pharmaceutical ingredient is a polypeptide drug, which can be one or a mixture of several of the following: leuprolide and / or a pharmaceutically acceptable salt thereof, triptorelin and / or a pharmaceutically acceptable salt thereof, goserelin and / or a pharmaceutically acceptable salt thereof. Further preferably, it can be any one or a mixture of several of the following: leuprolide acetate, triptorelin acetate, goserelin acetate.

[0016] Preferably, the mass percentage of the cosolvent and the biocompatible polymer material is 1-21wt%.

[0017] Preferably, the mass percentage of the active pharmaceutical ingredient and the biocompatible polymer material is 4-15wt%.

[0018] Preferably, the mass percentage concentration of the biocompatible polymer material in the organic solvent is 10-30wt%.

[0019] Preferably, the mass percentage concentration of the surfactant in the external water phase is 0.1-3.0wt%.

[0020] Preferably, the ratio of the mass of the organic solvent to the volume of the external water phase is 1:50-1:300 (g / mL).

[0021] Preferably, the organic solvent is dichloromethane.

[0022] Preferably, the biocompatible polymer material is one or a mixture of several of polylactic-co-glycolic acid (PLGA), polylactic acid (PLA), polyglycolide (PGA) and polycaprolactone (PCL).

[0023] Preferably, the surfactant is one or a mixture of several of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), β-cyclodextrin, poloxamer 188, pluronic F88, pluronic F127, gelatin, glycine, lysine, histidine, arginine, aspartic acid, glutamic acid span and tween.

[0024] Preferably, in step D), the mixed emulsion is solidified into wet microspheres, a protective agent is added, and drying is performed.

[0025] Preferably, the preparation method further comprises the following steps: after obtaining the mixed emulsion, stirring, solidification, filtration, water washing are performed on the mixed emulsion to form wet microspheres, and after adding a protective agent in the wet microspheres, drying is performed to obtain sustained-release microspheres containing a pharmaceutically active ingredient.

[0026] Preferably, the protective agent is one or a mixture of several of polyethylene glycol (PEG), gelatin, glycerol, mannitol, sucrose, trehalose, lactose, glucose, propylene glycol, sorbitol, zinc chloride, zinc sulfate, zinc acetate and human serum albumin.

[0027] Preferably, other excipients are added at the same time as the protective agent, and the other excipients are surfactants and / or excipients.

[0028] As another aspect of the present application, there is also provided a sustained-release drug microsphere for injection prepared according to any of the above methods.

[0029] According to the present application, in step A) of the method for preparing the sustained-release drug microsphere for injection of the present application, the oil phase can be a solution containing a biocompatible polymer material, a pharmaceutically active ingredient and a cosolvent. The pharmaceutically active ingredient can be leuprolide acetate, triptorelin acetate, goserelin acetate, etc.

[0030] In an embodiment according to the present application, the mass percentage of the cosolvent to the biocompatible polymer material is 1-21wt%, and the calculation formula is: mass percentage of the cosolvent to the biocompatible polymer material = mass of the cosolvent / mass of the biocompatible polymer material * 100%.

[0031] In an embodiment according to the present application, the mass percentage of the pharmaceutically active ingredient and the biocompatible polymer material is 4-15wt%, and the calculation formula is: mass percentage of the pharmaceutically active ingredient and the biocompatible polymer material = mass of the pharmaceutically active ingredient / mass of the biocompatible polymer material * 100%.

[0032] According to the present application, in step C) of the method for preparing the drug sustained-release microspheres for injection, the emulsion preparation method can be carried out by a high-shear mixing emulsifier, an ultrasonic disrupter, a high-pressure homogenizer, a static mixer or a combination thereof. Among them, the emulsion temperature needs to be kept between 0-15℃; the rotation speed of the high-shear emulsifier can be 3000rpm-8000rpm, and the shearing time can be 0.5min-10min; the pressure of the high-pressure homogenizer can be 100bar-800bar, and the number of continuous homogenization can be 2-6 times.

[0033] In the present application, the calculation method of the mass percentage concentration of the biocompatible polymer material in the organic solvent is: mass percentage concentration of the biocompatible polymer material in the organic solvent = mass of the biocompatible polymer material / (mass of the biocompatible polymer material + mass of the organic solvent) * 100%.

[0034] In an embodiment according to the present application, the mass percentage concentration of the biocompatible polymer material in the organic solvent is preferably 10-30wt%.

[0035] In a preferred embodiment according to the present application, the biocompatible polymer material is polylactic acid-glycolic acid copolymer (PLGA), and the molar ratio of lactide (LA) and glycolide (GA) in the PLGA is 50:50-85:15, the molecular weight is 5-100 kilodaltons, and the viscosity characteristic is 0.1-0.6dL / g; wherein the type and molecular weight of the PLGA include but are not limited to: PLGA (LA:GA is 50:50; Mw 10000-90000 daltons), PLGA (LA:GA is 55:45; Mw 15000-90000 daltons), PLGA (LA:GA is 65:35; Mw 15000-90000 daltons), PLGA (LA:GA is 75:25; Mw 10000-90000 daltons), or PLGA (LA:GA is 85:15; Mw 55000-90000 daltons).

[0036] In another preferred embodiment according to the present application, the biocompatible polymer material is polylactic acid (PLA), the molecular weight is 8-55 kilodaltons, and the viscosity characteristic is 0.1-0.75dL / g, for example, PLA (Mw 8000-32000 daltons).

[0037] According to the present application, in step A) of the method for preparing the drug sustained-release microspheres for injection, the cosolvent can be selected from one or more of poloxamer 188, poloxamer 407, polyethylene glycol, polysorbate, povidone, preferably the cosolvent is poloxamer 188.

[0038] According to the present application, in step A) of the method for preparing the drug sustained-release microspheres for injection, the way of adding the active pharmaceutical ingredient and the cosolvent into the oil phase can be direct sequential or simultaneous addition in proportion. The active pharmaceutical ingredient and the cosolvent can also be pretreated in any one or several of the following ways:

[0039] 1) The active pharmaceutical ingredient and the cosolvent are dissolved in water, then spray-dried or freeze-dried to obtain a solid mixture, and then added into the organic solvent;

[0040] 2) The active pharmaceutical ingredient and the cosolvent are mixed and hot-melt extruded, then cooled to obtain a solid mixture, and then added into the organic solvent.

[0041] The solid mixture after the above pretreatment can be quickly dissolved in the organic solvent, improving the dissolution efficiency and saving the microsphere preparation time.

[0042] According to the present application, in step B) of the method for preparing the drug sustained-release microspheres for injection, the surfactant can be selected from one or several of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), β-cyclodextrin, poloxamer 188, pluronic F88, pluronic F127, gelatin, glycine, lysine, histidine, arginine, aspartic acid, glutamic acid span, and tween; preferably, the surfactant is PVA, PVP or a combination thereof, and more preferably, the surfactant is polyvinyl alcohol (PVA).

[0043] In the present application, the mass percentage concentration of the surfactant in the external aqueous phase is calculated as follows: mass percentage concentration of the surfactant in the external aqueous phase = mass of the surfactant / (mass of the surfactant + mass of water) * 100%.

[0044] In the embodiments according to the present application, the mass percentage concentration of the surfactant in the external aqueous phase is 0.1-3wt%.

[0045] In the preferred embodiments according to the present application, in step B) of the method for preparing the drug sustained-release microspheres for injection, the ratio of the mass of the organic solvent to the volume of the external aqueous phase is preferably 1:50-1:300, in g / mL.

[0046] According to the present application, in step D) of the method for preparing the sustained-release microspheres for injection, if stirring is performed, the stirring speed can be 100-1000 rpm, and the stirring time can be 15-150 min.

[0047] According to the present application, in step D) of the method for preparing the sustained-release microspheres for injection, the solidification temperature can be 5℃-45℃, and the solidification time can be 2h-24h.

[0048] According to the present application, in step D) of the method for preparing the sustained-release microspheres for injection, a lyophilization protective agent is added to the wet microspheres obtained by solidifying the mixed emulsion. The protective agent is an auxiliary material added to the wet microspheres to increase the flowability and dispersibility of the dry powder of the microspheres obtained according to step D), and to adjust the osmotic pressure of the microspheres and protect the stability and activity of the small molecule drug. The lyophilization protective agent can be selected from one or a mixture of several of polyethylene glycol (PEG), gelatin, glycerol, mannitol, sucrose, trehalose, lactose, glucose, propylene glycol, sorbitol, zinc chloride, zinc sulfate, zinc acetate, and human serum albumin; preferably, the lyophilization protective agent is mannitol.

[0049] The present application also provides a sustained-release microsphere for injection, which comprises the sustained-release microsphere for injection prepared according to the above method, and the sustained-release microsphere for injection comprises the active ingredient of leuprolide, triptorelin, or goserelin, a biocompatible polymer carrier material, and pharmaceutically acceptable other auxiliary materials.

[0050] The pharmaceutically acceptable other auxiliary materials include a co-solvent, a surfactant, and an excipient. In addition, the pharmaceutically acceptable other auxiliary materials can also include a lyophilization protective agent.

[0051] The sustained-release microsphere for injection has a sustained release time specification of about 1.5-4 months, i.e., about six weeks to sixteen weeks. The "about" and "approximately" represent a difference of "(±1-6 days)".

[0052] According to the present application, the microsphere particle size (D50) of the sustained-release microsphere for injection prepared by the above method is 5-100 μm, not only the microsphere particle size distribution is narrow (SPAN value (SPAN=(D90-D10) / D50) is less than 2.5), but also the encapsulation efficiency is significantly improved, the burst release rate is reduced, and the release time is prolonged. In addition, compared with the existing leuprolide, triptorelin, and goserelin products, the sustained-release microsphere for injection containing the active pharmaceutical ingredient according to the present application provides optimization of the preparation method, and realizes a more sustained release time than the current marketed products of the active pharmaceutical ingredient. Based on a 1-month marketed product, a 6-week sustained release time can be achieved by the preparation method of the present application. Based on a 3-month marketed product, a 4-month sustained release time can be achieved by the preparation method of the present application.

[0053] The technical scheme of the present application has the following beneficial effects:

[0054] The preparation method of the present application is relatively simple and easy to operate and can be used for industrial operation, and has universality; at the same time, the injection sustained-release microsphere preparation prepared according to the preparation method has a relatively narrow particle size distribution, and the encapsulation rate is significantly improved, and the release time is prolonged.

[0055] 1) The present application provides a novel microsphere preparation method for leuprolide acetate, triptorelin and goserelin, which comprises the following steps: preparing a solid powder mixture by pretreating the active pharmaceutical ingredient and the cosolvent, then adding the solid powder mixture into the oil phase to make the active pharmaceutical ingredient fully dissolved in the oil phase, and then preparing the microspheres by using the o / w one-step emulsification method, which not only improves the encapsulation rate but also makes the drug release more stable and last longer.

[0056] 2) The injection sustained-release microsphere preparation prepared according to the preparation method of the present application has a relatively narrow particle size distribution, and the release time of the active pharmaceutical ingredient can last for about six weeks to four months. In addition, the microsphere preparation prepared by the present application can stably maintain the drug concentration in the blood of animals, so that the sustained-release microspheres can better maintain the blood drug concentration within six weeks to four months without large fluctuations in blood drug concentration, and better avoid the occurrence of toxic side effects.

[0057] The injection sustained-release microsphere preparation prepared by the preparation method of the present application shows that the pharmacodynamic index of rats in the drug effect kinetics experiment in rats shows that the castration level of testosterone in the serum of rats can be maintained in an effective state within six weeks to four months, that is, it is indicated that the active pharmaceutical ingredient can be maintained in an effective therapeutic concentration within six weeks to four months. BRIEF DESCRIPTION OF DRAWINGS

[0058] Figure 1 is an electron micrograph of the microspheres prepared in Example 1;

[0059] Figure 2 is an electron micrograph of the microspheres prepared in Example 4;

[0060] Figure 3 is the in vitro cumulative release curve of Examples 1, 2, 4, 5, 7, 8, 11 and Comparative Preparations 1-5;

[0061] Figure 4 is the rat in vivo blood drug concentration-time graph of Examples 1, 2, 4, 5, 7 and Comparative Preparations 1-3;

[0062] Figure 5 is the rat in vivo blood drug concentration-time graph of Examples 9, 11 and Comparative Preparations 4, 5;

[0063] Figure 6are rat in vivo testosterone concentration-time profiles of Example 1, 2, 4, 5, 7 and Comparative Formulation 1-3;

[0064] Figure 7 are rat in vivo testosterone concentration-time profiles of Example 9, 11 and Comparative Formulation 4, 5. DETAILED DESCRIPTION

[0065] The present application will be further described with reference to the accompanying drawings and specific examples, but the present application should not be limited by the specific embodiments disclosed below.

[0066] In the following examples, the preparation of microspheres for injection according to the method of the present application will be exemplified, wherein the leuprolide acetate used has the molecular formula C 59 H 84 N 16 O 12 C2H4O2, with a molar mass of 1269.45 g / mol (CAS: 124508-66-3); the triptorelin acetate used has the molecular formula C 64 H 82 N 18 O 13 C2H4O2, with a molar mass of 1371.52 g / mol (CAS: 140194-24-7); the goserelin acetate used has the molecular formula C 59 H 84 N 18 O 14 C2H4O2, with a molar mass of 1329.49 g / mol (CAS: 145781-92-6).

[0067] By pre-treating the solid powder mixture by dissolving the pharmaceutically active ingredient and the co-solvent and then spraying or freeze-drying, or by mixing and then directly hot-melt extruding, etc., the dissolution in the organic solvent can be accelerated. The examples of the present application use the method of directly adding the pharmaceutically active ingredient, and the methods used in the following examples are commonly used by those skilled in the art unless otherwise specified.

[0068] Example 1

[0069] An oil phase was prepared by dissolving 10.0 g of PLGA (molar ratio of glycolide to lactide 75:25, Mw=10000-55000 Dalton) in 30.0 g of dichloromethane, adding leuprolide acetate 0.5 g and poloxamer 0.15 g, and shaking / shearing to dissolve them completely; an aqueous solution of polyvinyl alcohol (PVA) for injection was prepared by dissolving 5000 mL of PVA at a mass percentage of 0.25% in distilled water, as an external water phase; the oil phase was mixed with the external water phase at about 10°C using a high-shear emulsifier, the shearing speed of the emulsifier was 4000 rpm, and the emulsification time was 0-10 minutes, and the mixture was uniformly emulsified to form an emulsion. The emulsion was removed of the organic solvent at a stirring speed of 300 rpm and a temperature of 20-25°C, and the microspheres were solidified for about 4 hours; the emulsion after solidification was filtered to collect the microspheres, washed with distilled water several times, and then collected, a protective agent was added, and the mixture was freeze-dried to obtain a leuprolide acetate microsphere preparation.

[0070] The average particle size (D50) of the microspheres of the preparation was 28 μm, and the SPAN value (SPAN=(D90-D10) / D50) was 1.83. The prepared sustained-release microspheres were quantitatively determined by HPLC, and the encapsulation efficiency was 88.61%.

[0071] Example 2

[0072] An oil phase was prepared by dissolving 10.0 g of PLGA (molar ratio of glycolide to lactide 75:25, Mw=10000-55000 Dalton) in 30.0 g of dichloromethane, adding leuprolide acetate 0.5 g and poloxamer 0.15 g, and shaking / shearing to dissolve them completely; an aqueous solution of polyvinyl alcohol (PVA) for injection was prepared by dissolving 5000 mL of PVA at a mass percentage of 0.25% in distilled water, as an external water phase; the oil phase was mixed with the external water phase at about 10°C using a high-shear emulsifier, the shearing speed of the emulsifier was 4000 rpm, and the emulsification time was 0-10 minutes, and the mixture was uniformly emulsified to form an emulsion. The emulsion was removed of the organic solvent at a stirring speed of 300 rpm and a temperature of 20-25°C, and the microspheres were solidified for about 4 hours; the emulsion after solidification was filtered to collect the microspheres, washed with distilled water several times, and then collected, a protective agent was added, and the mixture was freeze-dried to obtain a leuprolide acetate microsphere preparation.

[0073] The average particle size (D50) of the microspheres of the preparation was 28 μm, and the SPAN value (SPAN=(D90-D10) / D50) was 1.83. The prepared sustained-release microspheres were quantitatively determined by HPLC, and the encapsulation efficiency was 88.61%.

[0074] Example 3

[0075] An oil phase was prepared by dissolving 10.0 g of PLGA (molar ratio of glycolide to lactide 75:25, Mw=10000-55000 Dalton) in 30.0 g of dichloromethane, adding leuprolide acetate 0.5 g and poloxamer 1.0 g, and shaking / shearing to dissolve them completely; an aqueous solution of polyvinyl alcohol (PVA) for injection was prepared by dissolving 0.25% PVA in 2000 mL of distilled water; the oil phase was mixed with the external aqueous phase at about 10°C using a high-shear emulsifier at a shearing speed of 4000 rpm for 0-10 minutes to form an emulsion; the emulsion was stirred at 300 rpm and 20-25°C to remove the organic solvent and solidify the microspheres for 4 hours; the emulsion was filtered to collect the microspheres, washed with distilled water, and then collected; a protective agent was added and the mixture was freeze-dried to obtain a leuprolide acetate microsphere preparation.

[0076] The average particle size (D50) of the microspheres of the preparation was 31 μm, and the SPAN value (SPAN=(D90-D10) / D50) was 1.79. The prepared sustained-release microspheres were quantitatively determined by HPLC, and the encapsulation efficiency was 92.69%.

[0077] Example 4

[0078] An oil phase was prepared by dissolving 10.0 g of PLGA (molar ratio of glycolide to lactide 75:25, Mw=10000-55000 Dalton) in 30.0 g of dichloromethane, adding leuprolide acetate 0.5 g and poloxamer 1.0 g, and shaking / shearing to dissolve them completely; an aqueous solution of polyvinyl alcohol (PVA) for injection was prepared by dissolving 0.25% PVA in 2000 mL of distilled water; the oil phase was mixed with the external aqueous phase at about 10°C using a high-shear emulsifier at a shearing speed of 4000 rpm for 0-10 minutes to form an emulsion; the emulsion was stirred at 300 rpm and 20-25°C to remove the organic solvent and solidify the microspheres for 4 hours; the emulsion was filtered to collect the microspheres, washed with distilled water, and then collected; a protective agent was added and the mixture was freeze-dried to obtain a leuprolide acetate microsphere preparation.

[0079] The average particle size (D50) of the microspheres of the preparation was 31 μm, and the SPAN value (SPAN=(D90-D10) / D50) was 1.79. The prepared sustained-release microspheres were quantitatively determined by HPLC, and the encapsulation efficiency was 92.69%.

[0080] Example 5

[0081] An oil phase was prepared by dissolving 10.0 g of PLGA (molar ratio of glycolide to lactide 50:50, Mw=10000-55000 Dalton) in 40.0 g of dichloromethane, adding triptorelin acetate 0.5 g and poloxamer 1.5 g, and shaking / shearing to dissolve them completely; 2000 mL of a 1.0% polyvinyl alcohol (PVA) aqueous solution for injection was prepared as an external aqueous phase; the oil phase and the external aqueous phase were mixed at about 10°C using a high-shear emulsifier, the shearing speed of the emulsifier was 4000 rpm, and the emulsification time was 0-10 minutes, and the mixture was uniformly emulsified to form an emulsion. The emulsion was removed from the organic solvent at a stirring speed of 300 rpm and a temperature of 20-25°C, and the microspheres were solidified for 4 hours; the emulsion after solidification was filtered to collect the microspheres, washed with distilled water several times, then collected, and freeze-dried after adding a protective agent, thereby obtaining a triptorelin acetate microsphere preparation.

[0082] The average particle size (D50) of the microspheres of the preparation was 41 μm, and the SPAN value (SPAN=(D90-D10) / D50) was 1.98. The prepared sustained-release microspheres were quantitatively determined by HPLC, and the encapsulation efficiency was 92.40%.

[0083] Example 6

[0084] An oil phase was prepared by dissolving 10.0 g of PLGA (molar ratio of glycolide to lactide 50:50, Mw=10000-55000 Dalton) in 40.0 g of dichloromethane, adding triptorelin acetate 0.5 g and poloxamer 1.5 g, and shaking / shearing to dissolve them completely; 2000 mL of a 1.0% polyvinyl alcohol (PVA) aqueous solution for injection was prepared as an external aqueous phase; the oil phase and the external aqueous phase were mixed at about 10°C using a high-shear emulsifier, the shearing speed of the emulsifier was 4000 rpm, and the emulsification time was 0-10 minutes, and the mixture was uniformly emulsified to form an emulsion. The emulsion was removed from the organic solvent at a stirring speed of 300 rpm and a temperature of 20-25°C, and the microspheres were solidified for 4 hours; the emulsion after solidification was filtered to collect the microspheres, washed with distilled water several times, then collected, and freeze-dried after adding a protective agent, thereby obtaining a triptorelin acetate microsphere preparation.

[0085] The average particle size (D50) of the microspheres of the preparation was 41 μm, and the SPAN value (SPAN=(D90-D10) / D50) was 1.98. The prepared sustained-release microspheres were quantitatively determined by HPLC, and the encapsulation efficiency was 92.40%.

[0086] Example 7

[0087] An oil phase was prepared by dissolving 10.0 g of PLGA (molar ratio of glycolide to lactide 75:25, Mw=10,000-55,000 Dalton) in 25.0 g of dichloromethane, adding 0.5 g of goserelin acetate and 1.5 g of poloxamer, and shaking / shearing to dissolve them completely; 2,000 mL of a 0.25% polyvinyl alcohol (PVA) aqueous solution for injection was prepared as an external aqueous phase; and the oil phase and the external aqueous phase were mixed at about 10°C using a high-shear emulsifier at a shearing speed of 4,000 rpm for 0-10 minutes to form an emulsion. The emulsion was stirred at 300 rpm and 20-25°C to remove the organic solvent, and the microspheres were solidified by volatilization for 4 hours. The emulsion after solidification was filtered to collect the microspheres, washed with distilled water several times, and then collected. After adding a protective agent, the microspheres were freeze-dried to obtain a goserelin acetate microsphere preparation.

[0088] The average particle size (D50) of the microspheres of the preparation was 43 μm, and the SPAN value (SPAN=(D90-D10) / D50) was 1.88. The prepared sustained-release microspheres were quantitatively measured by HPLC, and the encapsulation efficiency was 87.60%.

[0089] Example 8

[0090] An oil phase was prepared by dissolving 20.0 g of PLA (Mw=8,000-55,000 Dalton) in 50.0 g of dichloromethane, adding 1.5 g of leuprolide acetate and 1.5 g of poloxamer, and shaking / shearing to dissolve them completely; 5,000 mL of a 0.25% polyvinyl alcohol (PVA) aqueous solution for injection was prepared as an external aqueous phase; and the oil phase and the external aqueous phase were mixed at 10°C using a high-shear emulsifier at a shearing speed of 4,000 rpm for 0-10 minutes to form an emulsion. The emulsion was stirred at 300 rpm and 20-25°C to remove the organic solvent, and the microspheres were solidified by volatilization for 4 hours. The emulsion after solidification was filtered to collect the microspheres, washed with distilled water several times, and then collected. After adding a protective agent, the microspheres were freeze-dried to obtain a leuprolide acetate microsphere preparation.

[0091] The average particle size (D50) of the microspheres of the preparation was 39 μm, and the SPAN value (SPAN=(D90-D10) / D50) was 1.95. The prepared sustained-release microspheres were quantitatively measured by HPLC, and the encapsulation efficiency was 90.01%.

[0092] Example 9

[0093] An oil phase was prepared by dissolving 10.0 g of PLGA (molar ratio of glycolide to lactide 75:25, Mw=55000-90000 Dalton) in 50.0 g of dichloromethane, adding leuprolide acetate 1.5 g and poloxamer 3.0 g, and shaking / shearing to dissolve them completely; an external aqueous phase was prepared by preparing 5000 mL of a 0.25% polyvinyl alcohol (PVA) aqueous solution for injection; and the oil phase and the external aqueous phase were mixed by a high-shear emulsifier at about 10°C, the shearing speed of the emulsifier was 4000 rpm, and the emulsification time was 0-10 minutes, to form an emulsion. The emulsion was removed of the organic solvent at a stirring speed of 300 rpm and a temperature of 20-25°C, and the microspheres were solidified for 4 hours; the emulsion after solidification was filtered to collect the microspheres, washed with distilled water several times, and then collected, and a protective agent was added to perform freeze-drying, to obtain a leuprolide acetate microsphere preparation.

[0094] The average particle size (D50) of the microspheres of the preparation was 37 μm, and the SPAN value (SPAN=(D90-D10) / D50) was 1.77. The prepared sustained-release microspheres were quantitatively determined by HPLC, and the encapsulation efficiency was 91.64%.

[0095] Example 10

[0096] An oil phase was prepared by dissolving 20.0 g of PLA (Mw=8000-55000 Dalton) in 80.0 g of dichloromethane, adding triptorelin acetate 1.5 g and poloxamer 1.5 g, and shaking / shearing to dissolve them completely; an external aqueous phase was prepared by preparing 5000 mL of a 0.25% polyvinyl alcohol (PVA) aqueous solution for injection; and the oil phase and the external aqueous phase were mixed by a high-shear emulsifier at 10°C, the shearing speed of the emulsifier was 4000 rpm, and the emulsification time was 0-10 minutes, to form an emulsion. The emulsion was removed of the organic solvent at a stirring speed of 300 rpm and a temperature of 20-25°C, and the microspheres were solidified for 4 hours; the emulsion after solidification was filtered to collect the microspheres, washed with distilled water several times, and then collected, and a protective agent was added to perform freeze-drying, to obtain a triptorelin acetate microsphere preparation.

[0097] The average particle size (D50) of the microspheres of the preparation was 36 μm, and the SPAN value (SPAN=(D90-D10) / D50) was 2.32. The prepared sustained-release microspheres were quantitatively determined by HPLC, and the encapsulation efficiency was 88.32%.

[0098] Example 11

[0099] An oil phase was prepared by dissolving 10.0 g of PLA (Mw = 8000-55000 Dalton) in 40.0 g of dichloromethane, adding triptorelin acetate 2.0 g and poloxamer 2.0 g, and shaking / shearing to fully dissolve; 5000 mL of a 0.25% polyvinyl alcohol (PVA) aqueous solution for injection was prepared as an external aqueous phase; the oil phase and the external aqueous phase were mixed in a high-shear emulsifier at 10°C, the shear speed of the emulsifier was 4000 rpm, the emulsification time was 0-10 minutes, and the mixture was uniformly emulsified to form an emulsion. The emulsion was removed from the organic solvent at a stirring speed of 300 rpm and a temperature of 20-25°C, and the volatilized microspheres were solidified for 4 hours; after solidification, the emulsion was filtered to collect the microspheres, washed with distilled water several times, then collected, and freeze-dried after adding a protective agent to obtain a triptorelin acetate microsphere preparation.

[0100] The average particle size (D50) of the microspheres of the preparation was 40 μm, and the SPAN value (SPAN = (D90-D10) / D50) was 1.98. The prepared sustained-release microspheres were quantitatively determined by HPLC, and the encapsulation efficiency was 89.81%.

[0101] Test Example 1: Microsphere Particle Size Test

[0102] About 10 mg of the microsphere preparation was added to about 1 mL of a dispersion medium and vortexed to mix, and then ultrasonically dispersed until no obvious agglomeration of particles was observed. The dispersion was added to a laser particle size analyzer (Chinese Pharmacopoeia 2020 Edition General Rule 0982 Third Method) (Malvern mastersizer 3000 laser particle size instrument or equivalent instrument) for measurement, with olive oil as the dispersion medium, a stirring speed of 2000 rpm per minute, an obscuration in the range of 5%-15%, a background / sample measurement time of 10 s, a dispersion medium refractive index of 1.47, a particle refractive index of 1.65, an absorbance of 0.1, and a particle density of 1 g / cm 3 Three consecutive measurements were made, and the average of the three results was taken as the reported value to obtain the D50 test result and its SPAN value.

[0103] Test Example 2: In Vitro Release Rate Test

[0104] In this Test Example 2, the triptorelin acetate, triptorelin acetate, and goserelin acetate sustained-release microsphere preparations prepared in Examples 1, 2, 4, 5, 7, 8, 11, and Comparative Examples 1-5 above were used as examples for in vitro release rate testing. The specific method is as follows:

[0105] Respective 20 mg of the prepared sustained-release microsphere preparation in different examples and comparative examples was precisely weighed and added into a 15 mL centrifuge tube, 15 mL of preheated release medium, which was 0.05 M pH 7.4 phosphate buffer, was added, and then the tube was placed in a 37 °C incubator. At the corresponding time point, 1 mL was sampled and 1 mL of the corresponding release medium was added. The 24-hour burst release rate and total cumulative release rate of the obtained examples 1, 2, 4, 5, 7, 8, 11 and comparative examples 1-5 were tested and are shown in Table 1:

[0106] Table 1: 24-hour burst release rate and total cumulative release rate of the obtained examples 1, 2, 4, 5, 7, 8, 11 and comparative examples 1-5 tested:

[0107] Test sample 24 hour burst rate (%) Total cumulative release rate (%) Duration of in vitro release (days) Example 1 1.5 98 45 Example 2 1.1 99 45 Example 4 1.3 97 45 Example 5 1.2 98 45 Example 7 1.6 99 45 Example 8 1.2 98 120 Example 11 0.8 99 120 Comparative formulation 1 2.5 98 24 Comparative formulation 2 2.3 99 31 Comparative formulation 3 2.8 99 22 Comparative formulation 4 1.5 99 90 Comparative formulation 5 2.2 100 100

[0108] The in-vitro cumulative release curve of the obtained examples 1, 2, 4, 5, 7, 8, 11 and comparative examples 1-5 tested is shown in Figure 3 .

[0109] Comparative Example 1: Comparison of Different Amounts of Cosolvent

[0110] In comparative example 1, comparative preparations 1-3 were prepared by using different amounts of cosolvent to prepare leuprolide acetate and goserelin acetate microspheres according to the above examples 1-4 of the application. The preparation methods of comparative preparations 1-3 were the same as examples 1-11, which used the single emulsion method to prepare microspheres. The main difference was that no cosolvent was added and the content of cosolvent was greater than 20%. However, due to the different amounts of cosolvent added, the prepared microspheres may have problems such as poor sphericity, large burst release, and short release period due to the failure of the active ingredient to completely dissolve in the oil phase.

[0111] Preparation of Comparative Preparation 1

[0112] After 10.0 g of PLGA (molar ratio of glycolide to lactide 75:25, Mw = 10000-55000 Dalton) was dissolved in 30.0 g of dichloromethane, 0.5 g of leuprolide acetate was added and shaken / sheared to mix uniformly to prepare an oil phase; 5000 mL of 0.25% polyvinyl alcohol (PVA) aqueous solution for injection was prepared as an external aqueous phase; the oil phase and the external aqueous phase were mixed at about 10 °C by a high-shear emulsifier, the shearing speed of the emulsifier was 4000 rpm, the emulsification time was 0-10 minutes, and the emulsion was mixed uniformly. The emulsion was removed from the organic solvent at a stirring speed of 300 rpm and a temperature of 20-25 °C, and the microspheres were volatilized and solidified for 4 hours; after solidification, the emulsion was filtered and collected by a filter, washed with distilled water several times, then collected, and freeze-dried after adding a protective agent to obtain leuprolide acetate microsphere preparation.

[0113] The microspheres of the preparation had an average particle size (D50) of 34 μm and a SPAN value (SPAN = (D90-D10) / D50) of 1.69. The prepared sustained-release microspheres were quantitatively determined by HPLC, and the encapsulation efficiency was 76.50%. The in-vitro release duration was 24 days.

[0114] Preparation of Comparative Preparation 2

[0115] After 10.0 g of PLGA (in which the molar ratio of glycolide to lactide was 75:25, and Mw = 10,000-55,000 Dalton) was dissolved in 30.0 g of dichloromethane, 0.5 g of leuprolide acetate and 3.0 g of poloxamer were added and dissolved by shaking / shearing to prepare an oil phase; 5,000 mL of a 0.25% polyvinyl alcohol (PVA) aqueous solution for injection was prepared as an external aqueous phase; and the primary emulsion was mixed with the external aqueous phase at about 10°C by a high-shear emulsifier at a shearing speed of 4,000 rpm for 0-10 minutes to uniformly form an emulsion. The emulsion was removed of organic solvents at a stirring speed of 300 rpm and a temperature of 20-25°C, and the microspheres were solidified by volatilization for 4 hours; the emulsion after solidification was filtered through a filter to collect the microspheres, which were washed with distilled water several times, then collected, and freeze-dried after the addition of a protective agent, thereby obtaining a leuprolide acetate microsphere preparation.

[0116] The microspheres of the preparation had an average particle size (D50) of 40 μm and a SPAN value (SPAN = (D90-D10) / D50) of 1.75. The prepared sustained-release microspheres were quantitatively determined by HPLC, and the encapsulation efficiency was 77.49%. The in-vitro release duration was 31 days.

[0117] Preparation of Comparative Preparation 3

[0118] After 10.0 g of PLGA (in which the molar ratio of glycolide to lactide was 75:25, and Mw = 10,000-55,000 Dalton) was dissolved in 25.0 g of dichloromethane, 0.5 g of goserelin acetate was added and mixed uniformly by shaking / shearing to prepare an oil phase; 2,000 mL of a 0.25% polyvinyl alcohol (PVA) aqueous solution for injection was prepared as an external aqueous phase; and the oil phase was mixed with the external aqueous phase at about 10°C by a high-shear emulsifier at a shearing speed of 4,000 rpm for 0-10 minutes to uniformly form an emulsion. The emulsion was removed of organic solvents at a stirring speed of 300 rpm and a temperature of 20-25°C, and the microspheres were solidified by volatilization for 4 hours; the emulsion after solidification was filtered through a filter to collect the microspheres, which were washed with distilled water several times, then collected, and freeze-dried after the addition of a protective agent, thereby obtaining a goserelin acetate microsphere preparation.

[0119] The microspheres of the preparation have an average particle size (D50) of 45 μm and a SPAN value (SPAN = (D90-D10) / D50) of 1.78. The prepared sustained-release microspheres are quantitatively determined by HPLC, and the encapsulation efficiency is 80.85%. The in-vitro release duration is 22 days.

[0120] The microspheres of the above preparation are observed under a scanning electron microscope, and a large number of broken microspheres are found, and the microsphere morphology is uneven, and a large number of particulate matter appears on the surface, and the apparent properties do not meet the requirements of the microsphere preparation. The prepared sustained-release microspheres are determined by HPLC, and the encapsulation efficiency is generally lower than that of Examples 1-11. It may be due to the fact that the drug is not completely dissolved or the proportion of the cosolvent in the microspheres is too large, and the amount of the polymer is too small, so that the emulsion droplets cannot be encapsulated, and it is difficult to form a complete spherical scaffold, resulting in the loss of most of the drug.

[0121] Comparative Example 2: Comparison of Different Emulsification Processes

[0122] In Comparative Example 2, Comparative Preparations 4-5 compare the preparation of leuprolide acetate and triptorelin acetate microspheres using a w / o / w double emulsion process based on the above Examples 8-11 of the application. The method for preparing Comparative Preparations 4-5 uses a double emulsion method to prepare microspheres, and the main difference from Examples 8-11 is that Examples 8-11 use an o / w emulsion method (add a cosolvent to help the active pharmaceutical ingredient dissolve in the oil phase), while Comparative Preparations 4-5 use a w / o / w double emulsion method (introduce an internal water phase to dissolve the active pharmaceutical ingredient in the internal water phase).

[0123] Preparation of Comparative Preparation 4

[0124] 1.5 g of leuprolide acetate is dissolved in 1.5 g of water, and the internal water phase is obtained after heating to completely dissolve it. Then 10.0 g of PLGA (molar ratio of glycolide to lactide is 75:25, Mw = 55000-90000 Dalton) is dissolved in 50.0 g of dichloromethane to prepare an oil phase. A 0.25% polyvinyl alcohol (PVA) aqueous solution for injection is prepared at a concentration of 5000 mL, and used as an external water phase. The oil phase is first added to the internal water phase, and a primary emulsion is formed by shearing with a disperser at a shearing rate of 10000 rpm. Then the primary emulsion is mixed with the external water phase by a high-shear emulsifier at about 10°C, and the shearing speed of the emulsifier is 4000 rpm, the emulsification time is 0-10 minutes, and the mixture is uniformly formed into a double emulsion. The double emulsion is removed at a stirring speed of 300 rpm and a temperature of 20-25°C to remove the organic solvent, and the microspheres are volatilized and solidified for 4 hours. After solidification, the emulsion is filtered and collected by a filter, washed with distilled water several times, then collected, and freeze-dried after adding a protective agent, to obtain leuprolide acetate microsphere preparation.

[0125] The microspheres of the preparation have an average particle size (D50) of 31 μm and a SPAN value (SPAN = (D90-D10) / D50) of 2.02. The prepared sustained-release microspheres were quantitatively determined by HPLC, and the encapsulation rate was 83.34%. The in-vitro release duration was 90 days.

[0126] Preparation of Comparative Preparation 5

[0127] 1.5 g of triptorelin acetate was dissolved in 1.5 g of water, and the inner water phase was obtained after heating to complete dissolution. Then, 10.0 g of PLA (Mw = 8000-55000 Dalton) was dissolved in 50.0 g of dichloromethane to prepare the oil phase. A 5000 mL aqueous solution of polyvinyl alcohol (PVA) with a concentration of 0.25% was prepared as the outer water phase. The oil phase was first added to the inner water phase, and the primary emulsion was formed by shearing with a disperser at a shearing rate of 10000 rpm. Then, the primary emulsion was mixed with the outer water phase by a high-shear emulsifier at about 10°C, and the shearing speed of the emulsifier was 4000 rpm. The emulsification time was 0-10 minutes, and the mixture was uniformly formed into a multiple emulsion. The organic solvent was removed from the multiple emulsion at a stirring speed of 300 rpm and a temperature of 20-25°C, and the microspheres were volatilized and solidified for 4 hours. After solidification, the emulsion was filtered and collected by a filter, and then washed with distilled water for several times. After collection, a protective agent was added, and the triptorelin acetate microspheres were obtained by freeze-drying.

[0128] The microspheres of the preparation have an average particle size (D50) of 34 μm and a SPAN value (SPAN = (D90-D10) / D50) of 2.13. The prepared sustained-release microspheres were quantitatively determined by HPLC, and the encapsulation rate was 81.19%. The in-vitro release duration was 100 days.

[0129] According to the in-vitro release test method described in Test Example 2 of the present application, the in-vitro release duration of Comparative Preparations 4-5 was about 90-100 days, which was significantly shorter than 125 days of Examples 8 and 11.

[0130] Test Example 3: Single-dose pharmacokinetics and pharmacodynamics experiments in rats

[0131] In this Test Example 3, the pharmacokinetics and pharmacodynamics experiments in rats were performed by taking the triptorelin acetate, triptorelin acetate, and goserelin acetate injection sustained-release microsphere preparations prepared in Examples 1, 2, 4, 5, 7, 9, 11, and Comparative Preparations 1-5 above as examples. The specific method is as follows:

[0132] Male adult SD rats were selected as the research object, the rats weighed 300-400 g, and the rats were administered by intramuscular injection. The prepared leuprolide acetate, triptorelin acetate, and goserelin acetate sustained-release microspheres for injection according to the method of the application were administered at a dose of 1.0 mg / kg (Examples 1, 2, 4, 5, 7, and Comparative Preparations 1-3) and at a dose of 1.6 mg / kg (Examples 9, 11, and Comparative Preparations 4-5), and 0.3 mL of blood was taken from the jugular vein at a specific time after administration, transferred to a centrifuge tube containing 33.33 mg / mL aprotinin in EDTA-K2 anticoagulant, and the centrifuge tube was inverted 5-10 times to mix the anticoagulant with the blood. The mixture was temporarily stored on wet ice at room temperature. The plasma sample was separated by centrifugation at 4°C at 4000 rpm per minute for 15 minutes in a high-speed refrigerated centrifuge as soon as possible, and stored in a -80°C refrigerator. The blood drug concentration and testosterone concentration (ng / mL) in the plasma sample at each time point were determined by LC / MS-MS. The in vivo blood drug concentration-time curve is shown in Figure 4-5 The in vivo testosterone concentration-time curve is shown in Figure 6-7 .

[0133] As can be seen from Figure 4 , the release of the prepared sustained-release microspheres for injection according to the method of the application in rats can last for 42 days, and the drug concentration can be maintained in a stable interval within 42 days. In contrast, the drug duration of the comparative preparation is about 30 days. As can be seen from Figure 5 , the release of the prepared sustained-release microspheres for injection according to the method of the application in rats can last for 120 days, and the drug concentration can be maintained in a stable interval within 122 days. In contrast, the drug duration of the comparative preparation is about 93 days.

[0134] As can be seen from Figure 6 , the prepared sustained-release microspheres for injection according to the method of the application can effectively inhibit the testosterone concentration level in the serum of rats in an effective state (1.0 ng / mL), and the action time can be stably maintained for 45 days. As can be seen from Figure 7 , the prepared sustained-release microspheres for injection according to the method of the application can effectively inhibit the testosterone concentration level in the serum of rats in an effective state (1.0 ng / mL), and the action time can be stably maintained for 120 days.

[0135] The above examples only express several embodiments of the application, and the description is more specific and detailed, but it cannot be understood as limiting the scope of the patent of the application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the application, several modifications and improvements can be made, which belong to the protection scope of the application. Therefore, the protection scope of the patent of the application should be subject to the appended claims.

Claims

1. A method for preparing drug sustained-release microspheres by adding a solubilizer, comprising the following steps: A) A biocompatible polymer material, a pharmaceutical active ingredient, and a co-solvent are dissolved and dispersed in an organic solvent to obtain an oil phase; B) Dissolve the surfactant in water to prepare an external aqueous phase; C) The oil phase is added to the external aqueous phase and mixed and emulsified to obtain a mixed emulsion; D) The mixed emulsion is cured and dried to obtain sustained-release microspheres containing the active pharmaceutical ingredient.

2. The method according to claim 1, characterized in that: The active pharmaceutical ingredient is one or a mixture of the following: leuprorelin and / or its pharmaceutically acceptable salts, triptorelin and / or its pharmaceutically acceptable salts, goserelin and / or its pharmaceutically acceptable salts.

3. The method according to claim 2, characterized in that, The active pharmaceutical ingredient is any one or a mixture of the following: leuprorelin acetate, triptorelin acetate, and goserelin acetate.

4. The method according to claim 1, characterized in that, The co-solvent is one or a mixture of the following: poloxamer 188, poloxamer 407, polyethylene glycol, polysorbate, and povidone.

5. The method according to claim 1, characterized in that, The mass percentage of the cosolvent to the biocompatible polymer material is 1-21 wt%.

6. The method according to claim 1, characterized in that, The mass percentage of the active pharmaceutical ingredient to the biocompatible polymer material is 4-15 wt%.

7. The method according to claim 1, characterized in that, The biocompatible polymer material has a mass percentage concentration of 10-30 wt% in the organic solvent.

8. The method according to claim 1, characterized in that, The surfactant has a mass percentage concentration of 0.1-3.0 wt% in the external aqueous phase.

9. The method according to claim 1, characterized in that, The ratio of the mass of the organic solvent to the volume of the external aqueous phase is 1:50-1:300 (g / mL).

10. The method according to claim 1, characterized in that, The organic solvent is dichloromethane.

11. The method according to claim 1, characterized in that, The biocompatible polymer material is one or a mixture of several of polylactic acid-glycolic acid copolymer (PLGA), polylactic acid (PLA), polyglycolic acid (PGA), and polyacetin lactone (PCL).

12. The method according to claim 11, characterized in that, The biocompatible polymer material is polylactic acid-glycolic acid copolymer (PLGA), and the molar ratio of glycolide (LA) to lactide (GA) in PLGA is 50:50-85:15, the molecular weight is 5-100 kilodaltons, and the viscosity is 0.1-0.6 dL / g; or the biocompatible polymer material is polylactic acid (PLA), the molecular weight is 8-55 kilodaltons, and the viscosity is 0.1-0.75 dL / g.

13. The method according to claim 1, characterized in that, The surfactant is one or a mixture of several of the following: polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), β-cyclodextrin, poloxamer 188, Pranic F88, Pranic F127, gelatin, glycine, lysine, histidine, arginine, aspartic acid, glutamic acid, Span, and Tween.

14. The method according to claim 1, characterized in that, In step A), the active pharmaceutical ingredient and the cosolvent are pretreated in any one or more of the following ways: 1) The active pharmaceutical ingredient and the cosolvent are dissolved in water and then spray-dried or freeze-dried to obtain a solid mixture, which is then added to the organic solvent; 2) The active pharmaceutical ingredient and the cosolvent are mixed and then hot-melted and extruded, cooled to obtain a solid mixture, which is then added to the organic solvent.

15. The method according to claim 1, characterized in that, In step D), the mixed emulsion is solidified into wet microspheres, a protective agent is added, and then dried.

16. The method according to claim 1, characterized in that, The preparation method further includes the following steps: after obtaining the mixed emulsion, the mixed emulsion is stirred, solidified, filtered, and washed with water to form wet microspheres, and a protective agent is added to the wet microspheres and then dried to obtain sustained-release microspheres containing the active pharmaceutical ingredient.

17. The method according to claim 15 or 16, characterized in that, The protective agent is one or a mixture of several of the following: polyethylene glycol (PEG), gelatin, glycerin, mannitol, sucrose, trehalose, lactose, glucose, propylene glycol, sorbitol, zinc chloride, zinc sulfate, zinc acetate, and human serum albumin.

18. The method according to claim 15 or 16, characterized in that, Other excipients are added along with the protective agent, wherein the other excipients are one or more of surfactants, excipients and lyophilization protective agents.

19. A drug sustained-release microsphere prepared by the method according to any one of claims 1-18.

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