Brexanolone long-acting microspheres and a preparation method thereof

Abstract

The application belongs to the field of pharmaceutical preparations and relates to a brexpiprazole long-acting microsphere and a preparation method thereof, which comprises the following steps: (1) dissolving brexpiprazole and a degradable polymer in an organic solvent to obtain a drug-containing polymer solution as an oil phase; (2) mixing the drug-containing polymer solution and a polyvinyl alcohol solution by microfluidic technology to obtain an oil-in-water emulsion; and (3) solidifying, washing and freeze-drying the oil-in-water emulsion under stirring to obtain the brexpiprazole long-acting microsphere. The application adjusts the volatile stirring time when the O / W primary emulsion is formed, thereby adjusting the in-vitro release rate of the final microsphere, and the microsphere without burst release, no lag period and slow release can be screened. The application has the advantages that the preparation process of the brexpiprazole long-acting microsphere is simple, easy to be industrialized, has high encapsulation efficiency, large drug loading, uniform microsphere particle size distribution, good flowability, good needle passability, is easier to be injected, has obvious slow-release effect, can be used for reducing the fluctuation of blood drug concentration and effectively improving the compliance of patients with mental illness.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of pharmaceutical preparations, and particularly relates to a brexpiprazole long-acting microsphere and a preparation method thereof. BACKGROUND

[0002] Brexpiprazole is an atypical antipsychotic drug, which has a regulatory effect on the monoaminergic neurotransmission system in the brain, is a partial agonist of 5-hydroxytryptamine (5-HT1A) and dopamine D2 receptors, an antagonist of 5-hydroxytryptamine (5-HT2A) receptors and dopamine α1 / 2 receptors, and has a wide binding affinity to other central monoamine receptor subtypes. Compared with typical antipsychotic drugs, brexpiprazole has a reduced extrapyramidal reaction. Compared with the atypical antipsychotic drug aripiprazole, brexpiprazole has increased affinity to 5-HT receptors, reduced activity to D2 receptors, better tolerance, and a lower incidence of akathisia. In clinical practice, brexpiprazole has a better trend in terms of efficacy on the negative symptoms and cognitive function of schizophrenia, and a faster onset when used as an adjunctive therapy for depression.

[0003]

[0004] Currently, the only brexpiprazole dosage forms on the market are tablets and orally disintegrating tablets, and the target dose is once a day, 2-4 mg each time. Since its launch, the global sales of brexpiprazole has been increasing year by year, from 0.51 million US dollars in 2015 to 13.74 million US dollars in 2020. However, due to the particularity of mental diseases and the relatively long treatment process, patients usually have poor compliance, which makes it difficult to administer regularly and reduces the therapeutic effect. At the same time, the incidence of cerebrovascular adverse reactions (such as stroke and transient ischemic attack) related to senile dementia in elderly patients with brexpiprazole tablets increases, which may be related to the fact that ordinary oral immediate-release preparations can easily reach a high required concentration and have a large fluctuation in blood drug concentration. Therefore, in order to improve patient compliance, reduce side effects, and expand the range of patients, it is of great significance to develop a brexpiprazole long-acting microsphere.

[0005] Patent WO 2023036003 A1 discloses a brexpiprazole long-acting preparation for injection and a preparation method thereof, specifically a microcrystalline injection. The drug crystals are dispersed in the form of micron-sized suspension, and the particle size distribution of this dosage form is wide, and the uneven particle size can easily lead to a large fluctuation in blood drug concentration, making it difficult to maintain a smooth blood drug concentration. At the same time, the preparation process of this patent is complex and difficult to realize industrialized production.

[0006] Patent CN 116531379 A discloses a brexpiprazole sustained-release composition and its preparation method and application. Dichloromethane is used as an organic solvent, three substances of polylactic acid, polylactic acid-glycolic acid copolymer and polycaprolactone are mixed in a certain proportion as a carrier, and an emulsified solvent evaporation method is used to prepare a brexpiprazole sustained-release composition. The dichloromethane solvent used in the prescription has great toxicity to the human body, and the solubility of brexpiprazole in dichloromethane is very small. The oil phase with dichloromethane as the solvent cannot realize the preparation of high drug loading microspheres. The carrier component polycaprolactone has a collagen stimulating effect, which can cause local hardening of the tissue, and has uncontrollable side effects for patients with immune diseases.

[0007] Patent CN 118477048 A discloses a brexpiprazole sustained-release microsphere and its preparation method. The emulsification evaporation time is more than 4h, and the evaporation and solidification need to be controlled at different temperatures, so the process is relatively complex and the production efficiency is not high. The preparation process adopts a fixed rotor shearing emulsification method, which is limited by batch differences in the process of scaling up. Different batches result in different parameters of the shearing mixer. In the process of scaling up, the problem of large amount of stirring / shearing unevenness is easy to occur, and the encapsulation rate and the yield of microspheres will also be greatly reduced. Therefore, the scaling up process has great challenges. SUMMARY

[0008] To solve the above technical problems, the present application uses benzyl alcohol / ethyl acetate system which is safer than dichloromethane as an organic solvent. Polylactic acid and polycaprolactone are not used, and only polylactic acid-glycolic acid copolymer, a safer degradable polymer, is used as a carrier to encapsulate the drug, avoiding certain uncontrollable risk factors. At the same time, microfluidic technology is used to prepare an injection brexpiprazole sustained-release microsphere with uniform particle size. Because of its round shape, good fluidity and good needle passing property, it is easier to inject. The preparation method is simple, the encapsulation rate and drug loading of the traditional method are significantly improved, and more importantly, the release rate of the microsphere can be adjusted by controlling the stirring and evaporation time, so that the microsphere with no burst release, no lag phase, slow release for two months or more is obtained.

[0009] The first object of the present application is to provide a preparation method of brexpiprazole long-acting microspheres, comprising the following steps:

[0010] Step (1): Dissolve brexpiprazole and degradable polymer in an organic solvent according to the mass ratio of 1:1-1:10 to obtain a drug-containing polymer solution as an oil phase;

[0011] Step (2): polyvinyl alcohol is dissolved in water to obtain a first aqueous phase with a concentration of 0.1-1.5%, and the oil phase and the first aqueous phase obtained in step (1) are mixed by microfluidic technology at a volume ratio of 1:1-1:45, the flow rate ratio of the oil phase to the first aqueous phase is 1:1-1:45, and the oil-in-water emulsion is obtained after the organic solvent volatilization, and the volatilization ratio is controlled to be 0-20% to obtain the oil-in-water emulsion;

[0012] Step (3): the oil-in-water emulsion obtained in step (2) is added to a second aqueous phase as a solidification phase for solidification, the volume of the solidification phase is 0.05-1.0 L / g of microspheres, the solidification time is 2-6 h, and after the solidification is completed, washing and drying are performed to obtain the brexpiprazole long-acting microspheres.

[0013] In step (1), the degradable polymer is polylactic acid-glycolic acid copolymer or polylactic acid.

[0014] In step (1), the organic solvent for forming the oil phase is a benzyl alcohol-ethyl acetate mixed solvent system.

[0015] As a further optimization scheme, in step (1), the brexpiprazole is dissolved in benzyl alcohol to obtain a brexpiprazole solution; the polylactic acid-glycolic acid copolymer or polylactic acid is dissolved in ethyl acetate to obtain a polymer solution; and then the brexpiprazole solution and the polymer solution are mixed with each other and vortexed and dispersed to obtain the oil phase.

[0016] As a further optimization scheme, in step (1), the mass concentration of the brexpiprazole solution is 2%-20%, and the mass concentration of the degradable polymer solution is 4%-35%.

[0017] As a further optimization scheme, in step (1), the mixing ratio of the brexpiprazole solution and the polymer solution is controlled so that the mass ratio of brexpiprazole to degradable polymer is 1:1-1:5.

[0018] As a further optimization scheme, in step (2), the concentration of the polyvinyl alcohol solution is 0.1-1%.

[0019] As a further optimization scheme, in step (2), the oil-in-water emulsion is obtained by pumping the oil phase and the first aqueous phase into a microfluidic reactor for mixing.

[0020] As a further optimization scheme, in step (2), the flow rate ratio of the oil phase to the first aqueous phase in the microfluidic reactor is 1:1-1:20.

[0021] As a further optimization scheme, in step (2), the volatilization ratio of the organic solvent in the primary emulsion is controlled to be 0-15%.

[0022] As a further optimization, in step (3), the solid phase volume is 0.1-0.5 L / g of microspheres.

[0023] A second object of the present application is to provide the long-acting brexpiprazole microspheres prepared by the above method. The obtained long-acting brexpiprazole microspheres have high encapsulation efficiency, large drug loading, uniform particle size distribution and round shape, good flowability and needle passability, and are easier to inject.

[0024] The present application has the following beneficial effects:

[0025] The preparation method of the present application can obtain long-acting brexpiprazole microspheres with high encapsulation efficiency, large drug loading, uniform particle size, round shape, and excellent needle passability, and the sustained-release effect lasts for six months.

[0026] The brexpiprazole sustained-release microspheres prepared by the method of the present application not only have excellent performance, but also use the safer polylactic acid-glycolic acid copolymer as the carrier material, and do not need to add other polymers such as polycaprolactone and polylactic acid to adjust the proportion, which is safer and friendlier to the body.

[0027] The present application also finds that the release speed of the microspheres can be adjusted by controlling the proportion of organic solvent volatilization, to obtain brexpiprazole microspheres with ideal release speed without burst release and release lag period, and without reducing the encapsulation efficiency and drug loading of the microspheres. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to make the content of the present application more easily and clearly understood, the present application will be further described in detail below according to specific embodiments of the present application and in conjunction with the accompanying drawings, in which:

[0029] Figure 1 The scanning electron microscope image of the sustained-release microspheres of Example 1 of the present application.

[0030] Figure 2 The scanning electron microscope image of the sustained-release microspheres of Example 4 of the present application.

[0031] Figure 3 The scanning electron microscope image of the sustained-release microspheres of Comparative Example 1 of the present application.

[0032] Figure 4 The scanning electron microscope image of the sustained-release microspheres of Comparative Example 2 of the present application.

[0033] Figure 5 The in-vitro release curve diagram of the sustained-release microspheres of Examples 1-6, 9, 10 and Comparative Example 2 of the present application. DETAILED DESCRIPTION

[0034] The present application will be further described in conjunction with the accompanying drawings and specific examples so that it can be better understood and implemented by those skilled in the art, but the examples are not intended to limit the present application.

[0035] In the present application, unless otherwise specified, the raw materials used are existing products, and the specific preparation operations and performance tests are conventional techniques. For example, stirring is a conventional technique, and the organic solvent is removed by conventional stirring evaporation in a fume hood.

[0036] In the present application, unless otherwise specified, the freeze dryer used for freeze drying is FDU-2110.

[0037] Example 1

[0038] 210 mg of brexpiprazole was weighed into 3 ml of benzyl alcohol to obtain a brexpiprazole solution; 420 mg of polylactic acid-glycolic acid copolymer (molar ratio of lactide to glycolide = 75:25, Mw = 90 kDa) was dissolved in 4 ml of ethyl acetate to obtain a polymer solution; the brexpiprazole solution and the polymer solution were mixed with each other and vortexed to disperse, serving as an oil phase. 7 mL of the oil phase and 35 mL of a 0.01 g / mL polyvinyl alcohol aqueous solution were delivered into a microreactor by a laminar flow pump at a flow rate ratio of 1:5 and a total flow rate of 20 mL / min, the obtained emulsion was stirred and evaporated to remove 5% of the weight of the emulsion, and then the dispersion system was poured into 125 mL of ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexpiprazole microsphere powder.

[0039] Example 2

[0040] 210 mg of brexpiprazole was weighed into 3 ml of benzyl alcohol to obtain a brexpiprazole solution; 420 mg of polylactic acid-glycolic acid copolymer (molar ratio of lactide to glycolide = 75:25, Mw = 130 kDa) was dissolved in 4 ml of ethyl acetate to obtain a polymer solution; the brexpiprazole solution and the polymer solution were mixed with each other and vortexed to disperse, serving as an oil phase. 7 mL of the oil phase and 35 mL of a 0.01 g / mL polyvinyl alcohol aqueous solution were delivered into a microreactor by a laminar flow pump at a flow rate ratio of 1:5 and a total flow rate of 20 mL / min, the obtained emulsion was stirred and evaporated to remove 5% of the weight of the emulsion, and then the dispersion system was poured into 125 mL of ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexpiprazole microsphere powder.

[0041] Example 3

[0042] Brexanolone 210 mg was dissolved in 3 ml of benzyl alcohol to obtain a brexanolone solution; polylactic acid-glycolic acid copolymer (molar ratio of ester-terminated lactide and glycolide = 75:25, Mw = 130 kDa) 420 mg was dissolved in 4 ml of ethyl acetate to obtain a polymer solution; the brexanolone solution and the polymer solution were mixed with each other and vortexed to disperse, as an oil phase. 7 mL of the oil phase and 35 mL of a 0.01 g / mL polyvinyl alcohol aqueous solution were delivered into a microreactor by a laminar pump at a flow rate ratio of 1:5 and a total flow rate of 20 mL / min, the obtained emulsion was stirred to volatilize 9.5% of the weight of the emulsion, and then the dispersion system was poured into 125 mL of ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexanolone microsphere powder.

[0043] Example 4

[0044] Brexanolone 210 mg was dissolved in 3 ml of benzyl alcohol to obtain a brexanolone solution; polylactic acid-glycolic acid copolymer (molar ratio of ester-terminated lactide and glycolide = 75:25, Mw = 130 kDa) 420 mg was dissolved in 4 ml of ethyl acetate to obtain a polymer solution; the brexanolone solution and the polymer solution were mixed with each other and vortexed to disperse, as an oil phase. 7 mL of the oil phase and 35 mL of a 0.01 g / mL polyvinyl alcohol aqueous solution were delivered into a microreactor by a laminar pump at a flow rate ratio of 1:5 and a total flow rate of 20 mL / min, the obtained emulsion was stirred to volatilize 9.5% of the weight of the emulsion, and then the dispersion system was poured into 125 mL of ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexanolone microsphere powder.

[0045] Example 5

[0046] Brexanolone 200 mg was dissolved in 4 ml of benzyl alcohol to obtain a brexanolone solution; polylactic acid-glycolic acid copolymer (molar ratio of ester-terminated lactide and glycolide = 75:25, Mw = 130 kDa) 400 mg was dissolved in 6 ml of ethyl acetate to obtain a polymer solution; the brexanolone solution and the polymer solution were mixed with each other and vortexed to disperse, as an oil phase. 10 mL of the oil phase and 50 mL of a 0.01 g / mL polyvinyl alcohol aqueous solution were delivered into a microreactor by a laminar pump at a flow rate ratio of 1:5 and a total flow rate of 20 mL / min, the obtained emulsion was stirred to volatilize 2% of the weight of the emulsion, and then the dispersion system was poured into 160 mL of ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexanolone microsphere powder.

[0047] Example 6

[0048] Take 160 mg brexpiprazole to dissolve in 4 ml benzyl alcohol to obtain brexpiprazole solution; take 480 mg polylactic acid-glycolic acid copolymer (molar ratio of ester-terminated lactide and glycolide = 75:25, Mw = 130 kDa) to dissolve in 8 ml ethyl acetate to obtain polymer solution; mix the brexpiprazole solution and the polymer solution with each other, vortex to disperse, as an oil phase. Through the laminar flow pump, 12 mL of the oil phase and 60 mL of the polyvinyl alcohol aqueous solution with a concentration of 0.01 g / mL are transported into the microreactor at a flow rate ratio of 1:5 and a total flow rate of 20 mL / min, the obtained emulsion is stirred to volatilize 5% of the weight of the emulsion, then the dispersion system is poured into 225 mL of ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexpiprazole microsphere powder.

[0049] Example 7

[0050] Take 160 mg brexpiprazole to dissolve in 4 ml benzyl alcohol to obtain brexpiprazole solution; take 480 mg polylactic acid-glycolic acid copolymer (molar ratio of ester-terminated lactide and glycolide = 75:25, Mw = 130 kDa) to dissolve in 8 ml ethyl acetate to obtain polymer solution; mix the brexpiprazole solution and the polymer solution with each other, vortex to disperse, as an oil phase. Through the laminar flow pump, 12 mL of the oil phase and 60 mL of the polyvinyl alcohol aqueous solution with a concentration of 0.01 g / mL are transported into the microreactor at a flow rate ratio of 1:5 and a total flow rate of 20 mL / min, the obtained emulsion is stirred to volatilize 5% of the weight of the emulsion, then the dispersion system is poured into 225 mL of ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexpiprazole microsphere powder.

[0051] Example 8

[0052] Take 160 mg brexpiprazole to dissolve in 4 ml benzyl alcohol to obtain brexpiprazole solution; take 480 mg polylactic acid-glycolic acid copolymer (molar ratio of ester-terminated lactide and glycolide = 75:25, Mw = 130 kDa) to dissolve in 8 ml ethyl acetate to obtain polymer solution; mix the brexpiprazole solution and the polymer solution with each other, vortex to disperse, as an oil phase. Through the laminar flow pump, 12 mL of the oil phase and 60 mL of the polyvinyl alcohol aqueous solution with a concentration of 0.01 g / mL are transported into the microreactor at a flow rate ratio of 1:5 and a total flow rate of 20 mL / min, the obtained emulsion is stirred to volatilize 5% of the weight of the emulsion, then the dispersion system is poured into 225 mL of ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexpiprazole microsphere powder.

[0053] Example 9

[0054] Take 480 mg brexpiprazole to dissolve in 4 ml benzyl alcohol to obtain brexpiprazole solution; take 480 mg polylactic acid-glycolic acid copolymer (molar ratio of ester-terminated lactide and glycolide = 75:25, Mw = 90 kDa) to dissolve in 4 ml ethyl acetate to obtain polymer solution; mix the brexpiprazole solution and the polymer solution with each other, vortex to disperse, as oil phase. Through the laminar flow pump, 8 mL oil phase and 40 mL 0.01 g / mL polyvinyl alcohol aqueous solution are transported into the microreactor at a flow rate ratio of 1:5 and a total flow rate of 20 mL / min, the obtained emulsion is stirred to volatilize 5% of the weight of the emulsion, then the dispersion system is poured into 135 mL ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexpiprazole microsphere powder.

[0055] Example 10

[0056] Take 480 mg brexpiprazole to dissolve in 4 ml benzyl alcohol to obtain brexpiprazole solution; take 480 mg polylactic acid-glycolic acid copolymer (molar ratio of ester-terminated lactide and glycolide = 75:25, Mw = 90 kDa) to dissolve in 4 ml ethyl acetate to obtain polymer solution; mix the brexpiprazole solution and the polymer solution with each other, vortex to disperse, as oil phase. Through the laminar flow pump, 8 mL oil phase and 40 mL 0.01 g / mL polyvinyl alcohol aqueous solution are transported into the microreactor at a flow rate ratio of 1:5 and a total flow rate of 20 mL / min, the obtained emulsion is stirred to volatilize 5% of the weight of the emulsion, then the dispersion system is poured into 135 mL ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexpiprazole microsphere powder.

[0057] Example 11

[0058] Take 480 mg brexpiprazole to dissolve in 4 ml benzyl alcohol to obtain brexpiprazole solution; take 480 mg polylactic acid-glycolic acid copolymer (molar ratio of ester-terminated lactide and glycolide = 75:25, Mw = 90 kDa) to dissolve in 4 ml ethyl acetate to obtain polymer solution; mix the brexpiprazole solution and the polymer solution with each other, vortex to disperse, as oil phase. Through the laminar flow pump, 8 mL oil phase and 40 mL 0.01 g / mL polyvinyl alcohol aqueous solution are transported into the microreactor at a flow rate ratio of 1:5 and a total flow rate of 20 mL / min, the obtained emulsion is stirred to volatilize 5% of the weight of the emulsion, then the dispersion system is poured into 135 mL ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexpiprazole microsphere powder.

[0059] Example 12

[0060] Take 4 g of brexpiprazole to be dissolved in 16 g of benzyl alcohol to obtain a brexpiprazole solution; take 20 g of polylactic acid-glycolic acid copolymer to be dissolved in 37 g of ethyl acetate to obtain a polymer solution; mix the brexpiprazole solution and the polymer solution with each other, and vortex to disperse, as an oil phase. The oil phase and a 0.1% polyvinyl alcohol aqueous solution are delivered into a microreactor by a laminar pump at a flow rate ratio of 1:20, the obtained emulsion is stirred to volatilize 15% of the weight of the emulsion, the dispersion system is then poured into 2400 mL of ultrapure water, and solidified for 6 h, followed by washing with water for 3 times, and freeze-drying to obtain brexpiprazole microsphere powder.

[0061] Comparative Example 1

[0062] Take 4 g of brexpiprazole to be dissolved in 16 g of benzyl alcohol to obtain a brexpiprazole solution; take 20 g of polylactic acid-glycolic acid copolymer to be dissolved in 37 g of ethyl acetate to obtain a polymer solution; mix the brexpiprazole solution and the polymer solution with each other, and vortex to disperse, as an oil phase. The oil phase and a 0.1% polyvinyl alcohol aqueous solution are delivered into a microreactor by a laminar pump at a flow rate ratio of 1:20, the obtained emulsion is stirred to volatilize 15% of the weight of the emulsion, the dispersion system is then poured into 2400 mL of ultrapure water, and solidified for 6 h, followed by washing with water for 3 times, and freeze-drying to obtain brexpiprazole microsphere powder.

[0063] Comparative Example 2

[0064] Take 4 g of brexpiprazole to be dissolved in 16 g of benzyl alcohol to obtain a brexpiprazole solution; take 20 g of polylactic acid-glycolic acid copolymer to be dissolved in 37 g of ethyl acetate to obtain a polymer solution; mix the brexpiprazole solution and the polymer solution with each other, and vortex to disperse, as an oil phase. The oil phase and a 0.1% polyvinyl alcohol aqueous solution are delivered into a microreactor by a laminar pump at a flow rate ratio of 1:20, the obtained emulsion is stirred to volatilize 15% of the weight of the emulsion, the dispersion system is then poured into 2400 mL of ultrapure water, and solidified for 6 h, followed by washing with water for 3 times, and freeze-drying to obtain brexpiprazole microsphere powder.

[0065] Comparative Example 3

[0066] Example 1 40 mg of brexpiprazole was dissolved in 1 mL of benzyl alcohol to obtain a brexpiprazole solution. 120 mg of polylactic acid-glycolic acid copolymer (molar ratio of carboxyl-terminated lactide to glycolide = 75:25, Mw = 12 kDa) was dissolved in 2 mL of ethyl acetate to obtain a polymer solution. The brexpiprazole solution and the polymer solution were mixed with each other and vortexed to disperse, as an oil phase. The oil phase was added dropwise to 15 mL of a 0.01 g / mL polyvinyl alcohol aqueous solution, the resulting emulsion was stirred to evaporate 5% by weight of the emulsion, and the dispersion system was poured into 90 mL of ultrapure water, stirred for 2 h, filtered, washed with water three times, and lyophilized to obtain brexpiprazole microspheres powder.

[0067] Comparative Example 4

[0068] 40 mg of brexpiprazole was dissolved in 1 mL of benzyl alcohol to obtain a brexpiprazole solution. 120 mg of polylactic acid-glycolic acid copolymer (molar ratio of carboxyl-terminated lactide to glycolide = 50:50, Mw = 12 kDa) was dissolved in 2 mL of ethyl acetate to obtain a polymer solution. The brexpiprazole solution and the polymer solution were mixed with each other and vortexed to disperse, as an oil phase. The oil phase was added dropwise to 15 mL of a 0.01 g / mL polyvinyl alcohol aqueous solution, the resulting emulsion was stirred to evaporate 5% by weight of the emulsion, and the dispersion system was poured into 90 mL of ultrapure water, stirred for 2 h, filtered, washed with water three times, and lyophilized to obtain brexpiprazole microspheres powder.

[0069] Comparative Example 5

[0070] 120 mg of brexpiprazole was dissolved in 1.3 mL of benzyl alcohol to obtain a brexpiprazole solution. 120 mg of polylactic acid-glycolic acid copolymer (molar ratio of carboxyl-terminated lactide to glycolide = 75:25, Mw = 90 kDa) was dissolved in 0.7 mL of ethyl acetate to obtain a polymer solution. The brexpiprazole solution and the polymer solution were mixed with each other and vortexed to disperse, as an oil phase. The oil phase was added dropwise to 10 mL of a 0.01 g / mL polyvinyl alcohol aqueous solution, the resulting emulsion was stirred to evaporate 5% by weight of the emulsion, and the dispersion system was poured into 60 mL of ultrapure water, stirred for 2 h, filtered, washed with water three times, and lyophilized to obtain brexpiprazole microspheres powder.

[0071] Comparative Example 6

[0072] Take 120 mg brexpiprazole dissolved in 3 ml benzyl alcohol to obtain a brexpiprazole solution; take 360 mg polylactic acid-glycolic acid copolymer (molar ratio of ester-terminated lactide and glycolide = 75:25, Mw = 12 kDa) dissolved in 6 ml ethyl acetate to obtain a polymer solution; mix the brexpiprazole solution and the polymer solution with each other, vortex to disperse, as an oil phase. Through the laminar flow pump, 9 mL of the oil phase and 27 mL of the polyvinyl alcohol aqueous solution with a concentration of 0.005 g / mL are transported into the microreactor at a flow rate ratio of 1:3 and a total flow rate of 20 mL / min. The obtained emulsion is stirred to volatilize 5% of the weight of the emulsion, and then the dispersion system is poured into 125 mL of ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexpiprazole microsphere powder.

[0073] Comparative Example 7

[0074] Take 120 mg brexpiprazole dissolved in 3 ml benzyl alcohol to obtain a brexpiprazole solution; take 360 mg polylactic acid-glycolic acid copolymer (molar ratio of ester-terminated lactide and glycolide = 75:25, Mw = 12 kDa) dissolved in 6 ml ethyl acetate to obtain a polymer solution; mix the brexpiprazole solution and the polymer solution with each other, vortex to disperse, as an oil phase. Through the laminar flow pump, 9 mL of the oil phase and 27 mL of the polyvinyl alcohol aqueous solution with a concentration of 0.005 g / mL are transported into the microreactor at a flow rate ratio of 1:3 and a total flow rate of 20 mL / min. The obtained emulsion is stirred to volatilize 5% of the weight of the emulsion, and then the dispersion system is poured into 125 mL of ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexpiprazole microsphere powder.

[0075] Comparative Example 8

[0076] Take 120 mg brexpiprazole dissolved in 3 ml benzyl alcohol to obtain a brexpiprazole solution; take 360 mg polylactic acid-glycolic acid copolymer (molar ratio of ester-terminated lactide and glycolide = 75:25, Mw = 12 kDa) dissolved in 6 ml ethyl acetate to obtain a polymer solution; mix the brexpiprazole solution and the polymer solution with each other, vortex to disperse, as an oil phase. Through the laminar flow pump, 9 mL of the oil phase and 27 mL of the polyvinyl alcohol aqueous solution with a concentration of 0.005 g / mL are transported into the microreactor at a flow rate ratio of 1:3 and a total flow rate of 20 mL / min. The obtained emulsion is stirred to volatilize 5% of the weight of the emulsion, and then the dispersion system is poured into 125 mL of ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexpiprazole microsphere powder.

[0077] Comparative Example 9

[0078] Take 200 mg brexpiprazole and dissolve in 4 ml benzyl alcohol to obtain a brexpiprazole solution; take 400 mg polylactic acid-glycolic acid copolymer (molar ratio of ester-terminated lactide and glycolide = 75:25, Mw = 12 kDa) and dissolve in 6 ml ethyl acetate to obtain a polymer solution; mix the brexpiprazole solution and the polymer solution with each other and vortex to disperse as an oil phase. Through a laminar flow pump, 10 mL of the oil phase and 50 mL of a 0.01 g / mL polyvinyl alcohol aqueous solution are delivered into a microreactor at a flow rate ratio of 1:5 and a total flow rate of 20 mL / min, the obtained emulsion is stirred to volatilize 5% of the weight of the emulsion, then the dispersion system is poured into 125 mL of ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexpiprazole microsphere powder.

[0079] Comparative Example 10

[0080] Take 200 mg brexpiprazole and dissolve in 4 ml benzyl alcohol to obtain a brexpiprazole solution; take 400 mg polylactic acid-glycolic acid copolymer (molar ratio of ester-terminated lactide and glycolide = 75:25, Mw = 12 kDa) and dissolve in 6 ml ethyl acetate to obtain a polymer solution; mix the brexpiprazole solution and the polymer solution with each other and vortex to disperse as an oil phase. Through a laminar flow pump, 10 mL of the oil phase and 50 mL of a 0.01 g / mL polyvinyl alcohol aqueous solution are delivered into a microreactor at a flow rate ratio of 1:5 and a total flow rate of 20 mL / min, the obtained emulsion is stirred to volatilize 5% of the weight of the emulsion, then the dispersion system is poured into 125 mL of ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexpiprazole microsphere powder.

[0081] Comparative Example 11

[0082] Take 200 mg brexpiprazole and dissolve in 4 ml benzyl alcohol to obtain a brexpiprazole solution; take 400 mg polylactic acid-glycolic acid copolymer (molar ratio of ester-terminated lactide and glycolide = 75:25, Mw = 12 kDa) and dissolve in 6 ml ethyl acetate to obtain a polymer solution; mix the brexpiprazole solution and the polymer solution with each other and vortex to disperse as an oil phase. Through a laminar flow pump, 10 mL of the oil phase and 50 mL of a 0.01 g / mL polyvinyl alcohol aqueous solution are delivered into a microreactor at a flow rate ratio of 1:5 and a total flow rate of 20 mL / min, the obtained emulsion is stirred to volatilize 5% of the weight of the emulsion, then the dispersion system is poured into 125 mL of ultrapure water, solidified for 2 h, washed with water for 3 times after filtration, and freeze-dried to obtain brexpiprazole microsphere powder.

[0083] Test Example 1 Drug loading and encapsulation efficiency of microspheres

[0084] Octadecylsilane-bonded silica gel was used as the packing material; 0.15% phosphoric acid:acetonitrile (68:32) was used as the mobile phase, and the detection wavelength was 215 nm; 10 mg of bripiprazole microspheres prepared in Examples 1-10 and Comparative Examples 1-11 were weighed, dissolved in dimethyl sulfoxide, and then diluted to 100 mL with 0.15% phosphoric acid solution. The solution was shaken well, and a portion was centrifuged at 12500 rpm. The supernatant was then analyzed by HPLC to determine the total drug concentration. 10 mg of microspheres were weighed, diluted to 10 mL with 0.15% phosphoric acid solution, and the supernatant was analyzed by HPLC to determine the free drug concentration. The total drug amount minus the free drug amount is the encapsulated drug amount; the formulas for calculating drug loading and encapsulation efficiency are as follows:

[0085]

[0086] Table 1. Drug loading and encapsulation efficiency of microspheres from different embodiments and comparative examples.

[0087] Sample Theoretical drug loading (%) Drug loading (%) Encapsulation efficiency (%) Example 1 33.33 31.93 99.81 Example 2 33.33 30.15 99.96 Example 3 33.33 34.22 98.22 Example 4 33.33 30.71 99.96 Example 5 33.33 32.63 99.92 Example 6 25.00 23.70 99.94 Example 7 33.33 32.21 99.24 Example 8 25.00 24.53 99.65 Example 9 50.00 42.19 98.44 Example 10 25.00 22.73 98.74 Example 11 33.33 30.33 99.78 Example 12 16.67 16.15 99.86 Comparative Example 1 33.33 25.35 98.75 Comparative Example 2 25.00 18.01 99.57 Comparative Example 3 25.00 19.07 98.14 Comparative Example 4 25.00 14.36 55.94 Comparative Example 5 25.00 17.69 89.09 Comparative Example 6 25.00 16.93 82.34 Comparative Example 7 25.00 21.50 84.71 Comparative Example 8 25.00 13.00 75.49 Comparative Example 9 25.00 5.01 9.64 Comparative Example 10 33.33 15.83 44.35 Comparative Example 11 33.33 / /

[0088] In Comparative Examples 1-5, this invention employed a method of dropwise addition of the oil phase to the aqueous phase followed by stirring to prepare bripiprazole microspheres. It was found that most samples prepared using this method achieved encapsulation efficiencies exceeding 95%, but significant differences remained overall. The process resulted in substantial drug loss, with the drug loading significantly lower than the theoretical loading. Despite attempts to modify various factors, such as using different amounts of raw materials, changing the polymer molecular weight, adjusting the solvent ratio, and using different polymer end-capping types, these attempts failed to completely resolve the issues with encapsulation efficiency and drug loading to achieve the desired results. Furthermore, the mass transfer process in this method is highly volume-dependent; once scaled up for production, the process parameters need to be readjusted, making scale-up production challenging.

[0089] In Examples 1-10 and Comparative Examples 6-11, this invention uses microfluidics to input two-phase solutions into a microfluidic device to prepare bripiprazole microspheres. Numerous process conditions, including flow rate ratio and total flow rate, stirring and evaporation time, polymer and formulation, solvent system, and curing conditions, were explored, and the following findings were made.

[0090] As shown in Table 1, Examples 2-4 changed the stirring degree of volatility, which had little effect on the microsphere encapsulation efficiency and drug loading, indicating that the process had good stability. The molecular weight of the polylactic acid-glycolic acid copolymer used in Examples 1, 2, and 8 had little effect on the microsphere encapsulation efficiency and drug loading, indicating that the change in PLGA molecular weight did not constitute a limiting factor within a certain range. However, when the PLGA was changed to carboxyl-terminated and the molar ratio of lactide to glycolide was 50:50 in Comparative Example 6, a significant decrease in encapsulation efficiency and drug loading was observed, indicating that the end-capping group of PLGA had an important influence on the preparation of brexpiprazole microspheres. In contrast, the scheme of choosing ester-terminated and lactide to glycolide molar ratio of 75:25 PLGA was more ideal. In addition, the use of dimethyl sulfoxide as an organic solvent in Comparative Example 10 resulted in a lower encapsulation efficiency, while in Comparative Example 11, due to the limited solubility of brexpiprazole in dichloromethane, a large amount of drug leakage occurred during the preparation process, and the final collected microspheres were so few that effective testing could not be performed. In contrast, the benzyl alcohol / ethyl acetate solvent system helped to improve the solubility of brexpiprazole and obtain higher encapsulation efficiency and drug loading.

[0091] As shown in Table 1, from the perspective of encapsulation efficiency and drug loading, the more optimal formulations were Examples 1-10, and the prepared microspheres had an encapsulation efficiency of more than 98% and a drug loading close to the theoretical drug loading. Among them, Example 9, the microspheres prepared by microfluidic technology with a drug loading ratio of 1:1, had a drug loading of 42% and an encapsulation efficiency of more than 98%. Despite extensive search of relevant literature, patents and market information, no brexpiprazole microsphere product has been found that can achieve a high drug loading of more than 40% while ensuring such a high encapsulation efficiency.

[0092] As shown in Table 1, it was also found that the O / W primary emulsion prepared by microfluidic technology in Example 4 did not need a stirring process and could directly be solidified to obtain microspheres with an encapsulation efficiency of more than 99% and a drug loading that was not much different from the theoretical drug loading. This scheme was particularly remarkable in terms of process simplification, greatly speeding up the production progress under the premise of ensuring quality, and was especially suitable for industrial production.

[0093] Test Example 2 Microsphere Particle Size

[0094] An appropriate amount of microspheres prepared in Examples 1-10 and Comparative Examples 1-11 were taken and divided into three parts, which were dispersed in water, respectively, and the microsphere particle size was determined by BT-2001 laser particle size distribution instrument, and the results are shown in Table 2.

[0095] Table 2 Microsphere Particle Size of Different Examples and Comparative Examples

[0096]

[0097]

[0098] As can be seen from Table 2, when the molecular weight of the polylactic acid-glycolic acid copolymer is small, the prepared microspheres have small particle size, and compared with other examples, small particle size microspheres need smaller screen for collection, which is easy to block the screen, and it is difficult to wash the microspheres with low efficiency, which is not suitable for industrial production. When the molecular weight of the polylactic acid-glycolic acid copolymer is above 90 kDa, microspheres with particle size of 50-80 μm can be prepared by the flow control device, and the particle size is uniform and the needle passability is good. In addition, when the drug loading ratio is increased to 1:1 and 1:2 (Comparative Examples 1 and 9), the particle size of the microspheres prepared by direct dropwise addition is greater than 100 μm, which is not suitable for muscle injection. Therefore, from the perspective of particle size, Examples 1-5, 7 and 9 are the preferred formulations.

[0099] Test Example 3: Determination of microsphere morphology and angle of repose

[0100] An appropriate amount of the microspheres prepared in Examples 1, 4 and Comparative Examples 1 and 2 were taken and the microsphere morphology was determined by scanning electron microscopy, and the results are shown in Figures 1-4 .

[0101] Table 3: Determination of microsphere angle of repose of different examples and comparative examples

[0102] Sample Angle of repose Example 1 37.6° Example 4 38.3° Comparative Example 1 44.9° Comparative Example 2 45.2°

[0103] As can be seen from the results of the angle of repose, the brexpiprazole microspheres prepared by microfluidic technology have a smaller angle of repose and better flowability.

[0104] According to the results of scanning electron microscopy and angle of repose determination, the brexpiprazole microspheres prepared by microfluidic technology are more round, have better flowability, good needle passability and are easier to inject.

[0105] Test Example 4: In vitro release rate of microspheres

[0106] 2 g of sodium hydroxide was weighed into 500 mL of water, 105 mL was discarded, 6.8 g of potassium dihydrogen phosphate and 605 mL of water were added and dissolved, and then 2 g of cetyltrimethylammonium bromide was added to obtain a PBS solution with a pH of 7.4 and containing 0.2% cetyltrimethylammonium bromide.

[0107] Respectively, 12 mg of the brexpiprazole microspheres prepared in Example 1-6, 9, 10 and Comparative Example 2 were weighed into a 100 mL conical flask with a stopper, 100 mL of 0.2% cetyltrimethylammonium bromide PBS solution was added, and the flask was placed in a 37°C water bath constant temperature shaking incubator. At 4h, 1d, 3d, 5d, 7d, … different time points, 1 mL was taken, centrifuged (8000 rpm, 5 min), and a small part of the supernatant was analyzed and saved. After the remaining microspheres were completely removed from the old release medium, they were replaced with fresh release medium, and sampling was continued. The samples were analyzed by high performance liquid chromatography, the cumulative release percentage was calculated, and the release rate-time release rate curve was plotted. The results are shown in Figure 5

[0108] As can be seen from Figure 5 The brexpiprazole microspheres can achieve a sustained release effect of 2 months or more. Examples 1 and 9 show that the greater the drug loading, the faster the release. Examples 3, 4, 6, 9 show that when the O / W primary emulsion is formed, the stirring time is different, and the release rate is also different, which also shows that the release rate can be adjusted by controlling the volatility of the organic solvent. Moreover, the in vitro release curves of the sustained-release microspheres prepared by the dropwise process (Comparative Example 2) and the microfluidic process (Example 6) of the same prescription can be found that the release of the prescription using the microfluidic process is relatively slower.

[0109] The above embodiments are exemplary, and the purpose is to illustrate the technical concept and characteristics of the present application, so that those skilled in the art can understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made in accordance with the spirit and essence of the present application shall be covered within the protection scope of the present application.​

Claims

1. A method for preparing long-acting microspheres of brexpiprazole, characterized by, The method comprises the following steps: Step (1): dissolving brexpiprazole and degradable polymer in an organic solvent to obtain a drug-containing polymer solution as an oil phase; Step (2): dissolving polyvinyl alcohol in water to obtain a first aqueous phase with a concentration of 0.1-1.5%, and mixing the oil phase and the first aqueous phase in a volume ratio of 1:1-1:45 by microfluidic technology, the flow rate ratio of the oil phase to the first aqueous phase being 1:1-1:45, to obtain a primary emulsion, and then volatilizing the organic solvent, the volatilization ratio being controlled at 0-20%, to obtain an oil-in-water emulsion; Step (3): adding the oil-in-water emulsion of step (2) to a second aqueous phase as a solidification phase for solidification, the volume of the solidification phase being 0.05-1.0 L / g of microspheres, the solidification time being 2-6 h, and then washing and drying after solidification to obtain the brexpiprazole long-acting microspheres; In step (1), the degradable polymer is an ester-terminated polylactic acid-glycolic acid copolymer, the molar ratio of lactide to glycolide being 75:25, and the weight average molecular weight of the degradable polymer being 90-130 kDa; In step (1), the organic solvent for forming the oil phase is a benzyl alcohol-ethyl acetate mixed solvent system; In step (1), brexpiprazole is dissolved in benzyl alcohol to obtain a brexpiprazole solution, and polylactic acid-glycolic acid copolymer or polylactic acid is dissolved in ethyl acetate to obtain a polymer solution, and then the brexpiprazole solution and the polymer solution are mixed to obtain the oil phase; In step (1), the mixing ratio of the brexpiprazole solution to the polymer solution is controlled so that the mass ratio of brexpiprazole to degradable polymer is 1:1-1:5; In step (2), the concentration of the polyvinyl alcohol solution is 0.1-1%; In step (2), the flow rate ratio of the oil phase to the first aqueous phase in the microfluidic reactor is 1:1-1:20; In step (1), the mass concentration of the brexpiprazole solution is 6.3% and the mass concentration of the degradable polymer solution is 10.4%, or the mass concentration of the brexpiprazole solution is 4.6% and the mass concentration of the degradable polymer solution is 6.9%, or the mass concentration of the brexpiprazole solution is 10.3% and the mass concentration of the degradable polymer solution is 11.7%.

2. The method of claim 1, wherein the brexpiprazole long-acting microspheres are prepared by the process comprising: In step (2), the oil-in-water emulsion is obtained by pumping the oil phase and the first aqueous phase into a microfluidic reactor for mixing.

3. The method of claim 1, wherein the brexpiprazole long-acting microspheres are prepared by the steps of: In step (2), the volatilization ratio of the organic solvent in the primary emulsion is controlled at 0-15%.

4. The method for preparing birepiperazole long-acting microspheres according to claim 1, characterized in that, In step (3), the volume of the solidification phase is 0.1-0.5 L / g of microspheres.

5. A long-acting microsphere of brexpiprazole, characterized by, The method is prepared according to any one of claims 1-4. The method is prepared according to any one of claims 1-4.

Images