Method for preparing perampanel sustained-release microspheres and perampanel sustained-release injection

Abstract

The present invention belongs to the technical field of sustained-release drug delivery of perampanel, and specifically provides a method for preparing perampanel sustained-release microspheres and a perampanel sustained-release injection. Based on an emulsion system, the present invention has developed a preparation method, which can be used to prepare long-acting perampanel sustained-release microspheres. The prepared microspheres have a round and regular morphology, good drug loading, high encapsulation efficiency, suitable particle size and uniform distribution, and can continuously release the perampanel drug for 14 to 42 days. The prepared long-acting perampanel sustained-release microspheres can be further developed into a long-acting perampanel sustained-release injection. Compared with the marketed perampanel formulation that is administered once a day, the dosing interval can be significantly extended, the number of clinic visits for drug collection can be reduced, the convenience of medication can be increased, the compliance of patients can be improved, and the risk of seizure induced by missed drug administration can be reduced. Especially for patients who are not suitable for oral administration, such as those with choking cough, dysphagia, nasogastric feeding, or fistula, the long-acting perampanel microspheres and formulations provide a new option for more convenient and safe drug administration.

Description

[0001] This application is a divisional application. The application number of the original application is 202410032962.9, and the filing date of the original application is January 10, 2024. The entire content of the original application is incorporated herein by reference. Technical Field

[0002] The present invention relates to the technical field of sustained-release drug delivery of perampanel, and specifically relates to a method for preparing perampanel sustained-release microspheres and a perampanel sustained-release injection. Background Art

[0003] Epilepsy is a common chronic neurological disease caused by multiple etiologies and second only to stroke, and requires long-term medication (generally for more than 3 to 5 years). For newly diagnosed epilepsy patients, the use of antiepileptic drugs (AEDs) for treatment is still the first choice, but the conditions of about 30% of patients have not been satisfactorily controlled. In addition, many patients have significant adverse reactions. In the 21st century, the research and development of antiepileptic drugs mainly targets refractory epilepsy, and also aims to improve the convenience of long-term medication and reduce the toxic and side effects of traditional drugs.

[0004] Perampanel is a highly selective and non-competitive α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) type glutamate receptor antagonist developed by Eisai Co., Ltd. in Japan. Perampanel reduces neuronal hyperexcitation by non-competitively binding to the AMPA receptor, achieving the purpose of preventing and treating epilepsy. Perampanel is the first highly selective AMPA receptor antagonist approved for marketing at present, with unique action mechanism, good drug tolerance, and broad-spectrum antiepileptic characteristics, and has been applied to patients with focal and generalized epilepsy in more than 55 countries. The molecular formula of perampanel 3 / 4 hydrate is as Figure 1 shown.

[0005] The marketed preparations of perampanel include tablets (specifications are 2mg, 4mg, 6mg, 8mg, 10mg, 12mg), granules (1%), and oral suspension (0.5mg / ml), all of which are administered once a day; the initial dose for adults is 2mg / day, and the dose can be titrated by increasing 2mg every 1 or 2 weeks, and the maintenance dose is 4 - 12mg / day. The common adverse reactions of perampanel include dizziness, irritability, fatigue, aggressive behavior, nausea, weight gain, etc. Research suggests that the adverse reactions of perampanel are dose-dependent.

[0006] The existing perampanel preparations have the following disadvantages:

[0007] (1) Inconvenient oral administration: All marketed formulations of perampanel require oral administration, which is very inconvenient for some epilepsy patients, such as those with choking cough, dysphagia, nasogastric feeding, and fistula patients, etc., for daily oral administration.

[0008] (2) Administer the drug once a day, with significant fluctuations in blood drug concentration and a high risk of adverse reactions.

[0009] (3) The harm of missing a dose of the drug is great: Epilepsy patients generally need to take medicine for a long time. The daily once-daily dosing frequency is relatively frequent, with poor patient compliance, and it is also easy to miss a dose. The risk of missing a dose in epilepsy patients is significantly higher than that in other patients. If epilepsy patients miss several doses in a row, the drug efficacy will decrease, which is very likely to induce epileptic seizures. Such seizures are generally more frequent and more severe than usual, and may even cause status epilepticus, endangering life.

[0010] In addition, according to the announcement of the National Medical Products Administration, perampanel (including its salts, isomers, and single formulations) has been subject to the management of Class II psychotropic substances since July 1, 2023. In the future, perampanel cannot be sold through the Internet. Patients need to go to the hospital to obtain a corresponding prescription for narcotic and psychotropic drugs and obtain the drug offline. Generally speaking, the prescription of Class II psychotropic substances does not exceed the dosage for 7 days. This means that patients need to visit the doctor frequently to pick up the medicine, increasing the cost of taking medicine.

[0011] Existing researchers have developed new perampanel preparations to reduce toxicity and side effects, improve bioavailability, and patient compliance, including oral tablets (CN113440489A), freeze-dried orally disintegrating tablets (CN104706604A), solid dispersion dry suspensions (CN107536805A), dispersible tablets (CN106619551A), oral soluble films (CN109106696A), nano-suspensions (CN113069415B), etc., which are all immediate-release preparations. Another patent CN106667968A provides a perampanel sustained-release capsule, which can extend the maintenance time of the perampanel therapeutic concentration in the body up to 12 hours, but the dosing interval is still very short, and the problem of frequent dosing has not been solved.

[0012] In recent years, due to the huge industrial value and broad application prospects of sustained-release microspheres, they have become one of the research hotspots in pharmaceutics and have been valued by major international pharmaceutical giants. Microspheres refer to microspherical entities formed by dissolving or dispersing drugs in carrier excipients, usually with a particle size between 1 and 250 μm. After being injected into the body, microspheres release drugs slowly at a certain rate through the mechanism of drug diffusion or carrier erosion, maintaining a stable blood drug concentration at the lesion site.

[0013] However, despite extensive searches, no patent or paper literature has been found to disclose an effective long-acting sustained-release perampanel microsphere preparation. Therefore, developing a long-acting sustained-release perampanel microsphere preparation to reduce the dosing frequency, reduce the number of patient visits, increase the convenience and compliance of patients taking medicine, avoid peak-valley phenomena, and reduce the occurrence of toxicity, side effects, and drug resistance has great clinical and economic significance. Summary of the Invention

[0014] The present invention provides a method for preparing perampanel sustained-release microspheres and a perampanel sustained-release injection, aiming to reduce the administration frequency of perampanel, improve the convenience of patients' medication, and also reduce the toxic and side effects caused by the drug concentration fluctuation in the body.

[0015] In the first aspect of the present invention, a long-acting sustained-release microsphere of perampanel is provided, which contains perampanel active ingredient and a high-molecular-weight carrier material. The theoretical mass ratio of the perampanel active ingredient is 10% - 35%, and the drug-loading ratio is 1:9 - 7:13. Through actual measurement, the drug loading is 9% - 34%, and the encapsulation efficiency is 45.8% - 99.2% (preferably above 90%), and generally, perampanel can be continuously released for 14 - 42 days.

[0016] The perampanel active ingredient can be one or a mixture of anhydrous substances, hydrates, and their salts.

[0017] The high-molecular-weight carrier material is selected from poly(lactic-co-glycolic acid) (PLGA) with a weight-average molecular weight of 12 - 145 KDa, polylactic acid (PLA), or polycaprolactone (PCL).

[0018] Among them, PLGA has flexible adjustability. In addition to the molecular weight, PLGA can also change the types of end groups and the molar ratio of lactic acid / glycolic acid monomers (L / G) to obtain microspheres with different properties. Therefore, the carrier material is more preferably PLGA.

[0019] Furthermore, the weight-average molecular weight of PLGA is preferably 47 - 145 KDa, the end groups can be ester groups, hydroxyl groups, or carboxyl groups, and the L / G can be 50 / 50 - 75 / 25.

[0020] Furthermore, the particle size D90 of the long-acting sustained-release microsphere of perampanel is ≤150 μm, and the span SPAN ≤2. The particle size is small and the distribution is uniform, having good needle-passing performance.

[0021] In the second aspect of the present invention, a method for preparing a long-acting sustained-release microsphere of perampanel is provided, including the following steps:

[0022] S1. Dissolve the high-molecular-weight carrier material in an oil-phase solvent;

[0023] S2. Dissolve the perampanel active ingredient in the oil-phase solvent containing the high-molecular-weight carrier material to form an oil phase (O);

[0024] S3. Dissolve the stabilizer in water to form an aqueous phase (W);

[0025] S4. Under stirring conditions, add the oil phase (O) obtained in S2 to the aqueous phase (W) obtained in S3, and mix evenly to form an O / W emulsion;

[0026] S5. Under stirring conditions, add the O / W emulsion to the solidifying phase. The emulsion droplets solidify in the solidifying phase to form microspheres, obtaining a suspension containing microspheres.

[0027] S6. Extract the microspheres from the suspension containing microspheres, namely the long-acting sustained-release microspheres of perampanel.

[0028] Specifically, the oil-phase solvent in S1 needs to contain a main solvent component and a secondary solvent component. The main solvent component is dichloromethane, and the secondary solvent component is selected from any one or more of methanol, ethanol, propylene glycol, and ethyl acetate.

[0029] In the implementation process of the present invention, through a large number of experiments, it is found that the type and composition ratio of the oil-phase solvent are crucial for the preparation of perampanel microspheres. It is known that PLGA with a molar ratio of lactic acid monomer (LA ratio) ≥ 50% is soluble in dichloromethane, and dichloromethane has a low boiling point (about 39.8 °C) and has a certain solubility in water. Therefore, dichloromethane can diffuse from the oil phase to the water phase and then be volatilized and removed through the liquid-gas surface, which is an ideal solvent for preparing microsphere products. In the present invention, perampanel is almost insoluble in water, easily soluble in dichloromethane, slightly soluble in acetonitrile and acetone, and slightly soluble in ethyl acetate, methanol, ethanol, and propylene glycol, and is suitable for preparing microspheres by the O / W emulsion solvent evaporation method. However, experiments have found that when only dichloromethane is used as the oil-phase solvent, the drug-carrier material mixture precipitates to obtain irregular particles, and it is difficult to prepare microspheres with a round shape and a high encapsulation rate. Under the condition of using a single oil-phase solvent dichloromethane, the present invention also tried several different polymer carrier materials, but found that no matter how the scheme was adjusted, microsphere products with qualified comprehensive performance could not be obtained.

[0030] In the implementation process of the present invention, it is found that by setting the oil-phase solvent to contain a main solvent component and a secondary solvent component, where the main solvent component is dichloromethane and the secondary solvent component is selected from methanol, ethanol, propylene glycol, and ethyl acetate, and on this premise, through comprehensive optimization and adjustment of the carrier material, preparation process, etc., a series of long-acting perampanel microspheres can be prepared. The continuous and stable release period of perampanel generally reaches more than 2 weeks, and the continuous and stable release period of the microsphere sample prepared by the preferred scheme can reach 6 weeks. Compared with ordinary preparations (such as tablets), the dosing interval can be greatly extended, the medication convenience can be increased, the patient compliance can be improved, and the possibility of missing drugs can be reduced.

[0031] Furthermore, the secondary solvent component is preferably methanol, ethanol, or propylene glycol, and more preferably ethanol.

[0032] Furthermore, in the oil-phase solvent, the mass ratio of the main solvent component to the secondary solvent component can be 4 / 1 to 6 / 1, and is preferably 5 / 1.

[0033] Further, the mass percentage of the polymer carrier material in the oil phase (O) is preferably 10-14%.

[0034] Further, the mass ratio of the perampanel active ingredient to the carrier material (drug loading ratio) is 1:9-7:13, that is, the theoretical drug loading of the microspheres is 10-35%, preferably 10%-30%.

[0035] Further, the stabilizer described in S3 is selected from one or more of polyvinyl alcohol (PVA), Tween, Span, sodium dodecyl sulfate, sodium carboxymethyl cellulose, polyvinylpyrrolidone, poloxamer, and is preferably polyvinyl alcohol (PVA). The concentration of PVA is preferably 0.1-5%, more preferably 1%.

[0036] Further, the mass ratio of the oil phase to the water phase is selected from 1:1-1:100, preferably 1:1-1:30, more preferably 1:10-1:30.

[0037] Further, the method of "mixing evenly" in S4 is selected from stirring, homogenization, ultrasonic treatment, and static mixing. The preferred method is homogenization, with a rotation speed of 1000-10000 rpm.

[0038] Specifically, the solidifying phase in S5 is a non-solvent of the carrier material, that is, the carrier material is poorly soluble or insoluble therein.

[0039] Preferably, the solidifying phase can be water or an aqueous solution containing additives, and the additives can be Tween, Span, sodium dodecyl sulfate, sodium dodecyl sulfonate, poloxamer, PVA, etc.

[0040] Further, the dosage of the solidifying phase can be selected to be 0-1000 times the theoretical weight of the microspheres, preferably 100-400 times.

[0041] Further, in S6, the microspheres can be obtained by filtration, washing, and drying from the suspension containing the microspheres, and dry and clean perampanel long-acting sustained-release microspheres are obtained.

[0042] The third aspect of the present invention is to provide a perampanel long-acting sustained-release injection containing the above-mentioned perampanel long-acting sustained-release microspheres.

[0043] Explanation of terms involved in the present invention

[0044] Theoretical drug loading: The weight percentage of the drug contained in the theoretical microspheres. Theoretical drug loading = (theoretical drug dosage / (theoretical drug dosage + theoretical carrier weight)) × 100%.

[0045] Measured drug loading: The weight percentage of the drug contained in the measured microspheres. Measured drug loading = (drug content in microspheres / microsphere weight) × 100%.

[0046] Entrapment efficiency: The weight percentage of the drug encapsulated in the microspheres. Entrapment efficiency = (amount of drug encapsulated in microspheres / total amount of encapsulated and unencapsulated drug in microspheres) × 100% = (1 - amount of unencapsulated drug in liquid / total amount of encapsulated and unencapsulated drug in microspheres) × 100%.

[0047] D 10 and D 50 and D 90 respectively refer to the particle sizes corresponding to 10%, 50%, and 90% in the cumulative particle size distribution diagram.

[0048] Span = (D 90 - D 10 ) / D 50 . The smaller the span, the narrower the distribution, that is, the more uniform the particle size.

[0049] Beneficial effects

[0050] In the present invention, a long-acting sustained-release microsphere of perampanel was prepared. The microspheres have a round morphology, good drug loading capacity, high entrapment efficiency, appropriate particle size and uniform distribution, and can continuously release the perampanel drug for 14 to 42 days. The long-acting sustained-release perampanel microspheres prepared in the present invention can be further developed into a long-acting sustained-release injection of perampanel. Compared with the once-daily administration of the marketed perampanel preparation, the dosing interval can be significantly extended, the number of visits to the doctor for medication can be reduced, the convenience of medication can be increased, the compliance of patients can be improved, and the risk of seizure induced by missed medication can be reduced. Especially for some patients who are not suitable for oral administration, such as patients with choking cough, dysphagia, nasogastric feeding, and fistula, the long-acting perampanel microspheres and preparations provide a new option for more convenient and safe drug administration. Description of the drawings

[0051] Appendix Figure 1 shows the molecular structural formula of perampanel 3 / 4 hydrate.

[0052] Appendix Figure 2 shows the microscopic morphology diagrams of Examples 1 to 8 and Comparative Examples 1 to 4.

[0053] Appendix Figure 3 shows the summary of the test results of Examples 1 to 8 and Comparative Examples 1 to 4.

[0054] Appendix Figure 4 shows the summary of the test results of Examples 2, 9, and 10.

[0055] Appendix Figure 5 shows the summary of the test results of Examples 2, 11 to 14.

[0056] Appendix Figure 6 shows the summary of the test results of Examples 13, 15 to 18.

[0057] AppendixFigure 7 Shown is a summary of the test results of Examples 13, 19 to 21.

[0058] Attached Figure 8 Shown is the microscopic morphology of Examples 13, 22, and 23.

[0059] Attached Figure 9 Shown is a summary of the test results of Examples 13, 22, and 23.

[0060] Attached Figure 10 Shown is the in vitro release curve of Examples 13, 22, and 23.

[0061] Attached Figure 11 Shown is the in vitro release curve of Comparative Examples 5 and 6.

[0062] Attached Figure 12 Shown is a summary of the test results of Examples 24 to 28.

[0063] Attached Figure 13 Shown is the in vitro release curve of Examples 24 to 28.

[0064] Attached Figure 14 Shown is a summary of the test results of Examples 22, 29 to 31.

[0065] Attached Figure 15 Shown is the in vitro release curve of Examples 22, 29 to 31.

[0066] Attached Figure 16 Shown is a summary of the test results of Examples 22, 32 to 38.

[0067] Attached Figure 17 Shown is the in vitro release curve of Examples 22, 32 to 38. Detailed implementation manners

[0068] Unless otherwise defined, the terms used in the present invention have the same meanings as those commonly understood by those skilled in the technical field to which the present invention pertains.

[0069] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.

[0070] Detection method:

[0071] Microsphere morphology: Take an appropriate amount of microspheres, disperse them with 0.1% PVA solution, drop them onto a glass slide, and observe the morphology under an optical microscope.

[0072] Drug loading amount: Weigh 50 - 60 mg of microspheres, dissolve them in a fixed amount of acetonitrile, then detect the concentration of perampanel by HPLC method, and calculate the drug loading amount.

[0073] Entrapment efficiency: Weigh 50 - 60 mg of microspheres, disperse them in a fixed amount of absolute ethanol for 5 minutes, then detect the concentration of perampanel in absolute ethanol to obtain the amount of free drug, and calculate the entrapment efficiency according to the formula: Entrapment efficiency = (1 - Amount of free drug / Drug loading amount of microspheres) × 100%.

[0074] Particle size and particle size distribution: Weigh about 50 mg of microspheres, place them in a 10 mL vial, add 0.1% Tween 80 aqueous solution, ultrasonicate for 1 min, and measure the particle size and particle size distribution of the microspheres with a laser particle size analyzer.

[0075] In vitro release: (1) Release medium: pH 7.4 phosphate buffer solution containing 1% sodium dodecyl sulfate and 25% ethanol, filtered through an organic filter membrane. (2) Take 10 mg of microspheres and place them in a 150 ml glass bottle, add 100 ml of the medium, and conduct an in vitro release test in a 37°C water bath with shaking at a speed of 100 r / min. Sample and analyze at each sampling point and replenish the liquid. Detect the concentration of perampanel in each sample by HPLC method, calculate the cumulative drug release amount and the cumulative release rate (%) = Cumulative drug release amount / Theoretical drug loading amount of microspheres × 100%, and plot the in vitro cumulative release curve.

[0076] Example 1:

[0077] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester - capped), 0.373 g of perampanel trihydrate (water content 3.5%, equivalent to 0.36 g of perampanel), dissolve them in 6.30 g of dichloromethane and 1.26 g of methanol to obtain an oil - phase solution. Weigh 27.00 g of 1% PVA solution as the water phase, and slowly add the oil - phase solution to the water phase while homogenizing at a speed of 5000 rpm to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, add the O / W emulsion to the solidifying phase while stirring and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90 μm and 20 μm sieves, wash them with water 3 times, and obtain powdery microspheres after freeze - drying.

[0078] Example 2:

[0079] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester-terminated) and 0.373 g of perampanel 3 / 4 hydrate (with 3.5% water content, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil-phase solution. Weigh 27.00 g of 1% PVA solution as the water phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the water phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, add the O / W emulsion to the solidifying phase while stirring and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them with water 3 times, and dry them to obtain powdery microspheres.

[0080] Example 3:

[0081] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester-terminated) and 0.373 g of perampanel 3 / 4 hydrate (with 3.5% water content, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of propylene glycol to obtain an oil-phase solution. Weigh 27.00 g of 1% PVA solution as the water phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the water phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, add the O / W emulsion to the solidifying phase while stirring and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them with water 3 times, and dry them to obtain powdery microspheres.

[0082] Example 4:

[0083] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester-terminated) and 0.373 g of perampanel 3 / 4 hydrate (with 3.5% water content, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of ethyl acetate to obtain an oil phase. Weigh 27.00 g of 1% PVA solution as the water phase. Under the condition of homogenization at a rotation speed of 5000 rpm, add the oil phase to the water phase to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, add the O / W emulsion to the solidifying phase while stirring and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them with water 3 times, and dry them to obtain powdery microspheres.

[0084] Example 5:

[0085] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester-terminated), 0.373 g of perampanel 3 / 4 hydrate (with 3.5% water content, equivalent to 0.36 g of perampanel), and dissolve them in 6.05 g of dichloromethane and 1.51 g of absolute ethanol to obtain an oil-phase solution. Weigh 54.0 g of 1% PVA solution as the aqueous phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the aqueous phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, and while stirring, add the O / W emulsion to the solidifying phase and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0086] Example 6:

[0087] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester-terminated), 0.373 g of perampanel 3 / 4 hydrate (with 3.5% water content, equivalent to 0.36 g of perampanel), and dissolve them in 6.48 g of dichloromethane and 1.08 g of absolute ethanol to obtain an oil-phase solution. Weigh 54.0 g of 1% PVA solution as the aqueous phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the aqueous phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, and while stirring, add the O / W emulsion to the solidifying phase and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0088] Example 7:

[0089] Weigh 1.08 g of PLA (Mw = 180 KDa), 0.373 g of perampanel 3 / 4 hydrate (with 3.5% water content, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil-phase solution. Weigh 27.00 g of 1% PVA solution as the aqueous phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the aqueous phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, and while stirring, add the O / W emulsion to the solidifying phase and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0090] Example 8:

[0091] Weigh 1.08 g of PCL (viscosity 1.75 dl / g) and 0.373 g of perampanel 3 / 4 hydrate (moisture content 3.5%, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil-phase solution. Weigh 27.00 g of 1% PVA solution as the water phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the water phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, and while stirring, add the O / W emulsion to the solidifying phase and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them with water 3 times, and dry them to obtain powdery microspheres.

[0092] Comparative Example 1:

[0093] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester-terminated), and dissolve it in 7.56 g of dichloromethane to obtain an oil-phase solution. Weigh 45.00 g of 1% PVA solution as the water phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the water phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, and while stirring, add the O / W emulsion to the solidifying phase and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through a 90-μm sieve, collect the solidified particles passing through the sieve, wash them with water 3 times, and dry them to obtain powdery microspheres.

[0094] Comparative Example 2:

[0095] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester-terminated) and 0.373 g of perampanel 3 / 4 hydrate (moisture content 3.5%, equivalent to 0.36 g of perampanel), and dissolve them in 7.56 g of dichloromethane to obtain an oil-phase solution. Weigh 27.00 g of 1% PVA solution as the water phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the water phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, and while stirring, add the O / W emulsion to the solidifying phase and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through a sieve with a pore size of 90 μm, collect the solidified particles passing through the sieve, wash them with water 3 times, and dry them to obtain powdery microspheres.

[0096] Comparative Example 3:

[0097] Weigh 1.08 g of PLA (Mw = 180 KDa) and 0.373 g of perampanel 3 / 4 hydrate (with 3.5% water content, equivalent to 0.36 g of perampanel), dissolve them in 7.56 g of dichloromethane to obtain an oil-phase solution. Weigh 27.00 g of 1% PVA solution as the water phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the water phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidification phase, add the O / W emulsion to the solidification phase while stirring and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through a sieve with a pore size of 90 μm, collect the solidified particles under the sieve, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0098] Comparative Example 4:

[0099] Weigh 1.08 g of PCL (viscosity 1.75 dl / g) and 0.373 g of perampanel 3 / 4 hydrate (with 3.5% water content, equivalent to 0.36 g of perampanel), dissolve them in 7.56 g of dichloromethane to obtain an oil-phase solution. Weigh 27.00 g of 1% PVA solution as the water phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the water phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidification phase, add the O / W emulsion to the solidification phase while stirring and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through a sieve with a pore size of 90 μm, collect the solidified particles under the sieve, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0100] Test Example 1

[0101] Take the samples of Examples 1 - 8 to detect the microsphere morphology, drug loading, and encapsulation efficiency. Detect the microsphere morphology of Comparative Example 1, and detect the microsphere morphology, drug loading, and encapsulation efficiency of Comparative Examples 2 - 4. The results are shown in Figure 2 and Figure 3 . Figure 2 The morphologies shown as S1 - S8 in Figure 2 are the morphologies of the corresponding Examples 1 - 8 respectively, and the morphologies shown as D1 - D4 in

[0102] The results of Comparative Examples 1 and 2 showed that the perampanel API itself had an adverse effect on the formation of microspheres. In Comparative Example 1, without adding perampanel drug, PLGA microspheres with a round morphology were obtained. In Comparative Example 2, perampanel was added, resulting in the inability to form regular spherical microsphere particles. The actual drug loading was 23.98%, but the encapsulation efficiency was extremely low, only 10.74%. This indicated that the presence of the perampanel API not only inhibited the formation of regular microspheres, but also was difficult to be evenly encapsulated in the microspheres during the microsphere formation process. Instead, it mainly accumulated on the surface of the microspheres in an attached form. Such a low encapsulation efficiency was not only unfavorable for prolonging the drug release period, but also easily caused a burst release phenomenon at the initial stage of drug administration, resulting in a significant deviation of the perampanel concentration in the body from the preset range.

[0103] The results of Comparative Examples 3 and 4 were similar to those of Comparative Example 2. Although different carrier materials, including PLA and PCL, were tried, the encapsulation efficiency was still extremely low, and under the microscope, they showed irregular particles and failed to form round spheres.

[0104] The results of Examples 1 to 4 showed that the composition of the oil-phase solvent had a significant impact on the morphology and encapsulation efficiency of perampanel microspheres. Using a mixed solvent of dichloromethane and methanol, ethanol, propylene glycol, or ethyl acetate as the oil-phase solvent, the obtained microspheres had significantly improved morphology and encapsulation efficiency compared with Comparative Examples 2 to 4. When the oil-phase solvent was dichloromethane and ethanol, the obtained microspheres were the most round, with fewer surface protrusions and a higher encapsulation efficiency.

[0105] The results of Examples 5 and 6 showed that the mass ratio of dichloromethane to ethanol had an impact on the morphology and encapsulation efficiency of perampanel microspheres. When the proportion of ethanol was too high or too low, the encapsulation efficiency would decrease. However, compared with Comparative Examples 2 to 4, the obtained microspheres in Examples 5 and 6 still had significantly improved morphology and significantly increased encapsulation efficiency. Further, the results of Examples 2, 7, and 8 showed that the type of carrier material also had a certain impact on the morphology, encapsulation efficiency, and drug loading of perampanel microspheres.

[0106] Example 9:

[0107] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester-terminated) and 0.373 g of perampanel 3 / 4 hydrate (with 3.5% moisture, equivalent to 0.36 g of perampanel), and dissolve them in 7.79 g of dichloromethane and 1.56 g of absolute ethanol to obtain an oil-phase solution. Weigh 27.00 g of 1% PVA solution as the aqueous phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the aqueous phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, add the O / W emulsion to the solidifying phase while stirring and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0108] Example 10:

[0109] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester-terminated) and 0.373 g of perampanel 3 / 4 hydrate (with 3.5% moisture, equivalent to 0.36 g of perampanel), and dissolve them in 5.22 g of dichloromethane and 1.04 g of absolute ethanol to obtain an oil-phase solution. Weigh 27.00 g of 1% PVA solution as the aqueous phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the aqueous phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, add the O / W emulsion to the solidifying phase while stirring and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0110] Test Example 2:

[0111] Take the samples of Example 9 and Example 10 to detect the drug loading and encapsulation efficiency of the microspheres. The results are shown in Figure 4 . The results show that under the preparation process conditions of this scheme, when the PLGA concentration (PLGA concentration = mass of PLGA / total mass of the oil phase × 100%) is between 10% and 14%, the influence on the encapsulation efficiency is relatively small, and the drug loading is the highest at 14%.

[0112] Examples 11 - 14:

[0113] The preparation methods of the perampanel microspheres in Examples 11 - 14 are basically the same as those in Example 2, except for the weight of the 1% PVA solution in the aqueous phase, which are 9.00 g, 54.00 g, 90.00 g, and 270.0 g of 1% PVA solution respectively.

[0114] Test Example 3:

[0115] Samples from Examples 11 to 14 were taken to detect the drug loading and encapsulation efficiency of the microspheres. The results of the oil-water ratio, drug loading, and encapsulation efficiency in Examples 2, 11 to 14 are shown in the appendix. Figure 5 The results showed that the oil-water ratio had an impact on the drug loading and encapsulation efficiency of perampanel microspheres. When the oil-water ratio was 1:1 to 1:30, the encapsulation efficiency could reach over 70%. Considering energy conservation and emission reduction under the condition of a relatively high encapsulation efficiency, the oil-water ratio of 1:10 was more preferably selected.

[0116] Example 15:

[0117] The preparation method of the perampanel microspheres in Example 15 was basically the same as that in Example 2, except that the weight of the aqueous phase was 90.00 g and the aqueous phase composition was a 5% PVA solution, as follows.

[0118] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester-terminated) and 0.373 g of perampanel trihydrate (water content 3.5%, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil-phase solution. Weigh 90.00 g of a 5% PVA solution as the aqueous phase. Under the condition of a rotation speed of 5000 rpm, while homogenizing, slowly add the oil-phase solution to the aqueous phase to form an O / W emulsion. Weigh 576.0 g of water as the solidification phase, and while stirring, add the O / W emulsion to the solidification phase and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90 μm and 20 μm sieves, wash them with water 3 times, and dry them to obtain powdery microspheres.

[0119] Examples 16 to 18:

[0120] The preparation methods of the perampanel microspheres in Examples 16 to 18 were basically the same as that in Example 15, except that the aqueous phase compositions were 0.1% PVA solution, 1% Tween 80, and 0.1% sodium dodecyl sulfate, respectively.

[0121] Test Example 4:

[0122] Samples from Examples 15 to 18 were taken to detect the drug loading and encapsulation efficiency of the microspheres, and samples from Examples 13, 15 to 18 were taken to detect the particle size and particle size distribution of the microspheres. The results are shown in the appendix. Figure 6 The results showed that the concentration and type of the aqueous phase stabilizer had little impact on the drug loading and encapsulation efficiency of perampanel microspheres.

[0123] Example 19

[0124] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester-terminated) and 0.373 g of perampanel 3 / 4 hydrate (moisture content 3.5%, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil-phase solution. Weigh 90.00 g of 1% PVA solution as the aqueous phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the aqueous phase while homogenizing to form an O / W emulsion. Weigh 144.0 g of water as the solidifying phase, add the O / W emulsion to the solidifying phase while stirring, and continuously stir for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0125] The preparation methods of the perampanel microspheres in Examples 20 and 21 are basically the same as those in Example 19, except that the weights of the solidifying phases are 1440.0 g and 72.0 g respectively, as follows.

[0126] Example 20:

[0127] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester-terminated) and 0.373 g of perampanel 3 / 4 hydrate (moisture content 3.5%, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil-phase solution. Weigh 90.00 g of 1% PVA solution as the aqueous phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the aqueous phase while homogenizing to form an O / W emulsion. Weigh 1440.0 g of water as the solidifying phase, add the O / W emulsion to the solidifying phase while stirring, and continuously stir for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0128] Example 21:

[0129] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester-terminated), 0.373 g of perampanel 3 / 4 hydrate (moisture content 3.5%, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil-phase solution. Weigh 90.00 g of 1% PVA solution as the aqueous phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the aqueous phase while homogenizing to form an O / W emulsion. Weigh 72.0 g of water as the solidifying phase, add the O / W emulsion to the solidifying phase while stirring, and then continue stirring for 4 hours to solidify the microspheres, obtaining a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0130] Test Example 5:

[0131] Detect the drug loading amount, encapsulation efficiency, particle size and particle size distribution of Examples 19 to 21, and the results are shown in the appendix Figure 7 . The results of Example 13 and Examples 19 to 21 show that the amount of the solidifying phase used has an impact on the drug loading amount and encapsulation efficiency. When the amount of the solidifying phase used is more than 100 times the theoretical mass of the microspheres, the encapsulation efficiency can reach more than 80%.

[0132] Example 22:

[0133] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester group-terminated), 0.373 g of perampanel 3 / 4 hydrate (moisture content 3.5%, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil-phase solution. Weigh 90.00 g of 1% PVA solution as the aqueous phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the aqueous phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, pre-cool it to about 5 °C with an ice-water bath in advance, then add the O / W emulsion to the solidifying phase while stirring, and continue stirring for 4 hours to solidify the microspheres, obtaining a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0134] Example 23:

[0135] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester - terminated), 0.36 g of perampanel, and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil - phase solution. Weigh 90.00 g of 1% PVA solution as the aqueous phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil - phase solution to the aqueous phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, pre - cool it to about 5 °C with an ice - water bath, then add the O / W emulsion to the solidifying phase while stirring, and continue stirring for 4 hours to solidify the microspheres, obtaining a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90 - μm and 20 - μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0136] Test Example 6:

[0137] Detect the drug - loading amount, encapsulation efficiency, particle size and particle size distribution of the samples in Examples 22 and 23, and detect the microsphere morphology and in vitro release of Examples 13, 22, and 23; the results are shown in Appendix Figures 8 - 10 。 Figure 8 The sample morphologies corresponding to Examples 13, 22, and 23 are shown as S13, S22, and S23 in the appendix respectively.

[0138] The perampanel microspheres in Examples 13 and 22 have round and regular morphologies and uniform particle sizes. The results show that the solidification temperature has an impact on the drug - loading amount and in vitro release of perampanel microspheres. Compared with Example 13, Example 22 uses a low - temperature solidification process, maintaining a relatively high drug - loading amount while maintaining a high encapsulation efficiency. Different solidification temperatures result in slightly different drug - release rates, but all can sustain release for 42 days.

[0139] The results of Examples 22 and 23 show that microspheres with round morphologies, good drug - loading amounts, and high encapsulation efficiencies can be prepared using either perampanel 3 / 4 hydrate or perampanel. The in vitro release rates are slightly different, but all can sustain release for 42 days.

[0140] Comparative Example 5:

[0141] Take 2.5 mg of the raw drug perampanel and place it in a 150 - ml glass bottle. Add 100 ml of the release medium (pH 7.4 phosphate buffer solution containing 1% sodium dodecyl sulfate and 25% ethanol), and conduct an in vitro release test in a 37 °C water - bath oscillator with a rotation speed of 100 r / min. Sampling and analysis are carried out at 5, 15, 30, and 60 min, and the liquid is replenished. The concentration of perampanel in each sample is detected by HPLC, the cumulative drug - release amount is calculated, and the cumulative release rate (%) is calculated to plot the in vitro cumulative release curve. The results of the release curve are shown in Appendix Figure 11 。

[0142] Comparative Example 6:

[0143] Take 2.5 mg of the raw material drug perampanel 3 / 4 hydrate and place it in a 150 ml glass bottle. Add 100 ml of the release medium (pH 7.4 phosphate buffer solution containing 1% sodium dodecyl sulfate and 25% ethanol), and conduct an in vitro release test in a 37 °C water bath with shaking at a rotation speed of 100 r / min. Sampling and analysis are carried out after 5, 15, 30, and 60 minutes, and the liquid is replenished. The concentration of perampanel in each sample is detected by HPLC method, the cumulative drug release amount is calculated, and the cumulative release rate (%) is calculated to make an in vitro cumulative release curve. The results of the release curve are shown in the appendix Figure 11 。

[0144] Under the same conditions as the in vitro release of the microspheres in Comparative Examples 5 and 6, after adding the raw material drug perampanel and perampanel 3 / 4 hydrate to the release medium, the drug dissolved rapidly and was completely released within 60 minutes. In contrast, the perampanel microspheres prepared in the examples had a very significant sustained-release effect.

[0145] Example 24

[0146] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester-terminated) and 0.373 g of perampanel 3 / 4 hydrate (moisture content 3.5%, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil-phase solution. Weigh 90.00 g of 1% PVA solution as the water phase. Under the condition of a rotation speed of 1000 rpm, while homogenizing, slowly add the oil-phase solution to the water phase to form an O / W emulsion. Weigh 576.0 g of water as the solidification phase, pre-cool it to about 5 °C with an ice-water bath in advance, then while stirring, add the O / W emulsion to the solidification phase, and continue to stir for 4 hours to solidify the microspheres to obtain a suspension. Then filter the suspension through a sieve with a pore size of 150 μm, collect the suspension under the sieve, then sub-pack it into centrifuge tubes, centrifuge at 5000 rpm × 5 min to collect the precipitate, and then wash it with water 3 times and dry it to obtain powdery microspheres.

[0147] The preparation methods of the perampanel microspheres in Examples 25 to 28 are basically the same as those in Example 24, except that the homogenization conditions are 3000, 5000, 7000, and 10000 rpm respectively.

[0148] Test Example 7:

[0149] Take the samples in Examples 24 to 28 to detect the drug loading amount, encapsulation rate, particle size and particle size distribution, and in vitro release of the microspheres. The results are shown in the appendix Figure 12 、 13 。The results show that the homogenization rotation speed has a great influence on the particle size of the perampanel microspheres, and thus affects the in vitro release. Within the range of 1000 - 10000 rpm, the drug loading and encapsulation of the microspheres are good, and the in vitro release can be maintained for more than 28 days.

[0150] Example 29:

[0151] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester-terminated) and 0.124 g of perampanel 3 / 4 hydrate (with 3.5% water content, equivalent to 0.12 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil-phase solution. Weigh 90.00 g of 1% PVA solution as the aqueous phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the aqueous phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, pre-cool it to about 5 °C with an ice-water bath in advance, then add the O / W emulsion to the solidifying phase while stirring, and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0152] Example 30:

[0153] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester-terminated) and 0.477 g of perampanel 3 / 4 hydrate (with 3.5% water content, equivalent to 0.46 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil-phase solution. Weigh 90.00 g of 1% PVA solution as the aqueous phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the aqueous phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, pre-cool it to about 5 °C with an ice-water bath in advance, then add the O / W emulsion to the solidifying phase while stirring, and continue stirring for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0154] Example 31:

[0155] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, ester - capped), 0.60 g of perampanel 3 / 4 hydrate (water content 3.5%, equivalent to 0.58 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil - phase solution. Weigh 90.00 g of 1% PVA solution as the water phase. Under the condition of a rotation speed of 5000 rpm, while homogenizing, slowly add the oil - phase solution to the water phase to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, pre - cool it to about 5 °C with an ice - water bath in advance, then while stirring, add the O / W emulsion to the solidifying phase, and continue to stir for 4 hours to solidify the microspheres, obtaining a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90 - μm and 20 - μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0156] Test Example 8:

[0157] Detect the drug - loading amount, encapsulation efficiency, particle size, and in vitro release of the samples in Examples 29 - 31. The results are shown in Appendix Figure 14 、 15 . The results show that the theoretical drug - loading amount has an impact on the encapsulation efficiency and in vitro release. When the theoretical drug - loading amount is between 10% and 35%, the encapsulation efficiency can reach over 77%, and in vitro, it can continuously release for more than 35 days, but the release rates are different. When the theoretical drug - loading amount is 35%, the initial burst release is the highest and the release is the fastest.

[0158] Example 32:

[0159] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 140 KDa, hydroxyl - capped), 0.373 g of perampanel 3 / 4 hydrate (water content 3.5%, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil - phase solution. Weigh 90.00 g of 1% PVA solution as the water phase. Under the condition of a rotation speed of 5000 rpm, while homogenizing, slowly add the oil - phase solution to the water phase to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, pre - cool it to about 5 °C with an ice - water bath in advance, then while stirring, add the O / W emulsion to the solidifying phase, and continue to stir for 4 hours to solidify the microspheres, obtaining a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90 - μm and 20 - μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0160] Example 33:

[0161] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 145 KDa, carboxyl end), 0.373 g of perampanel 3 / 4 hydrate (moisture content 3.5%, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil-phase solution. Weigh 90.00 g of 1% PVA solution as the aqueous phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the aqueous phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, pre-cool it to about 5 °C with an ice-water bath in advance, then add the O / W emulsion to the solidifying phase while stirring, and continue to stir for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0162] Example 34:

[0163] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 120 KDa, ester end-capped), 0.373 g of perampanel 3 / 4 hydrate (moisture content 3.5%, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil-phase solution. Weigh 90.00 g of 1% PVA solution as the aqueous phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the aqueous phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, pre-cool it to about 5 °C with an ice-water bath in advance, then add the O / W emulsion to the solidifying phase while stirring, and continue to stir for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0164] Example 35:

[0165] Weigh 1.08 g of PLGA (L:G = 75:25, Mw = 47 KDa, ester end-capped), 0.373 g of perampanel 3 / 4 hydrate (moisture content 3.5%, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil-phase solution. Weigh 90.00 g of 1% PVA solution as the aqueous phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the aqueous phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidifying phase, pre-cool it to about 5 °C with an ice-water bath in advance, then add the O / W emulsion to the solidifying phase while stirring, and continue to stir for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90-μm and 20-μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0166] Example 36:

[0167] Weigh 2.16 g of PLGA (L:G = 75:25, Mw = 12 KDa, ester - terminated), 0.746 g of perampanel 3 / 4 hydrate (moisture content 3.5%, equivalent to 0.72 g of perampanel), and dissolve them in 12.60 g of dichloromethane and 2.52 g of absolute ethanol to obtain an oil - phase solution. Weigh 90.00 g of 1% PVA solution as the water - phase. Under the condition of a rotation speed of 5000 rpm, while homogenizing, slowly add the oil - phase solution to the water - phase to form an O / W emulsion. Weigh 1152.0 g of water as the solidification phase, pre - cool it to about 5 °C with an ice - water bath in advance, then while stirring, add the O / W emulsion to the solidification phase, and continue stirring for 4 hours to solidify the microspheres, obtaining a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90 - μm and 20 - μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0168] Example 37:

[0169] Weigh 1.08 g of PLGA (L:G = 65:35, Mw = 60 KDa, carboxyl - terminated), 0.373 g of perampanel 3 / 4 hydrate (moisture content 3.5%, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil - phase solution. Weigh 90.00 g of 1% PVA solution as the water - phase. Under the condition of a rotation speed of 5000 rpm, while homogenizing, slowly add the oil - phase solution to the water - phase to form an O / W emulsion. Weigh 576.0 g of water as the solidification phase, pre - cool it to about 5 °C with an ice - water bath in advance, then while stirring, add the O / W emulsion to the solidification phase, and continue stirring for 4 hours to solidify the microspheres, obtaining a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90 - μm and 20 - μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0170] Example 38:

[0171] Weigh 1.08 g of PLGA (L:G = 50:50, Mw = 55 KDa, carboxyl end) and 0.373 g of perampanel trihydrate (water content 3.5%, equivalent to 0.36 g of perampanel), and dissolve them in 6.30 g of dichloromethane and 1.26 g of absolute ethanol to obtain an oil-phase solution. Weigh 90.00 g of 1% PVA solution as the water phase. Under the condition of a rotation speed of 5000 rpm, slowly add the oil-phase solution to the water phase while homogenizing to form an O / W emulsion. Weigh 576.0 g of water as the solidification phase, pre-cool it to about 5 °C with an ice-water bath in advance, then add the O / W emulsion to the solidification phase while stirring, and continue to stir for 4 hours to solidify the microspheres and obtain a suspension. Then filter the suspension through sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90 μm and 20 μm sieves, wash them 3 times with water, and dry them to obtain powdery microspheres.

[0172] Test Example 9:

[0173] Detect the drug loading, encapsulation efficiency, particle size, and in vitro release of the samples in Examples 32 to 38. The results are shown in the appendix Figure 16 、 17 . The results show that the end groups, molecular weight, and L / G of PLGA have a greater impact on in vitro release. When L / G = 75 / 25 and the end group is an ester group, the smaller the molecular weight of PLGA, the faster the release. When the molecular weight is 12 KDa, the encapsulation efficiency decreases significantly, and the release is rapid, and it is completely released in about 1 week. When the molecular weight is 47 KDa or more, the encapsulation efficiency can reach more than 90%, and the release can continue for 14 days or more. When the molecular weight is 140 - 145 KDa and L / G = 75 / 25, the release is the fastest when the end group is a carboxyl group, followed by a hydroxyl group, and the slowest is an ester group. When the molecular weight is 55 - 60 KDa and the end group is a carboxyl group, the greater the proportion of G, the faster the release.

[0174] By changing the molecular weight, L / G, and end groups of PLGA, the drug release rate of perampanel microspheres can be adjusted, which has the potential to be developed into sustained-release preparations with different dosing cycles and has broad application prospects. For example, Example 36 can be developed into a preparation with a dosing cycle of once a week, Example 38 can be developed into a preparation with a dosing cycle of once every two weeks, Example 37 can be developed into a preparation with a dosing cycle of once every three weeks, Example 35 can be developed into a preparation with a dosing cycle of once every four weeks, Examples 32, 33, and 34 can be developed into a preparation with a dosing cycle of once every five weeks, and Example 22 can be developed into a preparation with a dosing cycle of once every six weeks.

Claims

1. A method for preparing perampanel sustained-release microspheres, characterized in that: It includes the following steps: S1. Dissolve the polymer carrier material in the oil-phase solvent; S2. Dissolve the perampanel active ingredient in the oil-phase solvent containing the polymer carrier material to form an oil phase O; S3. Dissolve the stabilizer in water to form an aqueous phase W; S4. Add the oil phase O obtained in S2 to the aqueous phase W obtained in S3, mix uniformly to form an O / W emulsion; S5. Add the O / W emulsion to the solidifying phase, and the emulsion droplets solidify in the solidifying phase to form microspheres, obtaining a suspension containing microspheres; S6. Screen out the microspheres from the suspension containing microspheres, wash with water and dry to obtain the perampanel long-acting sustained-release microspheres; The oil-phase solvent contains a main solvent component and a secondary solvent component, wherein the main solvent component is dichloromethane, and the secondary solvent component is selected from any one or more of methanol, ethanol, propylene glycol, and ethyl acetate; The mass percentage of the polymer carrier material in the oil phase O is 10% - 14%; The mass ratio of the perampanel active ingredient to the polymer carrier material is 1:9 - 7:13, that is, the theoretical drug loading is between 10% and 35%; The oil phase O and the aqueous phase W are mixed in a mass ratio of 1:1 - 1:30; The mass ratio of the main solvent component to the secondary solvent component is 4 / 1 - 6 / 1; The polymer carrier material is selected from poly(lactic-co-glycolic acid) with a weight-average molecular weight of 12 - 145 KDa, polylactic acid, or polycaprolactone; The stabilizer is polyvinyl alcohol with a mass content of 0.1% - 5% in the aqueous phase W; The solidifying phase is water, and the dosage of the solidifying phase is 100 - 400 times the theoretical weight of the microspheres; Add the oil phase to the aqueous phase under the homogenization condition of 1000 - 10000 rpm.

2. The method according to claim 1, wherein: The secondary solvent component is ethanol, and the oil-phase solvent is a mixture formed by mixing dichloromethane and ethanol in a mass ratio of 4 / 1 - 6 / 1.

3. The method according to claim 1, characterized in that: The polymer carrier material is poly(lactic-co-glycolic acid), and its end groups are selected from one or more of ester groups, hydroxyl groups, and carboxyl groups. The molar ratio of lactic acid / glycolic acid monomers in the poly(lactic-co-glycolic acid) is 50 / 50 - 75 / 25.

4. According to the method described in claim 1, wherein: The polymer carrier material is poly(lactic-co-glycolic acid) (PLGA), the molar ratio (L / G) of lactic acid / glycolic acid monomers is 75:25, its weight-average molecular weight Mw = 140 KDa, and its end group is an ester group; In the oil-phase solvent, the main solvent component is dichloromethane, the secondary solvent component is ethanol, and the mass ratio of the main solvent component to the secondary solvent component is 5 / 1; The stabilizer is polyvinyl alcohol, and its mass content in the aqueous phase W is 1%; The oil phase O and the aqueous phase W are mixed in a mass ratio of 1:10; The solidifying phase is water, and it is pre-cooled to 5°C with an ice-water bath before adding the O / W emulsion; Extract the microspheres from the suspension containing microspheres through the following steps: filter the suspension with sieves with pore sizes of 90 μm and 20 μm, collect the particles between the 90 μm and 20 μm sieves, wash with water and dry to obtain powdery microspheres.

5. A perampanel long-acting sustained-release injection, characterized in that: The perampanel long-acting sustained-release injection contains the perampanel long-acting sustained-release microspheres prepared by the method according to any one of claims 1 to 4.

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