Donepezil sustained release preparation and preparation method thereof

Abstract

The invention belongs to the technical field of medicines, and particularly relates to a donepezil sustained release preparation and a preparation method thereof, the method comprises the following steps: mixing donepezil, a biodegradable polymer, an amphiphilic polymer and a stabilizer, shearing, curing, and freeze-drying to obtain donepezil microsphere freeze-dried powder. The donepezil sustained release preparation can realize controllable and sustained release of donepezil, the microspheres are good in character and high in stability, meanwhile, the preparation method is simple and convenient, and industrial large-scale production is easy to realize.

Description

Technical Field

[0001] The present invention belongs to the technical field of medicine, and particularly relates to a donepezil sustained-release preparation and a preparation method thereof. Background Art

[0002] Donepezil, used for the treatment of mild to moderate Alzheimer's disease, belongs to acetylcholinesterase inhibitors. By inhibiting the decomposition of acetylcholine, it increases the concentration of acetylcholine in the brain, thereby improving the cognitive function and memory of patients. Since it was developed by Eisai Co., Ltd. in Japan in 1983, various dosage forms of donepezil have been marketed, including tablets, orally disintegrating tablets, granules, and dry syrups. These dosage forms are mainly administered orally and are suitable for most patients. However, for patients with difficulty in swallowing or those who need to take medicine for a long time, the compliance of oral dosage forms is poor.

[0003] To improve the medication compliance of Alzheimer's patients and optimize the drug release characteristics, it is necessary to develop various novel drug delivery systems. Microsphere preparations are a drug delivery system in which drugs are encapsulated in a micron-sized polymer matrix and can be administered through various routes such as oral, injection, or topical administration, with great flexibility. However, there are also many technical bottlenecks: for example, the physicochemical properties of donepezil may lead to a low encapsulation rate in microspheres, and the selection of polymer materials, uneven particle size distribution of microspheres, etc. make it difficult to control the drug release rate: the preparation process involves emulsification, solvent evaporation, or spray drying, etc., with high technical difficulty and high production cost.

[0004] CN201480020234.0 discloses a non-oral pharmaceutical composition containing donepezil. By adding a poorly soluble salt of donepezil, such as cinchoninate, naphthalenedisulfonate, or ditanate, as a controlled-release agent, sustained-release is achieved. The results show that the dissolution rate of the drug is delayed with the increase in the concentration of the poorly soluble salt.

[0005] CN201880029854.9 discloses a sustained-release injection preparation containing donepezil. The preparation contains two or more kinds of microspheres, which contain poly(lactide) with different intrinsic viscosities, and the intrinsic viscosity of poly(lactide) is regulated to be 0.16 - 0.75 dL / g to achieve sustained release. This patent requires strict control of the intrinsic viscosity of poly(lactide), and the preparation method is cumbersome and the process conditions are harsh.

[0006] CN201880037391.0 discloses a method for preparing biodegradable microspheres with improved stability and storage stability. This preparation method involves preparing an emulsion containing a dispersed phase and a continuous phase, and then strictly removing a part of the continuous phase containing the organic solvent extracted from the dispersed phase at a removal rate of 2 to 200% (v / v) per minute, while supplying a new aqueous solution to replace the continuous phase, thereby avoiding residual organic solvents in the microspheres. This preparation method is cumbersome and requires strict control of the removal rate, otherwise it will affect the morphology, molecular weight and quality of the product.

[0007] CN202080077303.7 discloses a microsphere for sustained release, which improves the drug encapsulation rate in the microsphere by preventing the formation of drug crystals on the periphery or surface of the microsphere, so as to prevent the excessive release of the drug at the initial stage during administration.

[0008] CN202280067500.X discloses a sustained release microsphere containing donepezil. By distributing donepezil in two dispersed phases with different drug loadings, donepezil microspheres with different drug loadings are prepared, thereby achieving the sustained release of the active ingredient. This preparation method has a complex process and requires strict control of the drug loading in different microspheres, otherwise it will affect the sustained release effect.

[0009] In view of the problems existing in donepezil sustained release preparations in the prior art, there is an urgent need to provide a preparation and preparation method that can solve the problems such as the difficulty in controlling the release rate of donepezil, the complex microsphere preparation process, and the easy precipitation of drugs on the surface of microspheres. Summary of the Invention

[0010] In view of the technical problems in the prior art, the present invention provides a donepezil sustained release preparation and its preparation method. This preparation can achieve the controllable and sustained release of donepezil, the microspheres have good properties and high stability, and at the same time the preparation method is simple and easy to realize industrial scale-up production.

[0011] The technical solution of the present invention is: A preparation method of a donepezil sustained release preparation, comprising the following steps: adding donepezil and a biodegradable polymer into an organic solvent, and stirring until completely dissolved to obtain a degradable substance solution; dissolving an amphiphilic polymer and a stabilizer in injection water to obtain an amphiphilic substance solution, and adjusting the pH; mixing and shearing the degradable substance solution and the amphiphilic substance solution to obtain an emulsion; vacuum-curing the emulsion, screening and washing the microspheres to remove the amphiphilic substance and the stabilizer, and freeze-drying to obtain a donepezil microsphere lyophilized powder.

[0012] In the above method, the weight ratio of donepezil to the biodegradable polymer is 1:1.2 to 7.5, preferably a weight ratio of 1:4 to 6.

[0013] In the method, the biodegradable polymer is selected from one or more of poly(lactic-co-glycolic acid) (PLGA), polyhydroxyalkanoate (PHA), or poly(lactic acid) (PLA).

[0014] Preferably, in the method, the weight-average molecular weight of PLGA is 30 to 70 kDa, more preferably 50 kDa.

[0015] Preferably, in the method, the weight-average molecular weight of PHA is 15 to 40 kDa, more preferably 30 kDa.

[0016] Preferably, in the method, the weight-average molecular weight of PLA is 30 to 80 kDa, more preferably 50 kDa.

[0017] In the method, the organic solvent is a mixture of dichloromethane and an alcohol solvent, and the volume ratio of dichloromethane to the alcohol solvent is 1:0.1 to 0.5.

[0018] Preferably, in the method, the alcohol solvent is tert-butanol, isopropanol, or n-propanol.

[0019] Preferably, in the method, the weight ratio of donepezil to the volume of the organic solvent is 1:20 to 40, where the weight is in g and the volume is in mL.

[0020] Preferably, in the method, the pH is adjusted to 8.5 to 9.5.

[0021] In the method, the amphiphilic polymer is 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol (DSPE-PEG), polycaprolactone-polyethylene glycol (PCL-PEG), or poly(L-lactic acid)-polyethylene glycol (PLLA-PEG).

[0022] Preferably, in the method, the weight ratio of the lipid part to the PEG part in the amphiphilic polymer is 1:0.5 to 0.95.

[0023] Preferably, in the method, the molecular weight of the PEG part in the amphiphilic polymer is 2000, 3400, or 5000 Da.

[0024] Preferably, in the method, the component of polycaprolactone in PCL-PEG is 4000 to 7000 Da, more preferably 6000 Da.

[0025] Preferably, in the method, the molecular weight of poly(L-lactic acid) in PLLA-PEG is 4000 to 6000 Da, more preferably 5000 Da.

[0026] In the method, the mass fraction of the amphiphilic polymer in the amphiphilic substance solution is 0.3 to 3.0%.

[0027] In the method, the volume ratio of the degradable substance solution to the amphiphilic substance solution is 1:10 to 250.

[0028] In the method, the reagent for adjusting pH is an aqueous solution of hydrochloric acid, phosphoric acid, lactic acid, citric acid, sodium hydroxide or potassium hydroxide.

[0029] In the method, the stabilizer is mannitol, glucose or glycerol.

[0030] In the method, the mass fraction of the stabilizer in the amphiphilic substance solution is 5 to 10%.

[0031] Preferably, in the method, the shear rate of high-speed shearing is 2000 to 5000 r / min.

[0032] Preferably, in the method, the process of vacuum curing is: drying for 2 to 7 h under the conditions of 40 to 50 °C and a vacuum degree of 0.01 to 0.05 MPa.

[0033] Preferably, in the method, the steps of sieving and washing the microspheres are: sieving the microsphere emulsion through a vibrating sieve, rinsing the microspheres on the lower sieve with injection water after sieving, washing the microspheres with injection water 5 to 8 times, then transferring the microspheres on the lower sieve to a freeze-drying tray and placing them in a freeze dryer for freeze-drying.

[0034] Preferably, in the method, the process of freeze-drying is: pre-freezing at -40 to -45 °C for 2 to 3 h; sublimation drying: evacuating the freeze dryer and maintaining it at 0.20 ± 0.02 mbar, heating to -10 to 30 °C at a rate of 10 °C / h and maintaining for 10 to 15 h; desorption drying: evacuating the freeze dryer and maintaining it at 0.10 ± 0.02 mbar, raising the temperature to 30 to 50 °C and continuously drying for 10 to 20 h, then maintaining an ultimate vacuum for 2 h and taking out of the chamber.

[0035] The amphiphilic polymer in the present invention can be purchased, or prepared by the preparation methods in the prior art, or self-prepared by the following preparation method. As long as the weight average molecular weight and the proportion of the polymer meet the requirements, they can all be used for the preparation of the microspheres in the present invention, and the source is not limited. The following provides a preparation method of an amphiphilic polymer:

[0036] According to the weight ratio of the lipid part to the PEG part in the amphiphilic polymer being 1:0.5 - 0.95, the lipid part, PEG, and dibutyltin dilaurate were successively added to a reactor that had been fully dried at 130°C for 2 h. The reactor was sealed, filled with dry nitrogen and pressurized to >2 kg, and then heated to 150°C for reaction for 2 h. After cooling, dichloromethane was added for dissolution and dilution, followed by the addition of water for injection, and stirring was carried out at room temperature for 24 h. After standing for layer separation, the dichloromethane layer was dried with anhydrous magnesium sulfate and then filtered by suction. The filtrate was concentrated to dryness, dissolved in water for injection, and a blank polymer micelle solution was obtained. Ultrafiltration and concentration were carried out to obtain a concentrated solution, which was then freeze-dried to obtain the target product, the amphiphilic polymer.

[0037] The present invention has the following outstanding advantages compared with the prior art:

[0038] 1. The donepezil microspheres obtained in the present invention have good properties, with a round and smooth microsphere morphology and uniform particle size;

[0039] 2. By regulating the spatial distribution of the drug in the microspheres, the drug is concentrated in the center of the microspheres, realizing the controllable and sustained release of donepezil;

[0040] 3. The preparation method of the present invention is simple and easy to realize industrial-scale production. Description of the Drawings

[0041] Figure 1 It is the Raman spectrum of the donepezil microspheres obtained in Example 1 of the present invention. Detailed Embodiments

[0042] The following lists specific embodiments to further illustrate the present invention, but it does not limit the scope of the present invention in any way. Those skilled in the art can make various modifications or improvements according to the basic idea of the present invention, but as long as they do not depart from the basic idea of the present invention, they are within the scope of the present invention.

[0043] Example 1

[0044] 1) 1.2 g of donepezil and 4.8 g of PLGA (Mw: 50 kDa) were added to 36 mL of a mixed organic solvent (volume ratio of dichloromethane: tert-butanol is 1:0.3), and stirred until completely dissolved to obtain a degradable substance solution;

[0045] 2) 30.0 g of PLLA-PEG (where the Mw of PLLA and PEG are 5000 Da and 3400 Da respectively, and the weight ratio of PLLA and PEG is 1:0.7) was added to 1200 g of water for injection, stirred until dissolved, then 120 g of mannitol was added, stirred until completely dissolved, and the pH value was adjusted to 9.0 with sodium hydroxide solution or hydrochloric acid solution, and then made up to 1500 g with water for injection, stirred and mixed evenly to obtain an amphiphilic substance solution.

[0046] 3) Place the biodegradable substance solution and the amphiphilic substance solution in a shear machine and perform high-speed shearing at a shear rate of 4000 r / min to obtain an emulsion;

[0047] 4) Subject the emulsion to vacuum curing: dry it at 45 °C under a vacuum degree of 0.01 - 0.05 MPa for 5 h; then perform screening and ball washing. After screening, rinse the microspheres on the lower sieve with injection water. After washing the balls 6 times, transfer the microspheres on the lower sieve to a freeze-drying tray for standby;

[0048] 5) Subject the microspheres obtained in step 4) to freeze-drying according to the following procedure: pre-freeze at -40 to -45 °C for 3 h; sublimation drying: evacuate the freeze-dryer and maintain at 0.20 ± 0.02 mbar, heat up to -10 to 30 °C at a rate of 10 °C / h and maintain for 10 h; analytical drying: evacuate the freeze-dryer and maintain at 0.10 ± 0.02 mbar, raise the temperature to 30 to 50 °C and continue drying for 15 h, then maintain at an ultimate vacuum for 2 h. After taking out of the chamber, obtain the freeze-dried powder of donepezil microspheres.

[0049] Example 2

[0050] 1) Add 1.2 g of donepezil and 1.4 g of PLA (Mw: 50 kDa) to 24 mL of a mixed organic solvent (volume ratio of dichloromethane: isopropanol is 1:0.1), stir until completely dissolved to obtain a biodegradable substance solution;

[0051] 2) Weigh 4.5 g of DSPE-PEG (where the Mw of PEG is 2000 Da respectively, and the weight ratio of DSPE to PEG is 1:0.5), add it to 1200 g of injection water, stir to dissolve, then add 75 g of glucose, stir until completely dissolved, adjust the pH value to 8.5 with potassium hydroxide solution or lactic acid solution, and then make up the volume to 1500 g with injection water. After stirring and mixing evenly, it is used as the amphiphilic substance solution.

[0052] 3) Place the biodegradable substance solution and the amphiphilic substance solution in a shear machine and perform high-speed shearing at a shear rate of 2000 r / min to obtain an emulsion;

[0053] 4) Subject the emulsion to vacuum curing: dry it at 50 °C under a vacuum degree of 0.01 - 0.05 MPa for 2 h; then perform screening and ball washing. Screen the microsphere emulsion through an oscillating sieve. After screening, rinse the microspheres on the lower sieve with injection water. After washing the balls 5 times, transfer the microspheres on the lower sieve to a freeze-drying tray for standby;

[0054] 5) The microspheres obtained in step 4) are freeze-dried according to the following procedure: pre-freeze at -40 to -45 °C for 2 h; sublimation drying: evacuate the freeze-dryer and maintain at 0.20 ± 0.02 mbar, heat up to -10 to 30 °C at a rate of 10 °C / h and maintain for 15 h; desorption drying: evacuate the freeze-dryer and maintain at 0.10 ± 0.02 mbar, raise the temperature to 30 to 50 °C, continue drying for 10 h, and then maintain under ultimate vacuum for 2 h. After taking out of the chamber, the freeze-dried powder of donepezil microspheres is obtained.

[0055] Example 3

[0056] 1) Add 1.2 g of donepezil, 4.5 g of PHA (Mw: 30 kDa), and 4.5 g of PLGA (Mw: 50 kDa) to 48 mL of a mixed organic solvent (volume ratio of dichloromethane to n-propanol is 1:0.5), and stir until completely dissolved to obtain a degradable substance solution.

[0057] 2) Weigh 45.0 g of PCL-PEG (where the Mw of PCL and PEG are 6000 Da and 5000 Da respectively, and the weight ratio of PCL to PEG is 1:0.95), add it to 1200 g of injection water, stir to dissolve, then add 150 g of glycerol, stir until completely dissolved, adjust the pH value to 9.5 with sodium hydroxide solution or phosphoric acid solution, and then make up the volume to 1500 g with injection water. After stirring and mixing evenly, it is used as an amphiphilic substance solution.

[0058] 3) Place the degradable substance solution and the amphiphilic substance solution in a shearer for high-speed shearing at a shear rate of 5000 r / min to obtain an emulsion.

[0059] 4) Vacuum solidify the emulsion: dry at 40 °C under a vacuum degree of 0.01 to 0.05 MPa for 7 h; then perform screening and washing of the microspheres. Screen the microsphere emulsion through a vibrating screen, and after screening, wash the microspheres on the lower sieve with injection water. After washing the microspheres 8 times, transfer the microspheres on the lower sieve to a freeze-drying tray for standby.

[0060] 5) The microspheres obtained in step 4) are freeze-dried according to the following procedure: pre-freeze at -40 to -45 °C for 3 h; sublimation drying: evacuate the freeze-dryer and maintain at 0.20 ± 0.02 mbar, heat up to -10 to 30 °C at a rate of 10 °C / h and maintain for 10 h; desorption drying: evacuate the freeze-dryer and maintain at 0.10 ± 0.02 mbar, raise the temperature to 30 to 50 °C, continue drying for 20 h, and then maintain under ultimate vacuum for 2 h. After taking out of the chamber, the freeze-dried powder of donepezil microspheres is obtained.

[0061] Example 4

[0062] 1) Add 1.2 g of donepezil and 10.8 g of PLGA (Mw: 50 kDa) to 36 mL of a mixed organic solvent (volume ratio of dichloromethane to tert-butanol is 1:0.3), and stir until completely dissolved to obtain a degradable substance solution;

[0063] 2) Weigh 30.0 g of PLLA-PEG (where the Mw of PLLA and PEG are 5000 Da and 3400 Da respectively, and the weight ratio of PLLA to PEG is 1:0.7), add it to 1200 g of injection water, stir to dissolve, then add 120 g of mannitol, stir until completely dissolved, adjust the pH value to 9.0 with sodium hydroxide solution or hydrochloric acid solution, and then make up the volume to 1500 g with injection water. After stirring and mixing evenly, it serves as an amphiphilic substance solution.

[0064] 3) Place the degradable substance solution and the amphiphilic substance solution in a shearing machine for high-speed shearing at a shearing rate of 4000 r / min to obtain an emulsion;

[0065] 4) Carry out vacuum curing on the emulsion: dry at 45°C under a vacuum degree of 0.01 - 0.05 MPa for 5 h; then carry out screening and washing of the balls. Screen the microsphere emulsion through a vibrating sieve. After screening, wash the microspheres on the lower sieve with injection water. After washing the balls 6 times, transfer the microspheres on the lower sieve to a freeze-drying tray for standby;

[0066] 5) Carry out freeze-drying on the microspheres obtained in step 4) according to the following procedure: pre-freeze at -40 to -45°C for 3 h; sublimation drying: evacuate the freeze-dryer and maintain it at 0.20 ± 0.02 mbar, heat up to -10 to 30°C at a rate of 10°C / h and maintain for 10 h; analytical drying: evacuate the freeze-dryer and maintain it at 0.10 ± 0.02 mbar, raise the temperature to 30 to 50°C, continue drying for 15 h, and then carry out ultimate vacuum for 2 h. After taking out of the chamber, obtain the freeze-dried powder of donepezil microspheres.

[0067] Example 5

[0068] 1) Add 1.2 g of donepezil and 4.8 g of PLGA (Mw: 50 kDa) to 36 mL of a mixed organic solvent (volume ratio of dichloromethane to tert-butanol is 1:0.3), and stir until completely dissolved to obtain a degradable substance solution;

[0069] 2) Weigh 90.0 g of PLLA-PEG (where the Mw of PLLA and PEG are 5000 Da and 3400 Da respectively, and the weight ratio of PLLA to PEG is 1:0.7), add it to 1200 g of injection water, stir to dissolve, then add 120 g of mannitol, stir until completely dissolved, adjust the pH value to 9.0 with sodium hydroxide solution or hydrochloric acid solution, and then make up the volume to 1500 g with injection water. After stirring and mixing evenly, it serves as an amphiphilic substance solution.

[0070] 3) Place the biodegradable substance solution and the amphiphilic substance solution in a shearing machine for high-speed shearing at a shearing rate of 4000 r / min to obtain an emulsion;

[0071] 4) Vacuum-cure the emulsion: dry it at 45 °C under a vacuum degree of 0.01 - 0.05 MPa for 5 h; then perform screening and ball washing. Screen the microsphere emulsion through a vibrating screen, and after screening, rinse the microspheres on the lower sieve with injection water. After washing the balls 6 times, transfer the microspheres on the lower sieve to a freeze-drying tray for standby;

[0072] 5) Freeze-dry the microspheres obtained in step 4) according to the following procedure: pre-freeze at -40 to -45 °C for 3 h; sublimation drying: evacuate the freeze-dryer and maintain at 0.20 ± 0.02 mbar, heat up to -10 to 30 °C at a rate of 10 °C / h and maintain for 10 h; desorption drying: evacuate the freeze-dryer and maintain at 0.10 ± 0.02 mbar, raise the temperature to 30 to 50 °C and continue drying for 15 h, then maintain at an ultimate vacuum for 2 h. After taking out of the chamber, obtain the freeze-dried powder of donepezil microspheres.

[0073] Example 6

[0074] 1) Add 1.2 g of donepezil and 4.8 g of PLGA (Mw: 50 kDa) to 36 mL of a mixed organic solvent (volume ratio of dichloromethane to tert-butanol is 1:0.3), stir until completely dissolved to obtain a biodegradable substance solution;

[0075] 2) Weigh 30.0 g of PLLA-PEG (where the Mw of PLLA and PEG are 5000 Da and 3400 Da respectively, and the weight ratio of PLLA to PEG is 1:0.7), add it to 1200 g of injection water, stir to dissolve, then add 120 g of mannitol, stir until completely dissolved, adjust the pH value to 11.0 with sodium hydroxide solution or hydrochloric acid solution, and then make up the volume to 1500 g with injection water. After stirring and mixing evenly, it serves as the amphiphilic substance solution.

[0076] 3) Place the biodegradable substance solution and the amphiphilic substance solution in a shearing machine for high-speed shearing at a shearing rate of 4000 r / min to obtain an emulsion;

[0077] 4) Vacuum-cure the emulsion: dry it at 45 °C under a vacuum degree of 0.01 - 0.05 MPa for 5 h; then perform screening and ball washing. Screen the microsphere emulsion through a vibrating screen, and after screening, rinse the microspheres on the lower sieve with injection water. After washing the balls 6 times, transfer the microspheres on the lower sieve to a freeze-drying tray for standby;

[0078] 5) The microspheres obtained in step 4) are freeze-dried according to the following procedure: pre-freeze at -40 to -45 °C for 3 h; sublimation drying: evacuate the freeze-dryer and maintain at 0.20 ± 0.02 mbar, heat up to -10 to 30 °C at a rate of 10 °C / h and maintain for 10 h; desorption drying: evacuate the freeze-dryer and maintain at 0.10 ± 0.02 mbar, raise the temperature to 30 to 50 °C, continuously dry for 15 h, and then maintain an ultimate vacuum for 2 h. After taking out of the chamber, the freeze-dried powder of donepezil microspheres is obtained.

[0079] Comparative Example 1

[0080] 1) Add 1.2 g of donepezil and 4.8 g of PLGA (Mw: 50 kDa) to 36 mL of dichloromethane, stir until completely dissolved to obtain a solution of degradable substances.

[0081] 2) Weigh 30.0 g of PLLA-PEG (where the Mw of PLLA and PEG are 5000 Da and 3400 Da respectively, and the weight ratio of PLLA to PEG is 1:0.7), add it to 1200 g of injection water, stir to dissolve, then add 120 g of mannitol and 2.3 mL of tert-butanol, stir until completely dissolved, adjust the pH value to 9.0 with sodium hydroxide solution or hydrochloric acid solution, and then make up the volume to 1500 g with injection water. After stirring and mixing evenly, it is used as a solution of amphiphilic substances.

[0082] 3) Place the solution of degradable substances and the solution of amphiphilic substances in a shear machine for high-speed shearing at a shearing rate of 4000 r / min to obtain an emulsion.

[0083] 4) Vacuum solidify the emulsion: dry at 45 °C under a vacuum degree of 0.01 to 0.05 MPa for 5 h; then carry out screening and washing of the microspheres. Screen the microsphere emulsion through an oscillating sieve. After screening, wash the microspheres on the lower sieve with injection water. After washing the microspheres 6 times, transfer the microspheres on the lower sieve to a freeze-drying tray for standby.

[0084] 5) The microspheres obtained in step 4) are freeze-dried according to the following procedure: pre-freeze at -40 to -45 °C for 3 h; sublimation drying: evacuate the freeze-dryer and maintain at 0.20 ± 0.02 mbar, heat up to -10 to 30 °C at a rate of 10 °C / h and maintain for 10 h; desorption drying: evacuate the freeze-dryer and maintain at 0.10 ± 0.02 mbar, raise the temperature to 30 to 50 °C, continuously dry for 15 h, and then maintain an ultimate vacuum for 2 h. After taking out of the chamber, the freeze-dried powder of donepezil microspheres is obtained.

[0085] Comparative Example 2

[0086] 1) Add 1.2 g of donepezil and 4.8 g of PLGA (Mw: 50 kDa) to 36 mL of a mixed organic solvent (volume ratio of dichloromethane to tert-butanol is 1:0.3), and stir until completely dissolved to obtain a degradable substance solution;

[0087] 2) Weigh 30.0 g of polyvinyl alcohol and add it to 1200 g of injection water, stir to dissolve, then add 120 g of mannitol, stir until completely dissolved, adjust the pH value to 9.0 with sodium hydroxide solution or hydrochloric acid solution, and then make up the volume to 1500 g with injection water, stir and mix evenly to obtain an amphiphilic substance solution.

[0088] 3) Place the degradable substance solution and the amphiphilic substance solution in a shearer for high-speed shearing at a shear rate of 4000 r / min to obtain an emulsion;

[0089] 4) Vacuum solidify the emulsion: dry at 45 °C under a vacuum of 0.01 - 0.05 MPa for 5 h; then perform screening and washing of the microspheres. Screen the microsphere emulsion through a vibrating sieve, and after screening, wash the microspheres on the lower sieve with injection water. After washing the microspheres 6 times, transfer the microspheres on the lower sieve to a freeze-drying tray for standby;

[0090] 5) Freeze-dry the microspheres obtained in step 4) according to the following procedure: pre-freeze at -40 to -45 °C for 3 h; sublimation drying: evacuate the freeze-dryer and maintain at 0.20 ± 0.02 mbar, heat up to -10 to 30 °C at a rate of 10 °C / h and maintain for 10 h; desorption drying: evacuate the freeze-dryer and maintain at 0.10 ± 0.02 mbar, raise the temperature to 30 to 50 °C, continue drying for 15 h, and then maintain an ultimate vacuum for 2 h. After taking out of the box, obtain the freeze-dried powder of donepezil microspheres.

[0091] Comparative Example 3

[0092] 1) Add 1.2 g of donepezil and 4.8 g of PLGA (Mw: 50 kDa) to 36 mL of a mixed organic solvent (volume ratio of dichloromethane to tert-butanol is 1:0.3), and stir until completely dissolved to obtain a degradable substance solution;

[0093] 2) Weigh 30.0 g of PLLA-PEG (where the Mw of PLLA and PEG are 5000 Da and 3400 Da respectively, and the weight ratio of PLLA to PEG is 1:0.7) and add it to 1200 g of injection water, stir to dissolve, stir until completely dissolved, adjust the pH value to 9.0 with sodium hydroxide solution or hydrochloric acid solution, and then make up the volume to 1500 g with injection water, stir and mix evenly to obtain an amphiphilic substance solution.

[0094] 3) Place the solution of degradable substance and the solution of amphiphilic substance in a shearing machine for high-speed shearing at a shearing rate of 4000 r / min to obtain an emulsion;

[0095] 4) Carry out vacuum curing on the emulsion: dry for 5 h at 45 °C under a vacuum degree of 0.01 - 0.05 MPa; then carry out screening and ball washing. Screen the microsphere emulsion through an oscillating sieve. After screening, rinse the microspheres on the lower sieve with injection water. After washing the balls 6 times, transfer the microspheres on the lower sieve to a freeze-drying tray for standby;

[0096] 5) Carry out freeze-drying on the microspheres obtained in step 4) according to the following procedure: pre-freeze at -40 - -45 °C for 3 h; sublimation drying: evacuate the freeze-dryer and maintain at 0.20 ± 0.02 mbar, heat up to -10 - 30 °C at a rate of 10 °C / h and maintain for 10 h; analytical drying: evacuate the freeze-dryer and maintain at 0.10 ± 0.02 mbar, raise the temperature to 30 - 50 °C and continue drying for 15 h, then carry out ultimate vacuum for 2 h. After taking out of the box, obtain the freeze-dried powder of donepezil microspheres.

[0097] Comparative Example 4

[0098] 1) Add 1.2 g of donepezil and 4.8 g of PLGA (Mw: 50 kDa) to 36 mL of a mixed organic solvent (volume ratio of dichloromethane: tert-butanol is 1:0.3), stir until completely dissolved to obtain a solution of degradable substance;

[0099] 2) Weigh 30.0 g of PLLA-PEG (where the Mw of PLLA and PEG are 5000 Da and 3400 Da respectively, and the weight ratio of PLLA and PEG is 1:0.7), add it to 1200 g of injection water, stir to dissolve, then add 120 g of mannitol, stir until completely dissolved, measure the pH value to be 4.5, and then make up the volume to 1500 g with injection water, stir and mix evenly to obtain a solution of amphiphilic substance.

[0100] 3) Place the solution of degradable substance and the solution of amphiphilic substance in a shearing machine for high-speed shearing at a shearing rate of 4000 r / min to obtain an emulsion;

[0101] 4) Carry out vacuum curing on the emulsion: dry for 5 h at 45 °C under a vacuum degree of 0.01 - 0.05 MPa; then carry out screening and ball washing. Screen the microsphere emulsion through an oscillating sieve. After screening, rinse the microspheres on the lower sieve with injection water. After washing the balls 6 times, transfer the microspheres on the lower sieve to a freeze-drying tray for standby;

[0102] 5) The microspheres obtained in step 4) were freeze-dried according to the following procedure: pre-freezing at -40 to -45°C for 3 h; sublimation drying: evacuating the freeze-dryer and maintaining at 0.20 ± 0.02 mbar, heating to -10 to 30°C at a rate of 10°C / h and maintaining for 10 h; desorption drying: evacuating the freeze-dryer and maintaining at 0.10 ± 0.02 mbar, raising the temperature to 30 to 50°C and continuously drying for 15 h, then maintaining at ultimate vacuum for 2 h. After taking out of the chamber, the freeze-dried powder of donepezil microspheres was obtained.

[0103] Comparative Example 5

[0104] 3.5 g of biocompatible polymer Resomer R203H and 1.5 g of donepezil were mixed with 9.2 g of dichloromethane and stirred for more than 30 min until completely dissolved, and set aside; the continuous phase was an aqueous solution containing 1% (w / v) polyvinyl alcohol (viscosity: 4.8 to 5.8 mPa·s) and 30% (v / v) ethanol. A container containing the continuous phase was connected to an emulsification device equipped with a membrane (where the membrane had pores with a diameter of 40 μm), and the prepared dispersion phase was injected simultaneously to generate microspheres in the suspension. The obtained microsphere suspension was placed in a preparation vessel and stirred at 200 rpm. The temperature of the membrane emulsification device and the preparation vessel was maintained at 25°C. When the injection of the dispersion phase was completed, stirring continued for 30 min. In this step, while leaving 5 mL of the continuous phase, 455 mL of the remaining continuous phase was removed, and an equal amount of fresh continuous phase was added. The organic solvent was removed while maintaining the temperature at 40°C for 3 h. After removing the organic solvent, the temperature of the microsphere suspension was lowered to 25°C. The microsphere suspension was washed three times with deionized water to remove the residual polyvinyl alcohol, and then freeze-dried to obtain microspheres.

[0105] Experimental Example 1 Investigation of the properties and residual organic solvents of donepezil microspheres

[0106] 1) Observation of microsphere morphology

[0107] An appropriate amount of the solidified microsphere emulsion was taken, and the morphology of the microspheres was observed using an optical microscope. The conductive adhesive was adhered to the sample stage, an appropriate amount of the freeze-dried microsphere powder was evenly coated on the conductive adhesive, placed in an ion sputtering instrument, sputtered with gold for 90 s, and then the surface morphology of the microspheres was observed using a scanning electron microscope at a voltage of 10 kV.

[0108] 2) Determination of microsphere particle size

[0109] Take an appropriate amount of freeze-dried microsphere powder and place it in a dispersant (usually purified water is selected in the laboratory). After stirring and dispersing, add it to a Malvern laser particle size analyzer for particle size detection. The parameter settings are as follows: the obscuration is between 10% and 20%, the rotation speed is 2800 revolutions per minute, and measure after the obscuration is stable. The refractive index of the sample is 1.578, the refractive index of the medium is 1.330, the absorption rate is 0.000, the background measurement time is 10 seconds, and the sample measurement time is 10 seconds. The span value of the microspheres = (Dv 90 - Dv 10 ) / Dv 50 .

[0110] 3) Determination of residual solvents in microspheres

[0111] Test solution: Take about 100 mg of this product, accurately weigh it, place it in a headspace vial, accurately add 2 ml of dimethyl sulfoxide, seal it, and determine the residual solvents.

[0112] Reference solution: Take appropriate amounts of isopropanol, dichloromethane, tert-butanol, and n-propanol, accurately weigh them, add dimethyl sulfoxide and quantitatively dilute to prepare a mixed solution containing about 0.25 mg of isopropanol, 0.03 mg of dichloromethane, 0.175 mg of tert-butanol, and 0.25 mg of n-propanol per 1 ml. Accurately measure 2 mL and place it in a headspace vial, and seal it.

[0113] Chromatographic conditions: A capillary column with 6% cyanopropylphenyl-94% dimethylpolysiloxane (or similar polarity, 30 m × 0.32 mm × 1.8 μm) as the stationary phase; the initial temperature is 40°C, maintained for 5 minutes, heated at a rate of 20°C per minute to 200°C, and maintained for 5 minutes; the inlet temperature is 200°C; the detector temperature is 250°C; the detector is a flame ionization detector; the headspace vial equilibrium temperature is 80°C, and the equilibrium time is 30 minutes; the carrier gas is nitrogen; the column flow rate is 2.0 ml / min; the split ratio is 10:1; the injection volume is 1.0 mL.

[0114] Table 1 Microsphere determination results of each example and comparative example

[0115]

[0116]

[0117] The results show that the microspheres obtained in each embodiment of the present invention have a smaller particle size, uniform size, better morphology and properties, and less residual organic solvents. In Comparative Example 1, the high residual organic solvents may be caused by the absence of alcohol solvents in the oil phase. In Comparative Example 2, polyvinyl alcohol is used in the aqueous phase, and its mixing effect with the degradable substances is poor during the preparation of microspheres, resulting in non-uniform microsphere sizes and high residual dichloromethane and alcohol. In Comparative Example 3, no stabilizer is added, and the obtained microspheres not only have poor morphology, being oval-shaped, but also have non-uniform sizes. In Comparative Example 5, different preparation methods are used, and the obtained microspheres have a high residual organic solvent.

[0118] Investigation on the in vitro drug release rate of donepezil preparations in Experimental Example 2

[0119] Precisely weigh about 10 mg of donepezil microspheres and place them in 30 mL of HEPES buffer solution with pH 7.4. Put them into a water bath oscillator at 37 °C with an oscillation frequency of 100 rpm. Take out 1 mL at different time points and add the same amount of HEPES buffer solution. Filter the collected filtrate with a 0.45 μm needle filter, and then inject 20 μL of the solution into HPLC. Calculate the release degree of donepezil microspheres based on the filtrate concentration.

[0120] Table 2 Determination results of the in vitro drug release rate of each example and comparative example

[0121]

[0122]

[0123] The results show that the dissolution properties of the microspheres obtained in each embodiment of the present invention are better. In Comparative Example 1, when preparing, adding alcohol solvents to the aqueous phase affects the concentrated distribution of donepezil in the microspheres, shortening the sustained release time. In Comparative Example 2, using polyvinyl alcohol to replace the amphiphilic substance, its mixing effect with the degradable substances is poor during the preparation of microspheres, affecting the distribution of donepezil in the microspheres and resulting in incomplete dissolution. In Comparative Example 3, no stabilizer is added, and the prepared microspheres have non-uniform sizes and incomplete dissolution. In Comparative Example 4, the pH is not regulated, and the distribution of donepezil in the microspheres is dispersed, shortening the sustained release time. In Comparative Example 5, different preparation methods are used, and there is a drawback of incomplete dissolution.

[0124] Experimental Example 3

[0125] Raman spectrum test instrument method:

[0126]

[0127] Sample detection: Take an appropriate amount of donepezil microspheres, cut and process them, place the processed microspheres on a glass slide, and put the prepared sample into the Raman spectrum for sample detection.

[0128] The donepezil microspheres obtained in Example 1 were used for detection, and the results are as Figure 1 shown. By regulating the spatial distribution of the drug in the microspheres, the preparation method provided by the present invention realizes the formation of an obvious drug enrichment region of donepezil in the core of the microspheres. This core-shell distribution characteristic effectively establishes a concentration gradient for drug release, thereby realizing precise control of the release kinetics of donepezil.

Claims

1. A preparation method of a donepezil sustained-release preparation, characterized in that, The method comprises the following steps: adding donepezil and a biodegradable polymer into an organic solvent, and stirring until completely dissolved to obtain a degradable substance solution; dissolving an amphiphilic polymer and a stabilizer in water for injection to obtain an amphiphilic substance solution, and adjusting the pH; mixing the degradable substance solution and the amphiphilic substance solution, and shearing to obtain an emulsion; subjecting the emulsion to vacuum curing, screening, and washing the spheres to remove the amphiphilic substance and the stabilizer, and freeze-drying to obtain a freeze-dried powder of donepezil microspheres.

2. The method according to claim 1, characterized in that, In the method, the biodegradable polymer is selected from one or more of lactide-glycolide copolymer, polyhydroxyalkanoate, or polylactide copolymer.

3. The method according to claim 1, characterized in that In the method, the weight ratio of donepezil to the biodegradable polymer is 1:1.2 to 9, preferably a weight ratio of 1:4 to 6.

4. The method according to claim 1, wherein In the method, the amphiphilic polymer is distearoyl phosphatidylethanolamine-polyethylene glycol, polycaprolactone-polyethylene glycol, or poly(L-lactic acid)-polyethylene glycol.

5. The method according to claim 4, wherein In the method, the weight ratio of the lipid part to the PEG part in the amphiphilic polymer is 1:0.5 to 0.

95.

6. The method according to claim 1, wherein In the method, the organic solvent is a mixture of dichloromethane and an alcohol solvent, and the volume ratio of dichloromethane to the alcohol solvent is 1:0.1 to 0.

5.

7. The method according to claim 6, wherein In the method, the alcohol solvent is tert-butanol, isopropanol, or n-propanol.

8. The method according to claim 1, wherein In the method, the pH is adjusted to 8.5 to 9.

5.

9. The method according to claim 1, wherein In the method, the volume ratio of the degradable substance solution to the amphiphilic substance solution is 1:10 to 250.

10. The method according to claim 1, characterized in that, In the method, the stabilizer is mannitol, glucose, or glycerol.

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