Donepezil sustained-release microsphere, and preparation method therefor, pharmaceutical preparation, and use thereof

Abstract

A donepezil sustained-release microsphere, and a preparation method therefor, a pharmaceutical preparation, and the use thereof. The preparation method comprises the following steps: forming an aqueous phase (including a surfactant, an osmotic pressure regulator and water, and adjusting the pH value with a pH regulator); forming an oil phase (including donepezil, a carrier material and an organic solvent); adding the oil phase into the aqueous phase for dispersion to form a pre-emulsion, then carrying out membrane emulsification on the pre-emulsion to form an emulsion, and finally curing, washing and freeze-drying the emulsion to obtain the donepezil sustained-release microsphere. The preparation process is stable and controllable, with good batch-to-batch repeatability. The microspheres have smooth and intact microsphere surfaces, a uniform particle size distribution and controllable sizes, have a high drug loading capacity, can achieve long-term stable release, and have excellent injectability, so that the administration frequency can be reduced, and adverse reactions in the gastrointestinal tract can be alleviated.

Description

Donepezil sustained-release microspheres, preparation method thereof, pharmaceutical preparation and use thereof

[0001] Citation of Related Applications

[0002] This disclosure claims priority to an invention patent application filed with the Patent Office of China on January 2, 2024, with application number 202410004110.9 and titled “A sustained-release microsphere of donepezil, its preparation method, pharmaceutical preparation and use”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention belongs to the field of pharmaceutical preparations and relates to donepezil sustained-release microspheres, a preparation method thereof, a pharmaceutical preparation and uses thereof. Background Art

[0004] Alzheimer's disease (AD) is a chronic neurodegenerative disease that usually begins in the early and late stages of old age. Its main manifestations include progressive memory impairment, cognitive dysfunction, personality changes, and language disorders, which seriously affect social, occupational and life functions.

[0005] Due to the complex pathogenesis of Alzheimer's disease, current medications and other interventions cannot cure the disease. Most medications work by regulating certain neurotransmitters in the brain, primarily to alleviate symptoms and slow the progression of the disease, resulting in limited therapeutic effectiveness.

[0006] Cortical cholinergic neurotransmitter dysfunction is believed to be one of the causes of memory impairment and other cognitive impairments. Currently approved drugs for the treatment of AD are acetylcholinesterase (AChE) inhibitors and N-methyl-D-aspartate (NMDA) receptor antagonists. Donepezil is a second-generation central acetylcholinesterase inhibitor (AChEI) with high pharmacological activity, strong selectivity, and good safety. It is highly lipid-soluble and easily crosses the blood-brain barrier. It has a strong affinity for acetylcholinesterase and specifically binds to cholinesterase in the cerebral cortex, inhibiting cholinesterase activity. Therefore, it has a high efficacy and few adverse reactions. It is currently the first-line drug for the clinical treatment of mild to moderate Alzheimer's disease.

[0007] Currently, most commercially available preparations are oral preparations of donepezil hydrochloride, including oral tablets, capsules, oral solutions, etc., which need to be administered once a day, and a course of treatment lasts for 3 to 6 months. However, Alzheimer's patients have varying degrees of memory loss, and are prone to missing doses, taking the wrong doses, or even refusing to take them. When the disease progresses to a certain extent, patients will also experience difficulty swallowing, all of which are not conducive to improving the condition. In addition, oral donepezil hydrochloride has certain adverse reactions, such as nausea, vomiting, diarrhea, and lack of appetite. The control of Alzheimer's disease requires long-term maintenance, and long-term oral medication will lead to poor patient compliance and low medication accuracy.

[0008] The membrane emulsification method can prepare microspheres with uniform and controllable particle size, high encapsulation efficiency and low mechanical strength. Due to different drug indications and different administration routes, the in vivo environment of the microspheres is also different, thus putting forward different requirements for the type, particle size and distribution of drug-loaded microspheres. Therefore, it is necessary to strictly control the parameter regulation, condition optimization and related equipment improvement in the membrane emulsification operation. For example, highly hydrophilic polypeptide drugs and drugs with small molecular weight are very prone to drug escape. By adjusting factors such as membrane pore size, organic solvent type and related proportions and stirring rate, the microspheres can have better encapsulation efficiency and drug loading capacity. In addition, when using membrane emulsification technology, researchers also found that the operation process involves multidisciplinary knowledge and many influencing factors. At present, there is no complete set of theories to guide this preparation technology.

[0009] Summary of the Invention

[0010] Problems to be solved by the invention

[0011] In view of the above problems, the present invention aims to provide a donepezil sustained-release microsphere preparation with uniform particle size, high drug loading, long-term stable release, excellent injectability, stable and controllable preparation process, and good batch-to-batch reproducibility.

[0012] Solutions for solving problems

[0013] In a first aspect, the present invention provides a method for preparing donepezil sustained-release microspheres, comprising the following steps:

[0014] mixing a surfactant, an osmotic pressure regulator, and water, and adjusting the pH value of the mixture using a pH regulator to form an aqueous phase;

[0015] mixing donepezil, a carrier material, and an organic solvent to form an oil phase; and,

[0016] The oil phase is added to the water phase for dispersion to form a pre-emulsion, the pre-emulsion is then membrane emulsified to form an emulsion, and finally the emulsion is solidified, washed, and freeze-dried to obtain donepezil sustained-release microspheres.

[0017] As a further improvement of the present invention, the pre-emulsion is an oil-in-water pre-emulsion.

[0018] As a further improvement of the present invention, the surfactant is at least one of polyvinyl alcohol (PVA), Tween, sodium dodecyl sulfate (SDS), sodium dodecylbenzenesulfonate (SDBS) and polyoxyethylene octylphenol ether, preferably polyvinyl alcohol.

[0019] As a further improvement of the present invention, the weight ratio of the surfactant to donepezil is 1:5 to 20:5, preferably 4:5 to 8:5.

[0020] As a further improvement of the present invention, the osmotic pressure regulator is at least one of sodium chloride and potassium chloride, preferably sodium chloride.

[0021] As a further improvement of the present invention, the weight ratio of the osmotic pressure regulator to donepezil is 1:5 to 6:5, preferably 1.5:5 to 4:5.

[0022] As a further improvement of the present invention, the water is at least one of ultrapure water, redistilled water and water for injection, preferably ultrapure water.

[0023] As a further improvement of the present invention, the volume ratio of water to organic solvent is 5:1 to 50:1, preferably 8:1 to 14:1.

[0024] As a further improvement of the present invention, the pH regulator is at least one of hydrogen chloride or sodium hydroxide.

[0025] As a further improvement of the present invention, the pH adjuster adjusts the pH value of the mixture to 6.0 to 12.0, preferably 6.0 to 10.0.

[0026] As a further improvement of the present invention, the carrier material is a biodegradable carrier material.

[0027] As a further improvement of the present invention, the carrier material is at least one of polylactic acid-co-glycolic acid (PLGA), polylactic acid-polyethylene glycol (PELA) and polylactic acid (PLA), preferably polylactic acid-co-glycolic acid.

[0028] As a further improvement of the present invention, the intrinsic viscosity of the carrier material is 0.15 dL / g to 0.90 dL / g, preferably 0.4 dL / g to 0.7 dL / g.

[0029] As a further improvement of the present invention, the weight ratio of the carrier material to donepezil is 2:3 to 12:3, preferably 2:3 to 5:3.

[0030] As a further improvement of the present invention, the organic solvent is at least one of chloroform, dichloromethane, ethyl acetate, acetone, acetonitrile, and anhydrous ethanol, preferably dichloromethane.

[0031] As a further improvement of the present invention, the usage ratio of the organic solvent to donepezil is 4-20 mL:1 g, preferably 6-15 mL:1 g.

[0032] As a further improvement of the present invention, the dispersion is accomplished by at least one of stirring and ultrasound, preferably stirring, more preferably mechanical stirring.

[0033] As a further improvement of the present invention, the mechanical stirring time is 30 to 60 seconds, preferably 30 seconds.

[0034] As a further improvement of the present invention, the rotation speed of the mechanical stirring is 250-350 rpm, preferably 300 rpm.

[0035] As a further improvement of the present invention, the emulsification is accomplished by membrane emulsification.

[0036] As a further improvement of the present invention, the solidification is accomplished by volatilization or evaporation, preferably by reduced pressure volatilization, stirring volatilization or thin film evaporation, more preferably by reduced pressure volatilization.

[0037] As a further improvement of the present invention, the vacuum degree of the reduced pressure volatilization is -0.09 to -0.05 MPa, preferably -0.09 MPa.

[0038] As a further improvement of the present invention, the time for the reduced pressure volatilization is 20 to 300 minutes, preferably 20 to 240 minutes.

[0039] As a further improvement of the present invention, the temperature of the reduced pressure volatilization is 20-42°C, preferably 38°C.

[0040] As a further improvement of the present invention, the preparation method further comprises the following steps: solidifying the emulsion, washing it, and freeze-drying it.

[0041] In a second aspect, the present invention provides a sustained-release microsphere of donepezil, which is prepared using the above-mentioned preparation method.

[0042] As a further improvement of the present invention, the particle size of the donepezil sustained-release microspheres is 10 to 50 μm, preferably 25 to 35 μm.

[0043] As a further improvement of the present invention, the encapsulation efficiency of the donepezil sustained-release microspheres is above 80%, preferably above 90%.

[0044] As a further improvement of the present invention, the drug loading of the donepezil sustained-release microspheres is 20% to 60%, preferably 40% to 60%.

[0045] In a third aspect, the present invention provides a pharmaceutical preparation of donepezil, comprising the above-mentioned sustained-release microspheres.

[0046] As a further improvement of the present invention, the pharmaceutical preparation further comprises at least one pharmaceutically acceptable excipient.

[0047] As a further improvement of the present invention, the pharmaceutical preparation is a sustained-release preparation.

[0048] As a further improvement of the present invention, the pharmaceutical preparation is an injection.

[0049] In a fourth aspect, the present invention provides use of the sustained-release microspheres or the pharmaceutical preparation in preparing a drug for preventing and / or treating at least some diseases and / or conditions related to acetylcholinesterase.

[0050] As a further improvement of the present invention, the disease and / or disorder at least partially related to acetylcholinesterase is Alzheimer's disease.

[0051] Effects of the Invention

[0052] The beneficial effects of the present invention are:

[0053] (1) The preparation process of the present invention can reduce drug escape and avoid the risk of high burst release in the early stage of release.

[0054] (2) The sustained-release microspheres prepared by the present invention are loaded with a high content of donepezil, and the amount of microspheres used during administration (eg, injection) is relatively small, thereby avoiding injection nodules or other adverse reactions caused by a large injection volume.

[0055] (3) The microspheres prepared by the present invention have uniform particle size and excellent injectability.

[0056] (4) The preparation process of the present invention is stable and controllable, and has good economic benefits and broad application prospects.

[0057] (5) The long-acting sustained-release microsphere preparation prepared by the present invention can greatly reduce the frequency of medication for patients, and can effectively avoid fluctuations in blood drug concentrations caused by wrong or missed doses, or even recurrence or worsening of the disease.

[0058] (6) The microsphere preparation for injection prepared by the present invention can effectively avoid gastrointestinal adverse reactions and has obvious clinical advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] FIG1 is a scanning electron microscope image of the microspheres prepared in Example 1.

[0060] FIG2 is a scanning electron microscope image of the microspheres prepared in Example 2.

[0061] FIG3 is a scanning electron micrograph of the microspheres prepared in Example 3.

[0062] FIG4 is a scanning electron micrograph of the microspheres prepared in Example 4.

[0063] FIG5 is a scanning electron microscope image of the microspheres prepared in Example 5.

[0064] FIG6 is a scanning electron micrograph of the microspheres prepared in Example 6.

[0065] FIG7 is a scanning electron micrograph of the microspheres prepared in Example 7.

[0066] FIG8 is a scanning electron microscope image of the microspheres prepared in Example 8.

[0067] FIG9 is a scanning electron microscope image of the microspheres prepared in Comparative Example 1.

[0068] FIG10 is a scanning electron micrograph of the microspheres prepared in Comparative Example 2.

[0069] FIG11 is an in vitro cumulative release curve of five microspheres prepared in Examples 1, 5, 6, 7 and 8. DETAILED DESCRIPTION

[0070] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The word "exemplary" is used herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior or preferred over other embodiments.

[0071] In addition, numerous specific details are provided in the following detailed description to better illustrate the present invention. Those skilled in the art will appreciate that the present invention can be practiced without certain specific details. In other instances, methods, means, equipment, and steps well known to those skilled in the art are not described in detail in order to highlight the main points of the present invention.

[0072] Unless otherwise stated, the units used in this specification are international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0073] In this specification, the use of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0074] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "embodiments," etc., mean that the specific elements (e.g., features, structures, properties, and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0075] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints A and B.

[0076] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 10-40°C.

[0077] Donepezil sustained-release microspheres and preparation method thereof

[0078] The present invention provides a method for preparing donepezil sustained-release microspheres, which comprises the following steps:

[0079] mixing a surfactant, an osmotic pressure regulator, and water, and adjusting the pH value of the mixture using a pH regulator to form an aqueous phase;

[0080] mixing donepezil, a carrier material, and an organic solvent to form an oil phase; and,

[0081] The oil phase is added to the water phase for dispersion to form a pre-emulsion, the pre-emulsion is then membrane emulsified to form an emulsion, and finally the emulsion is solidified, washed, and freeze-dried to obtain donepezil sustained-release microspheres.

[0082] During preparation, donepezil diffuses from the oil phase to the aqueous phase due to osmotic pressure and isoelectric point factors, causing the drug to migrate to the exterior of the carrier material. This results in an excessively rapid initial release from the microspheres and poor long-term stable release. Furthermore, drug migration can also cause drug crystals to form around or on the surface of the microspheres, resulting in a rough surface and reduced drug loading. Furthermore, microsphere particle size significantly influences drug release behavior. Microspheres prepared using traditional preparation methods exhibit an uneven particle size distribution, which compromises stable drug release. Therefore, preventing drug escape and controlling microsphere size are crucial during preparation.

[0083] This invention prevents drug migration to the exterior of the microspheres by adding a certain amount of an osmotic pressure regulator to the aqueous phase and adjusting the pH of the aqueous phase. This results in a smoother microsphere surface, higher drug loading, and effective prevention of sudden drug release, while maintaining stable drug release. Furthermore, a membrane emulsification method produces an emulsion with a more uniform particle size. This eliminates the need for additional screening during microsphere washing and collection, ensuring controllable size, effectively preventing drug loss and enabling long-term, stable drug release.

[0084] In one embodiment of the present invention, the pre-emulsion in the above preparation method may be an oil-in-water pre-emulsion.

[0085] In one embodiment of the present invention, the surfactant in the above preparation method can be at least one of polyvinyl alcohol, Tween, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate and polyoxyethylene octylphenol ether, for example, polyvinyl alcohol, Tween or a mixture of the two in any proportion.

[0086] In one embodiment of the present invention, the surfactant in the above preparation method may be polyvinyl alcohol.

[0087] In one embodiment of the present invention, the weight ratio of the surfactant to donepezil in the above preparation method can vary within a certain range, for example, 1:5 to 20:5.

[0088] In one embodiment of the present invention, the weight ratio of the surfactant to donepezil in the above preparation method may be 4:5 to 8:5.

[0089] In one embodiment of the present invention, the osmotic pressure regulator in the above preparation method can be at least one of sodium chloride and potassium chloride, such as sodium chloride, potassium chloride or a mixture of the two in any proportion.

[0090] In one embodiment of the present invention, the osmotic pressure regulator in the above preparation method may be sodium chloride.

[0091] In one embodiment of the present invention, the weight ratio of the osmotic pressure regulator to donepezil in the above preparation method can vary within a certain range, for example, 1:5 to 6:5.

[0092] In one embodiment of the present invention, the weight ratio of the osmotic pressure regulator to donepezil in the above preparation method can be 1.5:5 to 4:5.

[0093] In one embodiment of the present invention, the water in the above preparation method can be at least one of ultrapure water, redistilled water and water for injection, such as ultrapure water, water for injection or a mixture of the two in any proportion.

[0094] In one embodiment of the present invention, the water in the above preparation method may be ultrapure water.

[0095] In one embodiment of the present invention, the volume ratio of water to organic solvent in the above preparation method can vary within a certain range, for example, 5:1 to 50:1.

[0096] In one embodiment of the present invention, the weight ratio of water to donepezil in the above preparation method may be 8:1 to 14:1.

[0097] In one embodiment of the present invention, the pH regulator in the above preparation method may be at least one of hydrogen chloride and sodium hydroxide.

[0098] In one embodiment of the present invention, the pH adjuster in the above preparation method can adjust the pH value of the mixture within a certain range, for example, 6.0 to 12.0.

[0099] In one embodiment of the present invention, the pH adjuster in the above preparation method can adjust the pH value of the mixture to 6.0-10.0.

[0100] In one embodiment of the present invention, the carrier material in the above preparation method may be a biodegradable carrier material.

[0101] In one embodiment of the present invention, the carrier material in the above preparation method can be at least one of polylactic acid-glycolic acid copolymer, polylactic acid-polyethylene glycol copolymer and polylactic acid, for example, polylactic acid-glycolic acid copolymer, polylactic acid-polyethylene glycol copolymer or a mixture thereof in any proportion.

[0102] In one embodiment of the present invention, the carrier material in the above preparation method may be poly(lactic acid-glycolic acid) copolymer.

[0103] In one embodiment of the present invention, the intrinsic viscosity of the carrier material in the above preparation method can be 0.15 dL / g to 0.90 dL / g. For example, the carrier material in the above preparation method can be a polylactic acid-glycolic acid copolymer with an intrinsic viscosity of 0.15 dL / g to 0.90 dL / g.

[0104] In one embodiment of the present invention, the intrinsic viscosity of the carrier material in the above preparation method can be 0.4dL / g to 0.7dL / g. For example, the carrier material in the above preparation method can be a polylactic acid-glycolic acid copolymer with an intrinsic viscosity of 0.4dL / g to 0.7dL / g.

[0105] In one embodiment of the present invention, the weight ratio of the carrier material to donepezil in the above preparation method can vary within a certain range, for example, 2:3 to 12:3.

[0106] In one embodiment of the present invention, the weight ratio of the carrier material to donepezil in the above preparation method may be 2:3 to 5:3.

[0107] In one embodiment of the present invention, the organic solvent in the above preparation method can be at least one of chloroform, dichloromethane, ethyl acetate, acetone, acetonitrile, and anhydrous ethanol, such as dichloromethane, ethyl acetate, or a mixture thereof in any proportion.

[0108] In one embodiment of the present invention, the organic solvent in the above preparation method may be dichloromethane.

[0109] In one embodiment of the present invention, the ratio of the organic solvent to donepezil in the above preparation method can vary within a certain range, for example, 4 to 20 mL: 1 g.

[0110] In one embodiment of the present invention, the ratio of the organic solvent to donepezil in the above preparation method can be 6-15 mL:1 g.

[0111] In one embodiment of the present invention, the dispersion in the above preparation method can be accomplished by at least one of stirring and ultrasound.

[0112] In one embodiment of the present invention, the dispersion in the above preparation method can be accomplished by stirring.

[0113] In one embodiment of the present invention, the dispersion in the above preparation method can be accomplished by mechanical stirring.

[0114] In one embodiment of the present invention, the time of mechanical stirring in the above preparation method can vary within a certain range, for example, 30 to 60 seconds.

[0115] In one embodiment of the present invention, the mechanical stirring time in the above preparation method can be 30 seconds.

[0116] In one embodiment of the present invention, the rotation speed of the mechanical stirring in the above preparation method can vary within a certain range, for example, 250 to 350 rpm.

[0117] In one embodiment of the present invention, the rotation speed of the mechanical stirring in the above preparation method can be 300 rpm.

[0118] In one embodiment of the present invention, the emulsification in the above preparation method can be accomplished by membrane emulsification.

[0119] In one embodiment of the present invention, the solidification in the above preparation method can be accomplished by volatilization or evaporation.

[0120] In one embodiment of the present invention, the solidification in the above preparation method can be accomplished by volatilization under reduced pressure, volatilization under stirring, or thin film evaporation.

[0121] In one embodiment of the present invention, the solidification in the above preparation method can be accomplished by volatilization under reduced pressure.

[0122] In one embodiment of the present invention, the vacuum degree of the reduced pressure volatilization in the above preparation method can vary within a certain range, for example, -0.09 to -0.05 MPa.

[0123] In one embodiment of the present invention, the vacuum degree of the reduced pressure volatilization in the above preparation method can be -0.09 MPa.

[0124] In one embodiment of the present invention, the reduced pressure volatilization time in the above preparation method can vary within a certain range, for example, 20 to 300 minutes.

[0125] In one embodiment of the present invention, the reduced pressure volatilization time in the above preparation method can be 20 to 240 minutes.

[0126] In one embodiment of the present invention, the reduced pressure volatilization temperature in the above preparation method can vary within a certain range, for example, 20-42°C.

[0127] In one embodiment of the present invention, the reduced pressure volatilization temperature in the above preparation method may be 38°C.

[0128] In one embodiment of the present invention, the preparation method may further comprise the following steps: solidifying the emulsion, followed by washing and freeze-drying.

[0129] Accordingly, the present invention provides a sustained-release microsphere of donepezil, which is prepared by the above preparation method.

[0130] In one embodiment of the present invention, the particle size of the donepezil sustained-release microspheres prepared by the above preparation method can be 10 to 50 μm.

[0131] In one embodiment of the present invention, the particle size of the donepezil sustained-release microspheres prepared by the above preparation method can be 25 to 35 μm.

[0132] In one embodiment of the present invention, the encapsulation efficiency of the donepezil sustained-release microspheres prepared by the above preparation method can be above 80%.

[0133] In one embodiment of the present invention, the encapsulation efficiency of the donepezil sustained-release microspheres prepared by the above preparation method can be above 90%.

[0134] In one embodiment of the present invention, the drug loading of the donepezil sustained-release microspheres prepared by the above preparation method can be 20% to 60%.

[0135] In one embodiment of the present invention, the drug loading of the donepezil sustained-release microspheres prepared by the above preparation method can be 40% to 60%.

[0136] Donepezil pharmaceutical preparations

[0137] The present invention provides a pharmaceutical preparation of donepezil, comprising the above-mentioned sustained-release microspheres.

[0138] In one embodiment of the present invention, the pharmaceutical preparation may further comprise at least one pharmaceutically acceptable excipient, such as a solvent, a solubilizer, a cosolvent, and the like.

[0139] In one embodiment of the present invention, the pharmaceutical preparation can be a preparation with a specific drug release behavior, such as a sustained-release preparation.

[0140] In one embodiment of the present invention, the pharmaceutical preparation can be a parenteral dosage form, such as an injection.

[0141] Medical uses of donepezil sustained-release microspheres and their pharmaceutical preparations

[0142] The present invention provides use of the sustained-release microspheres or the pharmaceutical preparation in preparing a drug for preventing and / or treating at least some diseases and / or conditions related to acetylcholinesterase.

[0143] In one embodiment of the present invention, the aforementioned disease and / or disorder at least partially related to acetylcholinesterase may be Alzheimer's disease.

[0144] Method for Determining Parameters of Donepezil Sustained-Release Microspheres

[0145] The particle size and particle size distribution determination method is used to determine the particle size and span value of the microspheres (the particle size distribution span, the smaller the span value, the more uniform the microsphere particle size), as follows:

[0146] Take 50 mg of microspheres, add them to 20 mL of water, shake and sonicate for 10 minutes to evenly disperse the microspheres, then add them to the sample slot of the laser particle size analyzer, measure the particle size and calculate the span value. The calculation formula is as follows:

[0147] Among them, D V,90％ 、D V,50％ and D V,10％ They represent the particle sizes of the microspheres when the volume fractions are 90%, 50% and 10%, respectively.

[0148] The drug loading and encapsulation efficiency of the microspheres were tested by high performance liquid chromatography, as follows:

[0149] Drug loading detection method: 25 mg of microspheres were completely dissolved in 80% v / v acetonitrile, then diluted to 50 mL, and 1 mL was diluted to 10 mL. 20 μL of the diluted solution was injected into an HPLC (Welch Ultimate XB-C18, 150×4.6 mm, 5 μm) and measured at a detection wavelength of 271 nm. The mobile phase used was prepared by mixing phosphate buffer (pH 5.0) and acetonitrile in a ratio of 7:3.

[0150] Encapsulation efficiency test method: 25 mg of microspheres were washed with PBS solution, the solid was completely dissolved with 80% v / v acetonitrile, and then diluted to 50 mL. Then 1 mL was diluted to 10 mL. The subsequent operation was the same as the drug loading test method.

[0151] The calculation formulas for drug loading and encapsulation efficiency are as follows:

[0152] Example

[0153] The embodiments of the present invention will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be obtained commercially.

[0154] Example 1:

[0155] 1.5 g of donepezil and 1.0 g of PLGA (LA:GA = 75:25, intrinsic viscosity 0.4-0.5 dL / g) were weighed and dissolved in 10 mL of dichloromethane to prepare O. 100 mL of a 1.0% aqueous polyvinyl alcohol solution was prepared as the external aqueous phase without pH adjustment to prepare W. O was added to W and mechanically stirred for 30 seconds at 300 rpm to prepare a pre-emulsion. The pre-emulsion was poured into a rapid membrane emulsifier for emulsification and dispersion using a membrane tube with a pore size of 20 μm. The emulsion was cured under vacuum at -0.09 MPa for 60 minutes at 38°C. After curing, the microspheres were washed and lyophilized to produce sustained-release microspheres containing donepezil.

[0156] The average particle size of the prepared sustained-release microspheres was 13 μm and the span value was 1.2, as determined by particle size and particle size distribution determination. The drug loading and encapsulation efficiency of the prepared sustained-release microspheres were determined by high performance liquid chromatography, with the drug loading being 49.5% and the encapsulation efficiency being 82.5%.

[0157] As can be seen from FIG1 , the donepezil sustained-release microspheres of Example 1 are relatively broken, with varying particle sizes. The surface of the microspheres is rough, often collapsed, and has a large number of tiny holes, allowing the drug to escape and precipitate into small flakes or block crystals.

[0158] Prior art suggests using an ice-water bath when preparing pre-emulsions to minimize drug escape. However, this temperature affects the viscosity of the dispersed and continuous phases, the solubility of the surfactant, the phase transition temperature, and the diffusion properties, affecting the interfacial tension between the two phases and, consequently, the particle size and performance of the microspheres. The present invention eliminates the need for cryogenic preparation, resulting in uniform microspheres with stable release.

[0159] Example 2:

[0160] 1.5 g of donepezil and 1.0 g of PLGA (LA:GA = 75:25, intrinsic viscosity 0.4-0.5 dL / g) were weighed and dissolved in 10 mL of dichloromethane to prepare O. 100 mL of a 1.0% aqueous polyvinyl alcohol solution was prepared as the external aqueous phase, and 1.0 g of sodium chloride was added without pH adjustment to prepare W. O was added to W and mechanically stirred for 30 seconds at 300 rpm to prepare a pre-emulsion. The pre-emulsion was poured into a rapid membrane emulsifier for emulsification and dispersion using a membrane tube with a pore size of 20 μm. The emulsion was cured under vacuum at -0.09 MPa for 60 minutes at 38°C. After curing, the microspheres were washed and lyophilized to produce sustained-release microspheres containing donepezil.

[0161] The average particle size of the prepared sustained-release microspheres was determined to be 12 μm using particle size and particle size distribution determination methods, and the Span value was 1.0. The drug loading and encapsulation efficiency of the prepared sustained-release microspheres were determined using high-performance liquid chromatography, and the drug loading and encapsulation efficiency were 51.1% and 85.17%.

[0162] Comparison of Figures 1 and 2 shows that in Example 2, when a certain amount of osmotic pressure regulator was added to the aqueous phase, the donepezil sustained-release microspheres still had damaged pores, many of which were collapsed, and drug still escaped and precipitated from the microspheres to form small or lumpy flaky crystals. However, the microsphere surfaces were relatively smooth and intact. This indicates that the addition of an osmotic pressure regulator in the present invention can inhibit drug escape and make the microsphere surfaces smoother.

[0163] Example 3:

[0164] 1.5 g of donepezil and 1.0 g of PLGA (LA:GA = 75:25, intrinsic viscosity 0.4-0.5 dL / g) were weighed and dissolved in 10 mL of dichloromethane to prepare O. 100 mL of a 1.0% aqueous polyvinyl alcohol solution was prepared as the external aqueous phase and adjusted to pH 6.0 with sodium hydroxide to prepare W. O was added to W and mechanically stirred for 30 seconds at 300 rpm to prepare a pre-emulsion. The pre-emulsion was poured into a rapid membrane emulsifier for emulsification and dispersion using a membrane tube with a pore size of 20 μm. The emulsion was cured under vacuum at -0.09 MPa for 60 minutes at 38°C. After curing, the emulsion was washed and lyophilized to produce donepezil-containing sustained-release microspheres.

[0165] The average particle size of the prepared sustained-release microspheres was 13 μm and the Span value was 0.7, as determined by particle size and particle size distribution determination. The drug loading and encapsulation efficiency of the prepared sustained-release microspheres were determined by high performance liquid chromatography, and the drug loading and encapsulation efficiency were 55.2% and 92.0%.

[0166] Comparing Figure 3 with Figure 1 , it can be seen that in Example 3, the pH was adjusted to 8. Although a significant amount of precipitated drug crystals were still present in the donepezil sustained-release microspheres in Figure 3 , the microsphere surface was relatively smooth and intact, with no apparent surface damage or large holes. This indicates that the addition of a pH adjuster in the present invention can effectively improve microsphere breakage and make the microsphere surface smoother.

[0167] Example 4:

[0168] 1.5 g of donepezil and 1.0 g of PLGA (LA:GA = 75:25, intrinsic viscosity 0.4-0.5 dL / g) were weighed and dissolved in 10 mL of dichloromethane to prepare O. 100 mL of a 1.0% aqueous polyvinyl alcohol solution was prepared as the external aqueous phase and adjusted to pH 10.0 with sodium hydroxide to prepare W. O was added to W and mechanically stirred for 30 seconds at 300 rpm to prepare a pre-emulsion. The pre-emulsion was then emulsified and dispersed in a rapid membrane emulsifier using a 20 μm pore size membrane tube. The emulsion was cured under vacuum at -0.09 MPa for 60 minutes at 38°C. After curing, the microspheres were washed and lyophilized to produce sustained-release microspheres containing donepezil.

[0169] The average particle size of the prepared sustained-release microspheres was 13 μm and the span value was 0.7, as determined by particle size and particle size distribution determination. The drug loading and encapsulation efficiency of the prepared sustained-release microspheres were determined by high performance liquid chromatography, and the drug loading was 57.5% and the encapsulation efficiency was 95.8%.

[0170] Comparison of Figures 1, 3, and 4 reveals that while some crystals still remain in the donepezil sustained-release microspheres of Example 4, these crystals are attached to the microspheres in the form of fine strips or filaments, with no significant escape to form lumps or flakes. No significant surface damage or large pores are observed. This indicates that the addition of a pH adjuster and maintenance of a moderately alkaline environment in the present invention can effectively reduce crystal escape and alleviate surface damage or large pores in the microspheres.

[0171] Example 5:

[0172] 3.0 g of donepezil and 2.0 g of PLGA (LA:GA = 50:50, intrinsic viscosity 0.6-0.7 dL / g) were weighed and dissolved in 20 mL of dichloromethane to prepare O. 200 mL of a 1.0% aqueous polyvinyl alcohol solution was prepared as the external aqueous phase and adjusted to pH 10.0 with sodium hydroxide to prepare W. O was added to W and mechanically stirred for 30 seconds at 300 rpm to prepare a pre-emulsion. The pre-emulsion was poured into a rapid membrane emulsifier for emulsification and dispersion using a membrane tube with a pore size of 20 μm. The emulsion was cured under vacuum at -0.09 MPa for 60 minutes at 38°C. After curing, the emulsion was washed and lyophilized to produce donepezil-containing sustained-release microspheres.

[0173] The average particle size of the prepared sustained-release microspheres was 14 μm and the span value was 0.7, as determined by particle size and particle size distribution determination. The drug loading and encapsulation efficiency of the prepared sustained-release microspheres were determined by high performance liquid chromatography, with a drug loading of 56.2% and an encapsulation efficiency of 93.4%.

[0174] As can be seen from FIG5 , some small plate-like crystals are present on the outside of the donepezil sustained-release microspheres of Example 5, and the surface of the microspheres is relatively smooth, intact, and undamaged.

[0175] Example 6:

[0176] 6g of donepezil and 4g of PLGA (LA:GA = 50:50, intrinsic viscosity 0.6-0.7 dL / g) were weighed and dissolved in 40mL of dichloromethane to prepare O. 400mL of a 1.0% aqueous polyvinyl alcohol solution was prepared as the external aqueous phase, 1.9g of sodium chloride was added, and the pH was adjusted to 10.0 with sodium hydroxide to prepare W. O was added to W and mechanically stirred for 30 seconds at 300rpm to prepare a pre-emulsion. The pre-emulsion was poured into a rapid membrane emulsifier for emulsification and dispersion using a membrane tube with a pore size of 20μm. The emulsion was cured under vacuum at -0.09MPa for 60 minutes at 38°C. After curing, the emulsion was washed and lyophilized to produce donepezil-containing sustained-release microspheres.

[0177] The average particle size of the prepared sustained-release microspheres was 14 μm and the span value was 0.5, as determined by particle size and particle size distribution determination. The drug loading and encapsulation efficiency of the prepared sustained-release microspheres were determined by high performance liquid chromatography, with a drug loading of 59.9% and an encapsulation efficiency of 99.8%.

[0178] Comparison of Figures 5 and 6 shows that the surface of the donepezil sustained-release microspheres in Example 6 is relatively smooth and intact, with virtually no depressions or voids, good particle size uniformity, and significantly reduced crystalline escape from the microspheres. At a high theoretical drug loading of 60%, a comparison with Example 5 demonstrates that the simultaneous addition of a pH adjuster and an osmotic pressure regulator not only significantly reduces crystal escape, but also results in a smooth microsphere surface with virtually no visible damaged pores.

[0179] Example 7:

[0180] 2.8g of donepezil and 4g of PLGA (LA:GA = 75:25, intrinsic viscosity 0.6-0.7 dL / g) were weighed and dissolved in 40mL of dichloromethane to prepare O. 400mL of a 1.0% aqueous polyvinyl alcohol solution was prepared as the external aqueous phase, 1.5g of sodium chloride was added, and the pH was adjusted to 10.0 with sodium hydroxide to prepare W. O was added to W and mechanically stirred for 30 seconds at 300rpm to prepare a pre-emulsion. The pre-emulsion was poured into a rapid membrane emulsifier for emulsification and dispersion using a membrane tube with a pore size of 20μm. The emulsion was cured under vacuum at -0.09MPa for 60 minutes at 38°C. After curing, the emulsion was washed and lyophilized to produce donepezil-containing sustained-release microspheres.

[0181] The average particle size of the prepared sustained-release microspheres was 12 μm and the span value was 0.6, as determined by particle size and particle size distribution determination. The drug loading and encapsulation efficiency of the prepared sustained-release microspheres were determined by high performance liquid chromatography, with a drug loading of 40.1% and an encapsulation efficiency of 97.8%.

[0182] Comparison of Figures 6 and 7 shows that the surface of the donepezil sustained-release microspheres of Example 7 is relatively smooth and intact, without depressions or voids, and with a small amount of microspheres of uneven particle size, indicating that no drug escape is observed in the donepezil microspheres prepared after reducing the drug loading.

[0183] Example 8:

[0184] 2.8g of donepezil and 4g of PLGA (LA:GA = 75:25, intrinsic viscosity 0.6-0.7 dL / g) were weighed and dissolved in 40mL of dichloromethane to prepare O. 400mL of a 1.0% aqueous polyvinyl alcohol solution was prepared as the external aqueous phase, 1.5g of sodium chloride was added, and the pH was adjusted to 10.0 with sodium hydroxide to prepare W. O was added to W and mechanically stirred for 30 seconds at 300rpm to prepare a pre-emulsion. The pre-emulsion was poured into a rapid membrane emulsifier for emulsification and dispersion using a membrane tube with a pore size of 50μm. The emulsion was cured under vacuum at -0.09MPa for 60 minutes at 38°C. After curing, the microspheres were washed and lyophilized to produce sustained-release microspheres containing donepezil.

[0185] The average particle size of the prepared sustained-release microspheres was 28 μm and the span value was 0.6, as determined by particle size and particle size distribution determination. The drug loading and encapsulation efficiency of the prepared sustained-release microspheres were determined by high performance liquid chromatography, with a drug loading of 40.9% and an encapsulation efficiency of 99.8%.

[0186] By comparing FIG7 and FIG8 , it can be seen that the surface of the donepezil sustained-release microspheres of Example 8 is relatively smooth and intact, without depressions or voids, and the particle size is relatively uniform, indicating that in the present invention, the appropriate expansion of the membrane pore size during membrane emulsification has no significant effect on the particle size distribution of the microspheres.

[0187] Comparative Example 1:

[0188] 1.0 g of donepezil and 1.0 g of PLGA (LA:GA = 50:50, intrinsic viscosity 0.2-0.3 dL / g) were weighed and dissolved in 10 mL of dichloromethane to prepare O. 100 mL of a 1.0% aqueous polyvinyl alcohol solution was prepared as the external aqueous phase without pH adjustment to prepare W. O was added to W and mechanically stirred for 30 seconds at 300 rpm to prepare a pre-emulsion. The pre-emulsion was poured into a rapid membrane emulsifier for emulsification and dispersion using a membrane tube with a pore size of 20 μm. The emulsion was cured under vacuum at -0.09 MPa for 60 minutes at 38°C. After curing, the microspheres were washed and lyophilized to produce sustained-release microspheres containing donepezil.

[0189] The average particle size of the prepared sustained-release microspheres was 13 μm and the span value was 1.5 as determined by particle size and particle size distribution determination. The drug loading and encapsulation efficiency of the prepared sustained-release microspheres were determined by high performance liquid chromatography, and the drug loading and encapsulation efficiency were 38.1% and 76.2%.

[0190] Comparison of Figures 2, 3, 6, and 9 reveals that the donepezil sustained-release microspheres prepared in Comparative Example 1 exhibited significant breakage, varying particle sizes, and a rough, often collapsed surface with numerous small pores. Drug escaped and precipitated into small flakes or blocky crystals. This demonstrates that the addition of both a pH adjuster and an osmotic pressure regulator significantly impacted drug escape, microsphere surface area, and drug loading.

[0191] Comparative Example 2:

[0192] 1.0 g of donepezil and 1.0 g of PLGA (LA:GA = 50:50, intrinsic viscosity 0.2-0.3 dL / g) were weighed and dissolved in 10 mL of dichloromethane to prepare O. 100 mL of a 1.0% aqueous polyvinyl alcohol solution was prepared as the external aqueous phase, 1.0 g of sodium chloride was added, and the pH was adjusted to 10.0 with sodium hydroxide to prepare W. O was added to W and mechanically stirred for 30 seconds at 300 rpm to prepare a pre-emulsion. The pre-emulsion was poured into a rapid membrane emulsifier for emulsification and dispersion using a membrane tube with a pore size of 50 μm. The emulsion was cured under vacuum at -0.09 MPa for 60 minutes at 45°C. After curing, the emulsion was washed and lyophilized to produce donepezil-containing sustained-release microspheres.

[0193] The average particle size of the prepared sustained-release microspheres was 13 μm and the span value was 1.8 as determined by particle size and particle size distribution determination. The drug loading and encapsulation efficiency of the prepared sustained-release microspheres were determined by high performance liquid chromatography, and the drug loading and encapsulation efficiency were 24.2% and 48.4%.

[0194] Comparison of Figures 6 and 10 reveals that the donepezil microspheres in Comparative Example 2 exhibit significant breakage and surface collapse, with uneven particle size and drug escaping and precipitating into small flakes or blocky crystals. This suggests that high temperatures during decompression and volatilization of the microspheres cause degradation of the carrier material, leading to microsphere breakage and collapse. This ultimately results in ineffective drug encapsulation and low drug loading.

[0195] Example 11: In vitro cumulative release experiment

[0196] 10 mg of microspheres and PBS buffer (pH 7.4) in Example 1, Example 5, Example 6, Example 7, and Example 8 were placed in a 250 mL conical flask and shaken at a constant temperature of 37 ° C on a water bath shaker. According to the sampling time, 1 mL of solution was taken from the conical flask and the same amount of PBS buffer was added. The collected solution was filtered with a 0.45 μm injection filter, and 10 μL of the above solution was detected using HPLC. The in vitro cumulative release curves of the microspheres prepared in the five groups of embodiments are shown in Figure 11.

[0197] As shown in Figure 11, the present invention effectively reduces drug escape and crystallization by controlling the aqueous phase pH and adjusting the osmotic pressure, thereby effectively reducing drug burst release. Increasing the microsphere particle size while appropriately reducing the drug loading effectively reduces the initial burst of drug release and prolongs the release period. The donepezil sustained-release microspheres prepared by the present invention exhibit long-term, stable release.

[0198] It should be noted that, although the technical solutions of the present invention are described with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto.

[0199] While various embodiments of the present invention have been described above, the above descriptions are intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A preparation method of donepezil sustained-release microspheres, characterized in that, The preparation method includes the following steps: Mix a surfactant, an osmotic pressure regulator and water, and use a pH regulator to adjust the pH value of the mixture to form an aqueous phase; Mix donepezil, a carrier material and an organic solvent to form an oil phase; and, Add the oil phase to the aqueous phase for dispersion to form a pre-emulsion, then subject the pre-emulsion to membrane emulsification to form an emulsion, and finally solidify the emulsion, wash and freeze-dry to obtain donepezil sustained-release microspheres.

2. The preparation method according to claim 1, wherein The pre-emulsion is an oil-in-water pre-emulsion.

3. The preparation method according to claim 1 or 2, wherein The surfactant is at least one of polyvinyl alcohol, Tween, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate and polyoxyethylene octylphenol ether, preferably polyvinyl alcohol; and / or, the weight ratio of the surfactant to donepezil is 1:5 to 20:5, preferably 4:5 to 8:5; and / or, The osmotic pressure regulator is at least one of sodium chloride and potassium chloride, preferably sodium chloride; and / or, the weight ratio of the osmotic pressure regulator to donepezil is 1:5 to 6:5, preferably 1.5:5 to 4:5; and / or, The water is at least one of ultrapure water, double-distilled water and water for injection, preferably ultrapure water; and / or, the volume ratio of the water to the organic solvent is 5:1 to 50:1, preferably 8:1 to 14:1; and / or, The pH regulator is at least one of hydrogen chloride and sodium hydroxide; and / or, the pH regulator adjusts the pH value of the mixture to 6.0 to 12.0, preferably 6.0 to 10.

0.

4. The preparation method according to any one of claims 1 to 3, wherein The carrier material is a biodegradable carrier material; preferably, the carrier material is at least one of poly(lactic-co-glycolic acid), poly(lactic acid)-poly(ethylene glycol) copolymer and poly(lactic acid), preferably poly(lactic-co-glycolic acid), more preferably, the intrinsic viscosity of the carrier material is 0.15 dL / g to 0.90 dL / g, preferably 0.4 dL / g to 0.7 dL / g; and / or, the weight ratio of the carrier material to donepezil is 2:3 to 12:3, preferably 2:3 to 5:3; and / or, The organic solvent is at least one of chloroform, dichloromethane, ethyl acetate, acetone, acetonitrile, absolute ethanol, preferably dichloromethane; and / or, the dosage ratio of the organic solvent to donepezil is 4 to 20 mL:1 g, preferably 6 to 15 mL:1 g.

5. The preparation method according to any one of claims 1 to 4, wherein The dispersion is completed by at least one of stirring and ultrasonic treatment, preferably stirring, more preferably mechanical stirring; preferably, the time of the mechanical stirring is 30 to 60 s; and / or, the rotation speed of the mechanical stirring is 250 to 350 rpm; and / or, The emulsification is completed by membrane emulsification; and / or, The curing is completed by volatilization or evaporation, preferably by reduced-pressure volatilization, stirring volatilization or thin-film evaporation, more preferably by reduced-pressure volatilization; preferably, the degree of vacuum for the reduced-pressure volatilization is -0.09 to -0.05 MPa; and / or, the time for the reduced-pressure volatilization is 20 to 300 min; the temperature for the reduced-pressure volatilization is 20 to 42 °C.

6. The preparation method according to any one of claims 1 to 5, wherein the preparation method further comprises the following steps: washing and freeze-drying the cured emulsion.

7. The preparation method according to any one of claims 1 to 6, wherein the particle size of the donepezil sustained-release microspheres is 10 to 50 μm, preferably 25 to 35 μm; and / or, the encapsulation efficiency of the donepezil sustained-release microspheres is more than 80%, preferably more than 90%; and / or, the drug loading of the donepezil sustained-release microspheres is 20% to 60%, preferably 40% to 60%.

8. A donepezil sustained-release microsphere, characterized in that, The sustained-release microspheres are prepared by the preparation method according to any one of claims 1 to 6.

9. A pharmaceutical preparation of donepezil, characterized in that, The pharmaceutical preparation comprises the sustained-release microspheres according to claim 8; preferably, the pharmaceutical preparation further comprises at least one pharmaceutically acceptable excipient; and / or, preferably, the pharmaceutical preparation is a sustained-release preparation; and / or, preferably, the pharmaceutical preparation is an injection.

10. Use of the sustained-release microspheres according to claim 8 or the pharmaceutical preparation according to claim 9 in the preparation of a drug for preventing and / or treating at least partially diseases and / or disorders related to acetylcholinesterase; preferably, the at least partially diseases and / or disorders related to acetylcholinesterase are Alzheimer's disease.

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