Palonosetron sustained release microsphere and preparation method thereof

Abstract

A preparation system of the palonosetron sustained-release microspheres comprises palonosetron or salt derivatives thereof, an organic solvent, a polymer sustained-release material, an emulsifier, a pH regulator and a freeze-drying protective additive, and the palonosetron sustained-release microspheres are characterized in that D90 of the palonosetron sustained-release microspheres is 15-40 [mu] m, the polymer sustained-release material is a lactide-glycolide copolymer, and D90 of the palonosetron sustained-release microspheres is 1-10 [mu] m. The molar ratio of polylactic acid to polyglycolic acid in the lactide-glycolide copolymer is (40-60): (40-60), and the weight-average molecular weight of the lactide-glycolide copolymer is 7-38 kDa. The palonosetron sustained-release microsphere provided by the invention is high in drug loading capacity and encapsulation efficiency, good in 7-day sustained-release effect, obvious in vomiting stopping effect and high in bioavailability.

Description

Technical Field

[0001] The present application belongs to the technical field of pharmaceutical reagent preparation, and in particular relates to a palonosetron sustained-release microsphere and a preparation method thereof. Background Art

[0002] Chemotherapy-induced nausea and vomiting refers to vomiting reactions caused by chemotherapy. It is reported that more than three-quarters of chemotherapy patients will experience varying degrees of nausea and vomiting, which seriously affects the quality of life of chemotherapy patients and reduces their chemotherapy compliance. Palonosetron is a selective 5-hydroxytryptamine 3 receptor (5-HT3) antagonist, mainly used to prevent acute and delayed nausea and vomiting caused by moderate to severe emetogenic chemotherapy. Palonosetron hydrochloride is prepared into a sustained-release long-acting injection, which is administered once by intramuscular or subcutaneous injection before chemotherapy, which can significantly improve patient compliance while ensuring the relief of nausea and vomiting during the delayed period. As an upgrade of traditional oral or injection forms, palonosetron sustained-release microspheres are a new method of drug delivery, which aims to achieve longer-lasting efficacy and reduce the frequency of administration by controlling the drug release rate, thereby improving patients' treatment compliance and quality of life.

[0003] Sustained-release microsphere technology refers to encapsulating drugs in tiny spheres made of specific materials. These microspheres can gradually dissolve in the body and slowly release drugs to maintain effective concentrations for a longer period of time. For palonosetron, the application of this technology means that a single dose can provide continuous protection for days or even weeks, which is particularly beneficial for cancer patients who need to receive long-term chemotherapy.

[0004] In June 2019, Su Lili et al. reported an article entitled "Preparation and Research of Palonosetron Hydrochloride PLGA Sustained-Release Microspheres" in Volume 47, Issue 12 of Guangzhou Chemical Industry. Palonosetron hydrochloride was encapsulated in PLGA (poly(lactide-co-glycolide)) as a polymer sustained-release material, and the process parameters such as aqueous phase pH and palonosetron hydrochloride / PLGA mass ratio were optimized. Finally, a high encapsulation rate of 82.75% was achieved, and the in vitro slow release was achieved within 7 days, but the drug loading was difficult to increase and the antiemetic effect was poor. Therefore, ensuring the slow release of palonosetron sustained-release microspheres for 7 days, improving the encapsulation rate, and increasing the drug loading and antiemetic effect are still problems to be solved. Summary of the invention

[0005] The present application provides a palonosetron sustained-release microsphere with high drug loading, high encapsulation rate, good 7-day sustained-release effect, obvious antiemetic effect and high bioavailability.

[0006] The present application provides a palonosetron sustained-release microsphere, the preparation system of which includes: palonosetron or its salt derivative, an organic solvent, a polymer sustained-release material, an emulsifier, a pH regulator, and a lyophilization protective agent. The D90 of the palonosetron sustained-release microsphere is 15 to 40 μm, the polymer sustained-release material is a lactide-glycolide copolymer, and the molar ratio of polylactic acid to polyglycolic acid in the lactide-glycolide copolymer is (40 to 60): (40 to 60).

[0007] Preferably, the weight average molecular weight of the lactide-glycolide copolymer is 7 to 38 kDa.

[0008] Preferably, the D90 of the palonosetron sustained-release microspheres is 20-25 μm, and the molar ratio of polylactic acid to polyglycolic acid in the lactide-glycolide copolymer is 50:50.

[0009] Preferably, the weight average molecular weight of the lactide-glycolide copolymer is 7 to 30 kDa.

[0010] Preferably, the weight composition ratio of palonosetron to the lactide-co-glycolide copolymer is 1:5 to 1:40.

[0011] Preferably, the concentration of the lactide-glycolide copolymer in the organic solvent is 100-225 mg / mL.

[0012] The present invention also provides a method for preparing palonosetron sustained-release microspheres, which is characterized by comprising:

[0013] (1) Preparation of oil phase: dissolving the API and the lactide-co-glycolide copolymer in an organic solvent to prepare an oil phase;

[0014] (2) Preparation of aqueous phase: adding an emulsifier and a pH adjuster to water and dissolving them to prepare an aqueous phase;

[0015] (3) Emulsification: adding the oil phase of step (1) to the water phase of step (2) under shearing condition, and emulsifying to obtain an emulsion;

[0016] (4) solidification: under stirring, the oil phase in the emulsion of step (3) is volatilized, and the emulsion droplets are solidified to form microspheres;

[0017] (5) washing the microspheres: separating the solution from step (4) from the microspheres and washing them;

[0018] (6) Freeze-drying: freeze-drying the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres.

[0019] Preferably, in step (2), the pH of the aqueous solution is in the range of 5 to 10.

[0020] Preferably, in step (3), the volume ratio of the oil phase to the water phase is 1:4 to 1:40.

[0021] Preferably, in step (3), the shear speed of emulsification is 3000-6000 rpm, and the shear speed can be 3000 rpm, 4000 rpm, 5000 rpm, or 6000 rpm.

[0022] Beneficial effects:

[0023] The inventors found through a large number of experiments that the particle size D90 of palonosetron sustained-release microspheres, the molar ratio of polylactic acid and polyglycolic acid in the polymer sustained-release material poly(lactide-co-glycolide), and the weight-average molecular weight of the poly(lactide-co-glycolide) copolymer have a significant effect on the drug loading and encapsulation efficiency of palonosetron sustained-release microspheres. The palonosetron sustained-release microspheres provided by the present invention have a drug loading of up to 3.5%, an encapsulation efficiency of over 90%, a good 7-day drug sustained-release effect, a significant antiemetic effect, and a high bioavailability. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 This is a comparison of the blood drug concentration of beagle dogs in microsphere group 1 and microsphere group 2 at 24 hours. Figure 2 This is a comparison chart of blood drug concentrations in beagle dogs in microsphere group 1 and microsphere group 2 for 7 days. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application are clearly described below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of the present application.

[0025] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0026] The present application is not limited to the above-mentioned specific implementation modes, which are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

[0027] The present application provides a palonosetron sustained-release microsphere, the preparation system of which includes: palonosetron or its salt derivative, an organic solvent, a polymer sustained-release material, an emulsifier, a pH regulator, and a lyophilization protective agent. The D90 of the palonosetron sustained-release microsphere is 15 to 40 μm, the polymer sustained-release material is a lactide-glycolide copolymer (hereinafter referred to as PLGA), the molar ratio of polylactic acid (hereinafter referred to as PLA) and polyglycolic acid (hereinafter referred to as PGA) in the lactide-glycolide copolymer is (40 to 60): (40 to 60), the weight average molecular weight (hereinafter referred to as Mw) of the lactide-glycolide copolymer is 7 to 38 kDa, and the weight composition ratio of the palonosetron to the lactide-glycolide copolymer is 1:5 to 1:40. The D90 of the palonosetron sustained-release microsphere can be 16 μm, 18 μm, 21 μm, 23 μm, 28 μm,

[0028] 30μm, 32μm, 36μm; the molar ratio of PLA and PGA can be 50:50, 45:55, 40:60, 55:45, 60:40; the Mw of PLGA can be 7kDa, 11kDa, 14kDa, 21kDa, 25kDa, 30kDa, 35kDa, 38kDa; the weight composition ratio of palonosetron (hereinafter referred to as API) to PLGA can be 1:5, 1:8, 1:10, 1:15, 1:17.6, 1:20, 1:25, 1:30, 1:35, 1:40.

[0029] In the following examples and comparative examples, dichloromethane is used as the organic solvent. In actual production, any one or more of dichloromethane, acetone, and methanol can be used. The concentration of the lactide-co-glycolide copolymer in the organic solvent is 100-225 mg / mL, which can be 100 mg / mL, 125 mg / mL, 150 mg / mL, 175 mg / mL, or 225 mg / mL. Polyvinyl alcohol is used as the emulsifier, and the emulsifier concentration is 0.05-2%. Sodium dihydrogen phosphate is used as the pH regulator. In actual production, one or more of disodium hydrogen phosphate, citric acid, and sodium hydroxide can be used. Mannitol is used as the lyophilization protective agent. In actual production, one or more of mannitol, sucrose, polyethylene glycol, sodium chloride, and Tween 80 can be used, but are not limited to the above.

[0030] The present invention also provides a method for preparing palonosetron sustained-release microspheres, comprising:

[0031] (1) Preparation of oil phase: dissolving the API and PLGA in an organic solvent to prepare an oil phase;

[0032] (2) Preparation of aqueous phase: adding an emulsifier and a pH adjuster to water and dissolving them to prepare an aqueous phase;

[0033] (3) Emulsification: adding the oil phase of step (1) to the water phase of step (2) under shearing condition, and emulsifying to obtain an emulsion;

[0034] (4) solidification: under stirring, the oil phase in the emulsion of step (3) is volatilized, and the emulsion droplets are solidified to form microspheres;

[0035] (5) washing the microspheres: separating the solution from step (4) from the microspheres and washing them;

[0036] (6) Freeze-drying: freeze-drying the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres.

[0037] In step (2), the pH value of the aqueous solution is in the range of 5 to 10, and can be 5, 6, 7, 8, 9, or 10.

[0038] In step (3), the volume ratio of the oil phase to the water phase is 1:4 to 1:40, and can be 1:5, 1:10, 1:20, 1:30, or 1:40.

[0039] In step (3), the shearing speed of emulsification is 3000-6000 rpm, and the shearing speed can be 3000 rpm, 4000 rpm, 5000 rpm, or 6000 rpm.

[0040] The palonosetron sustained-release microspheres provided by the present invention have higher drug loading and encapsulation efficiency, good 7-day drug sustained-release effect, significant antiemetic effect and high bioavailability.

[0041] The following is a further description in conjunction with specific embodiments and comparative examples.

[0042] Example 1

[0043] Weighing: weigh the raw and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 50:50, and the Mw of PLGA is 14 kDa.

[0044]

[0045]

[0046] Preparation of pH 7 phosphate buffer: weigh 0.14 g of sodium dihydrogen phosphate monohydrate and 0.36 g of disodium hydrogen phosphate dodecahydrate, add 200 mL of purified water, stir to dissolve, and obtain.

[0047] Preparation of 2% mannitol: weigh 0.07 g of mannitol, add 3.5 mL of purified water, stir to dissolve.

[0048] Preparation process:

[0049] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0050] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0051] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 5000 rpm for 5 min to obtain an emulsion;

[0052] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0053] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0054] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 1.

[0055] Example 2

[0056] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 50:50, the Mw of PLGA is 14 kDa, and the other prescription amounts are consistent with Example 1.

[0057] Preparation process:

[0058] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0059] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0060] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 6000 rpm for 5 min to obtain an emulsion;

[0061] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0062] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0063] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 2.

[0064] Example 3

[0065] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 50:50, the Mw of PLGA is 14 kDa, and the other prescription amounts are consistent with Example 1.

[0066] Preparation process:

[0067] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0068] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0069] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 4000 rpm for 5 min to obtain an emulsion;

[0070] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0071] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0072] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 3.

[0073] Example 4

[0074] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 50:50, the Mw of PLGA is 14 kDa, and the other prescription amounts are consistent with Example 1.

[0075] Preparation process:

[0076] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0077] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0078] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 3000 rpm for 5 min to obtain an emulsion;

[0079] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0080] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0081] (6) Freeze-drying: 2% mannitol solution was added to disperse the microspheres, and the microsphere sample of step (5) was freeze-dried to obtain palonosetron sustained-release microspheres, which were recorded as microspheres 4.

[0082] Example 5

[0083] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 45:55, the Mw of PLGA is 14 kDa, and the other prescription amounts are consistent with Example 1.

[0084] Preparation process:

[0085] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0086] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0087] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 5000 rpm for 5 min to obtain an emulsion;

[0088] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0089] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0090] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 5.

[0091] Example 6

[0092] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 40:60, the Mw of PLGA is 14 kDa, and the other prescription amounts are consistent with Example 1.

[0093] Preparation process:

[0094] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0095] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0096] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 5000 rpm for 5 min to obtain an emulsion;

[0097] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0098] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0099] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 6.

[0100] Example 7

[0101] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 55:45, the Mw of PLGA is 14 kDa, and the other prescription amounts are consistent with Example 1.

[0102] Preparation process:

[0103] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0104] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0105] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 5000 rpm for 5 min to obtain an emulsion;

[0106] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0107] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0108] (6) Freeze-drying: 2% mannitol solution was added to disperse the microspheres, and the microsphere sample of step (5) was freeze-dried to obtain palonosetron sustained-release microspheres, which were recorded as microspheres 7.

[0109] Example 8

[0110] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 60:40, the Mw of PLGA is 14 kDa, and the other prescription amounts are consistent with Example 1.

[0111] Preparation process:

[0112] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0113] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0114] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 5000 rpm for 5 min to obtain an emulsion;

[0115] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0116] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0117] (6) Freeze-drying: 2% mannitol solution was added to disperse the microspheres, and the microsphere sample of step (5) was freeze-dried to obtain palonosetron sustained-release microspheres, which were recorded as microspheres 8.

[0118] Example 9

[0119] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 50:50, the Mw of PLGA is 7 kDa, and the other prescription amounts are consistent with Example 1.

[0120] Preparation process:

[0121] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0122] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0123] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 5000 rpm for 5 min to obtain an emulsion;

[0124] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0125] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0126] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 9.

[0127] Example 10

[0128] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 50:50, the Mw of PLGA is 11 kDa, and the other prescription amounts are consistent with Example 1.

[0129] Preparation process:

[0130] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0131] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0132] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 5000 rpm for 5 min to obtain an emulsion;

[0133] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0134] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0135] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 10.

[0136] Embodiment 11

[0137] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 50:50, the Mw of PLGA is 30 kDa, and the other prescription amounts are consistent with Example 1.

[0138] Preparation process:

[0139] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0140] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0141] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 5000 rpm for 5 min to obtain an emulsion;

[0142] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0143] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0144] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 11.

[0145] Example 12

[0146] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 50:50, the Mw of PLGA is 25 kDa, and the other prescription amounts are consistent with Example 1.

[0147] Preparation process:

[0148] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0149] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0150] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 5000 rpm for 5 min to obtain an emulsion;

[0151] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0152] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0153] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 12.

[0154] Embodiment 13

[0155] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 50:50, the Mw of PLGA is 21 kDa, and the other prescription amounts are consistent with Example 1.

[0156] Preparation process:

[0157] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0158] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0159] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 5000 rpm for 5 min to obtain an emulsion;

[0160] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0161] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0162] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 13.

[0163] Comparative Example 1

[0164] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 50:50, the Mw of PLGA is 14 kDa, and the other prescription amounts are consistent with Example 1.

[0165] Preparation process:

[0166] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0167] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0168] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 8000 rpm for 5 min to obtain an emulsion;

[0169] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0170] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0171] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 14.

[0172] Comparative Example 2

[0173] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 50:50, the Mw of PLGA is 14 kDa, and the other prescription amounts are consistent with Example 1.

[0174] Preparation process:

[0175] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0176] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0177] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 2000 rpm for 5 min to obtain an emulsion;

[0178] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0179] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0180] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 15.

[0181] Comparative Example 3

[0182] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 50:50, the Mw of PLGA is 40 kDa, and the other prescription amounts are consistent with Example 1.

[0183] Preparation process:

[0184] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0185] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0186] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 5000 rpm for 5 min to obtain an emulsion;

[0187] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0188] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0189] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 16.

[0190] Comparative Example 4

[0191] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 40:60, the Mw of PLGA is 40 kDa, and the other prescription amounts are consistent with Example 1.

[0192] Preparation process:

[0193] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0194] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0195] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 5000 rpm for 5 min to obtain an emulsion;

[0196] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0197] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0198] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 17.

[0199] Comparative Example 5

[0200] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 30:70, the Mw of PLGA is 14 kDa, and the other prescription amounts are consistent with Example 1.

[0201] Preparation process:

[0202] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0203] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0204] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 5000 rpm for 5 min to obtain an emulsion;

[0205] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0206] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0207] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 18.

[0208] Comparative Example 6

[0209] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 70:30, the Mw of PLGA is 14 kDa, and the other prescription amounts are consistent with Example 1.

[0210] Preparation process:

[0211] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0212] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0213] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 5000 rpm for 5 min to obtain an emulsion;

[0214] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0215] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0216] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 19.

[0217] Comparative Example 7

[0218] Weighing: weigh the raw materials and auxiliary materials according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 75:25, the Mw of PLGA is 14 kDa, and the other prescription amounts are consistent with Example 1.

[0219] Preparation process:

[0220] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLGA in dichloromethane to prepare an oil phase;

[0221] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0222] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 5000 rpm for 5 min to obtain an emulsion;

[0223] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0224] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0225] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, denoted as microspheres 20

[0226] Comparative Example 8

[0227] Weighing: weigh the raw materials and excipients according to the prescription amount, wherein the molar ratio of PLA to PGA in PLGA is 100:0, that is, PLA is selected as the polymer sustained-release material of this comparative example, and the Mw of PLA is 21 kDa. The other prescription amounts are consistent with those in Example 1.

[0228] Preparation process:

[0229] (1) Preparation of oil phase: Dissolve the prescribed amount of palonosetron and PLA in dichloromethane to prepare an oil phase;

[0230] (2) Preparation of aqueous phase: dissolving polyvinyl alcohol in pH 7 phosphate buffer to prepare an aqueous phase;

[0231] (3) Emulsification: under shearing conditions, the oil phase of step (1) was added to the water phase of step (2), and emulsified at 5000 rpm for 5 min to obtain an emulsion;

[0232] (4) Solidification: Stirring at 40° C. and 150 rpm for 4 h to volatilize the oil phase in the emulsion of step (3) and solidify the emulsion droplets to form microspheres;

[0233] (5) Washing the microspheres: After the curing is completed, the solution in step (4) is separated from the microspheres by centrifugation at 3000 rpm for 5 min, and then the microspheres are washed three times by centrifugation with purified water;

[0234] (6) Freeze-drying: Add 2% mannitol solution to disperse the microspheres, and freeze-dry the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres, which are recorded as microspheres 21.

[0235] Examples 14 to 21

[0236] The difference between Examples 14 to 21 and Example 1 is that:

[0237] The only difference between Example 14 and Example 1 is that the weight composition ratio of API to PLGA in Example 14 is different, the amount of PLGA used in Example 14 is 1.7 g, and the other prescription amounts and process conditions are consistent with Example 1, and microspheres 22 are obtained.

[0238] The only difference between Example 15 and Example 1 is that the weight composition ratio of API to PLGA in Example 15 is different, the amount of PLGA used in Example 15 is 6.8 g, and the other prescription amounts and process conditions are consistent with Example 1, and microspheres 23 are obtained.

[0239] The only difference between Example 16 and Example 1 is that the concentration of PLGA in the organic solvent dichloromethane is different. The concentration of PLGA in dichloromethane is 125 mg / ml, the amount of PLGA used is 2.5 g, and the other prescription quantities and process conditions are consistent with Example 1, and microspheres 24 are obtained.

[0240] The only difference between Example 17 and Example 1 is that the concentration of PLGA in the organic solvent dichloromethane is different. The concentration of PLGA in dichloromethane is 175 mg / ml, the amount of PLGA used is 3.5 g, and the other prescription quantities and process conditions are consistent with Example 1, and microspheres 25 are obtained.

[0241] The only difference between Example 18 and Example 1 is that the volume ratio of the oil phase to the water phase is different. In Example 18, the volume ratio of the oil phase to the water phase is 1:5, that is, in step (2), the pH 7 phosphate buffer contains 0.07 g of sodium dihydrogen phosphate monohydrate, 0.18 g of sodium dihydrogen phosphate dodecahydrate and 100 ml of purified water, and the other prescription quantities and process conditions are consistent with Example 1, and microspheres 26 are obtained.

[0242] The only difference between Example 19 and Example 1 is that the volume ratio of the oil phase to the water phase is different. In Example 19, the volume ratio of the oil phase to the water phase is 1:20, that is, in step (2), the pH 7 phosphate buffer contains 0.28 g of sodium dihydrogen phosphate monohydrate, 0.72 g of sodium dihydrogen phosphate dodecahydrate and 400 ml of purified water, and the other prescription quantities and process conditions are consistent with Example 1, and microspheres 27 are obtained.

[0243] The only difference between Example 20 and Example 1 is that the pH value of the phosphate buffer added in step (2) of Example 20 is 6.5, and the preparation method is 0.184g of sodium dihydrogen phosphate monohydrate and 0.239g of sodium dihydrogen phosphate dodecahydrate dissolved in 200ml of purified water. The other prescription quantities and process conditions are consistent with Example 1, and microspheres 28 are obtained.

[0244] The only difference between Example 21 and Example 1 is that the pH value of the phosphate buffer added in step (2) of Example 21 is 7.5, and the preparation method is 0.092g of sodium dihydrogen phosphate monohydrate and 0.477g of sodium dihydrogen phosphate dodecahydrate dissolved in 200ml of purified water. The other prescription quantities and process conditions are consistent with Example 1, and microspheres 29 are obtained.

[0245] The microspheres 1-29 prepared in Examples 1-21 and Comparative Examples 1-8 were characterized.

[0246] (1) Particle size distribution

[0247] Weigh appropriate amounts of microspheres 1 to 21 and place them in appropriate amounts of aqueous solution containing 0.1% polysorbate 80 to disperse the microspheres uniformly. Place appropriate amounts of the suspension in a particle size analyzer, collect data, and record the equivalent diameter D90 of the largest particle when the cumulative distribution is 90% in the sample particle size distribution curve.

[0248] (2) Drug loading and encapsulation efficiency

[0249] The drug content in microspheres 1 to 21 was determined by high performance liquid chromatography (HPLC). Chromatographic conditions: C 18 Chromatographic column (4.6mmx150mm, 5μm); mobile phase is acetonitrile-water solution (28:72, V / V) containing trifluoroacetic acid (0.067%, V / V); flow rate is 1mL / min; detection wavelength is 210nm; column temperature is 30℃; injection volume: 10μL.

[0250] Accurately weigh 10 mg of microspheres 1-21 into a 10 mL volumetric flask, add an appropriate amount of acetonitrile solution containing 1% triethylamine, ultrasonically dissolve for 20 min, dilute to the scale with the above solvent, accurately measure the supernatant after centrifugation, dilute 5 times with methanol-water solution (70:30, V / V), take the supernatant after centrifugation and filter, and determine the concentration of palonosetron hydrochloride by HPLC.

[0251] Drug loading = drug content in microspheres / total weight of microspheres x 100%

[0252] Encapsulation efficiency = measured drug loading of microspheres / theoretical drug loading of microspheres x 100%

[0253] The particle size D90 of microspheres 1 to 21, the molar ratio of PLA to PGA in PLGA, the weight average molecular weight (Mw) of PLGA, the drug loading amount, and the encapsulation efficiency are shown in Table 1.

[0254] Table 1 D90 of microspheres 1 to 21, molar ratio of PLA to PGA in PLGA, weight average molecular weight (Mw) of PLGA, drug loading, and encapsulation efficiency

[0255]

[0256] Note: Due to the limitation of the detection method, the particle size of the microspheres will have an error of ±2μm. Therefore, it can be assumed that the D90 values ​​of microspheres 1, 5 to 8, 18, and 19 are consistent.

[0257] The experimental variables set during the preparation of Examples 14 to 21 and the drug loading and encapsulation efficiency of the prepared microspheres 22 to 29 are shown in Table 2.

[0258] Table 2 Experimental variables set during the preparation of Examples 14 to 21 and drug loading and encapsulation efficiency of the prepared microspheres 22 to 29

[0259]

[0260] The microspheres 1 to 29 prepared in Examples 1 to 21 and Comparative Examples 1 to 8 were subjected to in vitro release testing, and the testing method was as follows:

[0261] With 0.05% Tween 80-pH7.4 phosphate buffer as the dissolution medium, the centrifuge tube containing the test solution was placed on a shaker (37°C, 150rpm) and shaken. The centrifuge tube was centrifuged (1500 or 5000rpm, 10min) at 2 hours, 10 hours, 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, and 7 days, and the supernatant was filtered and 10ml of dissolution medium was added. The peak area of ​​the filtrate was determined by high performance liquid chromatography, the detector wavelength was 210nm; the flow rate was 1.0ml / min; the injection volume was 100μl, the running time was 25min; the column temperature was 30°C. Another appropriate amount of reference substance was accurately weighed and determined in the same way, and the cumulative release was calculated by the external standard method. The test results are shown in Table 3.

[0262] Table 3 In vitro release data of microspheres 1 to 29

[0263]

[0264] Evaluation criteria: 7-day in vitro release data, requiring that the release should not be too fast, that is, the cumulative release on the 4th day should not exceed 80%; nor should the release be too slow, that is, the cumulative release on the 7th day should not be less than 65%.

[0265] By observing Tables 1 to 3, we can see the following conclusions:

[0266] Comparing microspheres 1 to 4 with microspheres 14 and 15, it can be seen that the drug loading of microspheres 1 to 4 and microspheres 14 and 15 is above 3.5%, and the encapsulation rate is greater than 90%; when microspheres 1 to 4 are released in vitro for 4 days, the cumulative release is less than 80%, and the cumulative release in 7 days is greater than 65%, which can achieve the effect of 7-day long-term release; while when microspheres 14 are released in vitro for 4 days, the cumulative release is greater than 80%, which is too fast; the cumulative release of microspheres 15 on the seventh day is less than 65%, which is too slow to achieve the expected drug effect. Therefore, it can be seen that when other conditions are the same, the change of microsphere D90 will significantly affect the drug loading, encapsulation rate and in vitro release of the microspheres. That is, when other conditions are the same, when the particle size D90 of the microspheres is 15 to 40 μm, its drug loading is greater than 3.5%, and the encapsulation rate is greater than 90%, which can achieve the effect of 7-day long-term drug release.

[0267] Comparing microspheres 5-8 with microspheres 18-21, it can be seen that the drug loading of microspheres 5-8, 18, and 19 is all above 3.5%, and the encapsulation rate is greater than 90%; the drug loading and encapsulation rate of microspheres 20 and 21 are relatively low; when microspheres 5-8 are released in vitro for 4 days, the cumulative release is less than 80%, and the cumulative release in 7 days is greater than 65%, which can achieve the effect of 7-day long-term drug release; while the cumulative release of microspheres 18-21 on the seventh day is less than 65%, and the release is too slow to achieve the expected drug effect. Therefore, it can be seen that when other conditions are the same, the molar ratio of PLA to PGA in the capsule wall material PLGA will significantly affect the drug loading, encapsulation rate and in vitro release of the microspheres. That is, when other conditions are the same, when the molar ratio of PLA to PGA in the capsule wall material PLGA is (40-60): (40-60), its drug loading is greater than 3.5%, the encapsulation rate is greater than 90%, and the drug can be slowly released for more than 7 days.

[0268] Comparing microspheres 9-13 with microspheres 16 and 17, it can be seen that the drug loading of microspheres 9-13 is above 3.5%, and the encapsulation rate is greater than 90%; the drug loading of microspheres 16 and 17 is relatively low; when microspheres 9-13 are released in vitro for 4 days, the cumulative release is less than 80%, and the cumulative release in 7 days is greater than 65%, which can achieve the effect of 7-day long-term drug release; while when microspheres 16 are released in vitro for 4 days, the cumulative release reaches 80%, which is too fast; the cumulative release of microspheres 17 on the seventh day is less than 65%, which is too slow to achieve the expected drug effect. Therefore, when other conditions are the same, when the microsphere particle size D90 is 15-40μm, and the weight-average molecular weight of PLGA is 7-38kDa, its drug loading is greater than 3.5%, the encapsulation rate is greater than 90%, and the drug can be slowly released for more than 7 days.

[0269] Observing microspheres 1 and microspheres 22-23, it can be seen that the drug loading of microspheres 1 and microspheres 22-23 is above 3.5%, and the encapsulation rate is greater than 90%. When microspheres 1 and microspheres 22-23 are released in vitro for 4 days, the cumulative release is less than 80%, and the cumulative release for 7 days is greater than 65%, which can achieve the effect of 7-day long-term drug release. Therefore, in terms of weight ratio, when API:PLGA is 1:5-1:40, the prepared palonosetron sustained-release microspheres have a drug loading of greater than 3.5%, an encapsulation rate of greater than 90%, and can slowly release drugs for more than 7 days.

[0270] Observation of microspheres 1 and microspheres 24-25 shows that the drug loading of microspheres 1 and microspheres 24-25 is above 3.5%, the encapsulation rate is greater than 90%, and the cumulative release of microspheres 1 and microspheres 24-25 is less than 80% when released in vitro for 4 days, and the cumulative release for 7 days is greater than 65%, which can achieve the effect of 7-day long-term drug release. Therefore, when the concentration of PLGA in an organic solvent is 100-225 mg / ml by weight, the prepared palonosetron sustained-release microspheres have a drug loading of greater than 3.5%, an encapsulation rate of greater than 90%, and can slowly release drugs for more than 7 days.

[0271] Observation of microspheres 1 and microspheres 26-27 shows that the drug loading of microspheres 1 and microspheres 26-27 is above 3.5%, the encapsulation rate is greater than 90%, and the cumulative release of microspheres 1 and microspheres 26-27 is less than 80% when released in vitro for 4 days, and the cumulative release for 7 days is greater than 65%, which can achieve the effect of 7-day long-term drug release. Therefore, when the volume ratio of the oil phase to the water phase in the process of preparing microspheres is 1:4-1:40, the prepared palonosetron sustained-release microspheres have a drug loading of greater than 3.5%, an encapsulation rate of greater than 90%, and can slowly release drugs for more than 7 days.

[0272] Observation of microspheres 1 and microspheres 28-29 shows that the drug loading of microspheres 1 and microspheres 28-29 is above 3.5%, the encapsulation efficiency is greater than 90%, and the cumulative release of microspheres 1 and microspheres 28-29 is less than 80% when released in vitro for 4 days, and the cumulative release for 7 days is greater than 65%, which can achieve the effect of 7-day long-term drug release. Therefore, when the pH value of the aqueous phase in step (2) is 5-10, the prepared palonosetron sustained-release microspheres have a drug loading of greater than 3.5%, an encapsulation efficiency of greater than 90%, and can slowly release the drug for more than 7 days.

[0273] Drug efficacy test and 7-day blood drug concentration test:

[0274] Ten healthy beagle dogs with similar body shapes were evenly divided into two groups, named microsphere group 1 and microsphere group 2. They were injected with suspensions prepared with microspheres 1 and microspheres 21, respectively, and the antiemetic model was observed to verify the antiemetic effects of the two groups of microspheres in the acute phase. The blood drug concentration was tested for 7 days.

[0275] According to the beagle's body weight, the dose is 180μg / kg (i.e., 180μg of palonosetron sustained-release microspheres are injected for every kilogram of beagle's body weight). Weigh the corresponding weight of microspheres into the vial, seal it with a cap, and set aside. Prepare mannitol injection (Jiangsu Novo Bito New Drug Research and Development Co., Ltd., 250ml: 50g) as a diluent. Use a 1.0mL syringe to draw 0.5ml of mannitol injection, inject it into the vial, and shake it up and down for at least 30 seconds to fully suspend the drug in the bottle. After standing for 10 seconds, draw out the suspension, point the needle upward, and inject it all immediately after removing the bubbles.

[0276] One hour after intramuscular injection of suspension prepared by microspheres 1 and 21 into two groups of beagle dogs, respectively, all the beagle dogs in both groups were intravenously injected with cisplatin (3 mg / kg, concentration 2 mg / ml) to establish chemotherapy vomiting model. The number of vomiting times of beagle dogs within 5 hours after administration of cisplatin was observed and recorded. The experimental setting conditions are shown in Table 3.

[0277] Table 3 Efficacy test condition settings

[0278] Group No. Number of animals Dosage (μg / kg) Time of administration Route and frequency of administration Microsphere 1 5 180 D1 (1h before modeling) im single Microsphere 21 5 180 D1 (1h before modeling) im single

[0279] About 1 mL of blood samples were collected before administration (0h) and 5min, 15min, 30min, 1h, 2h, 3h, 4h, 6h, 8h, 12h, 24h, 48h (2d), 72h (3d), 96h (4d), 120h (5d), 144h (6d), and 168h (7d) after administration. The samples were placed in heparinized centrifuge tubes and centrifuged at 4000rpm for 10min. The supernatant plasma was taken and the blood drug concentrations of the two groups of beagle dogs were detected.

[0280] The results of the efficacy test are shown in Table 4.

[0281] Table 4 Results of drug efficacy test

[0282] Group Vomiting latency (min) Number of vomiting episodes Inhibition rate (%) Microsphere 1 268.6±70.2 0.2±0.4 98.9 Microsphere 21 138.0±25.9 6.4±3.6 63.2

[0283] The results showed that the number of vomiting events in beagle dogs in microsphere group 1 was significantly reduced compared with that in microsphere group 21, with inhibition rates of 98.9% and 63.2%, respectively. Therefore, the antiemetic effect of the palonosetron sustained-release microspheres provided by the present invention is significantly improved.

[0284] Comparison of blood drug concentrations of beagle dogs in microsphere group 1 and microsphere group 2 at 24 hours is shown in Figure 1 The comparison of blood drug concentrations of beagle dogs in microsphere group 1 and microsphere group 2 for 7 days is shown in the figure. Figure 2 .

[0285] Figure 1 The results showed that the Cmax of microsphere group 1 was higher than that of microsphere group 21 within 24 hours, which could quickly and effectively suppress vomiting. Figure 2 The results showed that both microsphere group 1 and microsphere group 21 could release the drug in the beagle dogs for 7 days, but the blood concentration of microsphere 21 was lower than that of microsphere 1 in the later stage, that is, the 7-day antiemetic effect of microsphere 1 was better than that of microsphere 21.

[0286] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present application, but the present application is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present application, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A palonosetron sustained-release microsphere, the preparation system of which comprises: Palonosetron or its salt derivatives, organic solvents, polymer sustained-release materials, emulsifiers, pH regulators, and lyophilization protective agents, characterized in that the D90 of the palonosetron sustained-release microspheres is 15 to 40 μm, the polymer sustained-release material is a lactide-glycolide copolymer, and the molar ratio of polylactic acid to polyglycolic acid in the lactide-glycolide copolymer is (40 to 60): (40 to 60).

2. The palonosetron sustained-release microspheres according to claim 1, characterized in that: The weight average molecular weight of the lactide-glycolide copolymer is 7 to 38 kDa.

3. The palonosetron sustained-release microspheres according to claim 1, characterized in that: The D90 of the palonosetron sustained-release microspheres is 20-25 μm, and the molar ratio of polylactic acid to polyglycolic acid in the lactide-glycolide copolymer is 50:

50.

4. The palonosetron sustained-release microspheres according to claim 3, characterized in that: The weight average molecular weight of the lactide-glycolide copolymer is 7 to 30 kDa.

5. The palonosetron sustained-release microspheres according to claim 1, characterized in that: The weight composition ratio of the palonosetron to the lactide-co-glycolide copolymer is 1:5 to 1:

40.

6. The palonosetron sustained-release microspheres according to claim 1, characterized in that: The concentration of the lactide-glycolide copolymer in the organic solvent is 100-225 mg / mL.

7. The method for preparing the palonosetron sustained-release microspheres according to any one of claims 1 to 6, characterized in that: include: (1) Preparation of oil phase: dissolving the API and the lactide-co-glycolide copolymer in an organic solvent to prepare an oil phase; (2) Preparation of aqueous phase: adding an emulsifier and a pH adjuster to water and dissolving them to prepare an aqueous phase; (3) Emulsification: adding the oil phase of step (1) to the water phase of step (2) under shearing condition, and emulsifying to obtain an emulsion; (4) solidification: under stirring, the oil phase in the emulsion of step (3) is volatilized, and the emulsion droplets are solidified to form microspheres; (5) washing the microspheres: separating the solution from step (4) from the microspheres and washing them; (6) Freeze-drying: freeze-drying the microsphere sample of step (5) to obtain palonosetron sustained-release microspheres.

8. The method for preparing palonosetron sustained-release microspheres according to claim 7, characterized in that: In the step (2), the pH of the aqueous solution is in the range of 5 to 10.

9. The method for preparing palonosetron sustained-release microspheres according to claim 7, characterized in that: In the step (3), the volume ratio of the oil phase to the water phase is 1:4 to 1:

40.

10. The method for preparing palonosetron sustained-release microspheres according to claim 7, characterized in that: In the step (3), the shear speed of the emulsification is 3000 to 6000 rpm.

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