A sustained-release microsphere injection of lappaconitine and a preparation method and application thereof

Abstract

The application provides a lappaconitine sustained-release microsphere injection and a preparation method and application thereof.The lappaconitine sustained-release microsphere injection has good safety, is convenient to use, has long drug efficacy, and has high patient compliance.The lappaconitine sustained-release microsphere injection prepared by the application can achieve the technical effects of reducing the administration frequency, prolonging the drug action time, reducing the blood drug concentration fluctuation, and improving the patient medication compliance;one administration can maintain the drug efficacy in the body for 1-2 months, and has high clinical application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biological medicine manufacturing, in particular to a bulleyaconitine A sustained-release microsphere, a preparation method thereof and application of the bulleyaconitine A sustained-release microsphere in treating rheumatoid arthritis and pain. BACKGROUND

[0002] Bulleyaconitine A (BLA) is a diterpene double-ester alkaloid isolated from Acomitum bulleyanum Diels. In 1983, Shanghai Institute of Materia Medica, Chinese Academy of Sciences confirmed that bulleyaconitine A has obvious analgesic and anti-inflammatory effects. As an excellent analgesic and anti-inflammatory drug, bulleyaconitine A is mainly used in the treatment of rheumatoid arthritis, rheumatoid arthritis, osteoarthritis, shoulder periarthritis, sprain and contusion of the waist and limbs, zoster abscess and pain in the late stage of cancer. Bulleyaconitine A is a new third analgesic drug, which does not belong to NSAIDs and has little psychological dependence and toxic effects on organic organs. Bulleyaconitine A also has certain immunomodulatory effects and obvious advantages in the treatment of rheumatoid diseases, and is suitable for long-term medication for chronic pain caused by various reasons. Studies have shown that the relative analgesic effect of bulleyaconitine A is 15.3-65.5 times that of morphine and 1208-7195 times that of aspirin. The onset time of bulleyaconitine A is slower than that of morphine, but the action time is longer than that of morphine. All types of addiction models and opiate receptor binding experiments are negative, confirming that bulleyaconitine A is a non-addictive analgesic different from morphine, which can avoid potential dangers such as gastrointestinal and cardiovascular and renal adverse reactions, drug dependence and the like caused by NSAIDs and opioid analgesics. In clinical practice, bulleyaconitine A is used for intramuscular injection in the treatment of patients with confirmed advanced cancer and ineffective treatment by various methods, and the pain relief rate is 95.3%, and there is no obvious adverse reaction.

[0003] At present, there are many defects in the marketed bulleyaconitine A injection, such as short drug effect time, frequent administration and poor patient medication compliance. Although the method for preparing a long-acting bulleyaconitine A injection is disclosed in the prior art such as CN101554364A, the overall drug action time is still short, which cannot meet the medication needs of patients. SUMMARY

[0004] The present application aims to provide a bulleyaconitine A sustained-release microsphere with good safety, convenient use, long drug effect time and high patient compliance, a preparation method thereof and application.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0006] The grass-ou-microsphere slow-release includes grass-ou and biodegradable polymer; preferably, the biodegradable polymer includes one or more of polylactic acid and polycaprolactone;

[0007] More preferably, the polylactic acid is racemic polylactic acid.

[0008] Preferably, the mass ratio of the above-mentioned grass-ou and biodegradable polymer is 1:1-1:20.

[0009] Preferably, the molecular weight of the biodegradable polymer is 5000-200000 Da; more preferably, the molecular weight is 10000-18000 Da.

[0010] The application also provides a grass-ou-microsphere slow-release injection, which includes the above-mentioned grass-ou-microsphere slow-release and dispersion medium.

[0011] Preferably, the components of the dispersion medium include CMC-Na, polysorbate 80 and 0.9% sterile NaCl aqueous solution.

[0012] The application also provides a preparation method of the grass-ou-microsphere slow-release, which includes the following steps: dissolving grass-ou and polylactic acid or polycaprolactone in organic solvent as oil phase; dissolving emulsifier in water as water phase; mixing the water phase with the oil phase, using high-speed shearing machine for emulsification to form emulsion; removing the solvent in the emulsion, solidifying the microspheres, and then extracting the solidified microspheres through 0.22 mu m microporous filter membrane, washing and freeze-drying to prepare the microspheres.

[0013] Preferably, the organic solvent is one or more of dichloromethane, trichloromethane, acetone, tetrahydrofuran, ethyl acetate, dimethyl sulfoxide and N, N-dimethyl formamide; more preferably, the organic solvent is dichloromethane.

[0014] Preferably, the emulsifier is polyvinyl alcohol.

[0015] Preferably, the mixing ratio of the water phase and the oil phase is 1:1-1:10.

[0016] The above-mentioned high-speed shearing machine needs to be used with a rotary evaporator, and the specific use method is to high-speed shear the mixture of the water phase and the oil phase to form emulsion, then dilute the emulsion by adding diluent, and remove the organic solvent by rotary evaporation to solidify the microspheres.

[0017] Preferably, the diluent is water or sodium chloride solution, and the use amount of the diluent is 1 to 3 times the volume of the emulsion.

[0018] The application also provides the use of the above-mentioned grass-ou-microsphere slow-release in the preparation of a drug for treating rheumatoid arthritis.

[0019] The application also provides application of the above-mentioned aconitum alkaloid B sustained-release microspheres in preparation of a medicine for treating pain.

[0020] Advantages of the application:

[0021] (1) The application provides a sustained-release preparation of aconitum alkaloid B, and compared with PLGA microspheres, the drug-loaded microspheres prepared by the application significantly improve drug loading and encapsulation efficiency, have no obvious burst release, and have a long release period. The sustained-release injection has low toxicity and side effects, and is a new preparation with high clinical application value.

[0022] (2) The application provides a sustained-release microsphere injection of aconitum alkaloid B, which has good safety, is convenient to use, has a long drug effect time, and has high patient compliance. The aconitum alkaloid B can be slowly released by intra-articular injection, which further increases the therapeutic effect of the preparation, so that the effect of long-term treatment of rheumatoid arthritis is achieved, the injection frequency is reduced, the patient compliance is increased, and the preparation process is simple to operate.

[0023] (3) The sustained-release microsphere injection of aconitum alkaloid B can achieve the purposes of reducing the frequency of drug administration, prolonging the action time of the drug, reducing the fluctuation of blood drug concentration, and improving the patient compliance. The drug effect can be maintained in the body for 1-2 months after one-time administration, and the sustained-release microsphere injection of aconitum alkaloid B has high clinical application value. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 : Scanning electron microscope image of the aconitum alkaloid B sustained-release microspheres in Example 1.

[0025] Figure 2 : Particle size and particle size distribution of the aconitum alkaloid B sustained-release microspheres The D50 value of the aconitum alkaloid B sustained-release microspheres is 15.81 μm, and the Span value is 1.61. The particle size of the microspheres is small, and the distribution is uniform.

[0026] Figure 3 : In-vitro release curve of the aconitum alkaloid B sustained-release microspheres.

[0027] Figure 4 : Degradation kinetics curve of aconitum alkaloid B.

[0028] Figure 5 : In-vitro release curve of the drug-loaded microspheres prepared by different molecular weight PLA in Example 3.

[0029] Figure 6 : In-vitro release curve of the drug-loaded microspheres prepared by different end-capped PLA in Example 5.

[0030] Figure 7 : In-vitro release curve of the drug-loaded microspheres prepared by different solidification methods in Example 7.

[0031] Figure 8 : Curve graph of the thickness change of the CIA rat foot.

[0032] Figure 9 : CIA rat arthritis score change curve.

[0033] Figure 10 : CIA rat hind paw appearance.

[0034] Figure 11 : CIA rat ankle pathological histology section.

[0035] Figure 12 : In vivo analgesic effect of lappaconitine sustained-release microspheres.

[0036] Figure 13 : CIA rat main organ pathological histology section. DETAILED DESCRIPTION

[0037] The present application provides lappaconitine sustained-release microspheres with good safety, convenient use, long drug effect time and high patient compliance, and a preparation method and application thereof.

[0038] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions.

[0039] The lappaconitine sustained-release microspheres comprise lappaconitine and biodegradable polymers; preferably, the biodegradable polymers comprise one or more of polylactic acid and polycaprolactone.

[0040] More preferably, the polylactic acid is racemic polylactic acid.

[0041] Preferably, the mass ratio of the above-mentioned lappaconitine and biodegradable polymers is 1:1-1:20; more preferably, the mass ratio is 1:4.

[0042] Preferably, the molecular weight of the biodegradable polymers is 5000-200000 Da; more preferably, the molecular weight is 10000-18000 Da.

[0043] The present application also provides lappaconitine sustained-release microsphere injections, comprising the above-mentioned lappaconitine sustained-release microspheres and a dispersion medium.

[0044] Preferably, the components of the dispersion medium comprise CMC-Na, polysorbate 80 and 0.9% sterile NaCl aqueous solution.

[0045] Optionally, 6 mg of lappaconitine sustained-release microspheres correspond to 1 mL of the dispersion medium, and the components of the dispersion medium are 5 mg / mL CMC-Na, 1 mg / mL polysorbate 80 and isotonic 0.9% sterile NaCl aqueous solution.

[0046] The application further provides a preparation method of the lappaconitine sustained-release microspheres, which comprises the following steps: dissolving lappaconitine and polylactic acid or polycaprolactone in an organic solvent as an oil phase; dissolving an emulsifier in water as an aqueous phase; mixing the aqueous phase with the oil phase, and using a high-speed shearing machine to emulsify to form an emulsion; removing the solvent in the emulsion to solidify the microspheres; and then performing suction filtration on the solidified microspheres through a 0.22 μm microporous filter membrane, and then performing washing and freeze-drying to prepare the microspheres.

[0047] Preferably, the organic solvent is one or more of dichloromethane, trichloromethane, acetone, tetrahydrofuran, ethyl acetate, dimethyl sulfoxide and N,N-dimethylformamide; more preferably, the organic solvent is dichloromethane.

[0048] Preferably, the emulsifier is polyvinyl alcohol.

[0049] Preferably, the mixing ratio of the aqueous phase to the oil phase is 1:1 to 1:10.

[0050] The high-speed shearing machine needs to be used in combination with a rotary evaporator, and the specific use method is as follows: the mixture of the aqueous phase and the oil phase is high-speed sheared to form an emulsion, then a dilution liquid is added to dilute the emulsion, and the organic solvent is removed through rotary evaporation to solidify the microspheres; preferably, the high-speed shearing parameters are 4000-8000 rpm high-speed shearing for 1.5-4.5 min.

[0051] Preferably, the dilution liquid is water or a sodium chloride solution, and the use amount of the dilution liquid is 1 to 3 times the volume of the emulsion.

[0052] The application further provides a lappaconitine sustained-release microsphere injection prepared by the preparation method.

[0053] The application further provides application of the lappaconitine sustained-release microspheres in preparation of a medicine for treating rheumatoid arthritis.

[0054] The application further provides application of the lappaconitine sustained-release microspheres in preparation of a medicine for treating pain.

[0055] In the application, all the raw material components are commercially available products well known by those skilled in the art, unless otherwise specified.

[0056] The technical solutions in the application will be clearly and completely described below in combination with the embodiments in the application. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments. Based on the embodiments in the application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0057] Embodiment 1

[0058] (1) Preparation of microspheres

[0059] Precisely weigh 200 mg of carboxyl-terminated racemic polylactic acid with a molecular weight of 150 KDa in 3 mL of dichloromethane, add 20 mg of aconitine, and vortex to dissolve thoroughly to obtain an organic phase. Use a 5 mL syringe to draw the organic phase, and slowly inject it into 35 mL of 1% PVA aqueous solution. Use an ice bath to shear at 7000 rpm for 3 min to obtain an emulsion. Dilute the emulsion with 1 volume of distilled water, and rotary evaporate for 30 min to remove the organic solvent to solidify the microspheres. The solidified drug-loaded microspheres are filtered through a 0.22 μm microporous filter membrane, washed with 300 mL of distilled water, centrifuged at 3000 rpm to remove the supernatant, and repeatedly washed three times. The drug-loaded microspheres are collected, and vacuum freeze-dried to obtain aconitine-loaded microspheres.

[0060] (2) Morphology and particle size of microspheres

[0061] Take an appropriate amount of drug-loaded sustained-release microspheres freeze-dried powder, uniformly disperse on double-sided carbon tape, sputter gold after ion plating film instrument, and observe by scanning electron microscopy. The microspheres are uniform in size, smooth in surface, well dispersed, and not adhered. The results are shown in Figure 1 .

[0062] The particle size and particle size distribution of aconitine sustained-release microspheres are determined by using a laser particle size analyzer. The determination results are shown in Figure 2 . The D 50 value of aconitine sustained-release microspheres is 15.81 μm, and the Span value is 1.61. The microspheres have a small particle size and uniform distribution.

[0063] (3) Determination of the encapsulation efficiency and drug loading of drug-loaded microspheres

[0064] UV method is used for detection. Precisely weigh 10 mg of aconitine reference substance in a 100 mL volumetric flask, dissolve and dilute to the mark with acetonitrile, mix well, and prepare a stock solution of 100 μg / mL. Dilute with acetonitrile to obtain a series of solutions of 30, 25, 20, 15, and 10 μg / mL, and filter with a 0.22 μm microporous filter membrane. Determine the absorbance A by UV spectrophotometry, and perform linear regression of the absorbance A versus the concentration C.

[0065] Precisely weigh 10 mg of drug-loaded sustained-release microspheres in a 50 mL volumetric flask, add 5 mL of acetonitrile, and ultrasonically oscillate to dissolve. Add acetonitrile to the mark, mix well, filter with a 0.22 μm microporous filter membrane, discard the initial filtrate, and take the subsequent filtrate to determine the absorbance by UV method.

[0066] Drug loading = (mass of drug in microspheres ÷ mass of microspheres weighed) × 100%

[0067] Encapsulation efficiency = (actual content of aconitine in microspheres ÷ amount of aconitine used for preparing microspheres) × 100%

[0068] As a result, the drug-loaded sustained-release microspheres obtained have an optimal encapsulation rate of 95.7%.

[0069] (4) In vitro release experiment of microspheres

[0070] Precisely weigh 10 mg of drug-loaded sustained-release microspheres in a 20 mL EP tube, add 15 mL of phosphate buffer with pH of 7.4, and incubate in a 37°C, 100 rpm water bath shaker. At the specified time point, centrifuge at 4000 rpm for 5 min to precipitate the microspheres, remove all the release medium, and supplement with an equal amount of fresh medium to meet the leakage condition. Filter the sample through a 0.22 μm filter membrane, take the filtrate, and measure the absorbance at 260 nm using UV method to calculate the cumulative release amount in vitro.

[0071] As shown in Table 1, the drug-loaded sustained-release microspheres have an optimal encapsulation rate of 95.7%. Figure 3 As shown in Table 1, the drug-loaded sustained-release microspheres have an optimal encapsulation rate of 95.7%.

[0072] (5) In vitro release stability detection of delphinine

[0073] HPLC method was used for detection. The mobile phase was 0.2% triethylamine aqueous solution (pH value was adjusted to 4.23±0.1 with phosphoric acid)-methanol (42:58), the flow rate was 1.0 mL / min, the column temperature was 25°C, and the detection wavelength was 260 nm. Precisely weigh 2.15 mg of delphinine in a 100 mL volumetric flask, add a certain amount of PBS (pH 7.4) buffer solution, ultrasonically dissolve, and then dilute to the mark, and shake well. After the sample was filtered through a 0.22 μm filter membrane, it was sealed in a 50 mL centrifuge tube and placed in a 37°C water bath shaker for shaking. At 2, 4, 8.5, 12, and 24 h, it was taken out and immediately placed in an ice water bath to terminate the hydrolysis reaction. The sample was filtered through a 0.22 μm filter membrane, the initial filtrate was discarded, and the filtrate was used for determination of the residual amount of delphinine by HPLC method. The residual concentration C (mol / mL) was calculated, and the degradation kinetics curve of delphinine in PBS (pH 7.4) at 37°C was plotted as lnC versus t. Figure 4 As shown in Table 1, the drug-loaded sustained-release microspheres have an optimal encapsulation rate of 95.7%. 2 = 0.9979, which is good linear. The calculated degradation amount of delphinine in PBS (pH 7.4) at 37°C for 24 h is 6.91%.

[0074] Accurately weigh 10 mg of drug-loaded sustained-release microspheres and place them in a sample vial. Add 5 mL of release buffer (phosphate buffer, pH 7.4), shake at 37°C and 100 rpm. On the third day, centrifuge at 4000 rpm for 5 min to precipitate the microspheres. Separate the supernatant, freeze-dry the precipitated drug-loaded microsphere residue, dissolve it in acetonitrile, and determine the aconitine content in the release supernatant and precipitated microspheres by HPLC. Compare the differences in absorption peaks. The HPLC results of the drug-loaded sustained-release microspheres before in vitro release are used as a reference. An absorption peak of aconitine appears at a retention time of approximately 8.39 min. A new absorption peak appears in the supernatant of the drug-loaded sustained-release microspheres after in vitro release at a retention time of approximately 14.85 min, with a peak area of ​​approximately 19.3% of the aconitine peak area, indicating that the aconitine released in vitro has degraded. However, the same absorption peak is also visible in the drug-loaded sustained-release microspheres after in vitro release at a retention time of approximately 8.39 min, but the peak area is extremely small, only 5.7% of the aconitine peak area. This indicates that aconitine encapsulated in sustained-release microspheres is more stable than the drug released in buffer solution, and that the carrier material has the function of protecting the drug and reducing its degradation.

[0075] Example 2

[0076] Different diluents were used to prepare aconitine sustained-release microspheres when diluting the emulsion, and the preparation method was the same as in Example 1.

[0077] Diluting the emulsion with different diluents and different volumes of diluent affects drug loading, encapsulation efficiency, and burst release. The results are shown in Table 1.

[0078] Table 1. Effects of different dilution levels of emulsion on the performance of drug-loaded microspheres.

[0079]

[0080] Example 3

[0081] Aconitum carmichaelii sustained-release microspheres were prepared using PLA of different molecular weights, following the same preparation method as in Example 1. The results of preparing drug-loaded microspheres using PLA of different molecular weights were compared. Figure 5 As shown.

[0082] Example 4

[0083] Drug-loaded microspheres were prepared using PLGA and PCL, with the remaining procedures the same as in Example 1. The results of the preparation of drug-loaded microspheres using PLA are shown in Table 2.

[0084] Table 2. Effects of different materials on the performance of drug-loaded microspheres.

[0085]

[0086]

[0087] Example 5

[0088] Effect of different end caps on microsphere properties

[0089] Drug-loaded microspheres were prepared using PLA with -COOR and -OH terminators, with the remaining operations the same as in Example 1. The results of preparing drug-loaded microspheres using PLA with -COOH terminators are shown in Table 3.

[0090] Table 3. Effects of different materials on the performance of drug-loaded microspheres

[0091]

[0092] Example 6

[0093] Effect of shear temperature on microsphere properties

[0094] The colostrum was prepared by room temperature shearing, with the remaining procedures the same as in Example 1. The results were compared with those of drug-loaded microspheres prepared by ice bath shearing.

[0095] Table 4. Effect of shear temperature on the properties of drug-loaded microspheres.

[0096]

[0097] Example 7

[0098] The Influence of Different Curing Methods on Microsphere Properties

[0099] The dichloromethane organic solvent was removed from the solidified microspheres by magnetic stirring at room temperature for 6 hours. The remaining operations were the same as in Example 1. The dichloromethane was removed by rotary evaporation for 30 minutes. The results are shown in Table 5.

[0100] Table 5. Effects of different curing methods on the properties of drug-loaded microspheres

[0101]

[0102] Example 8

[0103] Preparation of Aconitum carmichaelii sustained-release microsphere injection

[0104] Weigh 30 mg of the aconitine sustained-release microspheres prepared in Example 1 into a vial, add 5 mL of dispersion medium (5 mg / mL LMC-Na, 1 mg / mL polysorbate 80, isotonic 0.9% sterile NaCl aqueous solution), shake thoroughly to obtain the aconitine sustained-release microsphere injection.

[0105] Example 9

[0106] Application of the drug-loaded sustained-release microsphere injection prepared by the method in Example 8 in the CIA model of SD rats

[0107] (1) Animal modeling:

[0108] Add an appropriate amount of incomplete Freund's adjuvant to a 5 mL vial, followed by an equal volume of bovine type II collagen solution (collagen solution dissolved in 0.05 M acetic acid). While stirring at low speed with a homogenizer, add the bovine type II collagen solution dropwise. Keep the vial in an ice bath throughout the process to prevent protein denaturation caused by heat during stirring. After the addition is complete, continue mixing until a stable emulsion is produced at maximum speed (30,000 rpm / 2–3 min). During this process, continuously move the stirring position to ensure uniform mixing of the emulsion, thus preparing a stable emulsion.

[0109] For the initial immunization, a needle was inserted at the base of the tail of the SD rats, and 0.2 mL of an emulsion prepared with incomplete Freund's adjuvant and bovine type II collagen was injected subcutaneously into the tail. Seven days after the initial immunization, a booster immunization was given with an emulsion prepared with incomplete Freund's adjuvant and bovine type II collagen; the needle was inserted at the base of the tail, and 0.1 mL of the emulsion was injected subcutaneously into the tail. Drug administration was performed five weeks after the initial immunization.

[0110] (2) Animal experiments

[0111] The successfully modeled CIA rats were randomly divided into 3 groups:

[0112] Saline therapy group;

[0113] The commercially available Aconitum carmichaelii injection treatment group (Aconitum carmichaelii injection, Fuxiang (Dalian) Pharmaceutical Co., Ltd., approval number: National Drug Approval Number H21023347.), abbreviated as Aconitum carmichaelii injection;

[0114] The treatment group in Example 8 is referred to as aconitine microsphere injection.

[0115] Rats with successfully induced CIA were randomly divided into three groups: saline group, aconitine injection group, and aconitine microsphere group. Healthy SD rats served as the blank control group, with 6 rats in each group. One affected hind leg of each CIA rat was selected as the observation subject. In the aconitine injection group, 0.5 mL of aconitine injection was injected intramuscularly into the hind leg of the rat, with a dosage of 0.32 mg / kg, once every 2 weeks for 4 consecutive weeks. In the saline group and the aconitine microsphere group, 50 μL of saline or aconitine microspheres were injected into the ankle joint cavity of the hind leg of the rat, respectively, with a dosage of 1.28 mg / kg, once a day.

[0116] Every 7 days after administration, the plantar thickness of the treated paw was measured using calipers, and arthritis scores were assessed. Foot thickness change curves and arthritis score change curves were plotted. At week 14 post-primary immunization, SD rats were euthanized, and the hind paws of rats in each experimental group were photographed. The degree of arthritis was assessed using foot thickness change curves, arthritis score change curves, and gross images of the hind paws of CIA rats. Sections of the ankle joints of rats in each treatment group were prepared and stained with H&E and Safranin O-Fix Green for histopathological studies. Mechanoresonism in CIA rats was assessed using an electronic analgesic device. The heart, liver, spleen, lungs, kidneys, and other major organs of rats in each treatment group were dissected and separated, and sections were prepared for H&E staining to investigate the biosafety of aconitine injection and aconitine microspheres.

[0117] Compared with commercially available immediate-release herbicides, the drug-loaded sustained-release microsphere injection of this invention significantly prolonged the therapeutic effect to approximately 2 months in an SD rat model of CIA arthritis, and showed better therapeutic efficacy. Results are shown in […]. Figure 8 Curve showing changes in paw thickness in CIA rats; Figure 9 : Curve showing changes in arthritis scores in CIA rats; Figure 10 The hind paw morphology of CIA rats. Histopathological examination showed that the ankle joint tissue structure of rats in the aconitine microsphere treatment group almost returned to normal, while the ankle joint of rats in the aconitine injection treatment group showed obvious inflammation, bone erosion, and cartilage damage, only slightly better than the saline treatment group. This indicates that aconitine microspheres have a good therapeutic effect on bone erosion and cartilage damage. See [link to article]. Figure 11 Histopathological sections of the ankle joint of CIA rats. Compared to immediate-release aconitine injection, aconitine sustained-release microspheres provide a sustained and stable analgesic effect. See [link / reference]. Figure 12 The in vivo analgesic effect of aconitine sustained-release microspheres was observed. Furthermore, the aconitine microspheres showed no significant toxic side effects on the major organs of CIA rats, indicating good biocompatibility. See [link to study]. Figure 13 : Histopathological sections of major organs of CIA rats.

[0118] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A type of aconitine sustained-release microspheres, characterized in that, It includes aconitine and a biodegradable polymer; the biodegradable polymer is polylactic acid.

2. The aconitine sustained-release microspheres as described in claim 1, characterized in that, The mass ratio of aconitine to biodegradable polymer is 1:1 to 1:

20.

3. The aconitine sustained-release microspheres as described in claim 1, characterized in that, The biodegradable polymer has a molecular weight of 5,000 to 200,000 Da.

4. A sustained-release microsphere injection of aconitine, characterized in that, It includes the aconitine sustained-release microspheres and dispersion medium as described in any one of claims 1 to 3.

5. The method for preparing aconitine sustained-release microspheres according to any one of claims 1 to 3, characterized in that, The process includes the following steps: dissolving aconitine and polylactic acid in an organic solvent as the oil phase; dissolving an emulsifier in water as the aqueous phase; mixing the aqueous and oil phases and emulsifying them using a high-speed shearing machine to form an emulsion; removing the solvent from the emulsion to solidify the microspheres; filtering the solidified microspheres through a 0.22 μm microporous membrane, washing them, and then freeze-drying them to produce microspheres.

6. The preparation method according to claim 5, characterized in that, The organic solvent is one or more of dichloromethane, trichloromethane, acetone, tetrahydrofuran, ethyl acetate, dimethyl sulfoxide, and N,N-dimethylformamide; the emulsifier is polyvinyl alcohol.

7. The preparation method according to claim 5, characterized in that, The high-speed shearing machine needs to be used in conjunction with a rotary evaporator. The specific method of use is to shear the mixture of aqueous and oil phases at high speed to form an emulsion, then add a diluent to dilute the emulsion, and then use rotary evaporation to remove organic solvents to solidify the microspheres.

8. The preparation method according to claim 7, characterized in that, The diluent is water or sodium chloride solution, and the amount of diluent used is 1 to 3 times the volume of the emulsion.

9. The use of aconitine sustained-release microspheres as described in any one of claims 1 to 3 in the preparation of a drug for treating rheumatoid arthritis.

10. The use of aconitine sustained-release microspheres as described in any one of claims 1 to 3 in the preparation of pain-relieving drugs.

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