A kind of triamcinolone acetonide sustained-release microsphere, aseptic preparation method and sustained-release preparation

Abstract

The present invention belongs to the technical field of drug sustained-release preparations, and is specifically related to a triamcinolone acetonide sustained-release microsphere, an aseptic preparation method and a sustained-release preparation. The triamcinolone acetonide sustained-release microsphere has a microsphere body formed by the coagulation of polylactic-glycolic acid copolymer and a triamcinolone acetonide bulk drug embedded in the microsphere body, and the weight-average molecular weight Mw of the polymer in the microsphere is controlled within the range of 8.5 kDa~12.5 kDa, and the microsphere has the advantages of high encapsulation rate, large drug loading, less solvent residue, uniform particle size distribution, and stable and long-acting drug release. The aseptic preparation method of triamcinolone acetonide sustained-release microspheres adopts non-sterile operation in the solution preparation stage in the early stage and realizes sterilization by filtering and sterilizing the solution, and adopts aseptic operation in the microsphere formation stage in the later stage to ensure that the product is sterile, significantly reducing the coverage of aseptic production conditions, and significantly reducing production costs. On this basis, the present invention also provides a triamcinolone acetonide sustained-release preparation.

Description

[0001] This application is a divisional application. The application number of the original application is 202311050982.0, and the original application date is August 21, 2023. The entire contents of the original application are incorporated into this application by reference. Technical Field

[0002] The invention belongs to the technical field of drug sustained-release preparations, and specifically relates to triamcinolone acetonide sustained-release microspheres, a sterile preparation method and a sustained-release preparation. Background Art

[0003] Triamcinolone acetonide sustained-release microspheres were first approved for marketing by FLEXION THERAPS on October 6, 2017 by the U.S. FDA. It is a drug for treating pain in knee osteoarthritis.

[0004] Triamcinolone acetonide is a corticosteroid with anti-inflammatory and immunomodulatory effects. Its CAS number is 76-25-5 and its chemical formula is C 24 H 31 FO6, structural formula Figure 1 As shown. Triamcinolone acetonide solid is a white crystalline powder, which is soluble in acetone and has low solubility in other organic solvents such as dichloromethane, methanol, ethanol and water.

[0005] Considering the poor solubility of triamcinolone acetonide, the process for preparing triamcinolone acetonide sustained-release microspheres disclosed in the original patent US8828440B2 is to suspend the raw material in the organic phase in a solid state, so it is impossible to perform a sterilization filtration operation on the organic phase. Filtration sterilization refers to filtering the drug solution through a filter device to remove harmful impurities such as microorganisms therein to ensure that the drug reaches a purity that meets the standards. However, for the poorly soluble drug triamcinolone acetonide, it is suspended in the organic phase in a solid state, and it is difficult to pass through the filter device, which will affect the sterilization filtration operation. In addition, the triamcinolone acetonide raw material itself is unstable in nature, so terminal sterilization methods such as high temperature and irradiation are also not feasible.

[0006] Since triamcinolone acetonide suspension is not suitable for sterilization methods such as filtration sterilization, high temperature sterilization, and irradiation sterilization, the sterility of microsphere products can only be ensured by aseptic production processes, which significantly increases the technical difficulty and production costs. Specifically, aseptic production processes require highly automated and isolated operations throughout the production process, and have very high requirements for the hardware and software of production companies. First, the sterility assurance of the production environment requires the maintenance of a Class A environment, which involves the quality and operation management of high-efficiency filters, RABS, and isolators. Secondly, companies need to develop closed production processes to reduce open operations. Production personnel need to have a strong sense of GMP production and strictly follow aseptic operating procedures for production. In addition, aseptic production requires the use of sterile APIs, which are much more expensive than ordinary non-sterile raw materials and are not easy to obtain. Therefore, aseptic production processes are a great challenge to the hardware equipment and personnel quality of enterprises, and the production cost is also greatly increased compared to traditional processes. Summary of the invention

[0007] The first purpose of the present invention is to avoid using triamcinolone acetonide suspension as a raw material for preparing sustained-release microspheres, and to develop a method for preparing sustained-release microspheres based on triamcinolone acetonide homogeneous solution, so as to create conditions for adopting low-cost and simple and easy filtration sterilization operations, thereby greatly reducing the proportion of aseptic production processes that need to be implemented in the entire production process.

[0008] The second purpose of the present invention is to develop a triamcinolone acetonide sustained-release microsphere and preparation with high encapsulation rate, large drug loading, less solvent residue, uniform particle size distribution, and stable and long-lasting drug release.

[0009] The invention provides a method for preparing triamcinolone acetonide sustained-release microspheres, comprising the steps of adding an organic phase containing solvent dichloromethane (DCM), triamcinolone acetonide raw material, polylactic acid-glycolic acid copolymer (PLGA) and dioctyl sodium sulfosuccinate to an aqueous phase for emulsification to form an emulsion, and solidifying emulsion droplets dispersed in the emulsion to form triamcinolone acetonide sustained-release microspheres; in the process of preparing the organic phase, the triamcinolone acetonide raw material is dissolved in dichloromethane under the solubilization effect of dioctyl sodium sulfosuccinate; during solidification, the polylactic acid-glycolic acid copolymer precipitates and condenses to form microspheres as the content of dichloromethane in the emulsion droplets decreases, and the triamcinolone acetonide raw material is embedded in the microspheres, so as to prepare the triamcinolone acetonide sustained-release microspheres.

[0010] As a further preferred embodiment of the method for preparing triamcinolone acetonide sustained-release microspheres, the weight ratio of dioctyl sodium sulfosuccinate to triamcinolone acetonide API in the organic phase is in the range of 1:2 to 2:1.

[0011] The preparation method of triamcinolone acetonide sustained-release microspheres mainly comprises the following steps during implementation:

[0012] Step 1, preparing an organic phase: dissolving polylactic acid-glycolic acid copolymer in a solvent of dichloromethane, then adding dioctyl sodium sulfosuccinate to dissolve, then adding triamcinolone acetonide raw material, shaking and ultrasonicating to obtain a homogeneous solution;

[0013] Step 2, preparing the aqueous phase: adding the stabilizer into water and dissolving it to obtain a homogeneous solution;

[0014] Step 3, preparing an emulsion: under homogenizing conditions, slowly adding the organic phase obtained in step 1 to the aqueous phase obtained in step 2, and continuing to homogenize to obtain an emulsion;

[0015] Step 4, preparing microspheres: the emulsion prepared in step 3 is kept in a stirring state, and the emulsion droplets dispersed in the emulsion are solidified to form crude microspheres, which are then washed and freeze-dried to obtain the triamcinolone acetonide sustained-release microspheres.

[0016] In step 2, the stabilizer added when preparing the aqueous phase can inhibit the aggregation of the microspheres during the solidification process to a certain extent. The stabilizer can be selected from polyvinyl alcohol, poloxamer, carbomer, preferably polyvinyl alcohol.

[0017] In the process of preparing triamcinolone acetonide sustained-release microspheres, the raw material ratio of the organic phase and the aqueous phase can be implemented according to the following preferred scheme:

[0018] In step 1, an organic phase is prepared containing the following components:

[0019] Triamcinolone acetonide 0.7-0.9 weight portion;

[0020] 0.4-1.6 parts by weight of dioctyl sodium sulfosuccinate;

[0021] 15-20 parts by weight of dichloromethane;

[0022] 1.7-2.3 parts by weight of polylactic acid-glycolic acid copolymer;

[0023] In step 2, prepare an aqueous phase containing the following components:

[0024] 1.2-1.8 parts by weight of stabilizer;

[0025] 350~450 parts by weight of purified water

[0026] In the process of preparing triamcinolone acetonide sustained-release microspheres, a further preferred scheme for the raw material ratio of the organic phase and the aqueous phase is as follows:

[0027] In step 1, an organic phase consisting of the following components is prepared:

[0028] Triamcinolone acetonide 0.8 weight portion;

[0029] 0.4-1.6 parts by weight of dioctyl sodium sulfosuccinate;

[0030] 18 parts by weight of dichloromethane;

[0031] 2 parts by weight of poly(lactic acid-glycolic acid) copolymer;

[0032] In step 2, prepare an aqueous phase consisting of the following components:

[0033] 1.5 parts by weight of polyvinyl alcohol;

[0034] 400 parts by weight of purified water.

[0035] The present invention also provides a triamcinolone acetonide sustained-release microsphere, which comprises a microsphere body formed by coagulation of a polylactic acid-glycolic acid copolymer and a triamcinolone acetonide raw material drug embedded in the microsphere body, and the weight average molecular weight Mw of the polymer in the microsphere is controlled within the range of 85 kDa to 125 kDa.

[0036] In order to control the weight average molecular weight Mw of the polymer in the triamcinolone acetonide sustained-release microspheres within the range of 85 kDa to 125 kDa, an emulsion can be formed by mixing an aqueous phase and an oil phase containing the triamcinolone acetonide API and solidifying to obtain microspheres. Dioctyl sodium sulfosuccinate is added to the oil phase, and the weight ratio of dioctyl sodium sulfosuccinate to the triamcinolone acetonide API is controlled to be 1:2 to 2:1, so that the weight average molecular weight Mw of the polymer in the microspheres is controlled to be within the range of 85 kDa to 125 kDa.

[0037] As a further preferred embodiment of triamcinolone acetonide sustained-release microspheres, the drug loading is in the range of 24.5% to 25.0%, and the solvent residual rate is ≤0.04%.

[0038] As a further preferred embodiment of the triamcinolone acetonide sustained-release microspheres, the particle size D10 is in the range of 24.5 μm to 28.0 μm, and the particle size D90 is in the range of 70.0 μm to 72.5 μm.

[0039] On the basis of the above-mentioned triamcinolone acetonide sustained-release microspheres, the present invention also provides a triamcinolone acetonide sustained-release microsphere preparation for treating arthritis pain, specifically, a sterile diluent is added to a container containing triamcinolone acetonide sustained-release microspheres, and mixed evenly to form a suspension, that is, a triamcinolone acetonide sustained-release microsphere preparation is obtained. Wherein, the sterile diluent is an aqueous solution containing 0.9% by mass of sodium chloride, 0.5% by mass of sodium carboxymethyl cellulose and 0.1% by mass of Tween 80. When used, the triamcinolone acetonide sustained-release microsphere preparation is drawn with a syringe and injected into the patient's joint cavity, and a long-term pain relief effect of more than 12 weeks can be achieved.

[0040] Beneficial Effects

[0041] The method for preparing triamcinolone acetonide sustained-release microspheres provided by the present invention has an organic phase and an aqueous phase which are respectively homogeneous solutions, so it is not necessary to implement an extremely harsh aseptic production process for personnel, raw materials, equipment and environment in the early operations such as raw material preparation, organic phase preparation and aqueous phase preparation. Instead, after the organic phase and the aqueous phase are prepared, the organic phase and the aqueous phase are filtered and sterilized respectively, thereby ensuring that the sustained-release microsphere product meets the sterility requirement.

[0042] The present invention can prepare triamcinolone acetonide sustained-release microspheres with high encapsulation rate, large drug loading, less solvent residue, uniform particle size distribution, stable and long-acting drug release on the basis of simplified process, the encapsulation rate reaches 99%, the drug loading is nearly 25%, the solvent residue does not exceed 0.04%, the particle size distribution curve is normally distributed, the span Span≈1, and the drug release curve is stable and continuous within 0h~170h. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Shown is the structural formula of triamcinolone acetonide.

[0044] Figure 2 Shown are the prescription amounts for preparing samples of Example 1 and Comparative Examples a1 to d1.

[0045] Figure 3 Shown are the performance test results of samples of Example 1 and Comparative Examples a1 to d1.

[0046] Figure 4 Shown is an electron microscope photograph of the comparative example a1 sample.

[0047] Figure 5 Shown is the particle size distribution of the comparative example a1 sample.

[0048] Figure 6 Shown are the drug release curves of Example 1 and Comparative Examples a1 to d1.

[0049] Figure 7 Shown is an electron microscope photograph of the comparative example b1 sample.

[0050] Figure 8 Shown is the particle size distribution of the comparative example b1 sample.

[0051] Fig. 9 Shown is an electron microscope photograph of the comparative example c1 sample.

[0052] Fig.10 Shown is the particle size distribution of the comparative example c1 sample.

[0053] Fig.11 Shown is an electron microscope photograph of the comparative example d1 sample.

[0054] Fig.12 Shown is the particle size distribution of the comparative example d1 sample.

[0055] Fig.13 Shown is an electron microscope photograph of the sample of Example 1.

[0056] Fig.14 Shown is the particle size distribution of the sample of Example 1.

[0057] Fig.15 Shown are the molecular weights of the polymers in the samples of Example 1 and Comparative Examples a1 to d1.

[0058] Fig.16 Shown is the GPC gel chromatogram of the sample of Example 1.

[0059] Fig.17 Shown is the GPC gel chromatogram of the comparative example a1 sample.

[0060] Fig.18 Shown is the GPC gel chromatogram of the comparative example b1 sample.

[0061] Fig.19 Shown is the GPC gel chromatogram of the comparative example c1 sample.

[0062] Fig. 20 Shown is the GPC gel chromatogram of the comparative example d1 sample.

[0063] Fig.21 Shown are the prescription amounts for preparing comparative examples b1 to b6 samples.

[0064] Fig. 22 Shown are the performance test results of comparative examples b1 to b6 samples.

[0065] Fig.23 Shown are the prescription amounts for preparing comparative examples c1 to c4 samples.

[0066] Fig.24 Shown are the performance test results of samples of comparative examples c1 to c4.

[0067] Fig.25 Shown are the prescription amounts for preparing samples of comparative examples d1 to d8.

[0068] Fig.26 Shown are the performance test results of samples of comparative examples d1 to d8.

[0069] Fig. 27 Shown are the prescription amounts for preparing the samples of Examples 1 to 9.

[0070] Fig.28 Shown are the performance test results of samples from Examples 1 to 9.

[0071] Fig.29Shown are the molecular weights of the polymers in the samples of Examples 1 and through 9.

[0072] Fig.30 Shown are the drug release profiles of samples from Examples 1 and to 9. DETAILED DESCRIPTION

[0073] The triamcinolone acetonide sustained-release microspheres of the present invention are prepared according to the following method. Figure 2 Weigh the prescription amount shown, prepare a single solvent or a mixed solvent, then dissolve PLGA in the solvent, then do not add or selectively add sodium dioctyl succinate sulfonate or sodium dodecyl sulfate to dissolve, and finally add triamcinolone acetonide or triamcinolone acetonide acetate, shake and ultrasonicate for 10 minutes to obtain an organic phase. Add polyvinyl alcohol to purified water according to the prescription amount to completely dissolve it to obtain an aqueous phase. Under homogenous conditions, slowly add the organic phase to the aqueous phase and continue homogenizing for 5 minutes. After that, put the drug solution in a fume hood and use magnetic stirring to solidify for 3 hours. After the solidification is completed, wash with purified water, and put the washed microspheres into a freeze dryer for freeze drying to obtain a sustained-release microsphere sample.

[0074] The results are as follows Figure 3 As shown, the preparation method of comparative example a1 is similar to that of the original preparation. No other method is used to promote the dissolution of the API when preparing the organic phase. The organic phase is a suspension, and the triamcinolone acetonide API is suspended in the drug solution as solid particles. Therefore, the organic phase cannot be sterilized and filtered. Nevertheless, the method of comparative example a1 can also produce sustained-release microspheres with acceptable drug loading (23.64%) and encapsulation efficiency (82.32%). Most of the API dispersed in the form of particles in the suspension can also be finally encapsulated in the PLGA microspheres. However, according to Figure 4 and Figure 5 It can be seen that the sustained-release microspheres prepared in comparative example a1 are irregularly spherical in microscopic view, with poor size uniformity, uneven particle size distribution, and obvious differences in transparency between different microspheres, indicating that there are significant differences in the drug loading of different microspheres. Irregular morphology and size and uneven drug loading will have an adverse effect on the stable release of drugs. Figure 6 As shown, the release curve of the comparative example a1 sample also verifies this point. The triamcinolone acetonide raw material is released quickly in the early stage and slowly in the later stage, which is not conducive to maintaining a stable effective concentration of the drug in the human body.

[0075] The preparation method of comparative example b1 adopts the scheme of making the raw material drug into a soluble salt. Triamcinolone acetonide acetate can be dissolved in dichloromethane to form an organic phase homogeneous solution, so the organic phase can be sterilized and filtered. However, after using the soluble salt of triamcinolone acetonide, the drug loading (21.65%) and encapsulation rate (70.76%) of the obtained sustained-release microspheres were significantly reduced compared to the suspension drug. A decrease in the drug loading of the sustained-release microspheres will lead to a decrease in the drug concentration in the microspheres, thereby affecting the therapeutic effect, and also shortening the dosing cycle and reducing the convenience of medication for patients; a decrease in the encapsulation rate will make it easier for the drug to be released from the microspheres, causing excessive drug release in the early stage of medication, thereby increasing the risk of side effects. A decrease in the encapsulation rate also leads to a shortened dosing cycle, destroying the convenience of medication. From Figure 7 and 8 From the electron microscope photos and particle size distribution diagram shown, it can be seen that the microspheres prepared by the process of triamcinolone acetonide acetate soluble salt have very different sizes, and most of them are irregular spherical and have adhesion. Figure 6 It can also be seen from the release curve shown that the raw material triamcinolone acetonide acetate of the comparative example b1 sample is released rapidly in the early stage, there is an obvious burst release phenomenon, and the sustained release effect is not good.

[0076] The preparation method of comparative example c1 adopts the scheme of dissolving triamcinolone acetonide in a mixed solvent composed of acetone and dichloromethane. It is observed that the raw material triamcinolone acetonide is completely dissolved in the mixed solvent to form an organic phase homogeneous solution, so the organic phase can be sterilized and filtered. Although the introduction of the mixed solvent formed by acetone can also solve the dissolution problem of the raw material, according to Figure 3 The test results show that compared with the suspension solution, the drug loading (20.15%) and encapsulation efficiency (65.24%) of the microspheres prepared by this method have decreased significantly, which will affect the efficacy, increase the risk of side effects, and shorten the administration cycle. In addition, due to the use of composite solvents, the solvent is more difficult to remove during the preparation process, resulting in a significant increase in solvent residues and an increased risk of drug side effects. Fig. 9 It can also be seen from the electron microscope photo shown that due to excessive residual solvent, the microspheres are severely adhered to each other and the surface is rough. Fig.10 It can also be seen from the particle size distribution diagram that the particle size distribution of the microspheres prepared by this process is uneven and the overall size is small. Figure 6 It can also be seen from the release curve shown that the burst release phenomenon of the raw material drug of the comparative example c1 sample is very serious during the release process.

[0077] The preparation method of comparative example d1 adopts the scheme of adding an auxiliary agent to promote drug dissolution, and the auxiliary agent used is sodium dodecyl sulfate. Sodium dodecyl sulfate is a surfactant. After being added to the organic phase, it is observed that the raw material drug triamcinolone acetonide can be completely dissolved in dichloromethane to form an organic phase homogeneous solution, so the organic phase can be sterilized and filtered. Figure 3 The test results show that the drug loading (21.35%) and encapsulation efficiency (79.64%) of the microspheres solubilized with sodium dodecyl sulfate decreased to a certain extent compared with the suspension solution, which has a certain negative impact on the patient's medication. Fig.11 and Fig.12 It can be seen from the electron microscope photos and particle size distribution diagram that the sustained-release microspheres prepared in comparative example d1 are irregular spherical, with some adhesion between each other, and the size of the microspheres is very uneven. The morphology and size of the microspheres vary greatly, which can easily cause unstable release of the drug. Figure 6 As shown, it can be seen from the release curve of the comparative example d1 sample that the drug is released rapidly in the early stage, there is an obvious burst release phenomenon, and the drug release cycle is short, which is not conducive to maintaining a stable effective concentration of the drug in the human body and is not convenient for patients to take the drug.

[0078] The preparation method of Example 1 also adopts the scheme of adding an auxiliary agent that promotes drug dissolution. The auxiliary agent used is dioctyl sodium sulfosuccinate. It is observed that the raw material drug triamcinolone acetonide is completely dissolved in dichloromethane to form an organic phase homogeneous solution, so the organic phase can be subjected to a sterilization filtration operation. Surprisingly, as a surfactant, dioctyl sodium sulfosuccinate not only promotes the complete dissolution of the triamcinolone acetonide raw material drug, but also causes significant changes in the encapsulation and release behavior of the drug. Previously, triamcinolone acetonide was completely dissolved in the organic phase through various methods such as forming a soluble salt, using a mixed solvent, and adding an auxiliary agent sodium dodecyl sulfate, but ultimately resulted in varying degrees of decrease in drug loading and encapsulation efficiency, affecting drug efficacy, increasing drug side effects, and shortening the administration cycle. The sustained-release microspheres prepared under the solubilization effect of dioctyl sodium sulfosuccinate, such as Figure 3 As shown in the figure, compared with the suspension solution, not only did the drug loading (24.95%) and encapsulation efficiency (98.85%) not decrease, but also increased significantly, especially the encapsulation efficiency increased significantly to nearly complete encapsulation. Fig.13 and Fig.14 The electron microscope photos and particle size distribution diagrams shown also show that the microspheres prepared by this process have uniform color, smooth and round surface, normal particle size distribution, no obvious adhesion between the microspheres, and uniform dispersion. Most importantly, the drug burst release phenomenon that is common after solubilization of triamcinolone acetonide has also been significantly improved in the sample of Example 1. Figure 6The release curve of the sample in Example 1 shows that the drug release is steady and slow, there is no obvious burst release phenomenon in the early stage, and the drug release period is also significantly extended, which is conducive to maintaining a stable effective concentration of the drug in the human body and is more convenient for patients to take the drug.

[0079] In order to further study the reasons why the samples in Example 1 have obvious differences in drug release behavior, the present invention further uses GPC gel chromatography to detect the molecular weight of the polymer in the above samples, and the results are summarized in Fig.15 The GPC gel chromatograms of each sample are as follows: Figures 16 to 20 As shown. The results show that the molecular weight of the polymer forming the main body of the microspheres prepared by the scheme of completely dissolving triamcinolone acetonide by forming soluble salts, using mixed solvents, adding the auxiliary agent sodium dodecyl sulfate, etc. is relatively small, and the weight average molecular weight is concentrated between 30kDa and 45kDa. The weight average molecular weight of the polymer prepared by adding dioctyl sodium sulfosuccinate for solubilization is close to 100kDa, which is significantly higher than other schemes. Due to the increase in polymer molecular weight, the structural stability of the microspheres themselves is improved, and the combination of the drug and the microsphere body is strengthened, thereby delaying the release of the drug. Analysis may be that the sulfonated succinic acid group in dioctyl sodium sulfosuccinate is embedded in the interior of the high molecular weight polymer, which increases the binding force between polylactic acid and glycolic acid in PLGA, slowing down the degradation rate of the polymer.

[0080] In view of the problem that the raw material drug is not easy to dissolve to form an organic homogeneous solution during the preparation of triamcinolone acetonide sustained-release microspheres, thereby affecting the sterilization filtration operation, the present invention also studies various methods of making the raw material drug into a soluble salt, using a mixed solvent, and adding a solubilizer and a co-solvent.

[0081] Regarding the preparation of soluble salts, the present invention studies the process of preparing microspheres using triamcinolone acetonide acetate raw materials. Fig.21 Weigh the prescription amount shown, dissolve PLGA in DCM, then do not add or selectively add sodium dioctyl succinate sulfonate or sodium dodecyl sulfate to dissolve, and finally add triamcinolone acetate, shake and ultrasonicate for 10 minutes to obtain an organic phase. Add polyvinyl alcohol to purified water according to the prescription amount, heat and stir to completely dissolve, and obtain an aqueous phase. Under homogenous conditions, slowly add the organic phase to the aqueous phase and continue homogenizing for 5 minutes. After that, put the drug solution in a fume hood and use magnetic stirring to solidify for 3 hours. After the solidification is completed, wash with purified water, and put the washed microspheres into a freeze dryer for freeze drying to obtain a sustained-release microsphere sample.

[0082] The results showed that although triamcinolone acetate was more soluble than triamcinolone acetonide and the organic phase formed was a homogeneous solution, it was found that no matter how the prescription and process parameters were adjusted, the prepared microspheres had the problem of unqualified encapsulation efficiency. Fig. 22As shown in the figure, it can be seen from the encapsulation rate data that a large amount of raw materials are free on the surface of the microspheres, which will significantly accelerate the release rate of the drug and form a serious burst release phenomenon. Analysis may be that after the soluble salt is made, the binding force between the raw material and the high molecular polymer forming the microspheres is weakened, and effective drug loading cannot be achieved.

[0083] Regarding the use of mixed solvents, it is known that triamcinolone acetonide is only soluble in acetone and has poor solubility in other solvents. The present invention studies the use of acetone instead of dichloromethane and the use of a mixed solvent of acetone and dichloromethane to dissolve triamcinolone acetonide raw materials to prepare microspheres. Fig.23 Weigh the prescription amount shown, dissolve PLGA in DCM, add triamcinolone acetonide, shake and ultrasonicate for 10 minutes to obtain an organic phase. Add polyvinyl alcohol to purified water according to the prescription amount, stir and heat with vibration to completely dissolve, and obtain an aqueous phase. Under homogenization conditions, slowly add the organic phase to the aqueous phase and continue homogenizing for 5 minutes. After that, put the drug solution in a fume hood and use magnetic stirring to solidify for 3 hours. After solidification, wash with purified water, and put the washed microspheres into a freeze dryer for freeze drying to obtain a sustained-release microsphere sample.

[0084] The results show that when the amount of acetone added is low, the raw material still cannot be completely dissolved in the organic phase. Although the solubility problem of the raw material can be solved by increasing the amount of acetone, the encapsulation efficiency and drug loading will also decrease, and the solvent residue will increase significantly. Fig.24 As shown, when using acetone or a mixed solvent of acetone and dichloromethane, the encapsulation efficiency and drug loading are significantly reduced with the increase of the acetone ratio, and the average particle size of the microspheres is also small. Moreover, due to the introduction of acetone, it is difficult to completely remove it during the preparation process, and new residual solvents are added.

[0085] Regarding the addition of cosolvents or solubilizers, the present invention tried four other surfactants including sodium lauryl sulfate, poloxamer, tyloxapol and Tween 80. Fig.25 Weigh the prescription amount shown, dissolve PLGA in DCM, then add the surfactant, and finally add triamcinolone acetonide, shake and ultrasonicate for 10 minutes to obtain the organic phase. Add polyvinyl alcohol to purified water according to the prescription amount, heat and stir to completely dissolve, and obtain the aqueous phase. Under homogenization conditions, slowly add the organic phase to the aqueous phase and continue homogenization for 5 minutes. After that, put the drug solution in a fume hood and use magnetic stirring to solidify for 3 hours. After the solidification is completed, wash with purified water, and put the washed microspheres into a freeze dryer for freeze drying to obtain a sustained-release microsphere sample.

[0086] The results are as follows Fig.26As shown in the figure, the addition of sodium dodecyl sulfate can also greatly improve the solubility of triamcinolone acetonide, making the organic phase form a homogeneous solution, while the other three surfactants did not significantly improve the solubility of the raw materials and could not make the organic phase form a homogeneous solution. On the other hand, although the organic phase formed a homogeneous solution under the action of sodium dodecyl sulfate, the test results showed that the drug loading and encapsulation efficiency of the microspheres prepared by solubilization with sodium dodecyl sulfate were significantly reduced, which could not meet the requirements of practical applications.

[0087] It can be seen that, in order to solve the problem of low solubility of triamcinolone acetonide, the above-mentioned multiple schemes such as preparing soluble salts, using mixed solvents and adding solubilizers or co-solvents can mostly solve the dissolution problem of triamcinolone acetonide from a unilateral perspective. However, no matter how the scheme is adjusted, the prepared sustained-release microspheres cannot achieve the ideal drug release effect and are difficult to meet the actual use requirements.

[0088] In order to further verify the feasibility of the dioctyl sodium sulfosuccinate solubilization scheme, the present invention attempted the following Fig. 27 Multiple schemes with different ratios are shown. PLGA was weighed according to the prescription amount, and then sodium dioctyl succinate sulfonate was added to dissolve it. Finally, triamcinolone acetonide was added, shaken and ultrasonicated for 10 minutes to obtain an organic phase. Polyvinyl alcohol was added to purified water according to the prescription amount, heated and stirred to completely dissolve, and an aqueous phase was obtained. Under homogenous conditions, the organic phase was slowly added to the aqueous phase, and homogenization was continued for 5 minutes. After that, the drug solution was placed in a fume hood and solidified for 3 hours using magnetic stirring. After the solidification was completed, it was washed with purified water, and the washed microspheres were placed in a freeze dryer for freeze drying to obtain a sustained-release microsphere sample.

[0089] The results are as follows Fig.28 , Fig.29 , Fig.30 As shown, the various test indicators of Examples 1, 2, 3, 6, and 7 are relatively ideal, indicating that the ratio of dioctyl sodium sulfosuccinate to the raw material drug is kept in the range of 1:2 to 2:1 to achieve ideal results. Too low a ratio of dioctyl sodium sulfosuccinate will affect the solubilization effect and thus affect the quality of the microspheres, while too high a ratio will slow down the drug release rate of the microspheres and fail to maintain an effective drug concentration in the patient's body.

[0090] In the above cases, drug loading and encapsulation efficiency tests were performed using HPLC; particle size and particle size distribution were tested using a laser particle size analyzer; residual solvents were tested using gas chromatography; and the molecular weight of the polymer in the sustained-release microspheres was tested using GPC gel chromatography.

[0091] The above embodiments are exemplary, and their purpose is to illustrate the technical concept and features of the present invention so that people familiar with the technology in this field can understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A triamcinolone acetonide sustained-release microsphere, characterized in that: The invention has a microsphere body formed by coagulation of a polylactic acid-glycolic acid copolymer and a triamcinolone acetonide API embedded in the microsphere body, wherein the microsphere body is formed by precipitation and coagulation of the polylactic acid-glycolic acid copolymer from an emulsion containing both the polylactic acid-glycolic acid copolymer and the triamcinolone acetonide API, the triamcinolone acetonide API is embedded in the microsphere body when the polylactic acid-glycolic acid copolymer coagulates, and the weight average molecular weight Mw of the polymer in the microsphere is controlled within the range of 85 kDa to 125 kDa; The triamcinolone acetonide sustained-release microspheres are obtained by mixing an aqueous phase and an oil phase containing a triamcinolone acetonide API to form an emulsion and solidifying the mixture. Dioctyl sodium sulfosuccinate is added to the oil phase, and the weight ratio of dioctyl sodium sulfosuccinate to the triamcinolone acetonide API is controlled to be 1:2 to 2:1, so that the weight average molecular weight Mw of the polymer in the microspheres is controlled to be within the range of 85 kDa to 125 kDa. The oil phase is a homogeneous solution containing the following components: Triamcinolone acetonide 0.7-0.9 weight portion; 0.4-1.6 parts by weight of dioctyl sodium sulfosuccinate; 15-20 parts by weight of dichloromethane; 1.7-2.3 parts by weight of polylactic acid-glycolic acid copolymer; The aqueous phase is a homogeneous solution containing the following components: 1.2-1.8 parts by weight of stabilizer; 350~450 parts by weight of purified water 2. The triamcinolone acetonide sustained-release microspheres according to claim 1, characterized in that: The drug loading of the triamcinolone acetonide sustained-release microspheres is in the range of 24.5% to 25.0%, and the residual solvent rate is ≤0.04%; and / or The particle size D10 of the triamcinolone acetonide sustained-release microspheres is in the range of 24.5 μm to 28.0 μm, and the particle size D90 is in the range of 70.0 μm to 72.5 μm.

3. A triamcinolone acetonide sustained-release preparation for treating arthritis pain, characterized in that: The triamcinolone acetonide sustained-release preparation contains the triamcinolone acetonide sustained-release microspheres according to claim 1 or 2.

4. The triamcinolone acetonide sustained-release preparation for treating arthritis pain according to claim 3, characterized in that: The triamcinolone acetonide sustained-release preparation is a suspension prepared by uniformly mixing a sterile diluent with triamcinolone acetonide sustained-release microspheres, wherein the sterile diluent is an aqueous solution containing 0.9% by mass of sodium chloride, 0.5% by mass of sodium carboxymethyl cellulose and 0.1% by mass of Tween 80.

5. A method for aseptically preparing triamcinolone acetonide sustained-release microspheres, characterized in that: Step 1, preparing an organic phase homogeneous solution containing solvent dichloromethane, triamcinolone acetonide raw material, polylactic acid-glycolic acid copolymer and dioctyl sodium sulfosuccinate, and obtaining a sterile organic phase by filtering and sterilizing; Step 2, preparing a homogeneous aqueous solution containing a stabilizer, and filtering and sterilizing to obtain a sterile aqueous phase; Step 3, under homogenization conditions, adding the organic phase obtained in step 1 to the aqueous phase obtained in step 2, and continuing to homogenize to obtain an emulsion; Step 4, the emulsion prepared in step 3 is kept in a stirring state, and the emulsion droplets dispersed in the emulsion are solidified to form crude microspheres, and the crude microspheres are washed and freeze-dried to obtain triamcinolone acetonide sustained-release microspheres; The organic phase is a homogeneous solution containing the following components: Triamcinolone acetonide 0.7-0.9 weight portion; 0.4-1.6 parts by weight of dioctyl sodium sulfosuccinate; 15-20 parts by weight of dichloromethane; 1.7-2.3 parts by weight of polylactic acid-glycolic acid copolymer; The weight ratio of dioctyl sodium sulfosuccinate to triamcinolone acetonide is in the range of 1:2 to 2:1; The aqueous phase is a homogeneous solution containing the following components: 1.2-1.8 parts by weight of stabilizer; 350~450 parts by weight of purified water 6. The aseptic preparation method of triamcinolone acetonide sustained-release microspheres according to claim 5, characterized in that: The triamcinolone acetonide used in the organic phase is a non-sterile triamcinolone acetonide bulk drug.

7. The aseptic preparation method of triamcinolone acetonide sustained-release microspheres according to claim 6, characterized in that: The stabilizer used in preparing the aqueous phase is polyvinyl alcohol.

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