A high drug loading sustained-release microsphere and a preparation method and application thereof

Abstract

The application discloses a high-drug-loading sustained-release microsphere and a preparation method and application thereof, and the raw materials of the microsphere comprise an active drug, a carrier material, a foaming pore-forming agent and a surfactant. In the microsphere preparation process, the SPG membrane emulsification method is adopted and the foaming pore-forming agent is added, so that the drug loading and the encapsulation efficiency of the microsphere can be effectively improved, the active drug can be released immediately and continuously and slowly, the injection amount and the injection volume of the microsphere are reduced, the release lag period of the drug-loaded microsphere is eliminated, and no oral supplement preparation needs to be combined in the early injection period, so that the patient compliance is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of pharmaceutical preparations, and particularly relates to a high drug-loading sustained-release microsphere, a preparation method thereof, and an application thereof. Background Art

[0002] As a drug carrier, microspheres can well entrap drugs, control the drug release rate, improve the drug utilization rate, reduce the harm of drugs to the human body, maintain an effective blood drug concentration within a relatively long time range, thereby significantly reducing the dosing frequency and improving the medication compliance of patients. Therefore, drug-loaded microspheres have been widely studied and applied in the medical field. Currently, nearly 20 kinds of microsphere preparations are used for clinical treatment, and most of them are prepared by the emulsification method. The process of preparing microspheres by the emulsification method mainly includes two steps: the generation and solidification of emulsion droplets. Among them, the solidification rate of microspheres will affect the amount of drug diffusing into the continuous phase and thus affect the encapsulation efficiency.

[0003] The drug-loading amount of microspheres is directly related to the designed clinical dosing dose. Generally, the higher the drug-loading amount, the less the dosing amount. The encapsulation efficiency is more suitable for evaluating the preparation process level. Generally, the higher the encapsulation efficiency, the better the process. In addition, at the same dosing dose, increasing the drug-loading amount of microspheres can significantly reduce the amount of excipients used, reduce the amount of polymer used, reduce the injection volume, and reduce the side effects caused by excipients and their degradation products. Therefore, developing a preparation strategy for high drug-loading microspheres is of great significance for improving patient compliance and promoting the clinical application of microsphere preparations.

[0004] The currently clinically used risperidone microsphere injection Risperdal Consta (Chinese name: Hengde) is the first long-acting atypical antipsychotic preparation, which was developed by Janssen and approved by the FDA for marketing in 2003. This preparation is injected intramuscularly once every two weeks, reducing the dosing frequency and improving the disadvantages of frequent dosing of traditional preparations. However, its rapid release occurs at 4-6 weeks, and there is a drug release stagnation period in the first three weeks. After four injections, the drug steady state is reached approximately at 6-8 weeks. Therefore, when patients inject this preparation in the first three weeks, they must take oral tablets simultaneously to achieve the therapeutic effect. After three weeks, the dose is adjusted. In addition, it is difficult to accurately convert the dose between the oral preparation and the long-acting injectable microspheres, which also means that the PK characteristics are very complex, and it is impossible to avoid the peak and trough concentrations caused by taking drugs, resulting in inconvenient clinical use and poor patient compliance. The reason for the drug release lag period of this preparation is that PLGA with a molecular weight as high as 150,000 was selected. The selection of high molecular weight PLGA may be due to the limitation of its preparation technology to avoid the sudden release of drugs.

[0005] To address these issues, researchers have continuously conducted related studies. Chen Guoguang et al. prepared risperidone microspheres using low molecular weight PLGA (50:50, molecular weight 30,000) polymer material, achieving a drug loading of 18%. These microspheres maintained stable blood drug concentrations in vivo for 5-20 days, but the drug loading was low, and the rate of drug diffusion from the inside to the outside was still low in the initial injection stage. In a study of a risperidone microsphere composition that could induce sustained release for more than 4 weeks, disclosed in patent CN101653422A, the release stagnation period was eliminated by using uncapped PLGA and increasing the drug loading to over 45%. However, the formulation stability was poor; after long-term storage, the in vivo release behavior of the microspheres changed significantly. Furthermore, drug crystals precipitated during scaled-up production. In the study disclosed in CN106822042A, organic lipophilic substances such as fatty acids were added as release regulators during the microsphere preparation process to create pores on the surface and inside of the microspheres, increase the permeability of body fluids, and promote the dissolution of risperidone. However, the organic lipophilic substances need to be converted into carbon dioxide and water in the body before pores can be created, resulting in inconsistent pore formation time inside and outside the microspheres.

[0006] Therefore, for drug-loaded microspheres, it is necessary to find a simple and efficient preparation method to improve the drug loading and encapsulation efficiency, avoid drug burst release, and eliminate the release lag period in order to improve patient compliance and thus promote the clinical application of drug-loaded microspheres. Summary of the Invention

[0007] One objective of this invention is to provide a high-drug-loading sustained-release microsphere, the raw materials of which include: active drug, carrier material, foaming pore-forming agent, and surfactant;

[0008] The active drugs include, but are not limited to, risperidone, triamcinolone, progesterone, celecoxib, lidocaine, doxorubicin, galantamine, ropivacaine, rifampin, donepezil, curcumin, lovastatin, minocycline, galantamine, triptolide, ketoconazole, rivastigmine, bupivacaine, nimodipine, itraconazole, dexamethasone, and moxifloxacin;

[0009] The carrier material includes, but is not limited to, PLGA and / or PLA;

[0010] The foaming pore-forming agent includes, but is not limited to, NH4HCO3, NaHCO3, and H2O2;

[0011] The surfactants include, but are not limited to, polyvinyl alcohol, sodium lauryl sulfate, sodium lauryl sulfonate, Tween 80, and Tween 20;

[0012] The active drug content in the microspheres is 15% to 60%, and the mass ratio of the active drug to the carrier material is 1:10 to 2:1.

[0013] A second objective of this invention is to provide a method for preparing the above-mentioned high drug loading sustained-release microspheres, comprising the following steps:

[0014] Step 1: Dissolve the active drug and carrier material in an organic solvent to form an oil phase;

[0015] Step 2: Dissolve the foaming pore-forming agent in water to form an internal aqueous phase;

[0016] Step 3: Add the internal aqueous phase dropwise to the oil phase and emulsify under ice bath conditions to obtain a W1 / O type primary emulsion;

[0017] Step 4: Dissolve the surfactant in water to form an external aqueous phase;

[0018] Step 5: Pour the W1 / O type primary emulsion into the SPG storage tank, and let it enter the external aqueous phase through the membrane tube at 15-25℃ to form a W1 / O / W2 type double emulsion. Stir at 15-25℃ to evaporate the organic solvent, collect the microspheres by centrifugation, wash and dry to obtain sustained-release microspheres.

[0019] Furthermore, in step 1, the mass ratio of the active drug to the carrier material is 1:10 to 2:1, and the concentration of the carrier material in the organic solvent is 20 mg / mL to 100 mg / mL.

[0020] Furthermore, in step 2, the concentration of the foaming pore-forming agent in the internal aqueous phase is 10 mg / mL to 70 mg / mL.

[0021] Furthermore, in step 4, the concentration of the surfactant in the external aqueous phase is 0.1% to 3% w / v.

[0022] Furthermore, the volume ratio of the internal aqueous phase to the oil phase is 1:20 to 1:4, and the volume ratio of the oil phase to the external aqueous phase is 1:5 to 1:100.

[0023] A third objective of this invention is to provide a pharmaceutical composition in which the aforementioned microspheres are used as the active ingredient.

[0024] This invention employs SPG membrane emulsification and adds a foaming pore-forming agent during microsphere preparation, which can improve the drug loading and encapsulation efficiency of the microspheres. Furthermore, adding different concentrations of pore-forming agent yields porous microspheres with varying porosities, and adjusting the ratio of PLA to PLGA in the polymer can regulate the release rate and eliminate drug release lag.

[0025] The present invention has the following beneficial effects:

[0026] (1) In this invention, the selected foaming pore-forming agent generates gases such as CO2 and NH3 during solvent evaporation. The gas generation process promotes pore formation on the one hand and accelerates the solvent evaporation / microsphere solidification process on the other. The rapid precipitation of PLA / PLGA and active drugs helps to reduce the diffusion of drugs from emulsion droplets and microspheres and inhibits drug crystallization. However, when foaming pore-forming agents are added and combined with mechanical stirring and other methods to prepare porous microspheres, at the same stirring speed, due to the rapid generation of gas, the organic solvent in the oil phase will evaporate rapidly before the emulsion is completely formed into round emulsion droplets, resulting in non-round microspheres. In contrast, when using penetrating pore-forming agents and other methods combined with SPG membrane emulsification to prepare microspheres, the dispersed phase quickly passes through the SPG membrane pores and uses surface tension to quickly generate uniform emulsion droplets. Under the same solidification conditions (external aqueous phase volume, temperature, stirring speed), the time from emulsification to complete solidification of microspheres is shorter and the sphericity is higher, but the drug loading of the prepared microspheres is not significantly improved. Therefore, combining the gas-generating characteristics of foaming pore-forming agents with the rapid emulsion formation and solidification characteristics of SPG membrane emulsification can reduce drug diffusion from emulsion droplets and microspheres, allowing more drug to remain within the microspheres, thus achieving higher drug loading and encapsulation efficiency. Furthermore, the microspheres exhibit spherical shape and high sphericity. The method of preparing porous microspheres using SPG membrane emulsification combined with foaming pore-forming agents is simple, applicable to a variety of lipid-soluble drugs, and has strong versatility.

[0027] (2) The microspheres provided by this invention have high drug loading and high encapsulation efficiency. Taking risperidone microspheres as an example, the drug loading of commercially available risperidone microspheres from Hengde is 38-40%, while the sustained-release risperidone microspheres provided by this invention can reach a maximum drug loading of 60.1%. Compared with solid microspheres, the maximum drug loading increases from 25.2% to 44.2%, and the maximum encapsulation efficiency increases from 50.4% to 88.4%. Compared with microspheres prepared by mechanical stirring, microspheres prepared by SPG film emulsification combined with foaming pore-forming agents have higher sphericity and roundness. The increased drug loading and encapsulation efficiency of the microspheres reduce the amount of polymer used, reduce the injection volume, and mitigate the side effects caused by excipients and their degradation products, thereby increasing patient compliance and safety.

[0028] (3) The microspheres of this invention can be used to solve the problem of delayed drug release. Taking risperidone microspheres as an example, Hengde risperidone microspheres, launched in 2003, are administered intramuscularly every two weeks, which reduces the dosing frequency and improves efficacy compared to oral tablets. However, the rapid release of this formulation occurs in 4-6 weeks, with a drug release stagnation period in the first three weeks. After four injections, the drug reaches steady state in approximately 6-8 weeks. Therefore, patients must take oral tablets concurrently with the injection of this drug in the first three weeks to achieve the therapeutic effect, and then adjust the dosage after three weeks. The dosage between oral formulations and long-acting injectable microspheres is difficult to accurately convert, which also means that the PK characteristics are very complex, inconvenient for clinical use, and patient compliance remains poor. Microsphere drug release is achieved through diffusion and degradation mechanisms. For poorly soluble drugs such as risperidone, the high porosity and large specific surface area of ​​porous microspheres are conducive to drug diffusion and penetration into body fluids. In addition, risperidone is solidified and dispersed in solid PLGA and / or PLA through solvent evaporation, which can be considered an amorphization process in which crystalline drugs are transformed into an amorphous state. The use of SPG membrane emulsification combined with foaming pore-forming agents enables rapid solvent evaporation, resulting in rapid solidification of microspheres. Individual risperidone molecules do not have enough time to approach and move. Therefore, most of risperidone still exists in amorphous or molecular form in the PLGA and / or PLA matrix. Compared with crystalline drugs, its release rate is accelerated, thereby eliminating in vitro release lag and enabling immediate release after administration without the need for oral supplementation.

[0029] (4) In the preparation process of the microspheres of the present invention, by adjusting the concentration of the pore-forming agent, the porosity and pore size of the drug-loaded microspheres can be changed on the one hand, and the gas generation rate can be adjusted on the other hand, affecting the solidification rate and thus affecting the crystallization of the active drug, ultimately controlling the release rate of the active drug from the microspheres. Porous microspheres give the active drug specific drug release characteristics. The SPG membrane emulsification method combined with different concentrations of foaming pore-forming agents not only accelerates the drug release rate, enabling the drug to be released rapidly in a short time to exert its therapeutic effect without a release lag period, but also allows for the acquisition of microspheres with the target release rate by adjusting the concentration of the pore-forming agent and the ratio of PLA to PLGA in the polymer, so as to slowly release the drug in the later stage to maintain the efficacy, reduce the frequency of administration, and improve patient compliance. Attached Figure Description

[0030] Figure 1 The images shown are SEM images of risperidone porous microspheres from Example 1. A represents multiple microspheres, and B represents a single microsphere.

[0031] Figure 2 Optical microscope images of risperidone porous microspheres from Examples 3 and 4.

[0032] Figure 3 In the image, A is a SEM image of the risperidone porous microspheres of Example 3, and B is a SEM image of the risperidone porous microspheres of Example 23.

[0033] Figure 4 The images show the in vitro release curves of risperidone porous microspheres from different embodiments. Detailed Implementation

[0034] The preferred embodiments of the present invention will now be described in detail with reference to specific examples. It should be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from its spirit and essence.

[0035] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0036] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0037] Example 1

[0038] Weigh 75 mg of PLA 207S and 75 mg of risperidone and dissolve them in 1.5 mL of dichloromethane as the oil phase. Weigh 4.5 mg of NH4HCO3 and dissolve it in 0.15 mL of water as the inner aqueous phase. Pour the inner aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into an SPG storage tank and apply a pressure of 2 kPa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain risperidone PLA porous microspheres.

[0039] Compare with Example 1

[0040] Weigh 75 mg of PLA 207S and 75 mg of risperidone and dissolve them in 1.5 mL of dichloromethane as the oil phase. Pour the oil phase into an SPG storage tank and apply a pressure of 2 kPa at 15–25 °C to allow it to pass through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent. Collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain risperidone PLA solid microspheres.

[0041] Example 2

[0042] Weigh 75 mg of PLGA 755S and 75 mg of risperidone and dissolve them in 1.5 mL of dichloromethane as the oil phase. Weigh 4.5 mg of NH4HCO3 and dissolve it in 0.15 mL of water as the inner aqueous phase. Pour the inner aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into an SPG storage tank. Apply a pressure of 2 kPa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent. Collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain risperidone PLGA porous microspheres.

[0043] Compare with Example 2

[0044] Weigh 75 mg of PLGA 755S and 75 mg of risperidone and dissolve them in 1.5 mL of dichloromethane as the oil phase. Pour the oil phase into an SPG storage tank and apply a pressure of 2 kPa at 15–25 °C to allow it to pass through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent. Collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain risperidone PLGA solid microspheres.

[0045] Example 3

[0046] Weigh 75 mg of PLA207S and PLGA755S (PLA mass percentage 50%), dissolve 75 mg of risperidone in 1.5 mL of dichloromethane as the oil phase, and weigh 7.5 mg of NH4HCO3 in 0.15 mL of water as the inner aqueous phase. Pour the inner aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into an SPG storage tank, and apply a pressure of 2 kPa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain risperidone PLGA porous microspheres.

[0047] Compare with Example 3

[0048] Weigh 75 mg of PLA 207S and PLGA 755S (PLA mass percentage 50%), dissolve 75 mg of risperidone in 1.5 mL of dichloromethane as the oil phase, pour the oil phase into an SPG storage tank, apply a pressure of 2 kPa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution, stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water and vacuum dry to obtain risperidone PLA / PLGA solid microspheres.

[0049] Example 4

[0050] Weigh 75 mg of PLA 207S and PLGA 755S (PLA mass percentage 50%), dissolve 75 mg of risperidone in 1.5 mL of dichloromethane as the oil phase, and weigh 7.5 mg of NH4HCO3 in 0.15 mL of water as the aqueous phase. Pour the aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into 135 mL of 1% PVA (w / v) aqueous solution and magnetically stir at 350 rpm to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain risperidone PLGA porous microspheres.

[0051] Example 5

[0052] Weigh 75 mg of PLA 207S and PLGA 755S (PLA mass percentage 50%), dissolve 75 mg of risperidone in 1.5 mL of dichloromethane as the oil phase, and weigh 7.5 mg of NH4HCO3 in 0.15 mL of water as the aqueous phase. Pour the aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into 135 mL of 1% PVA (w / v) aqueous solution and disperse at 2500 rpm to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain risperidone PLGA porous microspheres.

[0053] Example 6

[0054] Weigh 75 mg of PLA207S and PLGA755S (PLA mass percentage 50%), dissolve 75 mg of risperidone in 1.5 mL of dichloromethane as the oil phase, and weigh 7.5 mg of NaCl in 0.15 mL of water as the inner aqueous phase. Pour the inner aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into an SPG storage tank, and apply a pressure of 2 kPa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain risperidone PLGA porous microspheres.

[0055] Example 7

[0056] Weigh 75 mg of PLA 207S and PLGA 755S (PLA mass percentage 50%), dissolve 75 mg of risperidone in 1.5 mL of dichloromethane as the oil phase, and weigh 7.5 mg of poloxamer in 0.15 mL of water as the inner aqueous phase. Pour the inner aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into an SPG storage tank, and apply a pressure of 2 kPa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain risperidone PLGA porous microspheres.

[0057] Examples 8-17

[0058] The prescription is shown in Table 1.

[0059] Table 1 Formulations of Risperidone PLA / PLGA Microspheres in Examples 8-17

[0060]

[0061] The microsphere preparation steps in Examples 8-17 are the same as in Example 3.

[0062] Example 18

[0063] Weigh 75 mg of PLA 207S and PLGA 755S (PLA mass percentage 50%), and dissolve 25 mg of triamcinolone acetonide in 1.5 mL of dichloromethane as the oil phase. Weigh 7.5 mg of NH4HCO3 in 0.15 mL of water as the inner aqueous phase. Pour the inner aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into an SPG storage tank, and apply a pressure of 2 kPa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain triamcinolone acetonide PLGA porous microspheres.

[0064] Compare with Example 4

[0065] Weigh 75 mg of PLA 207S and PLGA 755S (PLA mass percentage 50%), and dissolve 25 mg of triamcinolone acetonide in 1.5 mL of dichloromethane as the oil phase. Pour the oil phase into an SPG storage tank. At 15–25 °C, apply a pressure of 2 kPa to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent. Collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain triamcinolone acetonide PLA / PLGA solid microspheres.

[0066] Example 19

[0067] Weigh 75 mg of PLA 207S and PLGA 755S (PLA mass percentage 50%), dissolve 75 mg of progesterone in 1.5 mL of dichloromethane as the oil phase, and weigh 7.5 mg of NH4HCO3 in 0.15 mL of water as the inner aqueous phase. Pour the inner aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into an SPG storage tank, and apply a pressure of 2 kPa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain progesterone PLGA porous microspheres.

[0068] Compare with Example 5

[0069] Weigh 75 mg of PLA 207S and PLGA 755S (PLA mass percentage 50%), dissolve 75 mg of progesterone in 1.5 mL of dichloromethane as the oil phase, pour the oil phase into an SPG storage tank, apply a pressure of 2 kPa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution, stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water and vacuum dry to obtain progesterone PLA / PLGA solid microspheres.

[0070] Example 20

[0071] Weigh 75 mg of PLA 207S and PLGA 755S (PLA mass percentage 50%), dissolve 75 mg of celecoxib in 1.5 mL of dichloromethane as the oil phase, and weigh 7.5 mg of NH4HCO3 in 0.15 mL of water as the inner aqueous phase. Pour the inner aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into an SPG storage tank, and apply a pressure of 2 kPa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain celecoxib PLGA porous microspheres.

[0072] Example 21

[0073] Weigh 75 mg of PLA207S and PLGA755S (PLA mass percentage 50%), dissolve 75 mg of risperidone in 1.5 mL of dichloromethane as the oil phase, and weigh 7.5 mg of NaHCO3 in 0.15 mL of water as the inner aqueous phase. Pour the inner aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into an SPG storage tank, and apply a pressure of 2 Pa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain risperidone PLGA porous microspheres.

[0074] Example 22

[0075] Weigh 75 mg of PLA 207S and PLGA 755S (PLA mass percentage 50%), dissolve 75 mg of risperidone in 1.5 mL of dichloromethane as the oil phase, and weigh 7.5 mg of H2O2 in 0.15 mL of water as the inner aqueous phase. Pour the inner aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into an SPG storage tank, and apply a pressure of 2 kPa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain risperidone PLGA porous microspheres.

[0076] Example 23

[0077] Weigh 75 mg of PLA 207S and PLGA 755S (PLA mass percentage 50%), dissolve 75 mg of risperidone in 1.5 mL of dichloromethane as the oil phase, and weigh 1.5 mg of NH4HCO3 in 0.15 mL of water as the inner aqueous phase. Pour the inner aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into an SPG storage tank, and apply a pressure of 2 kPa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain risperidone porous microspheres.

[0078] Example 24

[0079] Weigh 75 mg of PLA 207S and PLGA 755S (PLA mass percentage 50%), dissolve 75 mg of risperidone in 1.5 mL of dichloromethane as the oil phase, and weigh 4.5 mg of NH4HCO3 in 0.15 mL of water as the inner aqueous phase. Pour the inner aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into an SPG storage tank, and apply a pressure of 2 kPa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain risperidone porous microspheres.

[0080] Example 25

[0081] Weigh 75 mg of PLA207S and PLGA 755S (PLA mass percentage 50%), and dissolve 75 mg of risperidone in 1.5 mL of dichloromethane as the oil phase. Weigh 6.0 mg of NH4HCO3 and dissolve it in 0.15 mL of water as the inner aqueous phase. Pour the inner aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into an SPG storage tank, and apply a pressure of 2 kPa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain risperidone porous microspheres.

[0082] Example 26

[0083] Weigh 75 mg of PLA 207S and PLGA 755S (PLA mass percentage 50%), dissolve 75 mg of risperidone in 1.5 mL of dichloromethane as the oil phase, and weigh 9.0 mg of NH4HCO3 in 0.15 mL of water as the inner aqueous phase. Pour the inner aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into an SPG storage tank, and apply a pressure of 2 kPa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain risperidone porous microspheres.

[0084] Example 27

[0085] Weigh 75 mg of PLA207S and PLGA755S (PLA mass percentage 50%), dissolve 75 mg of risperidone in 1.5 mL of dichloromethane as the oil phase, and weigh 10.5 mg of NH4HCO3 in 0.15 mL of water as the inner aqueous phase. Pour the inner aqueous phase into the oil phase and emulsify using a high-speed disperser at 8000 rpm for 3 min in an ice bath to obtain the W1 / O primary emulsion. Pour the W1 / O primary emulsion into an SPG storage tank, and apply a pressure of 2 kPa at 15–25 °C to force it through a 15 μm membrane tube into 135 mL of 1% PVA (w / v) aqueous solution to form a W1 / O / W2 type double emulsion. Stir at 350 rpm at 15–25 °C to evaporate the organic solvent, collect the microspheres by centrifugation, wash with water, and vacuum dry to obtain risperidone PLGA porous microspheres.

[0086] Test Example 1

[0087] Microsphere morphology

[0088] The morphology of the microspheres prepared in Example 3 was determined using scanning electron microscopy. Figure 1 As shown, the risperidone microspheres prepared in Example 3 are round and have a relatively uniform particle size distribution. The surface is uniformly distributed with pores of less than 1 μm, and all microspheres in the field of view are porous microspheres.

[0089] Test Example 2

[0090] Microsphere morphology

[0091] The microspheres prepared in Examples 3 and 4 were observed for morphology using an optical microscope. Figure 2 As shown, the risperidone microspheres prepared in Example 3 have a rounded morphology and good sphericity, while the microspheres prepared in Example 4 have poor sphericity. This indicates that using a foaming pore-forming agent combined with a stirring method results in poorly shaped porous microspheres. At the same stirring speed, due to the rapid generation of gas, the organic solvent in the oil phase evaporates quickly before the emulsion is fully formed into round droplets, resulting in non-round microspheres. In contrast, using a foaming pore-forming agent combined with an SPG membrane emulsifier yields microspheres with better sphericity and sphericity.

[0092] Test Example 3

[0093] Pore ​​state of microspheres prepared with different pore-forming agent concentrations

[0094] The microspheres prepared in Examples 3 and 23 were used to determine their morphology using scanning electron microscopy. Figure 3 As shown, the concentration of the pore-forming agent affects the pore state of porous microspheres. Microspheres prepared with a high concentration of pore-forming agent (A) have more pores than those prepared with a low concentration of pore-forming agent (B).

[0095] Test Example 4

[0096] Drug loading and encapsulation efficiency of microspheres

[0097] Accurately weigh 2 mg of risperidone porous microspheres prepared in Examples 1-19, 21-27 and the control example, place them in a 50 mL volumetric flask, add dichloromethane to completely dissolve them, and then dilute to volume with methanol. Using 279 nm as the detection wavelength for risperidone, filter through a 0.22 μm filter membrane and determine the drug content by ultraviolet-spectrum spectrophotometry. Calculate the drug loading and encapsulation efficiency of the microspheres according to the following formulas:

[0098] Drug loading (%) = Drug content in microspheres / Weight of microspheres × 100%

[0099] Encapsulation efficiency (%) = Drug content in microspheres / Theoretical drug loading × 100%.

[0100] Table 2. Drug loading and encapsulation efficiency of microspheres in Examples 1-27 and Comparative Examples 1-5

[0101]

[0102] A comparison of Examples 1-3, 18, and 19 with Comparative Examples 1-5 shows that the porous microspheres of the present invention have a maximum drug loading of 44.2% to 25.2% and a maximum encapsulation efficiency of 88.4% compared to the solid microspheres of the comparative examples. This indicates that by adding a foaming pore-forming agent to prepare the drug into porous microspheres, the present invention can significantly improve the drug loading and encapsulation efficiency of the microspheres, thereby reducing the amount of polymer used, reducing the injection volume, and increasing patient compliance and safety. The comparison of Examples 3-7 shows that the SPG membrane emulsification method combined with the use of a foaming pore-forming agent of the present invention increases the drug loading from a maximum of 23.4% to 44.2% and from a minimum of 36.2% compared to using only the SPG membrane emulsification method or only the foaming pore-forming agent. The encapsulation efficiency also increases from a maximum of 46.8% to 88.4% and from a minimum of 72.4% to 88.4%. This indicates that the combination of SPG membrane emulsification and the foaming pore-forming agent is a necessary factor in improving the drug loading of microspheres, and the combination of the two results in the greatest improvement in drug loading and encapsulation efficiency for preparing porous microspheres. The comparison of Examples 8-17 and 23-27 shows that polymer concentration, drug loading ratio, and pore-forming agent concentration all affect the drug loading and encapsulation efficiency of the microspheres. Within a certain range, the drug loading and encapsulation efficiency of the drug-loaded microspheres reach their highest values ​​of 60.1% and 90.1%, respectively.

[0103] Test Example 5

[0104] In vitro release behavior of microspheres

[0105] Take 1876 mL of water, 20 g of 1M HEPES buffer, 100 mL of 11.6% sodium chloride solution, 8 mL of sodium azide solution, and 0.4 mL of polysorbate-20, place them in the same container, mix well, adjust the pH to 7.4 ± 0.1 with dilute sodium hydroxide or dilute hydrochloric acid, and determine its milliosmolar concentration, which should be within 200 ± 20 mOsM. Accurately weigh 8 mg of dried microspheres from Examples 8–13, 23, 24, and 25, place them in a 250 mL high-pressure polyethylene bottle, add 200 mL of room temperature medium, tighten the cap, seal the bottle, and shake well. Prepare three parallel aliquots. Place each bottle in a constant temperature water bath and let it stand for 0 h. Take samples at 1, 2, 3…14 days. Before sampling, slowly rotate the bottle horizontally to prevent microspheres from adhering to the bottle wall where they are not immersed in solution, ensuring the solution is evenly suspended. Let it stand for at least 10 minutes to allow the microspheres to settle completely. Then, precisely draw 3 mL of solution from 3 cm below the liquid surface using a syringe with a needle, simultaneously adding an equal volume of isothermal solvent. Filter the collected solution through a 0.45 μm microporous membrane, and use the filtrate as the test solution. Determine the drug content using ultraviolet light, calculate the cumulative release percentage, and the release curve is shown in [Figure number missing]. Figure 4 .

[0106] See results Figure 4 As can be seen from the comparison of Examples 8-13, different ratios of PLA to PLGA in the polymer of the present invention affect the release rate of drug-loaded microspheres. The drug release rate decreases as the PLA ratio increases. For example, on day 6, when the PLA ratio in the polymer increased from 30% to 70%, the cumulative release of the prepared drug-loaded microspheres decreased from 100% to 16.2%. The drug release rate can be adjusted by regulating the ratio of PLA to PLGA. As can be seen from the comparison of Examples 24-26, the microspheres obtained by different pore-forming agent concentrations of the present invention have different release rates. The higher the pore-forming agent concentration, the faster the drug release. For example, on day 14, when the pore-forming agent concentration increased from 30% to 60%, the cumulative release of the prepared drug-loaded microspheres increased from 20.4% to 83%. The drug release rate can also be adjusted by regulating the ratio of the pore-forming agent. In addition, as the pore-forming agent concentration increases, the drug release lag period gradually shortens from 2 days to 0 days. By selecting a suitable concentration of pore-forming agent, the drug release lag can be completely eliminated, allowing for immediate release of the drug after administration.

Claims

1. A high drug load sustained release microsphere characterized in that, The raw materials of the microspheres include: active drugs, carrier materials, foaming pore-forming agents and surfactants; The active drugs are selected from risperidone, triamcinolone acetonide and progesterone; The carrier materials are PLGA and PLA; The foaming pore-forming agents are NH4HCO3, NaHCO3 or H2O2; The surfactants are polyvinyl alcohol, sodium dodecyl sulfate, sodium dodecyl sulfonate, Tween 80 or Tween 20; The mass content of the active drugs in the microspheres is 15% to 60%, and the mass ratio of the active drugs to the carrier materials is 1:10 to 2:

1. The preparation method of the high-drug-loading sustained-release microspheres includes the following steps: Step 1: dissolving the active drugs and the carrier materials in an organic solvent to form an oil phase; Step 2: dissolving the foaming pore-forming agent in water to form an inner aqueous phase; The concentration of the foaming pore-forming agent in the inner aqueous phase in step 2 is 10 mg / mL to 70 mg / mL; Step 3: adding the inner aqueous phase to the oil phase, emulsifying under ice bath conditions to obtain a W1 / O type primary emulsion; Step 4: dissolving the surfactant in water to form an outer aqueous phase; Step 5: pouring the W1 / O type primary emulsion into an SPG storage tank, passing through a membrane tube into the outer aqueous phase at 15 to 25°C to form a W1 / O / W2 type multiple emulsion, stirring at 15 to 25°C to volatilize the organic solvent, centrifuging to collect the microspheres, washing and drying to obtain the sustained-release microspheres.

2. The high drug load sustained release microspheres according to claim 1, characterized in that, The concentration of the carrier materials in the organic solvent in step 1 is 20 mg / mL to 100 mg / mL.

3. The high drug load sustained release microspheres according to claim 1, wherein, The concentration of the surfactant in the outer aqueous phase in step 4 is 0.1% to 3% w / v.

4. The high drug load sustained release microspheres of claim 1, wherein, The volume ratio of the inner aqueous phase to the oil phase is 1:20 to 1:4, and the volume ratio of the oil phase to the outer aqueous phase is 1:5 to 1:

100.

5. A pharmaceutical composition, characterized by, The high-drug-loading sustained-release microspheres of claim 1 are used as effective active ingredients.

Images