A method for preparing homogeneous polypeptide-polymer solid drug-loaded microspheres and application thereof

Abstract

The application discloses a preparation method of homogeneous polypeptide-polymer solid drug-loaded microspheres and application thereof. The method comprises the following steps: dispersing active polypeptides in water-soluble volatile monohydric alcohol, dissolving degradable high polymer in mutually soluble volatile organic solvents, controlling the mass ratio and volume ratio of two phases, and constructing a homogeneous polypeptide-high polymer composite solution; and then, using a spray granulation device, rapidly volatilizing the solvents under specific pressure and temperature conditions to obtain homogeneous solid microspheres. The application makes the high polymer chain segments fully spread by utilizing the solvent mutual solubility characteristics, overcomes the defects of traditional complex emulsion method, such as complicated process, long time consumption and uneven distribution of drugs, and the obtained microspheres are compact and uniformly distributed, and can effectively inhibit the burst release of drugs, so that the application has high application value in the fields of tissue engineering and drug delivery.

Description

Technical Field

[0001] This invention belongs to the field of biomedical technology, specifically relating to a method for preparing homogeneous polypeptide-polymer solid drug-loaded microspheres and their applications. Background Technology

[0002] Polymer microspheres (such as polycaprolactone PCL, polylactic acid PLLA, lactic acid-glycolic acid copolymer PLGA, etc.) are highly attractive polymers for human regeneration applications, with relatively good biocompatibility and degradability.

[0003] Peptide drugs (such as growth factors, cytokines, enzyme inhibitors, or biomimetic signal peptides) have shown great potential in areas such as tissue regeneration, immune modulation, and cancer treatment. Compared with traditional small-molecule chemical drugs, peptides generally possess higher biological activity, target specificity, and good biocompatibility. However, their clinical application faces significant challenges: most peptides are readily and rapidly degraded by enzymes in vivo, have extremely short plasma half-lives, and are difficult to cross biological barriers. Therefore, developing carrier systems that can protect peptide activity and achieve controlled, long-acting delivery is crucial.

[0004] Currently, peptide delivery relies heavily on systems such as injectable hydrogels, liposomes, or nanoparticles. While these systems offer some sustained-release effects, they generally suffer from limited drug loading, significant burst release effects, and insufficient mechanical strength. Theoretically, combining bioactive peptides with the aforementioned biodegradable polymers to prepare composite microspheres could synergistically leverage the biofunctionality of peptides with the structural support and sustained-release advantages of polymers, potentially yielding smart materials with excellent mechanical properties, controllable degradation rates, and active repair capabilities. However, a key technical challenge lies in achieving uniform composites of hydrophilic peptides and hydrophobic biodegradable polymers at the nanoscale or molecular scale to form homogeneous, stable, and solid microspheres, avoiding rapid burst release or inactivation caused by peptide accumulation on the microsphere surface. Traditional methods such as double emulsion solvent evaporation are insufficient to achieve uniform distribution of peptides within a hydrophobic polymer matrix. Therefore, developing a novel preparation method to achieve homogeneous integration of peptides and polymers while simultaneously loading other functional components is of significant value for constructing next-generation high-performance tissue engineering and drug delivery platforms. Summary of the Invention

[0005] The purpose of this invention is to provide a homogeneous polypeptide-polymer solid drug-loaded microsphere that has strong binding force with biodegradable polymers, exhibits uniform dispersion of polypeptides in the microspheres, avoids drug aggregation and release instability, has an adjustable degradation rate, and is environmentally responsive and biocompatible.

[0006] The technical solution adopted by this invention to solve the above-mentioned technical problems is as follows: a homogeneous polypeptide-polymer solid drug-loaded microsphere, comprising an active polypeptide and a biodegradable polymer matrix; the active polypeptide is uniformly distributed in the solid structure composed of the biodegradable polymer, and the active polypeptide and the biodegradable polymer are entangled to form a homogeneous composite structure. Through the globally homogeneous entanglement structure, the explosive release of the drug in the initial stage is greatly suppressed. The drug is firmly locked inside the solid matrix, resulting in a more stable release curve, prolonging the effective duration of drug action, and improving bioavailability.

[0007] To optimize the above technical solution, the following measures were also taken: Preferably, the average particle size of the microspheres is from 0.5 μm to 100 μm.

[0008] Preferably, the active polypeptide is selected from one or more of palmitoyl pentapeptide-4, palmitoyl copper blue peptide, cyclic pentapeptide, acetyl tetrapeptide-3, and acetyl hexapeptide-8; the biodegradable polymer matrix is ​​selected from one or more of polycaprolactone, polylactic acid-glycolic acid copolymer, chitosan, and polyethylene glycol; the biodegradable polymer matrix is ​​composed of a single polymer, or is composed of a blend of a base polymer and one or more synergistic components; the synergistic components are selected from one or more of chitosan and polyethylene glycol. The biodegradable polymer matrix is ​​composed of a single biodegradable polymer, or is composed of a blend of a base biodegradable polymer and one or more synergistic components; the active polypeptide is uniformly distributed throughout the biodegradable polymer matrix.

[0009] The present invention also provides a method for preparing the above-mentioned drug-loaded microspheres, which includes the following steps: 1) Disperse the active polypeptide in a water-soluble volatile monohydric alcohol solvent to obtain a polypeptide alcohol solution; 2) Dissolve one or more biodegradable polymers in a volatile solvent to obtain a polymer solution; 3) The polypeptide alcohol solution and the polymer solution are mixed in a volume ratio to obtain a polypeptide-polymer homogeneous composite solution, wherein the water-soluble volatile monohydric alcohol solvent is miscible with the volatile solvent; 4) The homogeneous polypeptide-polymer composite solution is spray-granulated to obtain homogeneous solid drug-loaded polypeptide-polymer microspheres. Traditional double emulsion (W / O / W) processes are extremely cumbersome, requiring multiple emulsifications and prolonged stirring, and are prone to uneven drug distribution, hollow microspheres, or drug aggregation at the interface. Utilizing the miscibility of alcohols and organic solvents, a molecular-level homogeneous composite solution is constructed before spraying, greatly simplifying the process, shortening preparation time, and ensuring uniform drug distribution within the microspheres from the outset, thus achieving a transformation from a complex multiphase system to a simple homogeneous system.

[0010] Preferably, in step 1), the mass ratio of the active peptide to the water-soluble volatile monohydric alcohol solvent is 1:5 to 1:200; in step 2), the mass ratio of the degradable polymer to the volatile solvent is 1:5 to 1:100; and in step 3), the volume ratio of the peptide alcohol solution to the polymer solution is 1:2 to 1:10. By quantifying these ratios, precise control of the "polymer chain segment unfolding state" is achieved. Polymers in a single organic solvent often exhibit a coiled state, easily encapsulating drugs to form aggregates; while peptides tend to aggregate in the aqueous phase. The peptide:alcohol and polymer:solvent ratios ensure sufficient dissolution / dispersion of both components in their initial state. The alcohol solution:organic solution ratio allows for fine-tuning of the polarity of the mixed solvent, forcing the polymer chains to fully unfold under solvation, uniformly capturing the peptide molecules like a "net," thus preventing phase separation of the drug during spraying.

[0011] Preferably, the water-soluble volatile monohydric alcohol solvent is selected from one or more of methanol and ethanol; the volatile solvent is selected from one or more of dichloromethane, chloroform, acetone, and dilute acetic acid aqueous solution. If the solvent evaporates too slowly, the droplets will coalesce during sedimentation, resulting in a wide particle size distribution and irregular shape. The selected dichloromethane, ethanol, etc., all have extremely high volatility. Under the high-temperature environment of spray granulation, the solvent can flash evaporate instantly, causing the polypeptide-polymer complex to transform from the liquid phase to the solid phase in a very short time, thereby locking in a solid structure and uniform particle size, and constructing a highly efficient "rapid evaporation-rapid spheroidization" system.

[0012] Preferably, the active peptide is selected from one or more of palmitoyl pentapeptide-4, palmitoyl copper blue peptide, cyclic pentapeptide, acetyl tetrapeptide-3, and acetyl hexapeptide-8; the biodegradable polymer is selected from one or more of polycaprolactone, polylactic acid, lactic acid-glycolic acid copolymer, chitosan, and polyethylene glycol. By encompassing a variety of peptides (such as palmitoyl pentapeptide) and polymers (such as PLGA and chitosan), this method demonstrates its strong versatility. By changing the polymer, users can freely control the degradation rate of the microspheres (e.g., reducing it from months for PCL to weeks for PLGA), making it adaptable to different tissue engineering scenarios and upgrading specific products into "universal drug delivery platforms." Preferably, step 4) of the spray granulation specifically involves: transferring the homogeneous polypeptide-polymer composite solution to a spray granulation device using a peristaltic pump; the nozzle diameter of the spray granulation device being 0.1 cm to 0.5 cm; the transfer rate of the peristaltic pump being 0.1 mL / s to 1.5 mL / s; the spray pressure of the spray granulation being 1.5 bar to 5 bar; and the spray granulation temperature being 45°C to 80°C, which is lower than the melting point of the biodegradable polymer; the spray-granulated product is cooled and settled in purified water, then filtered and lyophilized to obtain the homogeneous polypeptide-polymer solid drug-loaded microspheres. By limiting the nozzle diameter and transfer rate, the droplet volume of a single spray is physically defined. This ensures that the final product particle size stably falls within an ideal range, directly determining the injection performance and cell compatibility of the microspheres. Too low a temperature leads to incomplete solvent evaporation, causing microspheres to adhere; too high a temperature causes polymer melting, resulting in microspheres collapsing into sheets. This invention protects the morphological stability of the polymer while ensuring rapid solvent evaporation. The chosen pressure ensures that the droplets are fully atomized into extremely fine microdroplets. Temperature is a critical technical boundary. By limiting the temperature below the melting point while maximizing the efficiency of rapid solvent evaporation, the polymer maintains its semi-crystalline or amorphous state during solidification, thus forming dense, solid spheres rather than molten clumps. A process of "purified water sedimentation-filtration-lyophilization" achieves rapid cooling (quenching morphology) and low-temperature, gentle drying. This ensures that the microspheres maintain a homogeneous distribution in their final form and do not damage the bioactivity of the peptides.

[0013] The present invention also provides the use of the above-mentioned drug-loaded microspheres in the preparation of drugs or devices for assisted reproduction, medical aesthetic injection filling, aneurysm closure, and bone tissue support. Attached Figure Description

[0014] Figure 1 This is a SEM image of homogeneous palm blue copper peptide-PCL solid drug-loaded microspheres from Example 1 of the present invention. Figure 2 This is a TEM image of homogeneous palm blue copper peptide-PCL solid drug-loaded microspheres from Example 1 of the present invention. Figure 3 This is a high-angle annular dark-field imaging image of homogeneous palm blue copper peptide-PCL solid drug-loaded microspheres in Example 1 of the present invention. Figure 4 This is an elemental superposition diagram of homogeneous palm blue copper peptide-PCL solid drug-loaded microspheres in Example 1 of the present invention; Figure 5 This is a copper element distribution diagram of homogeneous palm blue copper peptide-PCL solid drug-loaded microspheres in Example 1 of the present invention. Figure 6 This is a gold element distribution diagram of homogeneous palm blue copper peptide-PCL solid drug-loaded microspheres in Example 1 of the present invention. Figure 7 This is a carbon element distribution diagram of homogeneous palm blue copper peptide-PCL solid drug-loaded microspheres in Example 1 of the present invention. Figure 8 This is an oxygen element distribution diagram of homogeneous palm blue copper peptide-PCL solid drug-loaded microspheres in Example 1 of the present invention; Figure 9 This is a nitrogen element distribution diagram of homogeneous palm blue copper peptide-PCL solid drug-loaded microspheres in Example 1 of the present invention; Figure 10 This is a schematic diagram of the line scanning region of homogeneous palm blue copper peptide-PCL solid drug-loaded microspheres in Example 1 of the present invention; Figure 11 This is a line scan of the elemental intensity of homogeneous palm blue copper peptide-PCL solid drug-loaded microspheres from Example 1 of the present invention. Figure 12 This is the energy spectrum of homogeneous palm blue copper peptide-PCL solid drug-loaded microspheres in Example 1 of the present invention; Figure 13 The infrared spectrum of homogeneous palm blue copper peptide-PCL solid drug-loaded microspheres in Example 1 of this invention is shown. Detailed Implementation

[0015] The present invention will be further described in detail below with reference to the accompanying embodiments.

[0016] The diagram shows the following symbols: C coating 1, Au coating 2, and microsphere interface 3.

[0017] Example 1: like Figures 1 to 13 As shown, this invention employs a series of characterization methods to perform in-depth analysis of the homogeneous palmitoyl copper blue peptide-PCL solid drug-loaded microspheres prepared in Example 1. SEM (Sequencing) was used to analyze the microspheres. Figure 1 ) and TEM Figure 2 This confirmed that the microspheres possess a regular spherical morphology and a dense, solid internal structure. HAADF-STEM ( Figure 3 ) and its accompanying element mapping diagram ( Figure 4-9 This directly demonstrates the uniform distribution of carbon (C), oxygen (O), nitrogen (N), and copper (Cu) elements throughout the microspheres, confirming the homogeneous composite state of the drug and matrix. Further analysis using line scanning... Figure 10-11 This quantified the uniformity of elemental distribution, ruling out drug aggregation on the surface. Finally, combined with EDS energy dispersive spectroscopy (EDS), Figure 12 ) and FT-IR infrared spectroscopy ( Figure 13 The study verified, from both atomic composition and functional group characteristics, that the active peptides could be successfully loaded into the PCL polymer matrix without destroying the chemical structure.

[0018] A method for preparing homogeneous polypeptide-polymer solid drug-loaded microspheres includes the following steps: The active peptides were dispersed in a water-soluble volatile monohydric alcohol to obtain an alcoholic solution; The mass ratio of the active polypeptide to the water-soluble volatile monohydric alcohol solvent is 1:5~200; the biodegradable polymer is dissolved in a volatile organic solvent to obtain an organic solution; The mass ratio of the biodegradable polymer to the volatile organic solvent is 1:5~100; The water-soluble volatile monohydric alcohol is miscible with the volatile organic solvent; the polypeptide alcohol solution and the polymer organic solution are mixed to obtain a polypeptide-polymer homogeneous composite solution; the volume ratio of the alcohol solution to the polymer organic solution is 1:2~10; The homogeneous polypeptide-polymer blend is spray-granulated to obtain homogeneous polypeptide-polymer solid drug-loaded microspheres. This invention utilizes water-soluble volatile monohydric alcohols to disperse bioactive polypeptides, followed by dissolving degradable polymers in organic solvents. Taking advantage of the miscibility of water-soluble volatile monohydric alcohols and organic solvents, and by limiting the mass ratios of the bioactive polypeptides to the water-soluble volatile monohydric alcohol solvent, the degradable polymer to the organic solvent, and the volume ratio of the polypeptide alcohol solution to the organic solution, the degradable polymer segments are fully expanded, thereby forming a uniformly dispersed homogeneous polypeptide-polymer composite solution.

[0019] After obtaining the homogeneous blend of polypeptide and polymer, the present invention performs spray granulation on the homogeneous blend of polypeptide and polymer to obtain homogeneous polypeptide-polymer solid drug-loaded microspheres.

[0020] In this invention, the spray granulation is preferably carried out in a spray granulation device. During spray granulation, the homogeneous polypeptide-polymer blend is preferably transported to the spray granulation device via a peristaltic pump, and the nozzle diameter of the spray granulation device is preferably 0.3 cm.

[0021] In this invention, the homogeneous polypeptide-polymer blend is preferably stirred during the transfer process. The peristaltic pump's transfer rate is preferably 1 / 16 to 2 mL / s, more preferably 1 to 1.5 mL / s, and even more preferably 1.2 to 1.3 mL / s. The spray pressure for the spray granulation is preferably 1.5 to 5 bar, more preferably 3 to 4 bar. The gas for spray granulation is preferably provided by nitrogen or argon. The spray granulation temperature is preferably 45 to 80°C, more preferably 50 to 65°C, and must be lower than the melting point of the biodegradable polymer. When the biodegradable polymer is polycaprolactone, the melting point of polycaprolactone is 60°C, and the spray granulation temperature is below 60°C. In this invention, if the nozzle diameter is too small, the solvent cannot be sprayed out; if it is too large, the droplets will be too large to form spheres. After passing through the spray nozzle, the system is broken into liquid droplets of relatively uniform and controllable size. At a high temperature, the water-soluble volatile monohydric alcohol and organic solvent rapidly evaporate, resulting in homogeneous polypeptide-polymer solid drug-loaded microspheres. During the spray granulation process, the product obtained after solvent evaporation is cooled in purified water and precipitated. It is then filtered and freeze-dried to obtain the homogeneous polypeptide-polymer solid drug-loaded microspheres. This invention does not have special requirements for the cooling, filtration, and drying processes; methods well-known to those skilled in the art can be used.

[0022] This invention also provides homogeneous polypeptide-polymer solid drug-loaded microspheres prepared by the preparation method described above, comprising active polypeptides and biodegradable polymers; the calcium phosphorus particles are entangled with the biodegradable polymers. In this invention, the particle size of the homogeneous polypeptide-polymer solid drug-loaded microspheres is preferably 0.5~100 μm, more preferably 20~60 μm.

[0023] In the homogeneous polypeptide-polymer blend of the present invention, during spray granulation, the water-soluble volatile monohydric alcohol and organic solvent rapidly evaporate, resulting in homogeneous solid microspheres. Compared to the cumbersome preparation process of the double emulsion method, which requires not only a homogenizing stirrer to concentrate the microsphere size but also a long time to evaporate the oil phase emulsion, thus consuming a great deal of time and energy, the preparation method of the present invention is simple and quick.

[0024] The following provides a preferred embodiment: palmitoyl copper blue peptide (pal-CuGHK) is mixed with ethanol at a mass ratio of 1:20 to obtain a pal-CuGHK alcohol solution; Polycaprolactone and dichloromethane were mixed at a mass ratio of 1:10 to obtain a PCL-organic solution; The pal-CuGHK alcohol solution and the PCL-organic solution were thoroughly mixed at a volume ratio of 1:4 to obtain a homogeneous polypeptide-polymer composite solution. The homogeneous polypeptide-polymer composite solution was fed into a spray granulation device with a nozzle diameter of 0.3 cm via a peristaltic pump. The peristaltic pump transfer rate was 0.2 mL / s, the spray pressure was 4 bar, and the chamber temperature was 50 °C. The spray-granulated product was settled into purified water at the bottom, filtered, and lyophilized to obtain 20-65 μm homogeneous polypeptide-polymer solid drug-loaded microspheres.

[0025] Example 2: The difference between this embodiment and Example 1 is that a specific synthesis method was used to prepare polycaprolactone.

[0026] ε-caprolactone and pentaerythritol, the initiator, were mixed in a reaction vessel at a molar ratio of 200:1 to 500:1. Stannous octoate at a mass fraction of 0.01% to 0.1% was added as a catalyst. Under nitrogen protection, the reaction system was heated to 120°C to 130°C and reacted for 24 to 48 hours under constant temperature stirring to allow ε-caprolactone to undergo ring-opening polymerization initiated by pentaerythritol, growing into a star structure. After the reaction was completed, the resulting product was dissolved in dichloromethane and purified by repeated precipitation three times with cold methanol at -40°C to -5°C (preferably -20°C). Subsequently, it was dried to constant weight in a vacuum drying oven at 30°C to 50°C (preferably 40°C) to obtain pure polycaprolactone for later use.

[0027] Palmitoyl copper blue peptide (pal-CuGHK) was mixed with ethanol at a mass ratio of 1:20 to obtain a pal-CuGHK alcohol solution; Star-PCL synthesized in step one above was mixed with dichloromethane at a mass ratio of 1:10 to obtain a Star-PCL-organic solution; the pal-CuGHK alcohol solution and the Star-PCL-organic solution were thoroughly mixed at a volume ratio of 1:4 to obtain a homogeneous polypeptide-polymer composite solution; the homogeneous polypeptide-polymer composite solution was fed into a spray granulation device with a nozzle diameter of 0.3 cm through a peristaltic pump, the peristaltic pump transfer rate was 0.2 mL / s, the spray pressure was 4 bar, and the chamber temperature was 50 °C; the spray granulation product was allowed to settle into purified water at the bottom, filtered, and lyophilized to obtain homogeneous polypeptide-polymer solid drug-loaded microspheres. Example 2 compared to Example 1 showed improvements in viscosity (↓23.2±0.2%), PDI (↓44.1±2.3%), and drug release rate (↑45.8±3.8%). It also exhibits good characteristics in terms of both drug loading efficiency (↑) and burst release rate (↓).

[0028] Example 3: The technical solution is as follows: Palmitoyl copper blue peptide (pal-CuGHK) is mixed with ethanol at a mass ratio of 1:20 to obtain a pal-CuGHK alcohol solution; Polycaprolactone (PCL) and polylactic acid-glycolic acid copolymer (PLGA) (the LA:GA ratio of PLGA is selected based on the molecular weight with optimized degradation potential) are mixed at a mass ratio of PCL to PLGA of 1:X (where X is between 1 and 5), and then mixed with dichloromethane solvent to obtain a PCL-PLGA composite organic solution; The pal-CuGHK alcohol solution and the PCL-PLGA composite organic solution are thoroughly mixed at a volume ratio (e.g., 1:3 to 1:5) to obtain a homogeneous polypeptide-polymer composite solution; The homogeneous polypeptide-polymer composite solution is fed into a spray granulation device with a nozzle diameter of 0.3 cm via a peristaltic pump. The peristaltic pump transfer rate is 0.2 mL / s, the spray pressure is 4 bar, and the chamber temperature is 50°C. The spray-granulated product was settled into purified water at the bottom, filtered, and freeze-dried to obtain 20-65 μm homogeneous polypeptide-polymer solid drug-loaded microspheres. The degradation curve and drug release rate of the drug-loaded system were synergistically regulated.

[0029] PLGA and PCL are both polyesters. When they are mixed in solution, they do not simply form a mixture, but rather, through interfacial interactions, they alter the hydrolysis rate of the entire support, enabling more precise control of the release curve. By precisely controlling the ratio of PCL to PLGA, the hydrolysis process of the support can exhibit rapid release in the initial stage and maintain stable and continuous release in the middle stage, thus overcoming the drawback of the flattened release curve of a single polymer.

[0030] Example 4: The technical solution is as follows: Palmitoyl copper blue peptide (pal-CuGHK) is mixed with ethanol at a mass ratio of 1:20 to obtain a pal-CuGHK alcohol solution; Polycaprolactone (PCL) is mixed with dichloromethane solvent to obtain a PCL-organic solution; In the second step or pretreatment stage, chitosan is dissolved in a dilute acidic aqueous solution, and its concentration is controlled to obtain a chitosan aqueous synergistic solution; The pal-CuGHK alcohol solution, PCL-organic solution, and chitosan aqueous synergistic solution are mixed in a two-step gradient according to their respective set volume ratios (e.g., 1:3:1~1:5:2) to obtain a polypeptide-polymer homogeneous composite solution; The polypeptide-polymer homogeneous composite solution is fed into a spray granulation device with a nozzle diameter of 0.3 cm through a peristaltic pump, the peristaltic pump transfer rate is 0.2 mL / s, the spray pressure is 4 bar, and the chamber temperature is 50℃; The spray-granulated product was settled into purified water at the bottom, and then subjected to pH adjustment and cross-linking stabilization treatment under physiological pH conditions. After filtration and freeze-drying, 20-65 μm homogeneous polypeptide-polymer solid drug-loaded microspheres were obtained. The introduction of chitosan endowed the microspheres with significant structural changes (such as swelling or dissolution) under specific environmental pH values, thereby achieving responsive drug release.

[0031] PCL microspheres require a "trigger" in the in vivo environment to improve their stability or achieve responsive release. Chitosan, as a pH-sensitive natural polymer, does not participate in the construction of the main structure, but rather acts as a cross-linking network forming agent and an environmentally responsive switch, working synergistically with the core PCL structure. The hydrophobic structure (PCL) formed by the water-soluble natural substance (chitosan) and organic solvent achieves cross-linking and stability through pH response, thus significantly outperforming simple mixed structures.

[0032] Example 5: The technical solution is as follows: Palmitoyl copper blue peptide (pal-CuGHK) is mixed with ethanol at a mass ratio of 1:20 to obtain a pal-CuGHK alcohol solution; Polycaprolactone (PCL) and polyethylene glycol (PEG) (the molecular weight and ratio of PEG are selected to achieve a synergistic surface wetting effect, for example, the mass ratio of PEG / PCL is between 0.2:1 and 0.8:1) are mixed, and then mixed with dichloromethane solvent to obtain a PCL-PEG composite organic solution; The pal-CuGHK alcohol solution and the PCL-PEG composite organic solution are thoroughly mixed at a volume ratio (e.g., 1:3~1:5) to obtain a homogeneous polypeptide-polymer composite solution; The homogeneous polypeptide-polymer composite solution is fed into a spray granulation device with a nozzle diameter of 0.3 cm through a peristaltic pump, the peristaltic pump transfer rate is 0.2 mL / s, the spray pressure is 4 bar, and the chamber temperature is 50℃; The spray-granulated product was settled into purified water at the bottom, filtered, and lyophilized to obtain 20-65 μm homogeneous polypeptide-polymer solid drug-loaded microspheres. These microspheres exhibited superior particle size distribution uniformity, higher yield, and stronger biocompatibility.

[0033] In spray granulation, the core mixture system (peptide, PCL) is prone to uneven droplet surface tension or excessive polymer chain entanglement during high-speed atomization, affecting the uniformity and yield of microspheres. PEG, as a surface-active synergist, can reduce the interfacial tension and viscosity of the mixture, thereby improving the stability of the spray process and the size uniformity of the microspheres. PEG is not used as a replacement for the structural framework, but rather as a functional "surface wetting aid / stabilizer." Its synergistic effect is mainly reflected in the optimization of the process (improving uniformity and yield), thereby optimizing the physical quality of the final product, which is difficult to achieve with traditional PCL systems.

[0034] Table 1. Overall Performance Comparison of Examples Example 1 Example 2 Example 3 Example 4 Example 5 Surface morphology Smooth and dense Smooth and dense Relatively uniform, microporous structure increased Rough, with porous microstructure Extremely smooth Particle size distribution (PDI) medium narrow medium Wider extremely narrow Degradation rate extremely slow extremely slow Adjustable Response (fluctuating with pH) Slightly faster than PCL drug Release curve Fast at the beginning, slow at the end Relatively stable sustained release Stepped Triggered release Ultra-stable sustained release biology Compatibility good good good excellent Excellent+ Although the invention has been described in conjunction with preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make various changes, substitutions and modifications to the subject matter listed herein without departing from the spirit and scope of the invention. Therefore, the scope of protection of the invention shall be determined by the scope defined in the claims.

Claims

1. A homogeneous polypeptide-polymer solid drug-loaded microsphere, characterized in that: It includes an active polypeptide and a biodegradable polymer matrix; the active polypeptide is uniformly distributed in a solid structure composed of the biodegradable polymer, and the active polypeptide and the biodegradable polymer are entangled with each other to form a homogeneous composite structure.

2. The homogeneous polypeptide-polymer solid drug-loaded microsphere according to claim 1, characterized in that: The average particle size of the microspheres is 0.5 μm to 100 μm.

3. The homogeneous polypeptide-polymer solid drug-loaded microsphere according to claim 1, characterized in that: The active polypeptide is selected from one or more of palmitoyl pentapeptide-4, palmitoyl copper blue peptide, cyclic pentapeptide, acetyl tetrapeptide-3, and acetyl hexapeptide-8; the biodegradable polymer matrix is ​​selected from one or more of polycaprolactone, polylactic acid-glycolic acid copolymer, chitosan, and polyethylene glycol; the biodegradable polymer matrix is ​​composed of a single polymer, or is composed of a blend of a base polymer and one or more synergistic components; the synergistic components are selected from one or more of chitosan and polyethylene glycol.

4. The method for preparing drug-loaded microspheres as described in claim 1, characterized in that, Includes the following steps: 1) Disperse the active polypeptide in a water-soluble volatile monohydric alcohol solvent to obtain a polypeptide alcohol solution; 2) Dissolve one or more biodegradable polymers in a volatile solvent to obtain a polymer solution; 3) The polypeptide alcohol solution and the polymer solution are mixed in a volume ratio to obtain a polypeptide-polymer homogeneous composite solution, wherein the water-soluble volatile monohydric alcohol solvent is miscible with the volatile solvent; 4) Spray granulation is performed on the homogeneous polypeptide-polymer composite solution to obtain homogeneous polypeptide-polymer solid drug-loaded microspheres.

5. The method according to claim 4, characterized in that: In step 1), the mass ratio of the active polypeptide to the water-soluble volatile monohydric alcohol solvent is 1:5 to 1:200; in step 2), the mass ratio of the degradable polymer to the volatile solvent is 1:5 to 1:100; in step 3), the volume ratio of the polypeptide alcohol solution to the polymer solution is 1:2 to 1:

10.

6. The method according to claim 4, characterized in that: The water-soluble volatile monohydric alcohol solvent is selected from one or more of methanol and ethanol; the volatile solvent is selected from one or more of dichloromethane, chloroform, acetone, and dilute acetic acid aqueous solution.

7. The method according to claim 4, characterized in that: The active polypeptide is selected from one or more of palmitoyl pentapeptide-4, palmitoyl copper peptide, cyclic pentapeptide, acetyl tetrapeptide-3, and acetyl hexapeptide-8; the biodegradable polymer is selected from one or more of polycaprolactone, polylactic acid, lactic acid-glycolic acid copolymer, chitosan, and polyethylene glycol.

8. The method according to claim 4, characterized in that: the spray granulation in step 4) specifically comprises: transferring the homogeneous polypeptide-polymer composite solution to a spray granulation device via a peristaltic pump, wherein the nozzle diameter of the spray granulation device is 0.1 cm to 0.5 cm; the transfer rate of the peristaltic pump is 0.1 mL / s to 1.5 mL / s; the spray pressure of the spray granulation is 1.5 bar to 5 bar; the temperature of the spray granulation is 45°C to 80°C, and the temperature of the spray granulation is lower than the melting point of the biodegradable polymer; the product of the spray granulation is cooled and precipitated in purified water, and then filtered and lyophilized to obtain the homogeneous polypeptide-polymer solid drug-loaded microspheres.

9. The use of the drug-loaded microspheres according to claim 1 in the preparation of drugs or devices for assisted reproduction, medical aesthetic injection filling, aneurysm closure, and bone tissue support.

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