WO2025060858A1 - Composite gel containing calcium hydroxyapatite microspheres having a core-shell structure, preparation method therefor, and use thereof - Google Patents

Abstract

The present application relates to the technical field of biomedical materials, and in particular, to a composite gel containing calcium hydroxyapatite microspheres having a core-shell structure, a preparation method therefor, and a use thereof. The composite gel comprises a gel carrier and microspheres dispersed in the gel carrier, the microspheres each comprise a core and a shell layer covering the core, the core is a biodegradable polymer, and the shell layer is calcium hydroxyapatite. After the composite gel containing calcium hydroxyapatite microspheres having a core-shell structure of the present application is implanted, calcium hydroxyapatite first comes into contact with human tissue and is degraded into calcium ions and phosphate ions, to stimulate collagen production for tissue remodeling; subsequently, the biodegradable polymer is also metabolically degraded; in addition, the degradation rate of calcium hydroxyapatite can control the exposure rate of the polymer microspheres, to achieve a long-term full filling effect. The gel has suitable viscoelasticity, so that the composite microspheres are uniformly suspended, and after being injected into a human body, the microspheres are still evenly dispersed in the gel.

Description

Composite gel containing core-shell structured calcium hydroxyapatite microspheres, preparation method and application thereof

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of the Chinese patent application filed with the China Patent Office on September 21, 2023, with application number 202311228107.7 and invention name “A composite gel containing core-shell structured hydroxyapatite calcium microspheres, preparation method and application thereof”, the entire contents of which are incorporated herein by reference.

Technical Field

The present application relates to the technical field of biomedical materials, and in particular to a composite gel containing core-shell structured calcium hydroxyapatite microspheres, a preparation method and application thereof.

Background Art

Due to injuries and aging, the human body may suffer from the loosening and loss of local soft tissues, and sometimes even the loss of soft tissue function. In clinical practice, local soft tissue enhancement can be used for treatment. Tissue enhancement materials are injected into the area that needs to be filled, so that the tissue bulge returns to its original shape and restores its function.

Calcium hydroxyapatite, also known as hydroxyapatite, is an inherent component of the human body, has good biocompatibility, and is an efficient material for soft tissue filling. However, the solubility of calcium hydroxyapatite under physiological conditions is extremely low, especially dense calcium hydroxyapatite will show a lower biodegradation rate. After the existing dense calcium hydroxyapatite injection microspheres are injected into the body, a large number of calcium hydroxyapatite microspheres gradually crystallize and harden at the injection site to form new solid tissue, causing the injection site to become stiff and the hard mass to be difficult to remove. If the hard mass tissue is forcibly removed, it will damage the nerves and blood vessels, causing deformity and depression at the removal site.

Therefore, how to optimize and improve the structure of hydroxyapatite calcium injection microspheres and their preparation method to obtain hydroxyapatite calcium microspheres that will not aggregate and harden after implantation, have good microsphere dispersibility and stability, degrade slowly, maintain a long-term filling effect, and are resistant to high-temperature sterilization and easy to inject, is a technical problem that needs to be urgently solved in this field.

Summary of the invention

In view of this, the primary purpose of the present application is to provide a composite gel containing core-shell structured calcium hydroxyapatite microspheres, wherein calcium hydroxyapatite is coated on the outside of biodegradable polymer microspheres, and after implantation, the calcium hydroxyapatite as the shell first contacts with human tissues and degrades into the form of calcium ions and phosphate ions, only stimulating the production of collagen to achieve tissue remodeling, and the exposed biodegradable polymer microspheres can also be metabolically degraded and will not become lumps that cannot be degraded or removed, and the exposure speed of the high-molecular polymer microspheres can be controlled according to the degradation speed of the calcium hydroxyapatite shell layer, so that it can achieve a long-term plumping filling effect without repeated injections. injection; since the high molecular polymer microspheres have poor heat resistance and are easy to deform during high temperature sterilization, with the protection of the calcium hydroxyapatite shell, the microspheres will not soften and deform, which is beneficial to reduce the friction during injection, and can also be extruded with a finer injection needle, reducing injection pain and better controlling the injection force and injection volume; choosing a suitable gel carrier can not only maintain appropriate viscoelasticity before and after sterilization to maintain the suspension state of the microspheres, but also make the composite gel filled in a pre-filled state before use, and can be directly injected when used, which is more conducive to clinical use, thereby effectively improving the efficiency of clinical use, and can also ensure that the composite gel can be stably stored in a room temperature environment. No special storage or transportation required.

Another object of the present application is to provide a method for preparing the composite gel containing the core-shell structured calcium hydroxyapatite microspheres.

Another object of the present application is to provide an application of the composite gel containing core-shell structured calcium hydroxyapatite microspheres in soft tissue filling.

In the first aspect, the present application provides a composite gel containing core-shell structured calcium hydroxyapatite microspheres, the composite gel comprising a gel carrier and microspheres dispersed in the gel carrier, the microspheres comprising a core and a shell layer coated on the outside of the core, the core being a biodegradable polymer, and the shell being calcium hydroxyapatite; the particle size of the microspheres is 15 μm to 150 μm.

In an optional embodiment, the mass ratio of the polymer to the calcium hydroxyapatite is 1:0.1-0.3.

In an optional embodiment, the biodegradable polymer is at least one of polylactic acid, poly-L-lactic acid, and polycaprolactone.

In an optional embodiment, the gel carrier includes a gel matrix, a solvent, a thickener, a humectant, and an anesthetic in a mass ratio of 0-3:30-99.5:0.5-5:0-60:0-1. The thickener and the solvent can form a gel. The thickener has the effects of bonding, suspending, thickening, emulsifying, and sustained release, and can achieve the application effect when mixed with the solvent.

In an optional embodiment, the volume ratio of the microspheres to the gel carrier is 1-5:6-9. In the composite gel, it is the microsphere part that ultimately plays a filling effect. The density of the core-shell structure microspheres prepared in different ratios will be different. The present application calculates the mass based on the volume ratio and then mixes them.

In an optional embodiment, the solvent is at least one of water for injection, PBS buffer, glucose, and sodium chloride aqueous solution.

In an optional embodiment, the gel matrix is at least one of sodium hyaluronate, carbomer, alginate, collagen, and chitosan.

In an optional embodiment, the thickener is at least one of gelatin, soluble starch, and a cellulose derivative.

In an optional embodiment, the humectant is at least one of glycerin, propylene glycol, butylene glycol, and sorbitol.

In an optional embodiment, the anesthetic is at least one of lidocaine hydrochloride, tetracaine hydrochloride, and ropivacaine hydrochloride.

In an optional embodiment, the sodium hyaluronate includes low molecular weight sodium hyaluronate with a molecular weight of 30W to 100W, medium molecular weight sodium hyaluronate with a molecular weight of 120W to 180W, and high molecular weight sodium hyaluronate with a molecular weight of 200W to 250W, and the mass ratio of the low molecular weight sodium hyaluronate to the medium molecular weight sodium hyaluronate and the high molecular weight sodium hyaluronate is 0.5 to 3:0.5 to 5:1 to 10.

In an optional embodiment, the cellulose derivative includes at least one of sodium carboxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, and oxidized cellulose.

In a second aspect, the present application provides a method for preparing a composite gel containing core-shell structured microspheres, comprising the following steps:

S1, respectively preparing calcium hydroxyapatite and a biodegradable polymer sphere, adding the calcium hydroxyapatite, the biodegradable polymer sphere and polyethylene glycol to a mixed solvent of water and alcohol, and mixing, so that the calcium hydroxyapatite Calcium is coated on the surface of the biodegradable polymer sphere to prepare core-shell structured calcium hydroxyapatite microspheres;

S2, preparing a gel carrier, adding the core-shell structured calcium hydroxyapatite microspheres obtained in step S1 into the gel carrier, and mixing well.

In an optional embodiment, in the mixing system of step S1, the mass percentage of polyethylene glycol is 4% to 5%.

In an optional embodiment, the mixing time in step S1 is 2 h to 4 h.

In an optional embodiment, the mass ratio of the biodegradable polymer spheres to the calcium hydroxyapatite is 1:0.1-0.3.

In an optional embodiment, the preparation method of calcium hydroxyapatite comprises: adding citric acid, a calcium source and a phosphorus source to a mixed solvent of water and ethanol, adjusting the pH value of the system to 9-11 for reaction, and the resulting precipitate is calcium hydroxyapatite.

In an optional embodiment, the method for preparing the biodegradable polymer spheres includes: separately preparing a stabilizer aqueous solution and a polymer solution, adding the polymer solution to the stabilizer aqueous solution which is constantly stirred, continuing stirring for a first time, and then heating the mixed system to evaporate the solvent to obtain polymer spheres.

In an optional embodiment, the preparation method of the gel carrier includes: adding a thickener to a moisturizer at least three times, mixing, and obtaining a first mixture; mixing a gel matrix with a solvent to obtain a second mixture; adding the first mixture to the second mixture, mixing, and obtaining a third mixture; adding an anesthetic to the third mixture, mixing, and obtaining a fourth mixture, which is the gel carrier.

In an optional embodiment, in the preparation system of calcium hydroxyapatite, the mass percentage of citric acid is 2% to 3%. Citric acid can maintain the stability of the system, reduce the formation of impurities such as calcium oxide, and is conducive to the formation of uniform and well-dispersed calcium hydroxyapatite.

In an optional embodiment, in the mixed solvent, the volume ratio of water to ethanol is 3:1-2, and citric acid, calcium source and phosphorus source are more easily dissolved in the mixed solvent of water and ethanol.

And/or, the mass ratio of the calcium source to the phosphorus source is 5-10:3-4.

In an optional embodiment, the calcium source is at least one of calcium nitrate and calcium chloride.

In an optional embodiment, the phosphorus source is at least one of diammonium hydrogen phosphate, sodium phosphate, and disodium hydrogen phosphate.

In an optional embodiment, the mass percentage of the stabilizer in the stabilizer aqueous solution is 0.7% to 5%.

In an optional embodiment, the stabilizer is at least one of polyvinyl alcohol and polyacrylic acid; preferably polyvinyl alcohol, because the water molecules of polyvinyl alcohol have hydrophilic and lipophilic structures, they are adsorbed on the surface of polymer particles to form a protective film, reduce interfacial tension and increase the viscosity of the system (medium). Therefore, the polyvinyl alcohol aqueous solution is used as a stabilizer in the emulsion polymerization process, and cooperates with the polymer to improve the stability of the emulsion polymerization system. The particle size of the microspheres is controlled by adjusting the mass percentage of the polyvinyl alcohol aqueous solution, and the uniformity of the particle size distribution and the ball-forming effect are further controlled. Microspheres can be prepared using different organic solvents and polymers during the preparation process; the choice of solvent will affect the raw material content of the polymer microspheres, as well as the subsequent solvent residue problem; the choice of polymer will affect the surface morphology and particle size of the microspheres; when preparing polylactic acid microspheres, the present application uses polylactic acid as the polymer and chloroform as the solvent, and the obtained microspheres have a good structure and a high encapsulation rate.

In an optional embodiment, the mass percentage of the polymer in the polymer solution is 8% to 15%.

In an optional embodiment, the polymer is at least one of polylactic acid, poly-L-lactic acid, and polycaprolactone.

In an optional embodiment, the solvent of the polymer solution is at least one of chloroform and dichloromethane.

In an optional implementation, the first time is 1 hour to 3 hours.

In an optional embodiment, the mass ratio of the gel matrix to the solvent, the thickener, the humectant, and the anesthetic is 0-3:30-99.5:0.5-5:0-60:0-1.

In an optional embodiment, the volume ratio of the core-shell structured calcium hydroxyapatite microspheres to the gel carrier is 1-5:6-9.

In an optional embodiment, when preparing the first mixture, the stirring temperature is maintained at 20°C to 65°C, and the stirring time is 5 min to 60 min.

In an optional embodiment, when preparing the second mixture, the stirring temperature is maintained at 20° C. to 65° C., and the stirring time is 0.5 h to 4 h.

In an optional embodiment, when preparing the third mixture, the stirring temperature is maintained at 20° C. to 65° C., and the stirring time is 3 min to 30 min.

In an optional embodiment, when preparing the fourth mixture, the stirring temperature is maintained at 20° C. to 65° C., and the stirring time is 10 min to 30 min.

In an optional embodiment, the mixing in step S2 is performed by maintaining the stirring temperature at 20° C. to 65° C. and the stirring time at 5 min to 40 min.

In an optional embodiment, the solvent is at least one of water for injection, PBS buffer, glucose, and sodium chloride aqueous solution.

In an optional embodiment, the gel matrix is at least one of sodium hyaluronate, carbomer, alginate, collagen, and chitosan; the sodium hyaluronate includes low molecular weight sodium hyaluronate with a molecular weight of 30W to 100W, medium molecular weight sodium hyaluronate with a molecular weight of 120W to 180W, and high molecular weight sodium hyaluronate with a molecular weight of 200W to 250W, and the mass ratio of the low molecular weight sodium hyaluronate to the medium molecular weight sodium hyaluronate and the high molecular weight sodium hyaluronate is 0.5 to 3:0.5 to 5:1 to 10.

In an optional embodiment, the thickener is at least one of gelatin, soluble starch, and a cellulose derivative; the cellulose derivative includes at least one of sodium carboxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, and oxidized cellulose.

In an optional embodiment, the humectant is at least one of glycerin, propylene glycol, butylene glycol, and sorbitol.

In an optional embodiment, the anesthetic is at least one of lidocaine hydrochloride, tetracaine hydrochloride, and ropivacaine hydrochloride.

In a third aspect, the present application provides the use of the above-mentioned composite gel containing core-shell structured microspheres in soft tissue filling.

Compared with the prior art, the technical solution of this application has the following advantages:

1. The composite gel containing core-shell structured calcium hydroxyapatite microspheres provided by the present application comprises a gel carrier and microspheres dispersed in the gel carrier, wherein the microspheres comprise a core and a shell layer coated on the outside of the core, wherein the core is a biodegradable polymer, and the shell layer is calcium hydroxyapatite. The present application wraps calcium hydroxyapatite on the outside of biodegradable polymer microspheres, and after implantation, the calcium hydroxyapatite as the shell layer first contacts human tissues and degrades into the form of calcium ions and phosphate ions, only stimulating collagen production to achieve tissue remodeling; at this time, the gradually exposed polymer microspheres are also metabolically degraded and will not become lumps that cannot be degraded or removed, and according to the degradation of the calcium hydroxyapatite shell layer, the calcium hydroxyapatite is degraded into calcium ions and phosphate ions, and the microspheres are ... The dissolution rate can control the exposure rate of the polymer microspheres, so that it can achieve a long-term full filling effect without repeated injections; since the heat resistance of biodegradable polymers is poor and they are easy to deform during high-temperature sterilization, with the protection of the calcium hydroxyapatite shell, the microspheres will not soften and deform, which is beneficial to reduce the friction during injection, and can also be extruded with a finer injection needle, reducing injection pain and better controlling the injection force and injection volume; choosing a suitable gel carrier can not only maintain appropriate viscoelasticity before and after sterilization to maintain the suspended state of the microspheres, but also make the composite gel filled in a pre-filled state before use, and directly injected when used, which is more conducive to clinical use, thereby effectively improving the efficiency of clinical use, and can also ensure that the composite gel can be stably stored in a room temperature environment without the need for special storage and transportation.

The gel of the present application has suitable viscoelasticity, which can make the microspheres evenly suspended. After being injected into the human body, the microspheres are still evenly dispersed in the gel, so that the microspheres are not easy to aggregate and clump; after the gel carrier is degraded and absorbed, the hydroxyapatite calcium as the shell layer is also degraded to expose the core polylactic acid microspheres, thereby reducing the formation of solid tissue;

The present application forms a dense shell layer on the outside of the polymer, which can reduce the agglomeration of the biodegradable polymer and obtain microspheres with smooth surface, good injection and not easy to agglomerate;

The control of the size of the microspheres mainly considers the migration and injectability of the microspheres in the body. The particle size of the core-shell structured calcium hydroxyapatite microspheres of the present application is 15μm to 150μm. The microspheres are suspended in a gel carrier and pre-filled in a syringe. The thinner the needle used for injection, the less painful the injection. When the microspheres are smaller than 15μm, the microspheres are prone to agglomeration and are easily phagocytosed by cells and eliminated through the lymphatic system after implantation in the body, making it difficult to play a role. When the microspheres are larger than 150μm, the microspheres are too large to pass through the injection needle, and needle clogging is likely to occur.

2. The composite gel containing core-shell structured hydroxyapatite calcium microspheres provided by the present application adopts sodium carboxymethyl cellulose with strong adhesion, so that the gel can be well matched with the tissue after injection; the addition of a moisturizer can exert its lubricating properties, reduce the friction during injection, and can be extruded with a finer-gauge injection needle, so as to better control the injection force and injection volume and reduce the pain of injection; the addition of a thickener solves the disadvantage of poor adhesion of tissue filling materials, so that after being injected into the tissue, it has strong position stability and will not wander or shift; the gel of the present application is prepared at room temperature, so it can be stably stored in a room temperature environment and does not require special storage and transportation; in addition, the gel prepared by the present application is filled in a pre-filled state before use, and can be directly injected when used, which is more conducive to clinical use, thereby effectively improving the efficiency of clinical use.

3. The preparation method of the composite gel containing core-shell structured hydroxyapatite calcium microspheres provided in the present application is to add hydroxyapatite calcium, biodegradable polymer spheres and polyethylene glycol to a mixed solvent of water and alcohol, and mix them so that the hydroxyapatite calcium is coated on the surface of the biodegradable polymer spheres to obtain core-shell structured hydroxyapatite calcium microspheres; add the core-shell structured hydroxyapatite calcium microspheres prepared above to a gel carrier and mix well. The present application adopts a sol-gel polymerization method to uniformly coat the hydroxyapatite calcium on a biodegradable polymer, and the surface is relatively uniform and smooth, and is uniformly dispersed in the carrier gel for soft tissue filling;

Calcium hydroxyapatite is uniformly deposited layer by layer under the action of polyethylene glycol to form completely encapsulated and dense microspheres; polyethylene glycol can solve the agglomeration problem in the preparation process of calcium hydroxyapatite, modify the surface of calcium hydroxyapatite, and maintain its shape.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the specific implementation of the present application or the technical solution in the prior art, the following will briefly introduce the drawings required for use in the specific implementation or the prior art description. Obviously, the drawings described below are For some implementation methods of the application, ordinary technicians in this field can derive other drawings based on these drawings without any creative work.

FIG. 1 is a SEM image of calcium hydroxyapatite microspheres having a core-shell structure prepared in Example 1 of the present application.

FIG. 2 is a high-magnification SEM image of calcium hydroxyapatite microspheres having a core-shell structure prepared in Example 1 of the present application.

FIG3 shows the agglomeration of calcium hydroxyapatite microspheres having a core-shell structure prepared in Example 1 of the present application.

FIG. 4 shows the agglomeration of calcium hydroxyapatite microspheres having a core-shell structure prepared in Example 2 of the present application.

FIG. 5 shows the agglomeration of calcium hydroxyapatite microspheres having a core-shell structure prepared in Example 3 of the present application.

FIG. 6 shows the agglomeration of calcium hydroxyapatite microspheres having a core-shell structure prepared in Example 4 of the present application.

FIG. 7 shows the agglomeration of calcium hydroxyapatite microspheres having a core-shell structure prepared in Example 5 of the present application.

FIG8 is a microscopic image of agglomeration of calcium hydroxyapatite microspheres having a core-shell structure prepared in Example 1 of the present application.

FIG. 9 is a microscopic image of agglomeration of calcium hydroxyapatite microspheres having a core-shell structure prepared in Example 2 of the present application.

FIG. 10 is a microscopic image of agglomeration of calcium hydroxyapatite microspheres having a core-shell structure prepared in Example 3 of the present application.

FIG. 11 is a microscopic image of agglomeration of calcium hydroxyapatite microspheres having a core-shell structure prepared in Example 4 of the present application.

FIG. 12 is a microscopic image of agglomeration of calcium hydroxyapatite microspheres having a core-shell structure prepared in Example 5 of the present application.

FIG. 13 is a sample picture of gels No. 1 to 3 prepared in the present application and comparative gel No. 1.

FIG. 14 is a microscopic image of the sterilized gel No. 1 of the present application.

FIG. 15 is a microscopic image of the sterilized gel No. 2 of the present application.

FIG. 16 is a microscopic image of the sterilized gel No. 3 of the present application.

FIG. 17 is a microscopic image of the comparative gel No. 1 of the present application after sterilization.

FIG. 18 is a schematic diagram of the gel injection point of the present application.

FIG. 19 shows the filling effects of the present application gel No. 1-3 and the comparative gel No. 1-2 one week after injection.

FIG. 20 shows the filling effects of the present application gel No. 1-3 and the comparative gel No. 1-2 one month after injection.

DETAILED DESCRIPTION

The following examples are provided for a better understanding of the present application, but are not limited to the best implementation mode described, and do not limit the content and protection scope of the present application. Any product identical or similar to the present application obtained by anyone under the inspiration of the present application or by combining the features of the present application with other prior arts shall fall within the protection scope of the present application.

If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be purchased commercially.

The surface of existing injectable composite microspheres is a porous structure with a rough surface, weak mechanical strength, rapid degradation, and inability to maintain a long-term filling effect; and after high-temperature sterilization, the microspheres are easily deformed, making subsequent injection more difficult.

To this end, the present application provides a composite gel containing core-shell structured calcium hydroxyapatite microspheres, the composite gel comprising a gel carrier and microspheres dispersed in the gel carrier, the microspheres comprising a core and a shell layer coated on the outside of the core, the core being a biodegradable polymer, and the shell being calcium hydroxyapatite. The present application wraps calcium hydroxyapatite on the outside of biodegradable polymer microspheres, and after implantation, the calcium hydroxyapatite as the shell layer first contacts human tissues and degrades into the form of calcium ions and phosphate ions, stimulating only collagen production to achieve tissue remodeling; at this time, the gradually exposed The polymer microspheres are also degraded by metabolism and will not become hard lumps that cannot be degraded or removed. In addition, the exposure rate of the high-molecular polymer microspheres can be controlled according to the degradation rate of the calcium hydroxyapatite shell, so that it can achieve a long-term plumping filling effect without repeated injections. Since biodegradable polymers have poor heat resistance and are easily deformed during high-temperature sterilization, with the protection of the calcium hydroxyapatite shell, the microspheres will not soften and deform, which is beneficial to reduce friction during injection, and can also be extruded with a finer-gauge injection needle, reducing injection pain and better controlling injection strength and injection volume. Choosing a suitable gel carrier can not only maintain appropriate viscoelasticity before and after sterilization to maintain the suspended state of the microspheres, but also make the composite gel filled in a pre-filled state before use, and directly injected when used, which is more conducive to clinical use, thereby effectively improving the efficiency of clinical use, and can also ensure that the composite gel can be stably stored in a room temperature environment without the need for special storage and transportation. The gel of the present application has suitable viscoelasticity, which can make the microspheres evenly suspended. After being injected into the human body, the microspheres are still evenly dispersed in the gel, so that the microspheres are not easy to aggregate and clump; after the gel carrier is degraded and absorbed, the hydroxyapatite calcium as the shell layer is also degraded to expose the core polylactic acid microspheres, thereby reducing the formation of solid tissue. The hydroxyapatite calcium microspheres containing a core-shell structure prepared by the present application are dense spheres, which avoid the composite microspheres from being easily deformed after high-temperature sterilization, making subsequent injection more difficult.

The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

In the following examples and comparative examples of the present application, the molecular weight of polyvinyl alcohol is 20,000-140,000, purchased from Adamas; the average molecular weight of polyacrylic acid is 450,000, purchased from Adamas; the molecular weight of polylactic acid is 60,000, purchased from Adamas; the molecular weight of poly-L-lactic acid is 10,000, purchased from Adamas; and the molecular weight of polycaprolactone is 150,000, purchased from Sigma.

In the following examples and comparative examples, % represents mass percentage.

Example 1

The composite gel containing core-shell calcium hydroxyapatite microspheres provided in this embodiment comprises the following steps:

(1) Preparation of polylactic acid microspheres:

Prepare 1L 0.7% polyvinyl alcohol aqueous solution in a container and stir it with an electric stirrer; weigh 11g of polylactic acid in another container and dissolve it in 100mL of chloroform. While stirring, add the chloroform solution of polylactic acid to the polyvinyl alcohol aqueous solution. After stirring for 2h, heat the solution in a water bath to volatilize the chloroform in the solution. After volatilization, wash, filter and dry to obtain polylactic acid microspheres.

(2) Preparation of calcium hydroxyapatite microspheres with core-shell structure:

Prepare 750mL of a mixed solution of 2.5% monohydrated citric acid in water and ethanol (the volume ratio of water to ethanol is 3:1) in a container, then add 9.98g of calcium nitrate tetrahydrate and 3.34g of diammonium hydrogen phosphate, stir to dissolve, then add ammonia water to adjust the solution pH to 10, react for 1 hour, form 4.25g of hydroxyapatite calcium precipitate, then add 30g of polyethylene glycol (4% by mass), after the polyethylene glycol is dissolved, add 15g of polylactic acid microspheres of step (1), react for 3 hours, and hydroxyapatite calcium is deposited on the surface of the polylactic acid microspheres, finally wash, filter, and dry to obtain hydroxyapatite calcium microspheres with a core-shell structure and a particle size of 15μm-150μm. Figures 1 and 2 are SEM images of core-shell structured hydroxyapatite calcium microspheres prepared in the examples of the present application, from which it can be seen that the surface structure is dense and non-porous.

(3) Preparation of gel carrier:

a. PBS buffer preparation: weigh 138g of sodium dihydrogen phosphate and dissolve it in water, then dilute to 1L to obtain sodium dihydrogen phosphate solution; weigh 142g of disodium hydrogen phosphate and dissolve it in water, then dilute to 1L to obtain disodium hydrogen phosphate solution; Sodium dihydrogen phosphate solution and 610 mL of sodium dihydrogen phosphate solution were mixed evenly to obtain 1 L of PBS buffer solution with a pH of 7.0;

b. Mix 120 g of glycerol and 8.5 g of sodium carboxymethyl cellulose, and stir at 25° C. for 15 min using an electric stirrer to obtain a first mixture;

c. Weigh 68.5 g of PBS buffer, add 0.25 g of low molecular weight sodium hyaluronate (molecular weight 80W), 0.25 g of medium molecular weight sodium hyaluronate (molecular weight 120W) and 0.5 g of high molecular weight sodium hyaluronate (molecular weight 220W) in sequence, and stir at 25° C. for 3 h using an electric stirrer to obtain a second mixture;

d. Add the first mixture to the second mixture, stir at 25° C. for 10 min to obtain a third mixture;

e. Weigh 2 g of lidocaine hydrochloride and add it to the third mixture. Use an electric stirrer to stir for 15 min at 25° C. and let stand for 4 h to obtain a gel. The contents of each component are: 0.5% sodium hyaluronate, 34.25% PBS buffer, 4.25% sodium carboxymethyl cellulose, 60% glycerol, and 1% lidocaine hydrochloride.

(4) Preparation of composite gel containing core-shell structured calcium hydroxyapatite microspheres:

The core-shell hydroxyapatite calcium microspheres prepared in step (2) are added to the carrier gel prepared in step (3), and stirred at 25° C. for 20 minutes to obtain a composite gel containing core-shell hydroxyapatite calcium microspheres, which is recorded as gel No. 1; wherein the volume ratio of the core-shell hydroxyapatite calcium microspheres to the gel carrier is 5:5.

Example 2

The composite gel containing core-shell calcium hydroxyapatite microspheres provided in this embodiment comprises the following steps:

(1) Polylactic acid microspheres were prepared using the same method as in Example 1.

(2) Preparation of calcium hydroxyapatite microspheres with core-shell structure:

Prepare 750 mL of a mixed solution of 2.5% citric acid monohydrate in water and ethanol (the volume ratio of water to ethanol is 2:1) in a container, then add 9.98 g of calcium nitrate tetrahydrate and 3.34 g of diammonium hydrogen phosphate, stir to dissolve, then add ammonia water to adjust the solution pH to 10, react for 1 hour, form 4.25 g of calcium hydroxyapatite precipitate, then add 30 g of polyethylene glycol (4% by mass), after the polyethylene glycol is dissolved, add 25 g of the polylactic acid microspheres of step (1), react for 3 hours, and calcium hydroxyapatite is deposited on the surface of the microspheres. Finally, wash, filter and dry to obtain calcium hydroxyapatite microspheres with a particle size of 15 μm-150 μm and a core-shell structure.

(3) Preparation of gel carrier:

a. Glucose solution preparation: weigh 25g glucose and dissolve it in water, and make up to 500mL;

b. Mix 10 g of butanediol and 6 g of gelatin, use an electric stirrer, and stir at 65° C. for 60 min to obtain a first mixture;

c. Weigh 177.8 g of glucose solution, add 6 g of collagen, use an electric stirrer, stir at 20° C. for 4 h to obtain a second mixture;

d. mixing the first mixture with the second mixture, and stirring at 20° C. for 25 min to obtain a third mixture;

e. Weigh 0.2 g of ropivacaine hydrochloride and add it to the third mixture. Use an electric stirrer to stir at 45° C. for 10 min. Let stand for 4 h to obtain a gel. The contents of each component are: 3% collagen, 88.9% glucose, 3% gelatin, 5% butanediol, and 0.1% ropivacaine hydrochloride.

(4) Preparation of composite gel containing core-shell structured calcium hydroxyapatite microspheres:

Add the core-shell calcium hydroxyapatite microspheres prepared in step (2) to the carrier gel prepared in step (3) The mixture was stirred at 50°C for 5 min to obtain a composite gel containing core-shell structured hydroxyapatite calcium microspheres, which was recorded as gel No. 2; wherein the volume ratio of the core-shell structured hydroxyapatite calcium microspheres to the gel carrier was 2:8.

Example 3

The composite gel containing core-shell calcium hydroxyapatite microspheres provided in this embodiment comprises the following steps:

(1) Polylactic acid microspheres were prepared using the same method as in Example 1.

(2) Preparation of calcium hydroxyapatite microspheres with core-shell structure:

Prepare 750 mL of a mixed solution of 2.5% citric acid monohydrate in water and ethanol (the volume ratio of water to ethanol is 3:2) in a container, then add 9.98 g of calcium nitrate tetrahydrate and 3.34 g of diammonium hydrogen phosphate, stir to dissolve, then add ammonia water to adjust the solution pH to 10, react for 1 hour, and form 4.25 g of calcium hydroxyapatite precipitate, then add 30 g of polyethylene glycol (4% by mass), after the polyethylene glycol is dissolved, add 42.5 g of polylactic acid microspheres from step (2), react for 3 hours, and calcium hydroxyapatite is deposited on the surface of the microspheres. Finally, wash, filter and dry to obtain calcium hydroxyapatite microspheres with a core-shell structure and a particle size of 15 μm-150 μm.

(3) Preparation of gel carrier:

a. Preparation of sodium chloride solution: weigh 4.5 g of sodium chloride and dissolve it in water, then make up to 500 mL;

b. Mix 60 g of sorbitol and 1 g of soluble starch, use an electric stirrer, and stir at 50° C. for 60 min to obtain a first mixture;

c. Weigh 136 g of sodium chloride solution, add 2 g of carbomer, use an electric stirrer, stir at 50° C. for 0.5 h to obtain a second mixture;

d. Mix the first mixture with the second mixture, and disperse them in a high-speed disperser at 20° C. for 5 minutes to obtain a third mixture;

e. Weigh 1 g of tetracaine hydrochloride and add it to the third mixture. Use an electric stirrer to stir at 20° C. for 30 minutes and let it stand for 4 hours to obtain a gel. The contents of each component are: carbomer 1%, sodium chloride solution 68%, soluble starch 0.5%, sorbitol 30%, and tetracaine hydrochloride 0.5%.

(4) Preparation of composite gel containing core-shell structured calcium hydroxyapatite microspheres:

The core-shell hydroxyapatite calcium microspheres prepared in step (2) are added to the carrier gel prepared in step (3), and stirred at 30° C. for 40 minutes to obtain a composite gel containing core-shell hydroxyapatite calcium microspheres, which is recorded as gel No. 3; wherein the volume ratio of the core-shell hydroxyapatite calcium microspheres to the gel carrier is 2:8.

Example 4

The composite gel containing core-shell calcium hydroxyapatite microspheres provided in this embodiment comprises the following steps:

(1) Preparation of poly (L-lactic acid) microspheres:

Prepare 1L 3% polyacrylic acid aqueous solution in a container and stir it with an electric stirrer; weigh 8g poly-L-lactic acid in another container and dissolve it in 100mL chloroform. While stirring, add the chloroform solution of poly-L-lactic acid to the polyacrylic acid aqueous solution. After stirring for 1h, heat the solution in a water bath to volatilize the chloroform in the solution. After volatilization, wash, filter and dry to obtain poly-L-lactic acid microspheres.

(2) Preparation of calcium hydroxyapatite microspheres with core-shell structure:

Prepare 750 mL of a 2% citric acid monohydrate mixed solution of water and ethanol in a container (the volume ratio of water to ethanol is 3: 1), then add 5g of calcium chloride and 3.86g of disodium hydrogen phosphate, stir to dissolve, then add sodium hydroxide to adjust the solution pH to 9, react for 1h, form 5g of calcium hydroxyapatite precipitate, then add 34g of polyethylene glycol (mass percentage is 4.5%), after the polyethylene glycol is dissolved, add 35g of poly-L-lactic acid microspheres of step (1), react for 3h, calcium hydroxyapatite is deposited on the surface of the microspheres, finally wash, filter and dry to obtain calcium hydroxyapatite microspheres with a particle size of 15μm-150μm and a core-shell structure.

(3) Preparation of gel carrier:

Weigh 196 g of water for injection, add 4 g of methyl cellulose, use an electric stirrer, stir for 60 min at 20° C., and let stand for 4 h to obtain a gel. The content of each component is: 98% water for injection and 2% methyl cellulose.

(4) Preparation of composite gel containing core-shell structured calcium hydroxyapatite microspheres:

The core-shell hydroxyapatite calcium microspheres prepared in step (2) are added to the carrier gel prepared in step (3), and stirred at 25° C. for 20 minutes to obtain a composite gel containing core-shell hydroxyapatite calcium microspheres, which is recorded as gel No. 4; wherein the volume ratio of the core-shell hydroxyapatite calcium microspheres to the gel carrier is 1:9.

Example 5

The composite gel containing core-shell calcium hydroxyapatite microspheres provided in this embodiment comprises the following steps:

(1) Preparation of polycaprolactone microspheres:

Prepare 1L 5% polyvinyl alcohol aqueous solution in a container and stir it with an electric stirrer; weigh 15g of polycaprolactone in another container and dissolve it in 100mL of chloroform. While stirring, add the chloroform solution of polycaprolactone to the polyvinyl alcohol aqueous solution. After stirring for 2h, heat the solution in a water bath to volatilize the chloroform in the solution. After evaporation, wash, filter and dry to obtain polycaprolactone microspheres.

(2) Preparation of calcium hydroxyapatite microspheres with core-shell structure:

Prepare 750 mL of a mixed solution of 3% monohydrated citric acid in water and ethanol (the volume ratio of water to ethanol is 3:1) in a container, then add 9.98 g of calcium nitrate tetrahydrate and 3.34 g of diammonium hydrogen phosphate ((NH ₄ ) ₂ HPO ₄ ), stir to dissolve, then add ammonia water to adjust the solution pH to 11, react for 1 hour, form 4.25 g of calcium hydroxyapatite precipitate, then add 30 g of polyethylene glycol (4% by mass), after the polyethylene glycol is dissolved, add 20 g of the polycaprolactone microspheres of step (1), react for 3 hours, and calcium hydroxyapatite is deposited on the surface of the microspheres, finally wash, filter and dry to obtain calcium hydroxyapatite microspheres with a particle size of 15 μm-150 μm and a core-shell structure.

(3) Preparation of gel carrier:

a. PBS buffer preparation: weigh 138g of sodium dihydrogen phosphate and dissolve it in water, then dilute to 1L to obtain a sodium dihydrogen phosphate solution; weigh 142g of disodium hydrogen phosphate and dissolve it in water, then dilute to 1L to obtain a disodium hydrogen phosphate solution; mix 390mL of the sodium dihydrogen phosphate solution and 610mL of the disodium hydrogen phosphate solution to obtain 1L of PBS buffer with a pH of 7.0;

b. Mix 52 g of propylene glycol and 8 g of oxidized cellulose, and stir at 35° C. for 5 min using an electric stirrer to obtain a first mixture;

c. Weigh 140 g of PBS buffer solution and mix it with the first mixture. Use an electric stirrer to stir at 20° C. for 30 min. Let stand for 4 h to obtain a gel. The content of each component is: 70% PBS buffer solution, 4% oxidized cellulose, and 26% propylene glycol.

(4) Preparation of composite gel containing core-shell structured calcium hydroxyapatite microspheres:

Add the core-shell calcium hydroxyapatite microspheres prepared in step (2) to the carrier gel prepared in step (3) The mixture was stirred at 25°C for 20 min to obtain a composite gel containing core-shell calcium hydroxyapatite microspheres, which was recorded as gel No. 5. The volume ratio of the core-shell calcium hydroxyapatite microspheres to the gel carrier was 2:8.

Comparative Example 1

This comparative example provides a composite gel containing polylactic acid microspheres, and its preparation method is as follows:

The polylactic acid microspheres prepared in Example 1 were added to the carrier gel prepared in Example 1, and stirred at 25° C. for 20 min to obtain a composite gel containing polylactic acid microspheres, which was recorded as comparative gel No. 1; wherein the volume ratio of polylactic acid microspheres to gel carrier was 5:6.

Comparative Example 2

This comparative example provides a composite gel containing calcium hydroxyapatite microspheres, and its preparation method is as follows:

The purchased calcium hydroxyapatite was mixed into the gel carrier prepared in step (3) of Example 1 at a volume ratio of 5:6 between microspheres and gel carrier, and recorded as comparative gel No. 2.

Experimental Example 1

The core-shell calcium hydroxyapatite microspheres prepared in Examples 1 to 5 were immersed in a newly prepared TRIS-HCL buffer solution with a mass ratio of 1:20 for degradation at a degradation temperature of 37° C. The agglomeration of the microspheres was observed after 6 months.

3 to 7 show the agglomeration of the core-shell calcium hydroxyapatite microspheres prepared in Examples 1 to 5. It can be seen that the microspheres are all in a dispersed state and in powder form without obvious agglomeration. Only a few needle-shaped crystals are observed in FIG. 3 .

FIG8 to FIG12 are microscopic images of agglomeration of calcium hydroxyapatite microspheres with a core-shell structure prepared in Examples 1 to 5. It can be seen that the microspheres are dispersed relatively evenly without obvious agglomeration.

Experimental Example 2

Sample pictures of gels No. 1 to 3 and comparative gel No. 1 prepared in the present application are shown in FIG13 . It can be seen from the figure that comparative gel No. 1 is more difficult to maintain a fixed shape and its appearance looks more turbid than gels No. 1-3.

Gels No. 1 to No. 3 and Comparative Gel No. 1 were placed in high temperature and high pressure resistant glass bottles, respectively, and then sterilized in a high pressure steam sterilizer at 121°C for 30 minutes. The morphology was then observed under a microscope as shown in Figures 14 to 17. Figures 14 to 16 are microscopic images of gels No. 1 to No. 3 after sterilization. It can be seen from the figures that the microspheres are evenly distributed and basically maintain a spherical state. Figure 17 is a microscopic image of comparative gel No. 1 after sterilization. It can be seen that about 80% of the microspheres cannot maintain a spherical shape, and the distribution of the microspheres is extremely uneven, making subsequent injection more difficult.

The sterilized gels were respectively filled into 1 mL syringes, each syringe was equipped with 18G and 22G needles, and the pushing force generated by squeezing the prepared gels through the injection needles of the 18G and 22G needles at a speed of 30 mm/min was shown in the following table;

Table 1 Pushing force measurement results of gel No. 1-5 and comparative gel No. 1

As can be seen from the above table, the thinner the needle size, the greater the pushing force; for 18G injection needle, the pushing force of the sterilized samples of gels No. 1 to 5 is 6.1-11G/N, and the gel in the syringe can be squeezed out smoothly; compared with the sterilized gels No. 1 to 5, the sterilized comparative gel No. 1 has a larger pushing force, and when using a 22G needle, the needle tip will be blocked. This may be due to the deformation of the microspheres after sterilization, the irregular shape leads to an increase in particle size, and uneven distribution in the gel, resulting in needle blockage; compared with gels No. 1-2, the pushing force of gels No. 3-5 is smaller, which may be due to the larger volume of the core-shell structured hydroxyapatite calcium microspheres prepared in Example 3-5 and the gel (Gel No. 1); in addition, the content of the thickener in the gel matrix is also an important factor affecting the pushing force of the gel. Too little thickener will affect the uniform suspension of the microspheres in the gel, and too much will increase the pushing force of the gel (Gel No. 2). When using an 18G injection needle, there is not much difference in pushing force between gel No. 1-2 and gel No. 3-5. When using a thinner 22G injection needle, the pushing force of No. 1 is greater than that of No. 2, and the pushing force of No. 3 is greater than that of No. 4 and greater than that of No. 5. This is because thinner injection needles are more sensitive to the viscoelasticity of the gel during the pushing process. The difference in gel viscoelasticity is due to the use of different gel carrier ratios to suspend microspheres of different volumes. The more microspheres added, the greater the viscoelasticity of the gel carrier is required, and the greater the viscoelasticity, the greater the pushing force required.

Experimental Example 3

According to the sterilization requirements in Experimental Example 2, the comparison gel No. 2 was placed in a high temperature and high pressure resistant glass bottle and sterilized in a high pressure steam sterilizer at 121°C for 30 minutes. At the same time, the sterilized gels No. 1-3 and the comparison gel No. 1 in Experimental Example 2 were injected into the subcutaneous tissue on both sides of the spine of the rabbit back under sterile conditions. Figure 18 is a schematic diagram of the injection point. An 18G injection needle was used with an injection volume of 0.3 mL. The filling effect of the injection site was observed 24 hours, 1 week, and 1 month after injection.

Observation 24 hours after injection showed no redness, swelling, ecchymosis, etc. at the injection sites of gels 1-3, and no allergic reaction; there were slight erythema at the injection sites of contrast gels 1 and 2, which was relieved after ice compress.

Observations one week after injection are shown in Figure 19. Comparative gel No. 1 injection point had no obvious filling effect because it was difficult to maintain a fixed shape after injection; Comparative gel No. 2 injection point had redness and swelling, and a lump of hardened microspheres at the injection site could be found by light touch; injection points No. 1-3 had no redness, swelling, bruises, etc., and no allergic reactions, and had obvious filling effects.

Observations one month after injection are shown in Figure 20. In contrast, no filler was observed at the injection site of gel No. 1, but there was slight redness and swelling, and the microspheres were degraded or shifted, and the filling effect on the injection site was not achieved. In contrast, the hardened lumps at the injection site of gel No. 2 were shifted, causing redness, swelling and bruises, and the filling effect on the injection site was not achieved. There was no displacement at injection sites 1-3, the microspheres degraded slowly, and there was an obvious filling effect.

Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims (10)

A composite gel containing core-shell structured calcium hydroxyapatite microspheres, characterized in that the composite gel comprises a gel carrier and microspheres dispersed in the gel carrier, the microspheres comprise a core and a shell layer coated on the outside of the core, the core is a biodegradable polymer, and the shell layer is calcium hydroxyapatite; the particle size of the microspheres is 15μm to 150μm. The composite gel containing core-shell structured calcium hydroxyapatite microspheres according to claim 1, characterized in that the mass ratio of the polymer to the calcium hydroxyapatite is 1:0.1-0.3; And/or, the biodegradable polymer is at least one of polylactic acid, poly-L-lactic acid, and polycaprolactone. The composite gel containing core-shell calcium hydroxyapatite microspheres according to claim 1, characterized in that the gel carrier comprises a gel matrix, a solvent, a thickener, a moisturizer, and an anesthetic in a mass ratio of 0 to 3:30 to 99.5:0.5 to 5:0 to 60:0 to 1; And/or, the volume ratio of the microspheres to the gel carrier is 1-5:6-9. The composite gel containing core-shell structured calcium hydroxyapatite microspheres according to claim 3, characterized in that the solvent is at least one of water for injection, PBS buffer, glucose, and sodium chloride aqueous solution; And/or, the gel matrix is at least one of sodium hyaluronate, carbomer, alginate, collagen, and chitosan; and/or, the thickener is at least one of gelatin, soluble starch, and cellulose derivatives; And/or, the moisturizing agent is at least one of glycerol, propylene glycol, butylene glycol, and sorbitol; And/or, the anesthetic is at least one of lidocaine hydrochloride, tetracaine hydrochloride, and ropivacaine hydrochloride. The composite gel containing core-shell structured calcium hydroxyapatite microspheres according to claim 4, characterized in that the sodium hyaluronate comprises low molecular weight sodium hyaluronate with a molecular weight of 30W to 100W, medium molecular weight sodium hyaluronate with a molecular weight of 120W to 180W, and high molecular weight sodium hyaluronate with a molecular weight of 200W to 250W, and the mass ratio of the low molecular weight sodium hyaluronate to the medium molecular weight sodium hyaluronate and the high molecular weight sodium hyaluronate is 0.5 to 3: 0.5 to 5: 1 to 10; And/or, the cellulose derivative includes at least one of sodium carboxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, and oxidized cellulose. A method for preparing a composite gel containing core-shell structured microspheres, characterized in that it comprises the following steps: S1, preparing calcium hydroxyapatite and biodegradable polymer spheres respectively, adding the calcium hydroxyapatite, the biodegradable polymer spheres and polyethylene glycol into a mixed solvent of water and alcohol, and mixing them so that the calcium hydroxyapatite is coated on the surface of the biodegradable polymer spheres to obtain core-shell structured calcium hydroxyapatite microspheres; S2, preparing a gel carrier, adding the core-shell structured calcium hydroxyapatite microspheres obtained in step S1 into the gel carrier, and mixing well. The method for preparing a composite gel containing core-shell structured microspheres according to claim 6, characterized in that in the mixing system of step S1, the mass percentage of polyethylene glycol is 4% to 5%; and/or, The mixing time in step S1 is 2h-4h; and/or, The mass ratio of the biodegradable polymer sphere to the calcium hydroxyapatite is 1:0.1-0.3; and/or, The preparation method of calcium hydroxyapatite comprises: adding citric acid, a calcium source and a phosphorus source to a mixed solvent of water and ethanol, adjusting the pH value of the system to 9-11 to react, and the resulting precipitate is calcium hydroxyapatite; and/or, The method for preparing the biodegradable polymer sphere comprises: preparing a stabilizer aqueous solution and a polymer solution respectively, adding the polymer solution to the stabilizer aqueous solution which is being continuously stirred, continuing stirring for a first time, and then heating the mixed system to volatilize the solvent to obtain the polymer sphere; and/or, The preparation method of the gel carrier includes: adding a thickener to a moisturizer, mixing, and obtaining a first mixture; mixing a gel matrix with a solvent, obtaining a second mixture; adding the first mixture to the second mixture, mixing, and obtaining a third mixture; adding an anesthetic to the third mixture, mixing, and obtaining a fourth mixture, which is the gel carrier. The method for preparing a composite gel containing core-shell structured microspheres according to claim 7, characterized in that in the preparation system of calcium hydroxyapatite, the mass percentage of citric acid is 2% to 3%; And/or, in the mixed solvent, the volume ratio of water to ethanol is 3:1-2; And/or, the mass ratio of the calcium source to the phosphorus source is 5-10:3-4; And/or, the calcium source is at least one of calcium nitrate and calcium chloride; And/or, the phosphorus source is at least one of diammonium hydrogen phosphate, sodium phosphate, and disodium hydrogen phosphate; And/or, the mass percentage of the stabilizer in the stabilizer aqueous solution is 0.7% to 5%; And/or, the stabilizer is at least one of polyvinyl alcohol and polyacrylic acid; And/or, the mass percentage of the polymer in the polymer solution is 8% to 15%; And/or, the polymer is at least one of polylactic acid, poly-L-lactic acid, and polycaprolactone; And/or, the solvent of the polymer solution is at least one of chloroform and dichloromethane; And/or, the first time is 1h to 3h; and/or, the mass ratio of the gel matrix to the solvent, the thickener, the moisturizer, and the anesthetic is 0-3:30-99.5:0.5-5:0-60:0-1; And/or, the volume ratio of the core-shell structured calcium hydroxyapatite microspheres to the gel carrier is 1-5:6-9; And/or, when preparing the first mixture, the stirring temperature is maintained at 20°C to 65°C, and the stirring time is 5min to 60min; and/or, when preparing the second mixture, the stirring temperature is maintained at 20° C. to 65° C., and the stirring time is 0.5 h to 4 h; And/or, when preparing the third mixture, the stirring temperature is maintained at 20° C. to 65° C., and the stirring time is 3 min to 30 min; And/or, when preparing the fourth mixture, the stirring temperature is maintained at 20° C. to 65° C., and the stirring time is 10 min to 30 min; And/or, the mixing in step S2 is performed at a stirring temperature of 20° C. to 65° C. and a stirring time of 5 min to 40 min. The method for preparing a composite gel containing core-shell structured microspheres according to claim 7, characterized in that the solvent is at least one of water for injection, PBS buffer, glucose, and sodium chloride aqueous solution; And/or, the gel matrix is at least one of sodium hyaluronate, carbomer, alginate, collagen, and chitosan; the sodium hyaluronate includes low molecular weight sodium hyaluronate with a molecular weight of 30W to 100W, medium molecular weight sodium hyaluronate with a molecular weight of 120W to 180W, and high molecular weight sodium hyaluronate with a molecular weight of 200W to 250W, and the mass ratio of the low molecular weight sodium hyaluronate to the medium molecular weight sodium hyaluronate and the high molecular weight sodium hyaluronate is 0.5 to 3:0.5 to 5:1 to 10; And/or, the thickener is at least one of gelatin, soluble starch, and cellulose derivatives; the cellulose derivatives include sodium carboxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, oxidized cellulose, One less; And/or, the moisturizing agent is at least one of glycerol, propylene glycol, butylene glycol, and sorbitol; And/or, the anesthetic is at least one of lidocaine hydrochloride, tetracaine hydrochloride, and ropivacaine hydrochloride. Use of the composite gel containing core-shell structured calcium hydroxyapatite microspheres as claimed in any one of claims 1 to 5 or the composite gel containing core-shell structured microspheres prepared by the preparation method as claimed in any one of claims 6 to 9 in soft tissue filling.