CN118903564A - Hydroxyapatite composite polyester microsphere and preparation method and application thereof - Google Patents

Abstract

The invention provides a hydroxyapatite composite polyester microsphere, a preparation method and application thereof, and relates to the technical field of biomedical materials, wherein the microsphere comprises 25-95 parts by mass of bioabsorbable polyester and 5-18 parts by mass of hydroxyapatite; the preparation method of the microsphere comprises the following steps: solution 1 of a bioabsorbable polyester in an organic solvent; adding hydroxyapatite into the solution 1 to obtain a solution 2; dissolving an emulsifying agent to obtain a solution 3; dropping the solution 2 into the solution 3 to obtain an emulsified solution; washing and drying to obtain hydroxyapatite composite polyester microspheres; the microspheres can be used to prepare a facial filling wrinkle-removing agent. The microsphere has proper size and clear boundary, can reduce the possibility of generating bad symptoms such as inflammation after filling the skin, and is stable and long-acting. The microsphere prepared by the preparation method provided by the invention has the advantages of proper size, clear boundary and good supporting effect after filling the skin.

Description

A kind of hydroxyapatite composite polyester microsphere and its preparation method and application

Technical Field

The invention relates to the technical field of biomedical materials, and in particular to hydroxyapatite composite polyester microspheres and a preparation method and application thereof.

Background Art

There are many methods for preparing microspheres. Among them, the emulsification method can make polymer materials into microspheres. Through the corresponding synthesis pathway, various functional components can be attached to the microspheres and delivered to the required parts by universal syringes. When the microspheres are injected into damaged or missing tissues, their structure can play a supporting or protective role in the early stage, and as the structure degrades, its load can play a repair and regeneration function. Hydroxyapatite (HA) is a material that is similar to the composition, structure and properties of bones and teeth in biological organisms. Its chemical formula is Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ , with an accurate chemical equivalent Ca/P=1.67, which is very similar to the human bone mineral structure. Therefore, it has many characteristics, such as good bone binding, biological activity, absorbability and excellent biocompatibility. More and more studies have shown that hydroxyapatite can also play a positive role in the regeneration and repair of soft tissues such as skin.

Micro plastic injections can remove wrinkles, reshape, rejuvenate, and resist aging by injecting microsphere suspension into the subcutaneous tissue. They are used to fill the forehead, cheeks, temples, and improve nasolabial folds. As a filling material for bone defects, it can fill bone defects and support and stabilize bone structure. In addition, microspheres can accelerate the transport of substances in the area where they are effective, which is beneficial to angiogenesis and nerve repair in the area. Traditional injectable microspheres are generally mainly composed of polyester bioabsorbable materials such as polylactic acid. Such absorbable medical polymers have been verified by theory and clinical practice for many years. They are non-toxic, have low immunogenicity, and have good biocompatibility. They are widely used in many fields such as tissue engineering and biomedicine. However, as a skin filler, polylactic acid alone has certain limitations: microspheres rely on the initial space-occupying effect to stimulate the secretion of subcutaneous proteins, and their efficacy is sensitive to size. Although larger microspheres can have a better space-occupying effect, their long degradation cycle will stimulate cells to form fibrous capsules, making it difficult for the implant to be completely absorbed, leading to complications such as cysts. Smaller microspheres can be absorbed smoothly, but they have a poor stimulating effect, a short duration in the body, and poor therapeutic effects. Therefore, while ensuring the initial position of the microspheres and stimulating the secretion of collagen by the subcutaneous fibrous tissue, regulating the overall degradation cycle of the microspheres is the key to significantly improving the use effect of injectable microspheres. Among polyester microspheres used for skin filling, hydroxyapatite has excellent biological activity, can actively interact with human tissue, has a more suitable degradation time, avoids complications such as cysts, has a more stable and long-lasting filling effect, and reduces the possibility of adverse tissues such as inflammation. However, the hydroxyapatite microspheres prepared by the methods in the prior art have poor dimensional stability and unclear boundaries of the microspheres, so the support effect and degradation effect are not ideal when applied to facial filling.

Summary of the invention

The invention provides a hydroxyapatite composite polyester microsphere and a preparation method and application thereof, so as to solve the problems that the hydroxyapatite microsphere prepared in the prior art has poor dimensional stability, unclear boundaries of the microsphere, and poor filling and degradability.

In order to solve the above-mentioned invention object, the technical solution provided by the present invention is as follows:

A hydroxyapatite composite polyester microsphere, the raw materials of which include 25-95 parts of bioabsorbable polyester and 5-18 parts of hydroxyapatite by weight.

Preferably, the D50 of the hydroxyapatite composite polyester microspheres is 6.1 μm to 29.1 μm.

Generally speaking, the effect and clinical manifestation of the microspheres can be judged by the appearance integrity and size of the microspheres. The size of polyester microspheres generally used in clinical practice is optimally 20 to 60 μm, which can both have a space-occupying stimulating effect and not increase the risk of cysts due to being too large. The D50 of the polyester microspheres of the present invention is 6.1 μm to 29.1 μm.

Preferably, the particle size of the hydroxyapatite is 20 nm to 45 nm.

Preferably, the bioabsorbable polyester is one of polylactic acid, polyglycolic acid and polycaprolactone.

A method for preparing hydroxyapatite composite polyester microspheres based on the above-mentioned method comprises the following steps:

S1, dissolving the bioabsorbable polyester in an organic solvent to obtain a solution 1 having a mass-volume concentration of 5% to 20%;

S2, adding hydroxyapatite to the solution 1 to obtain an oil phase suspension, i.e., solution 2;

S3, dissolving the emulsifier to obtain an emulsified aqueous solution, i.e., solution 3;

S4, adjusting the stirring speed of solution 3 to 400-1000 rpm, and simultaneously dropping solution 2 into solution 3 at a rate of 1000-3000 mL/h to obtain an emulsified solution;

In the preparation method of the present invention, the liquid in solution 2 is made into small balls by the shear force generated during the rotation of solution 3. In this process, the stirring speed of solution 3 and the dripping speed of solution 2, as well as the volume concentration of relevant solutes in solution 2 and solution 3 are key parameters for obtaining microspheres of suitable sizes. Only under the conditions and parameters of the present invention can hydroxyapatite composite polyester microspheres with qualified sizes and clear appearance be obtained.

S5. After the emulsification is completed, the stirring speed of the emulsified solution is adjusted to 150-200 rpm, and the temperature is reduced to 20-25° C. to volatilize the organic solvent;

S6, after standing, a precipitate is obtained, and the precipitate is washed and dried to obtain hydroxyapatite composite polyester microspheres.

Preferably, the organic solvent in S1 is one of dichloromethane, chloroform, ethyl acetate, dimethyl sulfoxide and acetone.

Preferably, the mass-volume concentration of the solute in the solution 3 in S3 is 2% to 3%.

Preferably, the emulsifier in S3 is one of polyvinyl pyrrolidone, Span 80 and polyvinyl alcohol, and the mass ratio of the bioabsorbable polyester in S1 to the emulsifier in S3 is (5-19): (12-18).

Preferably, the drying in S6 is vacuum drying or freeze drying.

An application of the hydroxyapatite composite polyester microspheres as described above in the preparation of facial filling and anti-wrinkle agents.

Microsphere fillers are generally used for facial filling to improve facial wrinkles in the early stage by occupying the space, and in the middle and late stages, polylactic acid microspheres are used to stimulate subcutaneous tissue to produce collagen to achieve a cosmetic effect. However, single polylactic acid microspheres often have uneven sizes, resulting in oversized microspheres that are not easy to degrade and absorb, and eventually form cysts, causing serious consequences such as local inflammatory lesions. Hydroxyapatite is added as an additional component in the present invention. Hydroxyapatite (HAP) is an inorganic material with good biocompatibility and strong biological activity. It is the main inorganic component of human and animal bones, has a certain solubility in the body, and can participate in the metabolic process in the body. Hydroxyapatite can promote the proliferation of adult dermal fibroblasts (hADF), and after injection, it can also significantly promote the regeneration of type I and type III collagen, and increase the collagen density of the dermis, so it shows potential in skin repair and regeneration. Hydroxyapatite stimulates the regeneration of collagen and promotes the repair of defective tissue, showing biological activity. In addition, due to its good biocompatibility and biodegradability, hydroxyapatite can be gradually replaced by new tissue in the body and eventually degraded into harmless calcium salts and phosphates without residual risk. The introduction of hydroxyapatite components can increase the overall degradation performance of the microspheres, make the degradation cycle more reasonable, and reduce the probability of complications such as fibrocystic fibrosis. At the same time, it increases the secretion of collagen and improves the overall use effect.

Compared with the prior art, the above technical solution has at least the following beneficial effects:

The hydroxyapatite composite polyester microspheres of the present invention are composed of hydroxyapatite and absorbable polyester, and are of suitable size, which can reduce the possibility of adverse symptoms such as inflammation of polyester microsphere products after being used for skin filling, and make the efficacy more stable and long-lasting. The present invention also provides a preparation method of hydroxyapatite composite polyester microspheres, strictly controlling various parameters, attaching hydroxyapatite to polyester microspheres by emulsification and making them evenly distributed, thereby obtaining a suitable degradation rate, improving the activity of microspheres in stimulating skin regeneration, and the prepared microspheres are of suitable size, clear boundaries, and good supporting effect after filling the skin. The prepared hydroxyapatite composite polyester microspheres can be applied to the field of facial filling and wrinkle removal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a microstructure diagram of hydroxyapatite composite polyester microspheres prepared in Example 1;

FIG2 is a microstructure diagram of hydroxyapatite composite polyester microspheres prepared in Example 2;

FIG3 is a microstructure diagram of hydroxyapatite composite polyester microspheres prepared in Example 3;

FIG4 is a microstructure diagram of hydroxyapatite composite polyester microspheres prepared in Comparative Example 1;

FIG. 5 is a microscopic diagram of the hydroxyapatite composite polyester microspheres prepared in Comparative Example 2.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Example 1

A hydroxyapatite composite polyester microsphere, the raw materials of which include 95 parts of bioabsorbable polyester and 5 parts of hydroxyapatite by weight, the particle size of the hydroxyapatite is 20nm, and the bioabsorbable polyester is polyglycolic acid.

A method for preparing hydroxyapatite composite polyester microspheres according to this embodiment comprises the following steps:

S1, weigh 95g of polyglycolic acid and dissolve it in ethyl acetate, and stir magnetically to accelerate the dissolution. The dissolution time is 8 hours. After the dissolution is completed, a solution with a total volume of 475mL is obtained, and a solution 1 with a mass-volume concentration of 20% is obtained;

S2, adding 5 g of hydroxyapatite to the solution 1 to obtain an oil phase suspension, i.e., solution 2;

S3, weigh 60g of polyvinyl pyrrolidone, and prepare it into an aqueous solution with a total volume of 3000mL with pure water, start stirring and heating to accelerate dissolution, and the dissolution time is 6 hours to obtain an emulsified aqueous solution, that is, a solution 3 with a mass-volume concentration of the solute of 2%;

S4, adjusting the stirring speed of solution 3 to 600 rpm, adjusting the stirring speed of solution 2 to 200 rpm, and simultaneously dropping solution 2 into solution 3 at a rate of 1000 mL/h to obtain an emulsified solution;

S5. After the emulsification is completed, the stirring speed of the emulsified solution is adjusted to 200 rpm, the temperature is lowered to 25° C., and the organic solvent is volatilized for 16 hours;

S6. After the organic phase evaporates completely, stop stirring and let stand for 10 hours. After the microspheres settle naturally, discard the supernatant, resuspend in pure water and wash the emulsified product by centrifugation. The centrifuge speed is set to 4000 rpm for 4 minutes each time. After washing 3 times, replace with anhydrous ethanol for washing once, collect and discard the supernatant by centrifugation;

S7. Dry the washed microspheres to obtain hydroxyapatite composite polyester microspheres. The drying method described here can be vacuum drying or freeze drying. The more suitable drying parameters are: the freeze drying temperature is -120°C~-80°C, and the vacuum degree is 1~100Pa; the vacuum drying temperature is 30°C~60°C, and the vacuum degree is 1~100Pa. In this embodiment, vacuum drying is used to dry the washed microspheres, and the vacuum degree is set not to exceed 30Pa, the temperature is 45°C, and the drying is carried out for 4h.

The microstructure of the hydroxyapatite composite polyester microspheres prepared in this example is shown in FIG1 .

The hydroxyapatite composite polyester microspheres of this example are used as the main raw material to prepare the agent for facial filling and wrinkle removal.

Example 2

A hydroxyapatite composite polyester microsphere, the raw materials of which include 25g of bioabsorbable polyester and 16.7g of hydroxyapatite by weight, the particle size of the hydroxyapatite is 30nm, and the bioabsorbable polyester is polycaprolactone.

A method for preparing hydroxyapatite composite polyester microspheres based on the above-mentioned method comprises the following steps:

S1, weigh 25g of polycaprolactone and dissolve it in acetone, and stir it with magnetic stirring to accelerate the dissolution. The dissolution time is 8 hours. After the dissolution is completed, a solution with a total volume of 500mL is obtained, and a solution 1 with a mass-volume concentration of 5% is obtained;

S2, adding 16.7 g of hydroxyapatite to the solution 1 to obtain an oil phase suspension, i.e., solution 2;

S3, weigh 75g of Span 80, and prepare it into an aqueous solution with a total volume of 3000mL with pure water, start stirring and heating to accelerate dissolution, and the dissolution time is 8 hours to obtain an emulsified aqueous solution, that is, a solution 3 with a mass-volume concentration of the solute of 2.5%;

S4, adjusting the stirring speed of solution 3 to 1000 rpm, adjusting the stirring speed of solution 2 to 600 rpm, and simultaneously dropping solution 2 into solution 3 at a rate of 3000 mL/h to obtain an emulsified solution;

S5. After the emulsification is completed, the stirring speed of the emulsified solution is adjusted to 150 rpm, the temperature is lowered to 20° C., and the organic solvent is volatilized;

S6. After the organic phase evaporates completely, stop stirring and let stand for 10 hours. After the microspheres settle naturally, discard the supernatant, resuspend in pure water and wash the emulsified product by centrifugation. The centrifuge speed is set to 4000 rpm for 5 minutes each time. After washing is repeated 5 times, replace with anhydrous ethanol for washing once, collect by centrifugation and discard the supernatant;

S7. The cleaned microspheres are dried by freeze drying, the vacuum degree is set not more than 5 Pa, the cold trap temperature is -100°C, and the drying is performed for 12 hours to obtain hydroxyapatite composite polyester microspheres.

The microstructure of the hydroxyapatite composite polyester microspheres prepared in this example is shown in FIG2 .

The hydroxyapatite composite polyester microspheres of this example are used as the main raw material to prepare the agent for facial filling and wrinkle removal.

Example 3

A hydroxyapatite composite polyester microsphere, the raw materials of which include 62.5 parts of bioabsorbable polyester and 18 parts of hydroxyapatite by weight, the particle size of the hydroxyapatite is 45nm, and the bioabsorbable polyester is polylactic acid.

A method for preparing hydroxyapatite composite polyester microspheres based on the above-mentioned method comprises the following steps:

S1, weigh 62.5g of polylactic acid and dissolve it in dichloromethane, and stir it with magnetic stirring to accelerate the dissolution. The dissolution time is 8 hours. After the dissolution is completed, a solution with a total volume of 500mL is obtained, and a solution 1 with a mass-volume concentration of 12.5% is obtained;

S2, adding 18 g of hydroxyapatite to the solution 1 and fully dispersing for more than 2 hours to obtain an oil phase suspension, i.e., solution 2;

S3, 90g of polyvinyl alcohol was prepared into an aqueous solution with a total volume of 3000mL with pure water, stirring and heating were started to accelerate dissolution, and the dissolution time was 8 hours to obtain an emulsified aqueous solution, i.e., a solution 3 with a mass-volume concentration of the solute of 3%;

S4, adjusting the stirring speed of solution 3 to 400 rpm, adjusting the stirring speed of solution 2 to 300 rpm, and simultaneously dropping solution 2 into solution 3 at a rate of 2700 mL/h to obtain an emulsified solution;

S5. After the emulsification is completed, the stirring speed of the emulsified solution is adjusted to 200 rpm, the temperature is lowered to 24° C., and the organic solvent is volatilized for 36 hours;

S6. After the organic phase evaporates completely, stop stirring and let stand for 10 hours. After the microspheres settle naturally, discard the supernatant, resuspend in pure water and wash the emulsified product by centrifugation. The centrifuge speed is set to 3500 rpm, 5 minutes each time, and the washing is repeated 5 times, and then the anhydrous ethanol is replaced for washing once. The supernatant is collected by centrifugation and discarded;

S7. Dry the cleaned microspheres by vacuum drying, set the vacuum degree not exceeding 30 Pa, the temperature to 45° C., and dry for 4 hours to obtain hydroxyapatite composite polyester microspheres.

The microstructure of the hydroxyapatite composite polyester microspheres prepared in this example is shown in FIG3 .

The hydroxyapatite composite polyester microspheres of this example are used as the main raw material to prepare the agent for facial filling and wrinkle removal.

The dichloromethane in Example 3 is replaced by dimethyl sulfoxide or chloroform to prepare microspheres similar to those in Example 3.

Comparative Example 1

This comparative example is similar to Example 1, except that in the preparation method of this comparative example, the amount of polyglycolic acid is 50 g, the amount of hydroxyapatite is 50 g, and the raw materials of the corresponding hydroxyapatite composite polyester microspheres include 50 parts of bioabsorbable polyester and 50 parts of hydroxyapatite in parts by mass.

The microstructure of the hydroxyapatite composite polyester microspheres prepared in Comparative Example 1 is shown in FIG. 4 .

The particle size distribution of the hydroxyapatite composite polyester microspheres prepared in Examples 1-3 and Comparative Example 1 is shown in Table 1;

Table 1 Particle size distribution of hydroxyapatite composite polyester microspheres prepared by different methods

It can be seen that the hydroxyapatite composite polyester microspheres prepared in Examples 1-3 have regular shapes and clear boundaries.

Comparative Example 2

This comparative example is similar to Example 1, except that in this comparative example, 120 g of polyvinyl pyrrolidone is added to S3. The microstructure of the microspheres prepared in this comparative example is shown in FIG5 , and it can be seen that the particle size of the prepared microspheres is too small.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims (10)

1. A hydroxyapatite composite polyester microsphere, characterized in that the raw materials thereof include 25 to 95 parts by mass of bioabsorbable polyester and 5 to 18 parts by mass of hydroxyapatite. 2. The hydroxyapatite composite polyester microsphere according to claim 1, characterized in that the D50 of the hydroxyapatite composite polyester microsphere is 6.1 μm ~ 29.1 μm. 3. The hydroxyapatite composite polyester microsphere according to claim 1, wherein the particle size of the hydroxyapatite is 20 nm to 45 nm. 4 . The hydroxyapatite composite polyester microsphere according to claim 1 , wherein the bioabsorbable polyester is one of polylactic acid, polyglycolic acid, and polycaprolactone. 5. A method for preparing hydroxyapatite composite polyester microspheres according to any one of claims 1 to 4, characterized in that it comprises the following steps; S1, dissolving the bioabsorbable polyester in an organic solvent to obtain a solution 1 having a mass-volume concentration of 5% to 20%; S2, adding hydroxyapatite to the solution 1 to obtain an oil phase suspension, i.e., solution 2; S3, dissolving the emulsifier to obtain an emulsified aqueous solution, i.e., solution 3; S4, adjusting the stirring speed of solution 3 to 400-1000 rpm, and simultaneously dropping solution 2 into solution 3 at a rate of 1000-3000 mL/h to obtain an emulsified solution; S5. After the emulsification is completed, the stirring speed of the emulsified solution is adjusted to 150-200 rpm, and the temperature is lowered to 20-25° C. to volatilize the organic solvent; S6, after standing, a precipitate is obtained, and the precipitate is washed and dried to obtain hydroxyapatite composite polyester microspheres. 6. The method according to claim 5, characterized in that the organic solvent in S1 is one of dichloromethane, chloroform, ethyl acetate, dimethyl sulfoxide, and acetone. 7. The method according to claim 5, characterized in that the mass-volume concentration of the solute in the solution 3 in S3 is 2% to 3%. 8. The method according to claim 5, characterized in that the emulsifier in S3 is one of polyvinyl pyrrolidone, Span 80, and polyvinyl alcohol, and the mass ratio of the bioabsorbable polyester in S1 to the emulsifier in S3 is (5-19): (12-18). 9. The method according to claim 5, characterized in that the drying in S6 is vacuum drying or freeze drying. 10. Use of the hydroxyapatite composite polyester microspheres according to any one of claims 1 to 4 in the preparation of facial filling and anti-wrinkle agents.