CN116328046A - Porous poly-L-lactic acid microspheres and facial fillers containing NMN and preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of biomedical materials, and discloses a porous poly-L-lactic acid microsphere containing NMN, a facial filler and a preparation method thereof. The preparation method of the porous poly-L-lactic acid microspheres comprises the following steps: taking the emulsion and the aqueous solution into the reaction vessel at a flow rate of 5-50mL/min and 500-2500mL/min respectively, and performing a high-speed shear reaction at a speed of 1000-5000rpm , to obtain a microsphere suspension; the microsphere suspension is vacuum-dried to obtain porous poly-L-lactic acid microspheres; the emulsion includes 2-20wt% poly-L-lactic acid, 3-30wt% polysorbate and 50-95wt% Organic solvent, the aqueous solution includes 0.5-2wt% polyvinyl alcohol, 0.2-2wt% β-nicotinamide mononucleotide, 0.5-5wt% gelatin and 91-98.8wt% water, and the volume ratio of the emulsion and the aqueous solution is 1: (3~15). The preparation method provided by the invention can prepare porous poly-L-lactic acid microspheres with regular shape, narrow particle size distribution and loaded with NMN. The facial filler prepared by using the microspheres as a raw material has excellent anti-wrinkle, skin rejuvenation and While whitening effect, it also has good safety.

Description

Porous poly-L-lactic acid microspheres and facial fillers containing NMN and preparation method thereof

technical field

The invention belongs to the technical field of biomedical materials, and in particular relates to a porous poly-L-lactic acid microsphere containing NMN, a facial filler and a preparation method thereof.

Background technique

In recent years, with the rapid development of the beauty industry, injectable facial fillers have developed rapidly and become an indispensable part of the field of aesthetic medicine. Traditional injectable facial fillers will be slowly absorbed after injection and eventually disappear. They can only play a temporary repairing role, require repeated re-injections, and have poor biocompatibility. They also cause inflammation and other risks of side effects. There are many types of facial fillers on the market, but it is still a great challenge to develop cosmetic products with good cosmetic effect, long-lasting but not permanent curative effect, few side effects and low incidence of adverse reactions.

Polylactic acid materials have the advantages of good biodegradability, good mechanical strength and processing performance, and good biocompatibility, so they are widely used in tissue engineering, orthopedic repair and fixation materials, drug delivery, and surgical sutures. A biomedical material approved by the Food and Drug Administration (FDA). Among them, poly-L-lactic acid can be slowly degraded into lactic acid in the body, and the degraded lactic acid can stimulate the formation of collagen, so that the collagen that is gradually lost with age can be replenished, so as to improve skin quality and fill skin sagging and depressions. The curative effect can last up to two years, and poly-L-lactic acid will eventually be degraded into CO ₂ and H ₂ O to be excreted; therefore, poly-L-lactic acid has become popular in the beauty industry in recent years.

In the current L-lactic acid facial fillers, L-lactic acid exists in the form of microparticles or microspheres, but the preparation process of L-lactic acid microspheres or microspheres is complicated, the particle size is poorly controllable, and the cost is high. Introducing other active components during the process, the microspheres or particles will have uneven particle size, irregular shape, poor reconstitution or uneven injection, which will cause adverse reactions such as subcutaneous nodules or redness, and the safety is poor .

Contents of the invention

In order to obtain a L-lactic acid microsphere with a regular porous spherical structure, narrow particle size distribution and good resolubility, and improve its safety when used as a facial filler, the present invention provides a porous poly-L-lactic acid containing NMN Microspheres and facial fillers and methods for their preparation.

In the first aspect, the preparation method of the porous poly-L-lactic acid microspheres provided by the present invention adopts the following technical scheme:

A preparation method of porous poly-L-lactic acid microspheres, the method specifically comprises the following steps:

S1. Take the emulsion and the aqueous solution into the reaction vessel at a flow rate of 5-50mL/min and 500-2500mL/min respectively, and perform a high-speed shear reaction at a speed of 1000-5000rpm to obtain a suspension of microspheres;

S2. Vacuum drying the microsphere suspension to obtain the porous poly-L-lactic acid microspheres;

Wherein, the emulsion includes 2-20wt% poly-L-lactic acid, 3-30wt% polysorbate and 50-95wt% organic solvent, and the aqueous solution includes 0.5-2wt% polyvinyl alcohol, 0.2-2wt% % β-nicotinamide mononucleotide, 0.5-5wt% gelatin and 91-98.8wt% water, and the added volume ratio of the emulsion and the aqueous solution is 1:(3-15).

In some specific embodiments, the gelatin is selected from animal gelatin and/or modified gelatin.

In some specific embodiments, the modified gelatin is selected from one or more of thiolated gelatin, phosphorylated gelatin, succinylated gelatin and urea-linked gelatin.

In some specific embodiments, the organic solvent is selected from one or more of chloroform, dichloromethane and absolute ethanol.

In some specific embodiments, the temperature of the vacuum drying is 45-80° C., the degree of vacuum is 0.05-0.08 MPa, and the time is 0.5-4 hours.

In some specific embodiments, the preparation method of the porous poly-L-lactic acid microspheres provided by the present invention further includes centrifuging, sieving or settling the microsphere suspension before vacuum drying.

In the second aspect, the porous poly-L-lactic acid microspheres provided by the present invention adopt the following technical solutions:

A porous poly-L-lactic acid microsphere, which is prepared by the above-mentioned preparation method of the porous poly-L-lactic acid microsphere.

In some specific embodiments, the porous poly-L-lactic acid microsphere has a porous spherical skeleton structure, and the porous spherical skeleton structure is loaded with β-nicotinamide mononucleotide.

In the third aspect, the facial filler provided by the present invention adopts the following technical solutions:

A facial filler, comprising 0.1-4wt% of the porous poly-L-lactic acid microspheres described in claim 6 or 7, 0.1-4wt% of mannitol, 0.0002-25wt% of carboxymethylcellulose sodium and 50-95wt% % water.

In some specific embodiments, the molecular weight of the sodium carboxymethylcellulose is 5000-500000 Da.

In the fourth aspect, the preparation method of the facial filler provided by the present invention adopts the following technical solutions:

A method for preparing a facial filler, the method comprising: taking the porous poly-L-lactic acid microspheres, mannitol and carboxymethyl Sodium cellulose was continuously stirred at a speed of 1000-10000 rpm for 5-45 minutes to obtain a mixture;

Mix the mixture with water according to the mass ratio of 1:(20-50), and keep stirring at a speed of 500-2500 rpm for 10-30 minutes to obtain a facial filler solution;

The facial filler solution is freeze-dried for 4-48 hours to obtain the facial filler.

Beneficial effect:

(1) In the present invention, the emulsion formulated with poly-L-lactic acid and polysorbate is used as the dispersed phase, and the aqueous solution prepared with polyethylene, β-nicotinamide mononucleotide and gelatin is used as the continuous phase, and the emulsion and aqueous solution According to a specific volume ratio and flow rate into the reaction vessel, under the action of high-speed mechanical shear force, a porous microsphere skeleton structure is formed, and β-nicotinamide monolayers are loaded or coated on the surface and interior of the porous microsphere skeleton structure. Nucleotides, the above-mentioned specific process and conditions to prepare porous poly-L-lactic acid microspheres, the obtained porous poly-L-lactic acid microspheres are regular in shape, the particle size ranges from 20 to 60 μm, the particle size distribution is narrow, the preparation process is relatively simple, and the particle size can be adjusted. Strong controllability and low cost, it has great practical application prospects in the technical field of biomedical materials;

(2) The facial filler compounded with porous poly-L-lactic acid microspheres as the main active component and mannitol and sodium carboxymethylcellulose has good resolubility, in which poly-L-lactic acid and β-nicotinamide alone Nucleotides can synergistically exert excellent effects, and the porous poly-L-lactic acid microspheres are spherical and have a relatively uniform particle size. The injection of this facial filler into the body will not cause serious inflammatory reactions, and it has excellent anti-wrinkle and skin rejuvenation effects. In addition to the whitening effect, it also has good safety.

Description of drawings

Fig. 1 is the SEM picture (35 μm) of the porous poly-L-lactic acid microsphere that embodiment 1 provides among the present invention;

Fig. 2 is the particle size dispersion diagram of the porous poly-L-lactic acid microspheres provided by Example 1 of the present invention;

Fig. 3 is the histological section diagram of stimulation to produce collagen after subcutaneous injection of the facial filler provided by Example 5 of the present invention in rabbits for 6 months;

Fig. 4 is a diagram of tissue slices stimulated to produce collagen 6 months after the facial filler provided by Comparative Example 4 of the present invention was subcutaneously injected into rabbits.

Detailed ways

The inventors of the present application have found in a large number of practices that the microspheres prepared from poly-L-lactic acid are not uniform in size and have poor dispersion; and, if β-nicotinamide mononucleotide (NMN) is introduced into the preparation of poly-L-lactic acid In addition, the final prepared particles will be in the shape of flakes, rods, and irregular shapes in addition to being spherical. When they are applied to facial fillers, they may cause severe inflammatory reactions in the body, and the safety is poor. .

The inventor has creatively designed the following scheme through creative efforts and a large number of experiments:

The emulsion containing 2-20wt% poly-L-lactic acid, 3-30wt% polysorbate and 50-95wt% organic solvent is used as the dispersed phase, including 0.5-2wt% polyvinyl alcohol, 0.2-2wt% β-smoke An aqueous solution of amide mononucleotide, 0.5-5wt% gelatin and 91-98.8wt% water is used as the dispersed phase, and the volume ratio of the two in the preparation process is 1:(3-15);

The emulsion and the aqueous solution enter the reaction vessel at a specific flow rate of 5-50mL/min and 500-2500mL/min respectively, and undergo high-speed shearing under the action of high-speed mechanical shear force generated by a high-speed rotor with a rotation speed of 1000-5000rpm. cutting reaction to obtain microsphere suspension;

The microsphere suspension is vacuum-dried to form micropores on the surface and inside of the microspheres while removing the organic solvent and water, and finally obtain porous poly-L-lactic acid microspheres.

Using the emulsion and aqueous solution provided in the present invention as raw materials, and using a specific preparation process, NMN is coated in the microspheres, and the microspheres have a regular spherical porous structure with a particle size of 20-60 μm; porous poly-L-lactic acid NMN and poly-L-lactic acid in the microspheres synergistically exert good whitening and skin rejuvenation effects, and the shape and size of the microspheres are controllable during the preparation process. Strong inflammatory response, with good safety.

In some specific embodiments, the content of poly-L-lactic acid in the emulsion is within the above range, specifically 2wt%, 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, 18wt%, 20wt% or any value in between.

In some specific embodiments, the content of polysorbate in the emulsion is within the above range, specifically 3wt%, 5wt%, 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, 23wt% , 25wt%, 27wt%, 30wt% or any value between them.

In the present invention, the organic solvent used in the emulsion has a certain influence on the shape and size of the finally prepared porous poly L-microspheres, specifically, it can be one of chloroform, dichloromethane and absolute ethanol or more; and the actual amount of organic solvent is adjusted according to the amount of poly-L-lactic acid and polysorbate when used.

In some specific embodiments, the content of polyvinyl alcohol in the aqueous solution is within the above range, specifically 0.5wt%, 0.7wt%, 0.9wt%, 1.0wt%, 1.2wt%, 1.5wt%, 1.8wt% wt%, 2.0 wt%, or any value between them.

In some specific embodiments, the content of β-nicotinamide mononucleotide in the aqueous solution is within the above range, specifically 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.7wt%, 1.0wt%, 1.5wt%, 1.7wt%, 2.0wt% or any value between them.

In some specific embodiments, the content of gelatin in the aqueous solution is within the above range, specifically 0.5wt%, 0.8wt%, 1.2wt%, 1.5wt%, 2.0wt%, 3.0wt%, 4.0wt% , 5.0wt% or any value between them.

In the present invention, the addition volume ratio of emulsion and aqueous solution affects the three-dimensional spatial structure of poly-L-lactic acid microspheres in the preparation process; There are many flaky or crown-like particles; and when the amount of aqueous solution added is too small, the formed porous polylactic acid microspheres are prone to agglomeration and poor uniformity. Therefore, only by using the emulsion and the aqueous solution disclosed in the present invention, the two are in a specific ratio and matched with a specific preparation process, can the porous poly-L-lactic acid particles with spherical shape, uniform particle size and good dispersibility be prepared. ball.

In some specific embodiments, the volume ratio of the emulsion and the aqueous solution is 1:3, 1:4, 1:5, 1:7, 1:10, 1:12, 1:13, 1:15 or their any value in between. In the present invention, the high-speed homogenizer in the reaction vessel rotates at a specific speed, and the generated high-speed mechanical shear force acts on the emulsion and aqueous solution entering the reaction vessel at a specific flow rate, and poly-L-lactic acid coats β- Nicotinamide mononucleotide aggregates at the same time to form microspheres with regular shape and uniform particle size.

In some specific embodiments, the rotating speed of the high-speed homogenizer in the reaction vessel is 1000rpm, 1100rpm, 1300rpm, 1500rpm, 2000rpm, 2300rpm, 2500rpm, 2700rpm, 3000rpm, 3200rpm, 3700rpm, 4000rpm, 4300rpm, 4500rpm, 4700rpm , 5000rpm or any value in between.

In some specific embodiments, the flow rate of the emulsion into the reaction vessel is 5mL/min, 8mL/min, 10mL/min, 12mL/min, 15mL/min, 18mL/min, 20mL/min, 25mL/min, 30mL /min, 35mL/min, 40mL/min, 50mL/min or any value between them.

In some specific embodiments, the flow rate of the aqueous solution into the reaction vessel is 500mL/min, 800mL/min, 900mL/min, 1000mL/min, 1200mL/min, 1500mL/min, 1800mL/min, 2000mL/min, 2500mL/min min or any value in between.

Adding gelatin during the preparation of porous poly-L-lactic acid microspheres is conducive to the formation of microspheres with uniform particle size; at the same time, in the process of vacuum drying, gelatin is used as a pore-forming agent to form holes in the interior and surface of the microspheres, and finally can Microsphere particles with porous spherical structure were prepared.

The gelatin used in the present invention can be animal gelatin, modified gelatin or a mixture of the two; wherein, animal gelatin refers to a kind of gelatin obtained by partially degrading collagen in connective tissues such as animal skin, bone, and sarcolemma. Macromolecular hydrocolloids.

In some specific embodiments, the modified gelatin can be but not limited to one or more of thiolated gelatin, phosphorylated gelatin, succinylated gelatin and urea-linked gelatin.

Among them, thiolated gelatin refers to the compound obtained by modifying the carboxyl group in the macromolecular chain of animal gelatin with disulfide, phosphorylated gelatin refers to the compound obtained by phosphorylation of animal gelatin, and succinylated gelatin refers to A compound obtained by modifying animal gelatin with succinamide, and urea-linked gelatin refers to a compound obtained by cross-linking hexamethylene diisocyanate and animal gelatin through a urea bridge.

In some preferred embodiments, thiolated gelatin or urea-linked gelatin is added to the aqueous solution to prepare porous poly-L-lactic acid microspheres. Thiolated gelatin and urea-linked gelatin can be degraded and completely absorbed in the body, and have good biological safety. sex.

In some specific embodiments, the temperature of vacuum drying is 45°C, 48°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C or any value between them. The vacuum degree is 0.05-0.08MPa, specifically 0.05MPa, 0.055MPa, 0.06MPa, 0.072MPa, 0.08MPa or any value between them, and the time is 0.5-4h, specifically 0.5h, 0.6h, 0.9h, 1.0 h, 1.3h, 1.5h, 1.8h, 2.0h, 2.2h, 2.5h, 3.0h, 3.5h, 4.0h or any value between them.

In some preferred embodiments, before vacuum drying, the microsphere suspension is centrifuged, sieved or sedimented to remove most of the organic solvent and water, which can effectively shorten the time required for vacuum drying, Greatly improve production efficiency and save production costs.

The present invention also provides porous poly-L-lactic acid microspheres prepared by the above method, which have a porous spherical skeleton structure, and β-nicotinamide mononucleotide is loaded on the porous spherical skeleton structure. Through the porous spherical framework structure, the two immiscible substances (poly-L-lactic acid and NMN) are fully combined in a superposition effect to exert the synergistic effect of poly-L-lactic acid and NMN, and the prepared porous poly-L-lactic acid microspheres The property is stable, easy to industrialize, and has a good application prospect.

In the facial filler provided by the present invention, the above porous poly-L-lactic acid microspheres are used as the main active ingredient, supplemented with mannitol and sodium carboxymethylcellulose. In facial fillers, the specific content of each component is:

In some specific embodiments, the content of the porous poly-L-lactic acid microspheres of the facial filler is 0.1wt%, 0.5wt%, 0.7wt%, 1.0wt%, 1.3wt%, 1.5wt%, 1.8wt%, 2.0wt% wt%, 2.4wt%, 2.8wt%, 3.0wt%, 3.3wt%, 3.5wt%, 3.8wt%, 4.0wt% or any value between them.

In some specific embodiments, the mannitol content of the facial filler is 0.1wt%, 0.5wt%, 0.7wt%, 1.0wt%, 1.3wt%, 1.5wt%, 1.8wt%, 2.0wt%, 2.4wt% %, 2.8wt%, 3.0wt%, 3.3wt%, 3.5wt%, 3.8wt%, 4.0wt% or any value between them.

In some specific embodiments, the content of sodium carboxymethylcellulose in the facial filler is 0.0002wt%, 0.001wt%, 0.005wt%, 0.01wt%, 0.05wt%, 0.1wt%, 1.0wt%, 2.4 wt%, 3.0wt%, 5.0wt%, 8.0wt%, 10.5wt%, 15.0wt%, 20wt%, 23wt%, 25wt% or any value between them.

Prepare the facial filler with the above content to increase the yield of the porous poly-L-lactic acid microspheres and reduce the weight loss, so that the porous poly-L-lactic acid microspheres can be released stably after the facial filler is injected into the body, which improves the safety of the facial filler. sex.

When the weight-average molecular weight of sodium carboxymethylcellulose is 5000-500000 Da, it can assist the porous poly-L-lactic acid microspheres to exert the best biological activity. In some specific embodiments, the weight average molecular weight of sodium carboxymethylcellulose is 5000Da, 10000Da, 50000Da, 100000Da, 150000Da, 200000Da, 250000Da, 300000Da, 350000Da, 400000Da, 450000Da, 500000Da or any value between them.

The present invention also provides the preparation method of above facial filler, and this method specifically comprises:

Take the porous poly-L-lactic acid microspheres, mannitol and sodium carboxymethyl cellulose according to the mass ratio of (10-50):(10-50):(5-15), and stir and mix them uniformly at 1000-10000rpm to obtain a mixture ;

Mix the mixture with water according to the mass ratio of 1:(20-50), and keep stirring at a speed of 500-2500 rpm for 10-30 minutes to obtain a facial filler solution;

The facial filler solution is freeze-dried for 4-48 hours to obtain the quasi-facial filler.

In some specific embodiments, the facial filler solution is freeze-dried for 4-48 hours at a temperature ranging from -60°C to 40°C and a pressure of 5-30Pa to obtain the quasi-facial filler.

The facial filler solution is freeze-dried in the process of cooling, heating, and cooling again, and the air pressure changes with the change of temperature.

In some specific embodiments, the temperature range during the freeze-drying process can be -60～40°C, -60～30°C, -60～10°C, -50～40°C, -50～20°C, -20～20°C 40°C, -10～40°C or any range between them; pressure is 5Pa, 6Pa, 8Pa, 10Pa, 14Pa, 16Pa, 18Pa, 20Pa, 23Pa, 25Pa, 27Pa, 29Pa, 30Pa or any value between them ; The freeze-drying time changes adaptively with changes in temperature and pressure, specifically 4h, 6h, 8h, 10h, 12h, 14h, 18h, 20h, 25h, 30h, 36h, 42h, 48h or their any value in between. In the present invention, the specific addition mass ratio of each component in the facial filler and the specific mixing method make the porous poly-L-lactic acid microspheres in the facial filler have good dispersibility, and the porous poly-L-lactic acid microspheres in the facial filler are combined with It has good resolubility, and the injection of the facial filler into the body will not cause severe inflammatory reactions. While having excellent anti-wrinkle, skin rejuvenation and whitening effects, it also has good safety.

The embodiments of the present invention will be described in detail below, and the examples of the embodiments are intended to explain the present invention and should not be construed as limiting the present invention. If no specific technique or condition is indicated in the examples, it shall be carried out according to the technique or condition described in the literature in this field or according to the product specification. The reagents or instruments used were not indicated by the manufacturer, and they were all commercially available conventional products.

In the following examples and comparative examples, the parts of each raw material refer to parts by weight.

Example 1.

This example is used to illustrate the preparation of porous poly-L-lactic acid microspheres, which specifically includes the following steps:

S1. Dissolve 10 parts of poly-L-lactic acid and 20 parts of polysorbate 60 in 70 parts of chloroform, stir and mix evenly to obtain an emulsion; take 1 part of NMN, 1 part of polyvinyl alcohol and 3 parts of The animal gelatin was dissolved in 95 parts of deionized water, stirred and mixed evenly to obtain an aqueous solution.

S2. With the emulsion as the dispersed phase and the aqueous solution as the continuous phase, the emulsion and the aqueous solution are added to the emulsification reactor at a flow rate of 10mL/min and 1500mL/min and a volume ratio of 1:3 through a vacuum magnetic pump, The rotation speed of the high-speed homogenizer in the emulsification reactor is 1000rpm, and the emulsion and the aqueous solution undergo a high-speed shear reaction under strong shear force to obtain a suspension of microspheres.

S3. Place the suspension containing the microspheres in a vacuum desiccator, and vacuum-dry for 4 hours at a temperature of 45° C. and a vacuum degree of 0.05 MPa to obtain porous poly-L-lactic acid microspheres.

It can be seen from Figure 1 and Figure 2 that the porous poly-L-lactic acid microspheres are regular in shape, have a porous spherical skeleton structure, and the particle size is in the range of 15-50 μm, with good particle size uniformity.

Embodiment 2～4.

Examples 2-4 Porous poly-L-lactic acid microspheres were prepared according to the method provided in Example 1, the differences are shown in Table 1, and other conditions were the same.

Table 1.

Comparative examples 1 to 3.

Comparative Examples 1-3 prepared porous poly-L-lactic acid microspheres according to the method provided in Embodiment 1, the differences are shown in Table 2, and other conditions were the same.

Table 2.

Test case 1.

Adopt BT-9300ST laser particle size analyzer to measure the particle size of the porous poly-L-lactic acid microspheres provided in Examples 1-4 and Comparative Examples 1-3, and count and calculate the average particle size and particle size polydispersity index according to the test results, The results are shown in Table 3.

table 3.

It can be seen from the test results that, compared with Comparative Examples 1 to 3, the microspheres prepared by the method provided in Examples 1 to 4 of the present invention have good dispersion and uniformity in particle size, indicating that only the microspheres disclosed in the present invention are used. Only when the emulsion and aqueous solution enter the reaction vessel at a specific flow rate, specific raw materials and input amount, can the microspheres with good particle size dispersion and uniformity, regular structure and uniform size be prepared, and the preparation method is heavy. Good performance.

Example 5.

This embodiment is used to illustrate the preparation of facial filler, specifically comprises the following steps:

S1. Take 10 parts of porous poly-L-lactic acid microspheres provided in Example 1, 10 parts of mannitol and 5 parts of sodium carboxymethylcellulose, and stir at a speed of 1000 rpm to obtain a mixture;

S2. Take 10 parts of the mixture and 200 parts of water, stir and mix evenly at a speed of 500 rpm for 20 minutes to obtain a filler solution;

S3. Freeze-dry the filler solution for 24 hours under the conditions of a temperature range of -50-20° C. and a pressure of 10-25 Pa to obtain a facial filler.

The weight-average molecular weight of sodium carboxymethylcellulose used in this example is 5000Da.

Embodiment 6～8.

Examples 6-8 Prepare facial fillers according to the method provided in Example 5, the differences are shown in Table 4, and other conditions are the same.

Table 4.

Comparative example 4～6.

Comparative Examples 4-6 prepared facial fillers according to the method provided in Example 5, the differences are shown in Table 5, and other conditions were the same.

table 5.

Test case 2.

Use the facial fillers provided in Examples 5-8 and Comparative Examples 4-6 to conduct in vitro bioequivalence experiments: inject the facial fillers provided in Examples 5-8 and Comparative Examples 4-6 subcutaneously into the abdomen of rabbits, and Tissue sections were taken at 8 weeks, 16 weeks, and 24 weeks to observe the stimulation of collagen hyperplasia and changes in collagen thickness. The collagen thickness was scored according to the microscopic method. The test results are shown in Figures 3 and 4 and Table 6.

Table 6.

From the test results in Figures 3 and 4 and Table 6, it can be seen that compared with Comparative Examples 4-6, when the facial fillers provided by Examples 5-8 of the present invention are subcutaneously injected into rabbits, they achieve good results. Collagen stimulating effect, with obvious collagen hyperplasia and anti-wrinkle effect. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be construed as limitations to the present invention. Variations, modifications, substitutions, and modifications to the above-described embodiments are possible within the scope of the present invention.

Claims (10)

1. The preparation method of the porous poly-L-lactic acid microsphere is characterized by comprising the following steps of:

s1, taking emulsion and aqueous solution, respectively entering a reaction container at flow rates of 5-50 mL/min and 500-2500 mL/min, and carrying out high-speed shearing reaction at a rotating speed of 1000-5000 rpm to obtain microsphere suspension;

s2, carrying out vacuum drying on the microsphere suspension to obtain the porous poly-L-lactic acid microsphere;

wherein the emulsion comprises 2-20wt% of poly-L-lactic acid, 3-30wt% of polysorbate and 50-95wt% of organic solvent, the aqueous solution comprises 0.5-2wt% of polyvinyl alcohol, 0.2-2wt% of beta-nicotinamide mononucleotide, 0.5-5wt% of gelatin and 91-98.8wt% of water, and the addition volume ratio of the emulsion to the aqueous solution is 1 (3-15).

2. The method for preparing porous poly-l-lactic acid microsphere according to claim 1, wherein the gelatin is selected from animal gelatin and/or modified gelatin;

optionally, the modified gelatin is selected from one or more of thiolated gelatin, phosphorylated gelatin, succinylated gelatin, and ureido gelatin.

3. The method for preparing porous poly-L-lactic acid microsphere according to claim 1, wherein the organic solvent is one or more selected from the group consisting of chloroform, methylene chloride and absolute ethanol.

4. The method for preparing porous poly-L-lactic acid microsphere according to claim 1, wherein the vacuum drying temperature is 45-80 ℃, the vacuum degree is 0.05-0.08 MPa, and the time is 0.5-4 h.

5. The method for preparing porous poly-L-lactic acid microsphere according to claim 1, further comprising centrifuging, sieving or settling the microsphere suspension before vacuum drying.

6. The porous poly-L-lactic acid microsphere is characterized in that the porous poly-L-lactic acid microsphere is prepared by the preparation method of the porous poly-L-lactic acid microsphere according to any one of claims 1 to 5.

7. The porous polylactic acid microsphere according to claim 6, wherein the porous polylactic acid microsphere has a porous spherical skeleton structure, and the porous spherical skeleton structure is loaded with β -nicotinamide mononucleotide.

8. A facial filler comprising 0.1 to 4wt% of the porous polylactic acid microsphere of claim 6 or 7, 0.1 to 4wt% of mannitol, 0.0002 to 25wt% of sodium carboxymethyl cellulose, and 50 to 95wt% of water.

9. The facial filler of claim 8, wherein the sodium carboxymethyl cellulose has a weight average molecular weight of 5000 to 500000Da.

10. A method of preparing the facial filler of claim 8 or 9, comprising: taking the porous poly-L-lactic acid microspheres, mannitol and sodium carboxymethylcellulose according to the mass ratio of (10-50) to (5-15), and continuously stirring for 5-45 min at the rotating speed of 1000-10000 rpm to obtain a mixture;

mixing the mixture with water according to the mass ratio of 1 (20-50), and continuously stirring for 10-30 min at the rotating speed of 500-2500 rpm to obtain facial filler solution;

and freeze-drying the facial filler solution for 4-48 hours to obtain the facial filler.

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