Hyaluronic acid microspheres, hyaluronic acid filler and application of hyaluronic acid microspheres and hyaluronic acid filler

Abstract

The invention discloses hyaluronic acid microspheres, a hyaluronic acid filling agent and application of the hyaluronic acid microspheres and the hyaluronic acid filling agent, and belongs to the technical field of hyaluronic acid materials. The particle size distribution of the hyaluronic acid microspheres is 20-70 [mu] m; the swelling degree of the hyaluronic acid microspheres is 5 to 40. The hyaluronic acid microsphere can be used as a soft tissue filler, can avoid the problems of redness and swelling, blood vessel blockage and the like, and improves the use safety.

Description

[0001] This case is a divisional application. The application date of the parent case is March 29, 2024, the application number is 2024103793884, and the name is "A kind of hyaluronic acid microspheres and their preparation method and application". Technical Field

[0002] The present invention relates to the technical field of hyaluronic acid materials, and in particular to hyaluronic acid microspheres, a hyaluronic acid filler and applications thereof. Background Art

[0003] Currently, a variety of soft tissue fillers are commercially available for facial aesthetic correction, including autologous fat, polymethyl methacrylate, hydroxyapatite, poly-L-lactic acid, polycaprolactone, and hyaluronic acid (HA). HA is the most widely used filler, with efficacy lasting approximately 6 to 24 months. However, as filler use increases, some risks (such as bruising, swelling and infection, vascular damage, and blindness) also increase.

[0004] HA is a high-molecular-weight linear mucopolysaccharide composed of repeating disaccharide units of D-glucuronic acid and N-acetylglucosamine. Modified HA gels have been studied for many years both domestically and internationally, and their application as soft tissue fillers is well established. Common filler products currently on the market are prepared by reacting HA with a crosslinker under alkaline conditions to form a gel. The resulting blocky gel is then mechanically crushed or pressed into particles. However, the resulting gel suffers from irregular particle morphology, large, and uneven particle size, and its use in facial augmentation can cause redness, swelling, and blood vessel blockage.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The object of the present invention is to provide a hyaluronic acid microsphere, a hyaluronic acid filler and applications thereof, so as to solve or improve the above-mentioned technical problems.

[0007] The present invention can be achieved like this:

[0008] In a first aspect, the present invention provides a hyaluronic acid microsphere having a particle size distribution of 20 μm to 70 μm and a swelling degree of 5 to 40.

[0009] In an optional embodiment, the hyaluronic acid microspheres further have at least one of the following characteristics:

[0010] Feature 1: The elastic modulus of hyaluronic acid microspheres at 5Hz is 40Pa~800Pa;

[0011] Feature 2: The viscosity modulus of hyaluronic acid microspheres at 5 Hz is 15 Pa to 1000 Pa;

[0012] Feature 3: The hyaluronic acid content in the hyaluronic acid microspheres is 5mg / mL to 40mg / mL;

[0013] Feature 4: The pushing force of hyaluronic acid microspheres is 9N~20N;

[0014] Feature 5: The osmotic pressure of hyaluronic acid microspheres is 240mOsmol / kg to 360mOsmol / kg;

[0015] Feature 6: The refractive index of hyaluronic acid microspheres is 1.32-1.35.

[0016] In a second aspect, the present invention provides a hyaluronic acid filler comprising a non-cross-linked sodium hyaluronate solution and at least one of the active ingredients and the hyaluronic acid microspheres of the aforementioned embodiment;

[0017] Wherein, the active ingredients include at least one of amino acids and lidocaine.

[0018] In a third aspect, the present invention provides a use of the hyaluronic acid microspheres or the hyaluronic acid filler according to the aforementioned embodiment, which can be used as a soft tissue filler, for example.

[0019] In an alternative embodiment, the hyaluronic acid microspheres or hyaluronic acid fillers are used as medical soft tissue fillers or cosmetic soft tissue fillers.

[0020] The beneficial effects of the present invention include:

[0021] The hyaluronic acid microspheres provided in this application have a narrow particle size distribution, which can prevent vascular embolism after injection into blood vessels. Furthermore, the hyaluronic acid microspheres have a small particle size and a correspondingly large specific surface area. Even in the event of overcorrection or misoperation leading to embolism, they can be rapidly degraded by injecting hyaluronidase into the problem area, greatly improving the safety of the injection. Furthermore, the hyaluronic acid microspheres provided in this application have good mechanical strength and can achieve an excellent filling effect after implantation, thus achieving the effectiveness of the filler. Furthermore, the hyaluronic acid microspheres also have a low pushing force, which facilitates injectability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is a microscope photograph of the hyaluronic acid microspheres provided in Example 1 of the present invention;

[0024] Figure 2 This is a microscope photograph of hyaluronic acid microspheres provided in Comparative Example 2 of the present invention;

[0025] Figure 3 Microscope photos of hyaluronic acid products provided for the existing product Runbaiyan (Huaxi Biotechnology Co., Ltd.);

[0026] Figure 4 This is a diagram showing the results of animal experiments in the test examples of the present invention. DETAILED DESCRIPTION

[0027] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0028] The hyaluronic acid microspheres, hyaluronic acid fillers and their applications provided in this application are described in detail below.

[0029] The present application provides a hyaluronic acid microsphere, the particle size distribution of which is 20 μm to 70 μm.

[0030] The hyaluronic acid microspheres have a relatively concentrated and uniform particle size distribution, which can avoid problems such as redness, swelling, and blood vessel blockage that can be caused by irregular particle shape, large particle size, or uneven particle size. It should be noted that hyaluronic acid microspheres with a particle size of less than 20 μm are easily phagocytosed by human macrophages, while those with a particle size greater than 70 μm can easily cause vascular embolism upon injection into blood vessels.

[0031] In addition, the hyaluronic acid microspheres provided in the present application have a smooth surface, have better biocompatibility, and are less likely to cause tissue redness, swelling, and inflammation.

[0032] The hyaluronic acid microspheres provided in the present application may have an elastic modulus of 40 Pa to 800 Pa (such as 40 Pa, 50 Pa, 80 Pa, 100 Pa, 150 Pa, 200 Pa, 250 Pa, 300 Pa, 400 Pa, 500 Pa, 600 Pa, 700 Pa or 800 Pa, etc., or other values ​​within the range of 40 Pa to 800 Pa) at a shear frequency of 5 Hz on a rheometer, and a viscous modulus of 15 Pa to 1000 Pa (such as 15 Pa, 50 Pa, 80 Pa, 100 Pa, 150 Pa, 220 Pa, 250 Pa, 300 Pa, 400 Pa, 500 Pa, 600 Pa, 700 Pa, 800 Pa, 900 Pa or 1000 Pa, etc., or other values ​​within the range of 15 Pa to 1000 Pa). The hyaluronic acid microspheres having the above elastic modulus and viscosity modulus can have better elasticity and viscosity, which is beneficial to improving the filling effect.

[0033] The swelling degree of the hyaluronic acid microspheres provided herein can be 5 to 40, such as 5, 8, 10, 12, 15, 18, 20, 25, 30, 35 or 40, or other values ​​within the range of 5 to 40. The hyaluronic acid microspheres having the above swelling degrees are suitable for use as fillers.

[0034] The hyaluronic acid content of the hyaluronic acid microspheres provided herein can be 5 mg / mL to 40 mg / mL, such as 5 mg / mL, 10 mg / mL, 15 mg / mL, 20 mg / mL, 25 mg / mL, 30 mg / mL, 35 mg / mL, or 40 mg / mL, or other values ​​within the range of 5 mg / mL to 40 mg / mL. Hyaluronic acid microspheres having such hyaluronic acid contents can achieve good filling effects.

[0035] The pushing force of the hyaluronic acid microspheres provided herein can be 9 N to 20 N, such as 9 N, 10 N, 12 N, 15 N, 18 N, or 20 N, or other values ​​within the range of 9 N to 20 N. Hyaluronic acid microspheres with a pushing force within this range can facilitate injection by the user while also reducing pain and discomfort after injection.

[0036] The osmotic pressure of the hyaluronic acid microspheres provided herein can be 240mOsmol / kg to 360mOsmol / kg, such as 240mOsmol / kg, 260mOsmol / kg, 280mOsmol / kg, 300mOsmol / kg, 320mOsmol / kg, 340mOsmol / kg or 360mOsmol / L, or other values ​​within the range of 240mOsmol / kg to 360mOsmol / kg. Hyaluronic acid microspheres with the above osmotic pressures can maintain an osmotic pressure that is relatively consistent with that of the human body, thereby avoiding significant water absorption or dehydration in the injection area after injection into the human body.

[0037] The refractive index of the hyaluronic acid microspheres provided herein can be 1.32 to 1.35, such as 1.32, 1.33, 1.34 or 1.35, or other values ​​within the range of 1.32 to 1.35. Hyaluronic acid microspheres having the above refractive index have high purity.

[0038] Continuing from the above, the hyaluronic acid microspheres provided by this application have a narrow particle size distribution, which can prevent vascular embolism after injection into blood vessels. At the same time, the hyaluronic acid microspheres have a small particle size and a correspondingly large specific surface area. Even in the event of overcorrection or misoperation resulting in embolism, they can be quickly degraded by injecting hyaluronidase into the problem area, greatly improving the safety of the injection. In addition, the hyaluronic acid microspheres provided by this application have good mechanical strength and can achieve an excellent filling effect after implantation, realizing the effectiveness of the filler. Moreover, the hyaluronic acid microspheres also have a low pushing force, which is conducive to achieving injectability.

[0039] Accordingly, the present invention also provides a method for preparing the above-mentioned hyaluronic acid microspheres, which may include the following steps:

[0040] mixing hyaluronic acid or its salt with a base and water, and then with a cross-linking agent to obtain an aqueous phase;

[0041] The aqueous phase and the oil phase are mixed and emulsified for the first time to obtain a dispersion;

[0042] emulsifying the dispersion for the second time to obtain an emulsion;

[0043] removing the oil phase from the emulsion to obtain cross-linked hyaluronic acid microspheres;

[0044] The first emulsification is carried out at a rotation speed of not less than 1000 rpm, and the second emulsification is carried out at a rotation speed of not less than 4000 rpm.

[0045] It should be noted that conventional technology uses a one-time emulsification method, which is prone to uneven emulsification. The part poured into the emulsifier first will be over-emulsified, forming small-particle microspheres, while the part poured into the emulsifier later will easily have incomplete emulsification problems, forming large-particle microspheres, and finally obtaining a microsphere product with a wide particle size distribution and poor particle size uniformity.

[0046] The present invention performs the first emulsification first and obtains the dispersion by pre-emulsification, which can accurately control the oil-water ratio of the emulsification, avoid uneven emulsification caused by the high viscosity of the water phase, better perform the next high-speed emulsification, and obtain microspheres with a narrow particle size distribution. Through the two-step cross-linking emulsification method, the number of times the microspheres are sheared by the emulsifier can be relatively consistent, and they can be fully emulsified. In addition, by first pre-emulsifying at a low speed and then emulsifying at a high speed, the time of high-speed emulsification can be reduced, avoiding the adhesion of microspheres and the demulsification of the emulsion caused by the increase in temperature during high-speed emulsification, and thus more accurately controlling the particle size distribution of the microspheres within the range of 20μm to 50μm.

[0047] For reference, the first emulsification is performed at 1000-2000 rpm for 5-30 minutes. For example, the rotation speed can be 1000 rpm, 1200 rpm, 1500 rpm, 1800 rpm, or 2000 rpm, or any other value within the range of 1000-2000 rpm. The emulsification time can be 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, or 30 minutes, or any other value within the range of 5-30 minutes.

[0048] The second emulsification is performed at 4000-8000 rpm for 10-30 minutes. For example, the rotation speed can be 4000 rpm, 4500 rpm, 5000 rpm, 5500 rpm, 6000 rpm, 6500 rpm, 7000 rpm, 7500 rpm, or 8000 rpm, or any other value within the range of 4000-8000 rpm. The emulsification time can be 10, 15, 20, 25, or 30 minutes, or any other value within the range of 10-30 minutes.

[0049] In the present invention, hyaluronates may illustratively but not limitatively include sodium hyaluronate, calcium hyaluronate, and magnesium hyaluronate. The content of hyaluronic acid or its salt in the aqueous phase may be 0.5 wt% to 20 wt%, such as 0.5 wt%, 1 wt%, 2 wt%, 5 wt%, 10 wt%, 12 wt%, 15 wt%, 18 wt%, or 20 wt%, or other values ​​within the range of 0.5 wt% to 20 wt%.

[0050] If the content of hyaluronic acid or its salt in the aqueous phase is too low, the product may not be viscous or elastic enough. If the content of hyaluronic acid or its salt in the aqueous phase is too high, the product may not dissolve well.

[0051] In the present invention, the content of alkali in the aqueous phase can be 0.5wt% to 5w%, such as 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt% or 5wt%, etc., and can also be other values ​​within the range of 0.5wt% to 5w%.

[0052] Illustratively, the base may include at least one of NaOH and KOH.

[0053] If the content of the alkali in the aqueous phase is too low, the cross-linking reaction may not occur or the cross-linking may be incomplete; if the content of the alkali in the aqueous phase is too high, the molecular chain of hyaluronic acid or its salt may be easily destroyed.

[0054] In the present invention, the content of the crosslinking agent in the aqueous phase can be 0.1wt% to 10w%, such as 0.1wt%, 0.2wt%, 0.5wt%, 1wt%, 2wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt% or 10wt%, etc., and can also be other values ​​within the range of 0.1wt% to 10w%.

[0055] Similarly, if the content of the cross-linking agent in the aqueous phase is too low, the cross-linking reaction may not occur or the cross-linking may be incomplete; if the content of the cross-linking agent in the aqueous phase is too high, the molecular chains of hyaluronic acid or its salts may be easily destroyed.

[0056] The cross-linking agent may illustratively but not limitatively include at least one of butanediol diglycidyl ether and divinyl sulfone.

[0057] For reference, the mixing temperature of the above materials may be 40° C. to 50° C. to allow the hyaluronic acid or its salt to be fully cross-linked.

[0058] In the present invention, the volume ratio of the oil phase to the water phase can be 1:1 to 10:1, such as 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1, or other values ​​within the range of 1:1 to 10:1. By mixing the water phase with the oil phase to form a water-in-oil system, microspheres with preferred morphology and size are obtained through a subsequent emulsification process.

[0059] The oil phase may illustratively but not limitatively include at least one of vegetable oil, mineral oil, silicone oil, liquid paraffin, dodecane, n-octane and cyclohexane.

[0060] For example, the removal of the oil phase from the emulsion can be performed by filtration.

[0061] As mentioned above, the preparation method of hyaluronic acid microspheres provided in the present application is simple, the reaction conditions are mild, the process is easy to control, and hyaluronic acid microspheres with excellent effects and high yield can be obtained.

[0062] In addition, the present invention also provides a hyaluronic acid filler, which includes a non-cross-linked sodium hyaluronate solution and at least one of the active ingredients and the above-mentioned hyaluronic acid microspheres.

[0063] By compounding non-cross-linked sodium hyaluronate solution with hyaluronic acid microspheres, the shear viscosity of the product can be increased.

[0064] By compounding the active ingredient with the hyaluronic acid microspheres, other functions of the product can be increased, such as moisturizing, whitening, etc. For example, the active ingredient may include at least one of amino acids and lidocaine.

[0065] It should be noted that the compounding relationship between the non-cross-linked sodium hyaluronate solution, the active ingredient and the hyaluronic acid microspheres can be set as needed and is not limited here.

[0066] Furthermore, the present invention also provides an application of the above-mentioned hyaluronic acid microspheres or the above-mentioned hyaluronic acid filler, for example, it can be used as a soft tissue filler.

[0067] For reference, hyaluronic acid microspheres or hyaluronic acid fillers can be used as medical soft tissue fillers or cosmetic soft tissue fillers.

[0068] For reference, hyaluronic acid microspheres or hyaluronic acid fillers can be used as facial soft tissue fillers.

[0069] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0070] Example 1

[0071] This embodiment provides a hyaluronic acid microsphere, the preparation process of which includes:

[0072] S1: Hyaluronic acid was mixed with NaOH and water, and then butanediol diglycidyl ether was added and mixed at 45° C. to obtain an aqueous phase.

[0073] The content of hyaluronic acid in the aqueous phase is 10 wt %, the content of NaOH in the aqueous phase is 2 wt %, and the content of butanediol diglycidyl ether in the aqueous phase is 5 wt %.

[0074] S2: The water phase and the oil phase are mixed and emulsified for the first time to obtain a dispersion.

[0075] The oil phase was silicone oil, and the volume ratio of the oil phase to the water phase was 5: 1. The first emulsification was carried out at 1500 rpm for 20 min.

[0076] S3: emulsifying the dispersion for the second time to obtain an emulsion.

[0077] The second emulsification was carried out at 6000 rpm for 20 min.

[0078] S4: removing the oil phase in the emulsion by filtration to obtain cross-linked hyaluronic acid microspheres.

[0079] Example 2

[0080] This embodiment provides a hyaluronic acid microsphere, the preparation process of which includes:

[0081] S1: Hyaluronic acid was mixed with NaOH and water, and then butanediol diglycidyl ether was added and mixed at 40° C. to obtain an aqueous phase.

[0082] The content of hyaluronic acid in the aqueous phase is 0.5 wt %, the content of NaOH in the aqueous phase is 0.5 wt %, and the content of butanediol diglycidyl ether in the aqueous phase is 0.1 wt %.

[0083] S2: The water phase and the oil phase are mixed and emulsified for the first time to obtain a dispersion.

[0084] The oil phase was silicone oil, and the volume ratio of the oil phase to the water phase was 1:1. The first emulsification was carried out at 1000 rpm for 30 min.

[0085] S3: emulsifying the dispersion for the second time to obtain an emulsion.

[0086] The second emulsification was carried out at 4000 rpm for 30 min.

[0087] S4: removing the oil phase in the emulsion by filtration to obtain cross-linked hyaluronic acid microspheres.

[0088] Example 3

[0089] This embodiment provides a hyaluronic acid microsphere, the preparation process of which includes:

[0090] S1: Hyaluronic acid was mixed with NaOH and water, and then butanediol diglycidyl ether was added and mixed at 50° C. to obtain an aqueous phase.

[0091] The content of hyaluronic acid in the aqueous phase is 20 wt %, the content of NaOH in the aqueous phase is 5 wt %, and the content of butanediol diglycidyl ether in the aqueous phase is 10 wt %.

[0092] S2: The water phase and the oil phase are mixed and emulsified for the first time to obtain a dispersion.

[0093] The oil phase was silicone oil, and the volume ratio of the oil phase to the water phase was 10:1. The first emulsification was performed at 2000 rpm for 5 min.

[0094] S3: emulsifying the dispersion for the second time to obtain an emulsion.

[0095] The second emulsification was carried out at 8000 rpm for 10 min.

[0096] S4: removing the oil phase in the emulsion by filtration to obtain cross-linked hyaluronic acid microspheres.

[0097] Example 4

[0098] The difference between this embodiment and embodiment 1 is that in S1, hyaluronic acid is replaced by sodium hyaluronate.

[0099] Example 5

[0100] The difference between this embodiment and embodiment 1 is that in S1, butanediol diglycidyl ether is replaced by divinyl sulfone.

[0101] Example 6

[0102] The difference between this embodiment and embodiment 1 is that in S2, the oil phase is mineral oil, specifically a mixture of an anhydrous derivative of D-mannitol and light mineral oil (MONTANIDE ISA51 VG).

[0103] Example 7

[0104] The difference between this embodiment and embodiment 1 is that in S2, the oil phase is liquid paraffin.

[0105] Example 8

[0106] The difference between this embodiment and embodiment 1 is that in S2, the oil phase is dodecane.

[0107] Example 9

[0108] The difference between this embodiment and embodiment 1 is that in S2, the oil phase is n-octane.

[0109] Example 10

[0110] The difference between this embodiment and embodiment 1 is that in S2, the oil phase is cyclohexane.

[0111] Comparative Example 1

[0112] The difference between this comparative example and Example 1 is that there is no step S3, that is, step S4 is directly performed after step S2.

[0113] Comparative Example 2

[0114] The difference between this comparative example and Example 1 is that there is no step S2, that is, after S1, the water phase and the oil phase are directly mixed and then emulsified for the second time according to the conditions in S3.

[0115] Comparative Example 3

[0116] The difference between this comparative example and Example 1 is that in S1, the content of hyaluronic acid in the aqueous phase is 25 wt %.

[0117] Comparative Example 4

[0118] The difference between this comparative example and Example 1 is that in S1, the content of NaOH in the aqueous phase is 10 wt %.

[0119] Comparative Example 5

[0120] The difference between this comparative example and Example 1 is that in S1, the content of butanediol diglycidyl ether in the aqueous phase is 15 wt %.

[0121] Comparative Example 6

[0122] The difference between this comparative example and Example 1 is that in S2, the volume ratio of the oil phase to the water phase is 0.5:1.

[0123] Comparative Example 7

[0124] The difference between this comparative example and Example 1 is that in S2, the volume ratio of the oil phase to the water phase is 12:1.

[0125] Comparative Example 8

[0126] The difference between this comparative example and Example 1 is that in S2, the rotation speed of the first emulsification is 800 rpm.

[0127] Comparative Example 9

[0128] The difference between this comparative example and Example 1 is that in S2, the rotation speed of the first emulsification is 2200 rpm.

[0129] Comparative Example 10

[0130] The difference between this comparative example and Example 1 is that in S3, the rotation speed of the second emulsification is 3800 rpm.

[0131] Comparative Example 11

[0132] The difference between this comparative example and Example 1 is that in S3, the rotation speed of the second emulsification is 8200 rpm.

[0133] Comparative Example 12

[0134] The difference between this comparative example and Example 1 is that in S3, the time for the second emulsification is 5 minutes.

[0135] Test example

[0136] ①. The performance of the hyaluronic acid microspheres obtained in Examples 1 to 10 and Comparative Examples 1 to 12 was tested. The results are shown in Table 1 and Figures 1 to 3 shown.

[0137] Among them, the particle size distribution is determined according to the wet method of the third method (light scattering method) of the Pharmacopoeia of the People's Republic of China (Part IV) 2020 edition 0982 Particle size and particle size distribution determination method, and the D 50 The result is in μm;

[0138] The elastic modulus and viscous modulus were measured according to "YY / T 0308-2015 Medical Sodium Hyaluronate Gel". At 25±2°C, a frequency sweep was performed using a rheometer at a shear rate of 0.001 to 100 Hz. The elastic modulus G' and viscous modulus G" were plotted against frequency and the results of the elastic modulus G' and viscous modulus G" were recorded. The units of the elastic modulus G' and viscous modulus G" were both Pa.

[0139] The swelling degree is determined according to "YY / T 0962-2021 Cross-linked Sodium Hyaluronate Gel for Plastic Surgery";

[0140] The pushing force is measured according to "YY / T 0962-2021 Cross-linked Sodium Hyaluronate Gel for Plastic Surgery" and its unit is N;

[0141] The osmotic pressure is determined according to "YY / T 0962-2021 Cross-linked Sodium Hyaluronate Gel for Plastic Surgery", and its unit is mOsmol / kg; the refractive index is determined according to "YY / T 0308-2015 Medical Sodium Hyaluronate Gel".

[0142] Table 1 Test results

[0143]

[0144] As can be seen from Table 1, the product obtained in the embodiment of the present invention has the advantages of narrow particle size distribution, large specific surface area, high mechanical strength, low pushing force, moderate osmotic pressure, and high purity.

[0145] Depend on Figures 1 to 3 Comparison shows that both Example 1 and Comparative Example 2 can prepare spherical sodium hyaluronate gel microspheres using the emulsification method. However, Comparative Example 2 does not have the S2 step compared to Example 1, and the particle size distribution is wider, and the particle size is more uneven than that of Example 1, indicating that the two-step emulsification can achieve control of a narrow particle size range of microspheres. Figure 3This is a marketed product of Huaxi Biotechnology. It does not adopt the emulsification method, and what is prepared is blocky and irregular sodium hyaluronate gel particles.

[0146] ②, taking the hyaluronic acid microspheres prepared in Example as an example, and the commercially available product Restylane No. 2 as the control group, the experiment was conducted in the following manner: the left ear artery of the experimental rabbit was punctured with an injection needle, and 0.5 mL of Restylane No. 2 was injected; the right ear artery of the experimental rabbit was punctured with an injection needle, and 0.5 mL of the sample was injected. The immediate phenomenon of the experimental rabbit's ear and the phenomenon within 3 weeks were observed and the observation records were made every day. The results after 3 weeks are as follows: Figure 4 shown.

[0147] Depend on Figure 4 It can be seen that after the injection of the hyaluronic acid microspheres provided in Example 1 of the present application, no blood vessel blockage and redness and swelling occurred; however, after the injection of the same type of product provided in the control group, obvious blood vessel blockage and redness and swelling occurred.

[0148] In summary, the preparation method of the hyaluronic acid microspheres provided by the present application is simple, the reaction conditions are mild, the process is easy to control, and the hyaluronic acid microspheres with excellent effect and high yield can be obtained. The obtained hyaluronic acid microspheres have a narrow particle size distribution, which can avoid vascular embolism after injection into a blood vessel; at the same time, the particle size of the hyaluronic acid microspheres is relatively small, and the corresponding specific surface area is relatively large. Even when embolism occurs due to overcorrection or misoperation, it can be rapidly degraded by injecting hyaluronidase into the problem area, which greatly improves the safety of injection. In addition, the hyaluronic acid microspheres provided by the present application have good mechanical strength and can play a better filling effect after implantation, thereby realizing the effectiveness of the filler; and the hyaluronic acid microspheres also have a relatively low pushing force, which is conducive to achieving injectability.

[0149] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A hyaluronic acid microsphere, characterized in that: The particle size distribution of the hyaluronic acid microspheres is 20 μm to 70 μm; the swelling degree of the hyaluronic acid microspheres is 5 to 40.

2. The hyaluronic acid microspheres according to claim 1, characterized in that The hyaluronic acid microspheres also have at least one of the following characteristics: Feature 1: The elastic modulus of the hyaluronic acid microspheres at 5 Hz is 40 Pa to 800 Pa; Feature 2: The hyaluronic acid microspheres have a viscosity modulus of 15 Pa to 1000 Pa at 5 Hz; Feature 3: The content of hyaluronic acid in the hyaluronic acid microspheres is 5 mg / mL to 40 mg / mL; Feature 4: The pushing force of the hyaluronic acid microspheres is 9N to 20N; Feature 5: The osmotic pressure of the hyaluronic acid microspheres is 240mOsmol / kg to 360mOsmol / kg; Feature 6: The refractive index of the hyaluronic acid microspheres is 1.32 to 1.

35.

3. A hyaluronic acid filler, characterized in that: The hyaluronic acid filler comprises at least one of a non-cross-linked sodium hyaluronate solution and an active ingredient and the hyaluronic acid microspheres according to claim 1 or 2; Wherein, the active ingredient includes at least one of amino acid and lidocaine.

4. A use of the hyaluronic acid microspheres according to any one of claims 1 to 2 or the hyaluronic acid filler according to claim 3, characterized in that: The hyaluronic acid microspheres or the hyaluronic acid filler are used as soft tissue fillers.

5. The use according to claim 4, characterized in that The hyaluronic acid microspheres or the hyaluronic acid filler are used as medical soft tissue fillers or cosmetic soft tissue fillers.

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