Sodium hyaluronate gel as well as preparation method and application thereof

Abstract

The invention discloses sodium hyaluronate gel as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The sodium hyaluronate solution is subjected to first pre-crosslinking at a low temperature, so that side reactions can be reduced, the yield of the prepared sodium hyaluronate gel is remarkably improved, meanwhile, secondary crosslinking is controlled at a high temperature, the crosslinking density of the sodium hyaluronate gel can be further improved, rapid degradation of the sodium hyaluronate gel is avoided, and the sodium hyaluronate gel has a good application prospect. The degradation time of the sodium hyaluronate gel is prolonged; by adding the antioxidant and the metal chelating agent, the degradation time of the sodium hyaluronate gel can be further prolonged; besides, by adopting dialysis treatment, impurity residues of the sodium hyaluronate gel can be removed, and the biocompatibility of the sodium hyaluronate gel is improved, so that the sodium hyaluronate gel has a relatively good application prospect in serving as a biological filling material.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and in particular relates to a sodium hyaluronate gel and a preparation method and application thereof. Background Art

[0002] Sodium hyaluronate is a glycosaminoglycan widely used in biopharmaceuticals, biomaterials, functional foods, and cosmetics. Natural sodium hyaluronate is prone to rapid degradation in human tissue. Traditionally, a solution involves introducing a crosslinking agent to form a network-like gel. This not only increases the degree of crosslinking but also significantly prolongs its degradation time.

[0003] Currently, sodium hyaluronate gel is mostly prepared using a single cross-linking agent or a high-temperature one-step cross-linking method. However, due to residual cross-linking agent, side reactions, or insufficient cross-linking, the raw material reaction is insufficient, resulting in a low yield of sodium hyaluronate gel. At the same time, insufficient cross-linking further causes rapid degradation of sodium hyaluronate gel. In addition, due to residual cross-linking agent, the biocompatibility of sodium hyaluronate gel is low.

[0004] In view of this, it is necessary to develop a new method for preparing sodium hyaluronate gel to solve the shortcomings in the existing technology. Summary of the Invention

[0005] The present invention aims to provide a sodium hyaluronate gel and its preparation method and application, so as to solve the problems of low yield, rapid degradation and low biocompatibility in existing sodium hyaluronate gel.

[0006] In a first aspect, the present invention provides a method for preparing a sodium hyaluronate gel, comprising the following steps: S1, dissolving sodium hyaluronate in a solvent to obtain a sodium hyaluronate solution; S2, adding an antioxidant to the sodium hyaluronate solution, and then adding a first cross-linking agent to carry out a first cross-linking reaction; continuing to add a second cross-linking agent to carry out a second cross-linking reaction, and after quenching, obtaining a cross-linked sodium hyaluronate gel; S3, dialyzing the cross-linked sodium hyaluronate gel, and then adding a metal chelating agent, and after freeze-drying and irradiation sterilization, obtaining a sodium hyaluronate gel; wherein, in step S2, the temperature of the first cross-linking reaction is lower than the temperature of the second cross-linking reaction.

[0007] In the present invention, the inventors have discovered that by subjecting a sodium hyaluronate solution to a first pre-crosslinking at low temperature, side reactions can be reduced and the yield of the prepared sodium hyaluronate gel can be significantly improved. Simultaneously, by controlling the secondary crosslinking at high temperature, the crosslinking density of the sodium hyaluronate gel can be further increased, thereby preventing its rapid degradation and prolonging its degradation time. Furthermore, by adding antioxidants and metal chelating agents, the degradation time of the sodium hyaluronate gel can be further prolonged. Furthermore, by using dialysis treatment, residual impurities in the sodium hyaluronate gel can be removed, thereby improving its biocompatibility. Therefore, the present invention has good application prospects as a biofiller material.

[0008] In some embodiments, in step S1, the molecular weight of sodium hyaluronate is 500,000-2,000,000 Da, the solvent includes phosphate buffer, and the mass concentration of the sodium hyaluronate solution is 3-5%.

[0009] In some embodiments, in step S2, the amount of the antioxidant added is 0.1-0.5 wt %, and the antioxidant includes at least one of sodium ascorbate and glutathione.

[0010] In some embodiments, in step S2, the amount of the first cross-linking agent added is 0.5-1.5 wt%, and the first cross-linking agent includes 1,4-butanediol diglycidyl ether; the temperature of the first cross-linking reaction is 30-45° C., and the time is 1-3 h.

[0011] In some embodiments, in step S2, the amount of the second cross-linking agent added is 0.1-0.3 wt%, and the second cross-linking agent includes genipin; the temperature of the second cross-linking reaction is 50-60° C., and the time is 3-8 h.

[0012] In some embodiments, in step S3, the dialysis treatment specifically includes: dialysis in a dialysate at a temperature of 0-4°C for 40-80 hours; wherein the dialysate includes an ethanol-water solution, and the volume ratio of ethanol to water in the ethanol-water solution is (2-4): (6-8).

[0013] In some embodiments, in step S3, the amount of the metal chelating agent added is 0.03-0.1 wt %, and the metal chelating agent includes disodium ethylenediaminetetraacetate.

[0014] In some embodiments, in step S3, irradiation sterilization specifically includes: using γ-ray irradiation sterilization with a radiation dose of 20-30 kGy.

[0015] In a second aspect, the present invention provides a sodium hyaluronate gel prepared by any of the above preparation methods.

[0016] In a third aspect, the present invention provides use of the sodium hyaluronate gel described above in preparing a biological filling material.

[0017] The beneficial effects of the present invention are as follows: unlike the prior art, the present invention reduces side reactions and significantly improves the yield of the prepared sodium hyaluronate gel by subjecting the sodium hyaluronate solution to a first pre-crosslinking at low temperature. Simultaneously, the secondary crosslinking is controlled at a high temperature, which further increases the crosslinking density of the sodium hyaluronate gel, prevents its rapid degradation, and prolongs the degradation time of the sodium hyaluronate gel. Furthermore, by adding antioxidants and metal chelating agents, the degradation time of the sodium hyaluronate gel can be further prolonged. Furthermore, dialysis treatment can be used to remove residual impurities in the sodium hyaluronate gel, thereby improving its biocompatibility. Therefore, the present invention has good application prospects as a biofiller material. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The figure is a flow chart of the preparation method of the sodium hyaluronate gel of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] For experimental methods in the examples where specific conditions are not specified, generally conventional conditions and conditions described in the manual or conditions recommended by the manufacturer were followed. The general equipment, materials, reagents, etc. used were all commercially available unless otherwise specified.

[0021] Currently, existing sodium hyaluronate gels have problems such as low yield, rapid degradation, and low biocompatibility.

[0022] In order to solve the problems of low yield, rapid degradation, low biocompatibility, etc. in existing sodium hyaluronate gel, the present invention provides a sodium hyaluronate gel and a preparation method and application thereof.

[0023] In a first aspect, the present invention provides a method for preparing a sodium hyaluronate gel, comprising the following steps: S1, dissolving sodium hyaluronate in a solvent to obtain a sodium hyaluronate solution; S2, adding an antioxidant to the sodium hyaluronate solution, and then adding a first cross-linking agent to carry out a first cross-linking reaction; continuing to add a second cross-linking agent to carry out a second cross-linking reaction, and after quenching, obtaining a cross-linked sodium hyaluronate gel; S3, dialyzing the cross-linked sodium hyaluronate gel, and then adding a metal chelating agent, and after freeze-drying and irradiation sterilization, obtaining a sodium hyaluronate gel; wherein, in step S2, the temperature of the first cross-linking reaction is lower than the temperature of the second cross-linking reaction.

[0024] In the present invention, the inventors have discovered that by subjecting a sodium hyaluronate solution to a first pre-crosslinking at low temperature, side reactions can be reduced and the yield of the prepared sodium hyaluronate gel can be significantly improved. Simultaneously, by controlling the secondary crosslinking at high temperature, the crosslinking density of the sodium hyaluronate gel can be further increased, thereby preventing its rapid degradation and prolonging its degradation time. Furthermore, by adding antioxidants and metal chelating agents, the degradation time of the sodium hyaluronate gel can be further prolonged. Furthermore, by using dialysis treatment, residual impurities in the sodium hyaluronate gel can be removed, thereby improving its biocompatibility. Therefore, the present invention has good application prospects as a biofiller material.

[0025] In some embodiments, in step S1, the molecular weight of sodium hyaluronate is 500,000-2 million Da, for example, 500,000 Da, 800,000 Da, 1 million Da, 1.5 million Da, 1.8 million Da, 2 million Da, or other values ​​within this range; the solvent includes phosphate buffer, and the pH value is 7.2-7.6, preferably 7.4; the mass concentration of the sodium hyaluronate solution is 3-5% (W / V), for example, 3%, 3.5%, 4%, 4.5%, or other values ​​within this range.

[0026] In the present invention, by controlling the molecular weight of sodium hyaluronate within a specific range, the subsequent cross-linking reaction is facilitated and the yield of sodium hyaluronate gel is improved.

[0027] It is understood that the solvent can be selected from conventional solvents in the prior art according to actual use needs, as long as it can dissolve sodium hyaluronate and facilitate the subsequent cross-linking reaction. For example, in the present invention, the solvent preferably includes phosphate buffer.

[0028] In some embodiments, in step S2, the amount of antioxidant added is 0.1-0.5 wt%, for example, it can be 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt% or other values ​​within this range; and the antioxidant includes at least one of sodium ascorbate and glutathione.

[0029] In the present invention, by adding a specific content of antioxidant, the degradation time of sodium hyaluronate gel can be prolonged.

[0030] It is understood that the type and amount of the antioxidant can be adjusted according to actual use needs, as long as it has an antioxidant effect. For example, in the present invention, the amount of the antioxidant added is preferably 0.1-0.5wt%, and the antioxidant preferably includes at least one of sodium ascorbate and glutathione.

[0031] In some embodiments, in step S2, the amount of the first cross-linking agent added is 0.5-1.5 wt%, for example, it can be 0.5 wt%, 0.7 wt%, 1 wt%, 1.3 wt%, 1.5 wt% or other values ​​within this range; and the first cross-linking agent includes 1,4-butanediol diglycidyl ether (BDDE); the temperature of the first cross-linking reaction is 30-45°C, for example, it can be 30°C, 35°C, 40°C, 45°C or other values ​​within this range; the time is 1-3 h, for example, it can be 1 h, 1.5 h, 2 h, 2.5 h, 3 h or other values ​​within this range.

[0032] In the present invention, the inventors further discovered that by controlling the amount of the first cross-linking agent added, the temperature and time of the first cross-linking reaction within a specific range, side reactions can be reduced and the yield of the prepared sodium hyaluronate gel can be significantly improved.

[0033] In some embodiments, in step S2, the amount of the second cross-linking agent added is 0.1-0.3 wt%, for example, it can be 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, 0.3 wt% or other values ​​within this range; and the second cross-linking agent includes genipin; the temperature of the second cross-linking reaction is 50-60°C, for example, it can be 50°C, 52°C, 55°C, 58°C, 60°C or other values ​​within this range; the time is 3-8h, for example, it can be 3h, 4h, 5h, 6h, 7h, 8h or other values ​​within this range.

[0034] In the present invention, the inventors further discovered that by controlling the amount of the second cross-linking agent added, the temperature and time of the second cross-linking reaction within a specific range, the cross-linking density of the sodium hyaluronate gel can be further increased, thereby avoiding its rapid degradation and further prolonging the degradation time of the sodium hyaluronate gel.

[0035] In some embodiments, in step S3, the dialysis treatment specifically includes: dialysis in a dialysate at a temperature of 0-4°C (for example, 0°C, 1°C, 2°C, 3°C, 4°C or other values ​​within the range) for 40-80 hours, for example, 40 hours, 50 hours, 60 hours, 70 hours, 80 hours or other values ​​within the range; wherein the dialysate includes an ethanol-water solution, and the volume ratio of ethanol to water in the ethanol-water solution is (2-4): (6-8), for example, 2:6, 2:7, 2:8, 3:6, 3:7, 3:8, 4:6, 4:7, 4:8 or other ratios within the range.

[0036] In the present invention, the inventors further discovered that by controlling the parameters of the dialysis treatment within a specific range, the residual impurities in the sodium hyaluronate gel can be further removed and its biocompatibility can be significantly improved.

[0037] In some embodiments, in step S3, the amount of the metal chelating agent added is 0.03-0.1 wt%, for example, 0.03 wt%, 0.05 wt%, 0.07 wt%, 0.1 wt% or other values ​​within this range; and the metal chelating agent includes disodium ethylenediaminetetraacetate (EDTA-2Na).

[0038] In the present invention, by adding a specific content of metal chelating agent, the degradation time of sodium hyaluronate gel can be prolonged.

[0039] It is understood that the type and amount of the metal chelating agent can be adjusted according to actual use needs, as long as the hydrolysis reaction can be suppressed. For example, in the present invention, the amount of the metal chelating agent is preferably 0.03-0.07wt%, and the metal chelating agent preferably includes disodium ethylenediaminetetraacetic acid.

[0040] In some embodiments, in step S3, irradiation sterilization specifically includes: using γ-ray irradiation sterilization, with a radiation dose of 20-30 kGy, for example, 20 kGy, 22 kGy, 25 kGy, 28 kGy, 30 kGy or other values ​​within this range.

[0041] In the present invention, irradiation sterilization is performed using a specific dose of gamma rays, thereby removing microorganisms in the sodium hyaluronate gel, thereby facilitating subsequent applications.

[0042] In a second aspect, the present invention provides a sodium hyaluronate gel prepared by any of the above preparation methods.

[0043] The sodium hyaluronate gel provided by the present invention has the advantages of long degradation time and good biocompatibility.

[0044] In a third aspect, the present invention provides use of the sodium hyaluronate gel described above in preparing a biological filling material.

[0045] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0046] See also Figure 1 , which is a flow chart of the preparation method of the sodium hyaluronate gel of the present invention. Specifically, the preparation method comprises the following steps: S1, dissolving sodium hyaluronate in a solvent to obtain a sodium hyaluronate solution; S2, adding an antioxidant to the sodium hyaluronate solution, and then adding a first cross-linking agent to carry out a first cross-linking reaction; continuing to add a second cross-linking agent to carry out a second cross-linking reaction, and after quenching, obtaining a cross-linked sodium hyaluronate gel; S3, dialyzing the cross-linked sodium hyaluronate gel, and then adding a metal chelating agent. After freeze-drying and irradiation sterilization, the sodium hyaluronate gel is obtained.

[0047] Example 1 A method for preparing sodium hyaluronate gel comprises the following steps: S1. Dissolve sodium hyaluronate with a molecular weight of 1.2 million Da in a phosphate buffer solution with a pH of 7.4 to obtain a sodium hyaluronate solution with a mass concentration of 4% (W / V); S2. Add 0.3 wt % sodium ascorbate to the sodium hyaluronate solution obtained in step S1, then add 1 wt % 1,4-butanediol diglycidyl ether (BDDE), and cross-link at 40° C. for 2 h. Continue to add 0.2 wt % genipin, cross-link at 55° C. for 4 h, and quench with 1 M glycine to obtain a cross-linked sodium hyaluronate gel. S3. The cross-linked sodium hyaluronate gel obtained in step S2 was immersed in pre-cooled (4°C) ethanol water (volume ratio of 3:7) and dialyzed for 48 hours. The gel was removed and then 0.05wt% of disodium ethylenediaminetetraacetic acid (EDTA-2Na) was added. The gel was freeze-dried, cut into uniform particle size (100-300μm), and sterilized by gamma ray irradiation (dose of 25kGy) to obtain sodium hyaluronate gel.

[0048] Example 2 A method for preparing sodium hyaluronate gel comprises the following steps: S1. Dissolve sodium hyaluronate with a molecular weight of 500,000 Da in a phosphate buffer solution with a pH of 7.4 to obtain a sodium hyaluronate solution with a mass concentration of 4% (W / V); S2. Add 0.3 wt % sodium ascorbate to the sodium hyaluronate solution obtained in step S1, then add 1 wt % 1,4-butanediol diglycidyl ether (BDDE), and cross-link at 40° C. for 2 h. Continue to add 0.15 wt % genipin, cross-link at 55° C. for 4 h, and quench with 1 M glycine to obtain a cross-linked sodium hyaluronate gel. S3. The cross-linked sodium hyaluronate gel obtained in step S2 was immersed in pre-cooled (4°C) ethanol water (volume ratio of 3:7) and dialyzed for 48 hours. The gel was removed and then 0.05wt% of disodium ethylenediaminetetraacetic acid (EDTA-2Na) was added. The gel was freeze-dried, cut into uniform particle size (100-300μm), and sterilized by gamma ray irradiation (dose of 25kGy) to obtain sodium hyaluronate gel.

[0049] Example 3 A method for preparing sodium hyaluronate gel comprises the following steps: S1. Dissolve sodium hyaluronate with a molecular weight of 2 million Da in a phosphate buffer solution with a pH of 7.4 to obtain a sodium hyaluronate solution with a mass concentration of 5% (W / V); S2. Add 0.5 wt% sodium ascorbate to the sodium hyaluronate solution obtained in step S1, then add 1.5 wt% 1,4-butanediol diglycidyl ether (BDDE), and cross-link at 40°C for 2 h. Then, add 0.3 wt% genipin, cross-link at 55°C for 6 h, and quench with 1 M glycine to obtain a cross-linked sodium hyaluronate gel. S3. The cross-linked sodium hyaluronate gel obtained in step S2 was immersed in pre-cooled (4°C) ethanol water (volume ratio of 3:7) and dialyzed for 48 hours. The gel was removed and then 0.1wt% disodium ethylenediaminetetraacetic acid (EDTA-2Na) was added. The gel was freeze-dried, cut into uniform particle size (100-300μm), and sterilized by gamma ray irradiation (dose of 25kGy) to obtain sodium hyaluronate gel.

[0050] Example 4 A method for preparing sodium hyaluronate gel comprises the following steps: S1. Dissolve sodium hyaluronate with a molecular weight of 1.2 million Da in a phosphate buffer solution with a pH of 7.4 to obtain a sodium hyaluronate solution with a mass concentration of 4% (W / V); S2. Add 0.2 wt % sodium ascorbate and 0.1 wt % sodium ascorbate to the sodium hyaluronate solution obtained in step S1, then add 1 wt % 1,4-butanediol diglycidyl ether (BDDE), and cross-link at 40° C. for 2 h. Then, add 0.2 wt % genipin, cross-link at 55° C. for 6 h, and quench with 1 M glycine to obtain a cross-linked sodium hyaluronate gel. S3. The cross-linked sodium hyaluronate gel obtained in step S2 was immersed in pre-cooled (4°C) ethanol water (volume ratio of 3:7) and dialyzed for 48 hours. The gel was removed and then 0.05wt% of disodium ethylenediaminetetraacetic acid (EDTA-2Na) was added. The gel was freeze-dried, cut into uniform particle size (100-300μm), and sterilized by gamma ray irradiation (dose of 25kGy) to obtain sodium hyaluronate gel.

[0051] Comparative Example 1 In this comparative example, the preparation method of sodium hyaluronate gel is basically the same as that in Example 1, except that in step S2, after adding 1 wt % of 1,4-butanediol diglycidyl ether (BDDE), cross-linking is carried out at a temperature of 55° C. for 2 h.

[0052] Comparative Example 2 In this comparative example, the preparation method of sodium hyaluronate gel is basically the same as that in Example 1, except that sodium ascorbate is not added in step S2; and disodium edetate is not added in step S3.

[0053] Comparative Example 3 In this comparative example, the preparation method of sodium hyaluronate gel is basically the same as that in Example 1, except that in step S3, the temperature of the ethanol water is 10°C.

[0054] Comparative Example 4 In this comparative example, the preparation method of sodium hyaluronate gel is basically the same as that in Example 1, except that in step S3, the temperature of the ethanol water is 25°C.

[0055] Performance Testing The yield, BDDE residue and half-life (tested at 37° C. using 10 U / mL hyaluronidase) of the sodium hyaluronate gels prepared in Examples 1-4 and Comparative Example 1 were tested. The results are shown in Table 1 below.

[0056] Table 1 Performance test results

[0057] As can be seen in Table 1, the sodium hyaluronate gels prepared in Examples 1-4 exhibited high yields, low BDDE residues, and long half-lives, demonstrating excellent performance. In Comparative Example 1, the first crosslinking temperature was higher, resulting in a significantly reduced yield, high BDDE residues, and a short half-life, significantly reducing the performance of the sodium hyaluronate gel. These results demonstrate that controlled low-temperature pre-crosslinking can improve the performance of the sodium hyaluronate gel.

[0058] Furthermore, the half-life of the sodium hyaluronate gels prepared in Example 1 and Comparative Example 2 was tested. The results showed that the half-life of the sodium hyaluronate gel in Comparative Example 2 was only 22 days, and the gel was yellowish (accumulation of by-products), and its performance was significantly reduced.

[0059] Furthermore, the BDDE residue and swelling ratio of the sodium hyaluronate gels prepared in Example 1 and Comparative Examples 3-4 were tested, and the results are shown in Table 2 below.

[0060] Table 2 Performance test results

[0061] As can be seen from Table 2, compared with Comparative Examples 3 and 4, in the present invention, purification at a low temperature of 4° C. can maintain the integrity of the gel network to the greatest extent and reduce BDDE residues.

[0062] In summary, the present invention reduces side reactions and significantly improves the yield of the prepared sodium hyaluronate gel by subjecting the sodium hyaluronate solution to a first pre-crosslinking at low temperature. Simultaneously, the secondary crosslinking is performed at a high temperature, which further increases the crosslinking density of the sodium hyaluronate gel, prevents its rapid degradation, and prolongs the degradation time of the sodium hyaluronate gel. Furthermore, by adding antioxidants and metal chelating agents, the degradation time of the sodium hyaluronate gel can be further prolonged. Furthermore, dialysis treatment can remove residual impurities in the sodium hyaluronate gel, thereby improving its biocompatibility.

[0063] It should be noted that the above embodiments all belong to the same inventive concept, and the description of each embodiment has its own focus. For any details not described in individual embodiments, reference may be made to the description in other embodiments.

[0064] The above-described embodiments merely illustrate the implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for preparing sodium hyaluronate gel, characterized in that: The steps include: S1. dissolving sodium hyaluronate in a solvent to obtain a sodium hyaluronate solution; S2. adding an antioxidant to the sodium hyaluronate solution, and then adding a first cross-linking agent to perform a first cross-linking reaction; continuing to add a second cross-linking agent to perform a second cross-linking reaction, and after quenching, obtaining a cross-linked sodium hyaluronate gel; S3, dialyzing the cross-linked sodium hyaluronate gel, adding a metal chelating agent, freeze-drying, and irradiating to obtain a sodium hyaluronate gel; Wherein, in step S2, the temperature of the first cross-linking reaction is lower than the temperature of the second cross-linking reaction.

2. The method for preparing sodium hyaluronate gel according to claim 1, wherein In step S1, the molecular weight of the sodium hyaluronate is 500,000-2,000,000 Da, the solvent includes phosphate buffer, and the mass concentration of the sodium hyaluronate solution is 3-5%.

3. The method for preparing sodium hyaluronate gel according to claim 1, wherein In step S2, the antioxidant is added in an amount of 0.1-0.5 wt %, and the antioxidant includes at least one of sodium ascorbate and glutathione.

4. The method for preparing sodium hyaluronate gel according to claim 1, wherein In step S2, the amount of the first cross-linking agent added is 0.5-1.5 wt%, and the first cross-linking agent includes 1,4-butanediol diglycidyl ether; The temperature of the first cross-linking reaction is 30-45° C., and the time is 1-3 hours.

5. The method for preparing sodium hyaluronate gel according to claim 1, wherein In step S2, the amount of the second cross-linking agent added is 0.1-0.3 wt %, and the second cross-linking agent includes genipin; The temperature of the second cross-linking reaction is 50-60° C., and the time is 3-8 hours.

6. The method for preparing sodium hyaluronate gel according to claim 1, wherein In step S3, the dialysis treatment specifically includes: dialysis in a dialysate at a temperature of 0-4°C for 40-80 hours; Wherein, the dialysate comprises an ethanol aqueous solution, and the volume ratio of ethanol to water in the ethanol aqueous solution is (2-4): (6-8).

7. The method for preparing sodium hyaluronate gel according to claim 1, wherein: In step S3, the amount of the metal chelating agent added is 0.03-0.1 wt %, and the metal chelating agent includes disodium ethylenediaminetetraacetate.

8. The method for preparing sodium hyaluronate gel according to claim 1, wherein In step S3, the irradiation sterilization specifically includes: using γ-ray irradiation sterilization with a radiation dose of 20-30 kGy.

9. A sodium hyaluronate gel, characterized in that: The method is prepared according to any one of claims 1 to 8.

10. Use of the sodium hyaluronate gel according to claim 9 in preparing a biological filling material.

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