Butyl-glycine cross-linked sodium hyaluronate gel as well as composition and preparation method thereof

Abstract

The invention discloses a butyl-glycine cross-linked sodium hyaluronate gel and a composition and a preparation method thereof. The cross-linked sodium hyaluronate gel is a gel mixture formed by swelling gel of cross-linked hyaluronic acid and salt thereof in a sodium chloride phosphate physiological buffer solution, wherein the gel of the cross-linked hyaluronic acid and the salt thereof is prepared by cross-linking the hyaluronic acid or the salt thereof with a cross-linking agent; wherein the D50 particle size distribution range of the gel mixture is 300-3000 [mu] m, so that the gel mixture can better simulate the physical characteristics of healthy joint synovial fluid and provide more effective lubricating and buffering effects under the condition of the same gel molecular weight and energy storage elastic modulus, thereby relieving joint friction and pain and improving the curative effect of cross-linked sodium hyaluronate maintained in vivo.

Description

Technical Field

[0001] The present invention relates to the field of pharmaceutical compositions, and in particular to a butylated glycerol cross-linked sodium hyaluronate gel, a composition thereof, and a preparation method thereof. Background Art

[0002] Osteoarthritis (OA) is a common degenerative joint disease characterized by the destruction of articular cartilage, bone hyperplasia, and inflammation around the joints. It is the most common type of arthritis and is more common in middle-aged and elderly individuals, but can also develop prematurely due to joint injury, obesity, or genetic factors.

[0003] The treatment principles of osteoarthritis mainly include three aspects: relieving pain, inhibiting inflammatory response, and promoting cartilage repair. Common treatment methods include physical therapy (such as exercise therapy, weight management, massage, etc.), drug therapy, surgical treatment, and nutritional support. In drug treatment, anti-inflammatory drugs are commonly used by doctors for analgesia and anti-inflammatory purposes, among which non-steroidal anti-inflammatory drugs (NSAIDs) are the first choice. Although NSAIDs are effective in analgesia and anti-inflammation, they cannot cure the disease or reverse joint damage. In addition, long-term use of NSAIDs may cause gastrointestinal adverse reactions (such as gastric ulcers, bleeding, etc.), and may also cause potential damage to the cardiovascular system and kidney function, so they should be used with caution.

[0004] Hyaluronic acid is a key component of synovial fluid and is crucial for maintaining normal joint function. It not only imparts excellent viscoelasticity to synovial fluid but also protects articular cartilage, maintaining its ideal cushioning properties. However, in patients with osteoarthritis, hyaluronic acid in synovial fluid exhibits significant abnormalities, manifested by reduced molecular weight, decreased concentration, and decreased viscoelasticity.

[0005] LG's marketed product, Hyruan ONE, is a drug used to treat osteoarthritis. It provides lubrication, reduces inflammation, and relieves pain in the joints. Its long-lasting effects, lasting up to six months, are remarkable. However, in practice, most patients require further injections within six months to alleviate pain and other symptoms.

[0006] In order to improve the efficacy of osteoarthritis injection drugs in the body, it is necessary to conduct further research on this type of drugs. Summary of the Invention

[0007] The purpose of the present invention is to provide a butylated hydroxypropyl hyaluronate cross-linked sodium hyaluronate gel with controllable particle size, stable therapeutic effect and small side effects.

[0008] The technical solution of the present invention is:

[0009] The present invention provides a cross-linked hyaluronic acid gel. The cross-linked hyaluronic acid and salt thereof gel is prepared by cross-linking hyaluronic acid or its salt with a cross-linking agent. The D50 particle size distribution range of the cross-linked hyaluronic acid gel is 300-800 μm, 500-1000 μm, 750-1250 μm, 1000-1500 μm, 1250-1750 μm, 1500-2000 μm, 1750-2250 μm, 2000-2500 μm, 2250-2750 μm, and 2500-3000 μm.

[0010] The present invention also provides an injection composition containing a cross-linked hyaluronic acid gel, which is a gel mixture formed by swelling a cross-linked hyaluronic acid or its salt gel in a sodium phosphate chloride physiological buffer solution, wherein the cross-linked hyaluronic acid or its salt gel is prepared by cross-linking hyaluronic acid or its salt with a cross-linking agent, and the concentration of the hyaluronic acid or its salt is 15-25 g / L; the sodium phosphate chloride physiological buffer solution includes 6-12 g / L of sodium chloride, 0.01-0.1 g / L of potassium dihydrogen phosphate or sodium dihydrogen phosphate, and 10 g / L of sodium chloride. Disodium hydrogen phosphate or potassium dihydrogen phosphate 0.1-0.5 g / L, and water for injection as a solvent; wherein the D50 particle size distribution range of the gel mixture is 300-800 μm, 500-1000 μm, 750-1250 μm, 1000-1500 μm, 1250-1750 μm, 1500-2000 μm, 1750-2250 μm, 2000-2500 μm, 2250-2750 μm, and 2500-3000 μm.

[0011] In some embodiments, the molecular weight of hyaluronic acid or its salt is 2-4 million Da, and the storage elastic modulus of the cross-linked hyaluronic acid and its salt gel is 100-600 Pa, preferably 200-500 Pa.

[0012] In some embodiments, the hyaluronic acid or its salt is selected from one or a combination of hyaluronic acid, sodium hyaluronate, potassium hyaluronate, calcium hyaluronate, magnesium hyaluronate, ammonium hyaluronate, tetrabutylammonium hyaluronate, bismuth hyaluronate and zinc hyaluronate, preferably sodium hyaluronate.

[0013] In some embodiments, the crosslinking agent is selected from 1,4-butanediol diglycidyl ether, glycerol triglycidyl ether, resorcinol diglycidyl ether, allyl glycidyl ether, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether or neopentyl glycol diglycidyl ether, preferably 1,4-butanediol diglycidyl ether.

[0014] In some embodiments, when the concentration of potassium dihydrogen phosphate is 0.01-0.1 g / L, the concentration of sodium dihydrogen phosphate is 0.1-0.5 g / L.

[0015] In other embodiments, when the concentration of sodium dihydrogen phosphate is 0.01-0.1 g / L, the concentration of potassium dihydrogen phosphate is 0.1-0.5 g / L.

[0016] The present invention also provides a method for preparing a cross-linked hyaluronic acid gel, comprising the following steps:

[0017] (1) Mixing: Sodium hyaluronate with a molecular weight of 2-4 million Da is mixed with an alkaline solution, and then a cross-linking agent with a mass ratio of 0.5-5% of the mass of the sodium hyaluronate is added to the sodium hyaluronate solution and mixed evenly; wherein the mass ratio of the sodium hyaluronate to the alkaline solution is (0.1-1):1;

[0018] (2) Cross-linking treatment: The mixture obtained in step (1) is cross-linked at 20°C-60°C for 10-50 hours to prepare a cross-linked sodium hyaluronate gel; wherein the alkaline solution is one of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution or ammonia water; the cross-linking agent is any one of 1,4-butanediol diglycidyl ether, glycerol triglycidyl ether, resorcinol diglycidyl ether, allyl glycidyl ether, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether or neopentyl glycol diglycidyl ether;

[0019] (3) Washing: Prepare a sodium phosphate chloride physiological buffer solution and add a hydrochloric acid solution in an amount equal to that of the alkaline solution. Add the cross-linked sodium hyaluronate gel obtained in step (2) to the sodium phosphate chloride physiological buffer solution and let it stand for 1-20 hours. Then discard the supernatant and repeatedly rinse with sodium phosphate chloride physiological buffer solution until the pH is 7-10; wherein the sodium phosphate chloride physiological buffer solution includes 6-12 g / L sodium chloride, 0.01-0.1 g / L potassium dihydrogen phosphate or sodium dihydrogen phosphate, 0.1-0.5 g / L disodium hydrogen phosphate or potassium dihydrogen phosphate, and the balance is water for injection;

[0020] (4) Swelling: The cross-linked sodium hyaluronate gel washed in step (3) is allowed to swell for 6-20 hours to obtain a gel mixture;

[0021] (5) Grinding: Grinding the gel mixture obtained by swelling in step (4) into cross-linked sodium hyaluronate gel particles, wherein the particle size D50 distribution range of the cross-linked sodium hyaluronate gel particles is 300-800 μm, 500-1000 μm, 750-1250 μm, 1000-1500 μm, 1250-1750 μm, 1500-2000 μm, 1750-2250 μm, 2000-2500 μm, 2250-2750 μm, and 2500-3000 μm; the methods for grinding the gel mixture include but are not limited to: cutting grinding, stirring grinding, wet grinding, low-temperature grinding, extrusion screening, etc.;

[0022] (6) Sterilization: The cross-linked sodium hyaluronate gel particles crushed in step (5) are stirred and homogenized, and then sterilized with wet heat at 121° C. for 10-30 minutes to obtain the cross-linked sodium hyaluronate gel.

[0023] The present invention also provides a method for preparing an injectable composition containing a cross-linked hyaluronic acid gel, comprising the following steps:

[0024] (1) Mixing: Sodium hyaluronate with a molecular weight of 2-4 million Da is mixed with an alkaline solution, and then a cross-linking agent with a mass ratio of 0.5-5% of the mass of the sodium hyaluronate is added to the sodium hyaluronate solution and mixed evenly; wherein the mass ratio of the sodium hyaluronate to the alkaline solution is (0.1-1):1;

[0025] (2) Cross-linking treatment: The mixture obtained in step (1) is cross-linked at 20°C-60°C for 10-50 hours to prepare a cross-linked sodium hyaluronate gel; wherein the alkaline solution is one of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution or ammonia water; the cross-linking agent is any one of 1,4-butanediol diglycidyl ether, glycerol triglycidyl ether, resorcinol diglycidyl ether, allyl glycidyl ether, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether or neopentyl glycol diglycidyl ether;

[0026] (3) Washing: Prepare a sodium phosphate chloride physiological buffer solution and add a hydrochloric acid solution in an amount equal to that of the alkaline solution. Add the cross-linked sodium hyaluronate gel obtained in step (2) to the sodium phosphate chloride physiological buffer solution and let it stand for 1-20 hours. Then discard the supernatant and repeatedly rinse with sodium phosphate chloride physiological buffer solution until the pH is 7-10; wherein the sodium phosphate chloride physiological buffer solution includes 6-12 g / L sodium chloride, 0.01-0.1 g / L potassium dihydrogen phosphate or sodium dihydrogen phosphate, 0.1-0.5 g / L disodium hydrogen phosphate or potassium dihydrogen phosphate, and the balance is water for injection;

[0027] (4) Swelling: The cross-linked sodium hyaluronate gel washed in step (3) is allowed to swell for 6-20 hours to obtain a gel mixture;

[0028] (5) Grinding: Grinding the gel mixture obtained by swelling in step (4) into cross-linked sodium hyaluronate gel particles, wherein the particle size D50 distribution range of the cross-linked sodium hyaluronate gel particles is 300-800 μm, 500-1000 μm, 750-1250 μm, 1000-1500 μm, 1250-1750 μm, 1500-2000 μm, 1750-2250 μm, 2000-2500 μm, 2250-2750 μm, and 2500-3000 μm; the methods for grinding the gel mixture include but are not limited to: cutting grinding, stirring grinding, wet grinding, low-temperature grinding, extrusion screening, etc.;

[0029] (6) Sterilization: The cross-linked sodium hyaluronate gel particles crushed in step (5) are stirred and homogenized, and then sterilized with wet heat at 121° C. for 10-30 min;

[0030] (7) Filling: The cross-linked sodium hyaluronate gel particles sterilized in step (6) are filled into a pre-filled syringe and sterilized with wet heat at 121° C. for 10-30 min to obtain a cross-linked sodium hyaluronate gel injection.

[0031] The butylated sodium hyaluronate gel cross-linked with dapoxetine and its injectable composition are used to alleviate osteoarthritis. Furthermore, the injectable composition or cross-linked sodium hyaluronate gel injection is administered via intra-articular injection. Furthermore, the joint is specifically the knee joint.

[0032] Compared with the prior art, the beneficial effect of the present application is that: the present invention swells the cross-linked sodium hyaluronate gel in a sodium phosphate chloride physiological buffer solution and then crushes it to a particle size of 300-3000 μm, which can effectively control the particle size distribution of the cross-linked sodium hyaluronate gel, so that under the conditions of the same gel molecular weight and storage elastic modulus, it can better simulate the physical properties of healthy joint synovial fluid, provide more effective lubrication and cushioning effects, thereby reducing joint friction and pain, and improving the therapeutic effect of cross-linked sodium hyaluronate maintained in the body. DETAILED DESCRIPTION

[0033] The present application is further illustrated below by means of specific examples. It should be understood that the examples of the present application are merely used to illustrate the present application, and are not intended to limit the present application. The experimental methods for which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under conditions recommended by the manufacturer. The raw and auxiliary materials for which specific sources are not specified in the following examples are generally conventional products available on the market. Technical solutions obtained by simple improvements to the present application or by equivalent replacement of conventional means or components based on the technical solutions of the present application fall within the scope of protection of the present application.

[0034] Example 1

[0035] A method for preparing an injectable composition of butanol-crosslinked hyaluronic acid gel comprises the following steps:

[0036] (1) Mixing: Sodium hyaluronate with a molecular weight of 2-4 million Da is mixed with an alkaline solution, and then a cross-linking agent with a mass ratio of 0.5-5% of the mass of the sodium hyaluronate is added to the sodium hyaluronate solution and mixed evenly; wherein the mass ratio of the sodium hyaluronate to the alkaline solution is (0.1-1):1;

[0037] (2) Cross-linking treatment: The mixture obtained in step (1) is cross-linked at 20°C-60°C for 10-50 hours to prepare a cross-linked sodium hyaluronate gel (storage elastic modulus of 100-600 Pa); wherein the alkaline solution is one of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution or ammonia water; and the cross-linking agent is 1,4-butanediol diglycidyl ether;

[0038] (3) Washing: Prepare a sodium phosphate chloride physiological buffer solution, and add a hydrochloric acid solution in an amount equal to that of the alkaline solution. Add the cross-linked sodium hyaluronate gel obtained in step (2) to the sodium phosphate chloride physiological buffer solution and let it stand for 1-20 hours. Then discard the supernatant and repeatedly rinse with sodium phosphate chloride physiological buffer solution until the pH is 7-10; wherein the concentration of hyaluronic acid or its salt is 20 g / L, the sodium phosphate chloride physiological buffer solution includes 6-12 g / L of sodium chloride, 0.01-0.1 g / L of sodium dihydrogen phosphate, 0.1-0.5 g / L of potassium dihydrogen phosphate, and the balance is water for injection;

[0039] (4) Swelling: The cross-linked sodium hyaluronate gel washed in step (3) is allowed to swell for 6-20 hours to obtain a gel mixture;

[0040] (5) pulverizing: pulverizing the gel mixture obtained by swelling in step (4) into cross-linked sodium hyaluronate gel particles by extrusion and sieving, wherein the cross-linked sodium hyaluronate gel particles have a particle size distribution range of D50 of 300-800 μm;

[0041] (6) Sterilization: The cross-linked sodium hyaluronate gel particles crushed in step (5) are stirred and homogenized, and then sterilized with wet heat at 121° C. for 10-30 min;

[0042] (7) Filling: The cross-linked sodium hyaluronate gel particles sterilized in step (6) are filled into a pre-filled syringe and sterilized with wet heat at 121° C. for 10-30 min to obtain a cross-linked sodium hyaluronate gel injection.

[0043] Example 2-10

[0044] Example 2-10 is basically the same as Example 1, except that the D50 particle size distribution range of the cross-linked sodium hyaluronate gel particles in Example 2-10 is 500-1000 μm, 750-1250 μm, 1000-1500 μm, 1250-1750 μm, 1500-2000 μm, 1750-2250 μm, 2000-2500 μm, 2250-2750 μm, and 2500-3000 μm, respectively.

[0045] Comparative Example 1-2

[0046] Comparative Example 1-2 is substantially the same as Example 1, except that the D50 particle size distribution ranges of the cross-linked sodium hyaluronate gel particles in Comparative Example 1-2 are 50-250 μm and 4000-4500 μm, respectively.

[0047] Comparative Example 3

[0048] Comparative Example 3 is the commercially available product Hyruan ONE.

[0049] Test Example 1: Rabbit joint cavity local irritation test

[0050] Thirteen samples, including Examples 1-10 and Comparative Examples 1-3, were injected into rabbit knee joints twice, 0.2 ml each time, one week apart. Specimens were collected 48 hours after the second injection for histological examination to compare the irritation of the two samples to the joint tissue. Obvious redness and swelling were observed after injection of the samples from Examples 1-10 and Comparative Examples 1-3 into the rabbit knee joints.

[0051] Test Example 2: Human Effect Experiment

[0052] 1. Experimental methods

[0053] 70 outpatients with knee arthritis were randomly divided into 14 groups, each with 5 people, including a blank control group, Example 1-10 groups, and Comparative Example 1-3 groups. Each person in the Example 1-10 group and the Comparative Example 1-3 group was injected with each group of drugs (specification: 3ml, 60mg of sodium hyaluronate) into the knee joint cavity, while the blank control group was injected with 3ml of normal saline. The average WOMAC arthritis index score and VAS pain score scale were used to evaluate the improvement of clinical symptoms and changes in articular cartilage structure and function in each group before and after intervention, and statistical analysis was performed.

[0054] Visual analogue scale (VAS): used to assess the pain intensity index. The scoring criteria are: the average value for mild pain is 2.57±1.04, the average value for moderate pain is 5.18±1.41, and the average value for severe pain is 8.41±1.35.

[0055] The comparison of VAS scores before and after the intervention is shown in Table 1, and the comparison of WOMAC knee joint scores before and after the intervention is shown in Table 2.

[0056] Table 1 Comparison of VAS scores before and after intervention

[0057]

[0058]

[0059] Note: * indicates no significant difference compared with the blank control group before injection (P>0.05), # indicates significant difference compared with the patients in this group before injection (P<0.05), & indicates extremely significant difference compared with the patients in this group before injection (P<0.01).

[0060] Evaluation of results: As can be seen from Table 1, the patients in the blank control group injected with normal saline did not experience any relief of pain after 1 month, 2 months, 3 months, 4 months, 5 months, and 6 months of injection. However, after the injection of the medicines of Examples 1-10 of the present invention, the patients' pain was significantly reduced compared to the pain before the injection of the medicines, and the pain could be maintained for up to 6 months. The pain in Comparative Example 1 was significantly alleviated after 1 month and 2 months of drug injection, but the pain gradually increased after 3-6 months. The pain relief effect of Comparative Example 2 was not as obvious as that of Examples 1-10 after 1 month, 2 months, 3 months, 4 months, 5 months, and 6 months of drug injection. Although Comparative Example 3 (commercially available product Hyruan ONE) can also maintain mild pain indicators within 1-4 months, its scores after 5-6 months are higher than those of Examples 1-10 of the same period, i.e., the pain values ​​are higher.

[0061] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A cross-linked hyaluronic acid gel, wherein the cross-linked hyaluronic acid gel is prepared by cross-linking hyaluronic acid or its salt with a cross-linking agent, characterized in that: The D50 particle size distribution range of the cross-linked hyaluronic acid gel is 300-800 μm, 500-1000 μm, 750-1250 μm, 1000-1500 μm, 1250-1750 μm, 1500-2000 μm, 1750-2250 μm, 2000-2500 μm, 2250-2750 μm, and 2500-3000 μm.

2. An injectable composition comprising a cross-linked hyaluronic acid gel, the injectable composition being a gel mixture formed by swelling a gel of cross-linked hyaluronic acid or a salt thereof in a sodium phosphate chloride physiological buffer solution, wherein the cross-linked hyaluronic acid or a salt thereof gel is prepared by cross-linking hyaluronic acid or a salt thereof with a cross-linking agent, and the concentration of the hyaluronic acid or a salt thereof is 15-25 g / L; the sodium phosphate chloride physiological buffer solution comprises 6-12 g / L sodium chloride, 0.01-0.1 g / L potassium dihydrogen phosphate or sodium dihydrogen phosphate, 0.1-0.5 g / L disodium hydrogen phosphate or potassium dihydrogen phosphate, and water for injection as a solvent; It is characterized in that The D50 particle size distribution range of the gel mixture is 300-800 μm, 500-1000 μm, 750-1250 μm, 1000-1500 μm, 1250-1750 μm, 1500-2000 μm, 1750-2250 μm, 2000-2500 μm, 2250-2750 μm, and 2500-3000 μm.

3. The cross-linked hyaluronic acid gel according to claim 1 or 2, wherein The molecular weight of the hyaluronic acid or its salt is 2-4 million Da, and the storage elastic modulus of the cross-linked hyaluronic acid and its salt gel is 100-600 Pa.

4. The cross-linked hyaluronic acid gel according to claim 1, 2 or 3, wherein: The hyaluronic acid or its salt is selected from one or a combination of hyaluronic acid, sodium hyaluronate, potassium hyaluronate, calcium hyaluronate, magnesium hyaluronate, ammonium hyaluronate, tetrabutylammonium hyaluronate, bismuth hyaluronate and zinc hyaluronate.

5. The cross-linked hyaluronic acid gel according to claim 1 or 2, wherein The crosslinking agent is selected from 1,4-butanediol diglycidyl ether, glycerol triglycidyl ether, resorcinol diglycidyl ether, allyl glycidyl ether, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether or neopentyl glycol diglycidyl ether.

6. The composition for injection according to claim 2, wherein When potassium dihydrogen phosphate is 0.01-0.1g / L, disodium hydrogen phosphate is 0.1-0.5g / L; or when sodium dihydrogen phosphate is 0.01-0.1g / L, dipotassium hydrogen phosphate is 0.1-0.5g / L.

7. A method for preparing a cross-linked hyaluronic acid gel, characterized in that: The following steps are involved: (1) Mixing: Sodium hyaluronate with a molecular weight of 2-4 million Da is mixed with an alkaline solution, and then a cross-linking agent with a mass ratio of 0.5-5% of the mass of the sodium hyaluronate is added to the sodium hyaluronate solution and mixed evenly; wherein the mass ratio of the sodium hyaluronate to the alkaline solution is (0.1-1):1; (2) Cross-linking treatment: The mixture obtained in step (1) is cross-linked at 20°C-60°C for 10-50 hours to prepare a cross-linked sodium hyaluronate gel; wherein the alkaline solution is one of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution or ammonia water; and the cross-linking agent is any one of 1,4-butanediol diglycidyl ether, glycerol triglycidyl ether, resorcinol diglycidyl ether, allyl glycidyl ether, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether or neopentyl glycol diglycidyl ether; (3) Washing: Prepare a sodium phosphate chloride physiological buffer solution, and add a hydrochloric acid solution in an amount equal to that of the alkaline solution. Add the cross-linked sodium hyaluronate gel obtained in step (2) to the sodium phosphate chloride physiological buffer solution and let it stand for 1-20 hours. Then discard the supernatant and repeatedly rinse with sodium phosphate chloride physiological buffer solution until the pH is 7-10; wherein the sodium phosphate chloride physiological buffer solution includes 6-12 g / L sodium chloride, 0.01-0.1 g / L potassium dihydrogen phosphate or sodium dihydrogen phosphate, 0.1-0.5 g / L disodium hydrogen phosphate or potassium dihydrogen phosphate, and the balance is water for injection; (4) Swelling: The cross-linked sodium hyaluronate gel washed in step (3) is allowed to swell for 6-20 hours to obtain a gel mixture; (5) pulverizing: pulverizing the gel mixture obtained by swelling in step (4) into cross-linked sodium hyaluronate gel particles, wherein the cross-linked sodium hyaluronate gel particles have a particle size distribution range of D50 of 300-800 μm, 500-1000 μm, 750-1250 μm, 1000-1500 μm, 1250-1750 μm, 1500-2000 μm, 1750-2250 μm, 2000-2500 μm, 2250-2750 μm, and 2500-3000 μm; (6) Sterilization: The cross-linked sodium hyaluronate gel particles crushed in step (5) are stirred and homogenized, and then sterilized with wet heat at 121° C. for 10-30 minutes to obtain the cross-linked sodium hyaluronate gel.

8. A method for preparing an injectable composition containing a cross-linked hyaluronic acid gel, characterized in that: The following steps are involved: (1) Mixing: Sodium hyaluronate with a molecular weight of 2-4 million Da is mixed with an alkaline solution, and then a cross-linking agent with a mass ratio of 0.5-5% of the mass of the sodium hyaluronate is added to the sodium hyaluronate solution and mixed evenly; wherein the mass ratio of the sodium hyaluronate to the alkaline solution is (0.1-1):1; (2) Cross-linking treatment: The mixture obtained in step (1) is cross-linked at 20°C-60°C for 10-50 hours to prepare a cross-linked sodium hyaluronate gel; wherein the alkaline solution is one of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution or ammonia water; and the cross-linking agent is any one of 1,4-butanediol diglycidyl ether, glycerol triglycidyl ether, resorcinol diglycidyl ether, allyl glycidyl ether, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether or neopentyl glycol diglycidyl ether; (3) Washing: Prepare a sodium phosphate chloride physiological buffer solution, and add a hydrochloric acid solution in an amount equal to that of the alkaline solution. Add the cross-linked sodium hyaluronate gel obtained in step (2) to the sodium phosphate chloride physiological buffer solution and let it stand for 1-20 hours. Then discard the supernatant and repeatedly rinse with sodium phosphate chloride physiological buffer solution until the pH is 7-10; wherein the sodium phosphate chloride physiological buffer solution includes 6-12 g / L sodium chloride, 0.01-0.1 g / L potassium dihydrogen phosphate or sodium dihydrogen phosphate, 0.1-0.5 g / L disodium hydrogen phosphate or potassium dihydrogen phosphate, and the balance is water for injection; (4) Swelling: The cross-linked sodium hyaluronate gel washed in step (3) is allowed to swell for 6-20 hours to obtain a gel mixture; (5) pulverizing: pulverizing the gel mixture obtained by swelling in step (4) into cross-linked sodium hyaluronate gel particles, wherein the cross-linked sodium hyaluronate gel particles have a particle size distribution range of D50 of 300-800 μm, 500-1000 μm, 750-1250 μm, 1000-1500 μm, 1250-1750 μm, 1500-2000 μm, 1750-2250 μm, 2000-2500 μm, 2250-2750 μm, and 2500-3000 μm; (6) Sterilization: The cross-linked sodium hyaluronate gel particles crushed in step (5) are stirred and homogenized, and then sterilized with wet heat at 121° C. for 10-30 min; (7) Filling: The cross-linked sodium hyaluronate gel particles sterilized in step (6) are filled into a pre-filled syringe and sterilized with wet heat at 121° C. for 10-30 min to obtain a cross-linked sodium hyaluronate gel injection.

9. Use of the cross-linked hyaluronic acid gel or the injectable composition according to any one of claims 1 to 8 in alleviating osteoarthritis.

10. The use according to claim 9, characterized in that The injection composition or cross-linked sodium hyaluronate gel injection is administered through bone-joint cavity injection.

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