A process for the preparation of gelatin-based hemostatic particles containing oxidized regenerated cellulose

Abstract

The application discloses a preparation method of gelatin-based hemostatic particles containing oxidized regenerated cellulose, and the hemostatic particles are composed of gelatin, oxidized regenerated cellulose and polyethylene glycol. The gelatin is crosslinked by EDC / NHS to control the degradation time, a small amount of oxidized regenerated cellulose is added to improve the hemostatic capacity, and a small amount of polyethylene glycol is added to improve the hydrophilicity. The prepared hemostatic particles have the advantages of fast hemostatic speed, short degradation time and excellent biology.

Description

Technical Field

[0001] This invention relates to the field of medical hemostatic materials, and in particular to a method for preparing gelatin-based hemostatic granules containing oxidized regenerated cellulose. Background Technology

[0002] With the rapid improvement of medical technology and the continuous expansion of the scope of surgical treatment, shortening the operation time and reducing intraoperative and postoperative bleeding have an important impact on the patient's recovery. In particular, rapid hemostasis is of great significance for saving lives in various emergencies and harsh environmental conditions.

[0003] Traditional hemostasis methods include using the blood-absorbing ability of products to stop further bleeding from the wound, such as hemostatic gauze and sponges; and applying external pressure to reduce bleeding. However, these two methods are less effective for irregular areas. To achieve better hemostasis, research has begun on developing new hemostatic materials based on existing materials and technologies, such as zeolite, starch, chitosan / oxidized regenerated cellulose hemostatic powder, collagen / gelatin / alginate sponges, and other polymeric products. However, zeolite and starch mainly achieve hemostasis by absorbing water from the blood, but this can easily lead to wound inflammation. Chitosan, as a medical device, is difficult to trace; oxidized regenerated cellulose degrades into an acidic state, which can inhibit inflammation; and gelatin / collagen sponges are difficult to apply to irregular areas and have a long degradation cycle. Therefore, developing new, highly effective hemostatic agents is essential to address the limitations of traditional hemostatic materials. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing gelatin-based hemostatic granules containing oxidized regenerated cellulose, so as to solve the limitations of hemostatic materials mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for preparing gelatin-based hemostatic granules containing oxidized regenerated cellulose specifically includes the following steps:

[0007] S1. Prepare an aqueous solution of sodium hydroxide and urea, pre-cool it to obtain a mixed alkaline solution, and add microcrystalline cellulose to the mixed alkaline solution to prepare a microcrystalline cellulose solution.

[0008] S2. Add ethanol to the microcrystalline cellulose solution described in step S1 to precipitate cellulose. Soak and wash with purified water until the pH is 6-8, and filter to obtain regenerated cellulose. Take a portion of the regenerated cellulose to test its solid content.

[0009] S3. The regenerated cellulose filtered in step S2 is oxidized using a TEMPO-sodium bromide-sodium hypochlorite system. The pH of the solution is adjusted to 10.5-10.8. The oxidized regenerated cellulose is then soaked and washed with purified water until the pH is 6-8. It is then freeze-dried and ground to obtain oxidized regenerated cellulose particles.

[0010] S4. Prepare a gelatin aqueous solution; based on the alkaline solution in step S1, add the oxidized regenerated cellulose particles obtained in step S3 to prepare an oxidized regenerated cellulose solution; mix the gelatin aqueous solution and the oxidized regenerated cellulose solution, adjust the pH to 6-7 with hydrochloric acid solution, cool to form a gel, and then break it into 2-5 mm gel blocks.

[0011] S5. After crosslinking the gel block described in step S4 with an EDC / NHS aqueous solution for 4-6 hours, soak and wash it with purified water, and dry it until the water content is less than 90%; the mass ratio of EDC to NHS and water is 0.3:0.075:99.625.

[0012] S6. Soak the dried gel block obtained in step S5 in a polyethylene glycol aqueous solution. After the polyethylene glycol is completely absorbed, dry it and then freeze-dry it to obtain a sponge.

[0013] S7. Grind the sponge obtained in S6 to obtain hemostatic granules, place them in the outer packaging, and sterilize them.

[0014] Preferably, in step S1, the mass concentration of the microcrystalline cellulose solution is 1% to 6%, and the mass ratio of sodium hydroxide to urea and water is 7:12:81.

[0015] Preferably, in step S2, the amount of anhydrous ethanol added is 0.2 to 1 times the mass of the microcrystalline cellulose solution in step S1.

[0016] Preferably, in step S3, after adding purified water, the ratio of the solid content of the TEMPO-sodium bromide-sodium hypochlorite system to the regenerated cellulose in every 200-250 ml of the oxidized cellulose is 0.02 g: 0.2 g: 18-36 ml: 4 g; the sodium hypochlorite is a 12% (w / w) solution, and the order of addition is TEMPO, sodium bromide, regenerated cellulose, and sodium hypochlorite; the oxidation time is 3-16 h.

[0017] Preferably, in step S4, the mass concentration of the gelatin solution is 5% to 20%; the mass concentration of the oxidized regenerated cellulose solution is 1% to 10%; and the mass ratio of the gelatin solution to the oxidized regenerated cellulose is 1:0.0025 to 1:0.05.

[0018] Preferably, in step S5, the mass ratio of gelatin to the aqueous solution of EDC / NHS in the gel block is 1:40, the soaking and crosslinking time is 4~6h, and the crosslinking temperature is 4℃.

[0019] Preferably, in step S6, the mass ratio of the dried gel block to polyethylene glycol is 1:0.025 to 1:0.1, and the polyethylene glycol has a molecular weight of 400, 600 or 1000; and it is dried to a water content of 70% to 90%.

[0020] Preferably, the drying method in step S5 is vacuum drying at 37°C, and the drying method in step S6 is vacuum drying at 37°C and vacuum freeze drying.

[0021] Preferably, in step S7, the hemostatic particles have a particle size of 100μm to 200μm.

[0022] A gelatin-based hemostatic granule containing oxidized regenerated cellulose is prepared using the aforementioned method for preparing gelatin-based hemostatic granules containing oxidized regenerated cellulose.

[0023] The beneficial effects of this invention are:

[0024] (1) The hemostatic granules prepared by the present invention are non-cytotoxic and suitable for in vivo application (such as surgical hemostasis). They can be absorbed and degraded by the human body, and the degradation cycle is short, avoiding the need for secondary removal surgery.

[0025] (2) The present invention combines oxidized regenerated cellulose with gelatin, which significantly shortens the clotting time of gelatin.

[0026] (3) The hemostatic granules prepared by the present invention have high porosity and are coated with a small amount of polyethylene glycol on the surface, which can quickly absorb water from the blood when they come into contact with blood.

[0027] (4) The hemostatic granules prepared by the present invention have good sprayability, achieving uniform coverage of complex wounds and can be precisely applied to bleeding sites.

[0028] (5) The present invention provides a method for preparing gelatin-based hemostatic granules containing oxidized regenerated cellulose. Attached Figure Description

[0029] Figure 1 Cell survival rate;

[0030] Figure 2 In vitro degradation test data;

[0031] Figure 3 This is a diagram illustrating an intramuscular injection. Detailed Implementation

[0032] The embodiments of the present invention will be described in detail below with reference to the examples. However, those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention. Specific conditions not specified in the examples shall be carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0033] Example 1:

[0034] S1. Weigh sodium hydroxide, urea, and water in a mass ratio of 7:12:81, mix them evenly, and pre-cool them in a refrigerator to -18°C to obtain a mixed alkaline solution; take 2g of microcrystalline cellulose and place it in 98g of the above alkaline solution, stir at room temperature to obtain a 2% microcrystalline cellulose solution.

[0035] S2. Pour 20g of anhydrous ethanol into the S1 solution to rapidly precipitate the cellulose; soak and wash several times with purified water until the pH is 6-8 to obtain regenerated cellulose; take the filtered solid and test its solid content.

[0036] S3. Weigh 0.02g, 0.2g, and 4g of TEMPO, sodium bromide, regenerated cellulose (based on solid content), and sodium hypochlorite (12% by mass concentration) in sequence. Place 36ml of the mixture in 200ml of purified water. Adjust the pH to 10.5-10.8 with sodium hydroxide solution. Stir for 3 hours, then soak and wash several times with purified water until the pH is 6-8. Freeze-dry and grind to obtain oxidized regenerated cellulose particles.

[0037] S4. Prepare 100g of 10% gelatin aqueous solution; based on the alkaline solution in S1, prepare 1g of 5% oxidized regenerated cellulose solution; mix the gelatin aqueous solution and the oxidized regenerated cellulose solution evenly, adjust the pH to 6-7 with 1mol / L hydrochloric acid solution, cool to form a gel, and then break it into 2-5mm gel blocks.

[0038] The mass ratio of S5 and EDC / NHS aqueous solution was 0.3:0.075:99.625, and the mass ratio of gelatin to EDC / NHS aqueous solution was 1:40. The soaking and crosslinking time was 4 hours, and the crosslinking temperature was 4℃. After the process, the product was soaked and washed several times with purified water, and the dried product had a moisture content of less than 90%.

[0039] S6. Prepare 25g of 2% PEG1000 aqueous solution and soak the cross-linked gel obtained in S5. After the polyethylene glycol is completely absorbed, dry it to a water content of 90% and freeze-dry it to obtain a sponge.

[0040] S7. Grind the sponge obtained in S6 to obtain hemostatic granules.

[0041] Example 2:

[0042] S1. Weigh sodium hydroxide, urea, and water in a mass ratio of 7:12:81, mix them evenly, and pre-cool them in a refrigerator to -18°C to obtain a mixed alkaline solution; take 6g of microcrystalline cellulose and place it in 94g of the above alkaline solution, stir at room temperature to obtain a 6% microcrystalline cellulose solution;

[0043] S2. Pour 100g of anhydrous ethanol into the S1 solution to rapidly precipitate the cellulose; soak and wash several times with purified water until the pH is 6-8 to obtain regenerated cellulose; take the filtered solid and test its solid content.

[0044] S3. Weigh 0.02g, 0.2g, and 4g of TEMPO, sodium bromide, regenerated cellulose (based on solid content), and sodium hypochlorite (12% by mass concentration) in sequence. Place 18ml of the mixture in 250ml of purified water. Adjust the pH to 10.5-10.8 with sodium hydroxide solution. Stir for 16 hours, then soak and wash several times with purified water until the pH is 6-8. Freeze-dry and grind to obtain oxidized regenerated cellulose particles.

[0045] S4. Prepare 200g of 5% gelatin aqueous solution; based on the alkaline solution in S1, prepare 2.5g of 1% oxidized regenerated cellulose solution; mix the gelatin aqueous solution and the oxidized regenerated cellulose solution evenly, adjust the pH to 6-7 with 1mol / L hydrochloric acid solution, cool to form a gel, and then break it into 2-5mm gel blocks.

[0046] The mass ratio of S5 and EDC / NHS aqueous solution was 0.3:0.075:99.625, and the mass ratio of gelatin to EDC / NHS aqueous solution was 1:40. The soaking and crosslinking time was 5 hours, and the crosslinking temperature was 4℃. After the process, the product was soaked and washed several times with purified water, and the moisture content was less than 90% after drying.

[0047] S6. Prepare 50g of 2% PEG400 aqueous solution and soak the cross-linked gel obtained in S5. After the polyethylene glycol is completely absorbed, dry it to a water content of 80% and freeze-dry it to obtain a sponge.

[0048] S7. Grind the sponge obtained in S6 to obtain hemostatic granules.

[0049] Example 3:

[0050] S1. Weigh sodium hydroxide, urea, and water in a mass ratio of 7:12:81, mix them evenly, and pre-cool them in a refrigerator to -18°C to obtain a mixed alkaline solution; take 1g of microcrystalline cellulose and place it in 99g of the above alkaline solution, stir at room temperature to obtain a 1% microcrystalline cellulose solution.

[0051] S2. Pour 30g of anhydrous ethanol into the S1 solution to rapidly precipitate the cellulose; soak and wash several times with purified water until the pH is 6-8 to obtain regenerated cellulose; take the filtered solid and test its solid content.

[0052] S3. Weigh 0.02g, 0.2g, and 4g of TEMPO, sodium bromide, regenerated cellulose (based on solid content), and sodium hypochlorite (12% by mass concentration) in sequence. Place 27ml of the mixture in 200ml of purified water. Adjust the pH to 10.5-10.8 with sodium hydroxide solution. Stir for 9 hours, then soak and wash several times with purified water until the pH is 6-8. Freeze-dry and grind to obtain oxidized regenerated cellulose particles.

[0053] S4. Prepare 50g of 20% gelatin aqueous solution; based on the alkaline solution in S1, prepare 5g of 10% oxidized regenerated cellulose solution; mix the gelatin aqueous solution and the oxidized regenerated cellulose solution evenly, adjust the pH to 6-7 with 1mol / L hydrochloric acid solution, cool to form a gel, and then break it into 2-5mm gel blocks.

[0054] The mass ratio of S5 and EDC / NHS aqueous solution was 0.3:0.075:99.625, and the mass ratio of gelatin to EDC / NHS aqueous solution was 1:40. The soaking and crosslinking time was 6 hours, and the crosslinking temperature was 4℃. After the process, the product was soaked and washed several times with purified water, and the dried product had a moisture content of less than 90%.

[0055] S6. Prepare 12.5g of 2% PEG600 aqueous solution and soak the cross-linked gel obtained in S5. After the polyethylene glycol is completely absorbed, dry it to a water content of 70% and freeze-dry it to obtain a sponge.

[0056] S7. Grind the sponge obtained in S6 to obtain hemostatic granules.

[0057] Comparative Example 1:

[0058] S1. Weigh sodium hydroxide, urea and water in a mass ratio of 7:12:81, mix them evenly and then pre-cool them in a refrigerator to -18°C to obtain a mixed alkaline solution.

[0059] Take 12g of microcrystalline cellulose and place it in 88g of the above alkaline solution. Stir at room temperature to obtain a 12% microcrystalline cellulose solution.

[0060] Everything else is the same as in Example 1.

[0061] Comparative Example 2:

[0062] S2. Pour 500g of anhydrous ethanol into the S1 solution to rapidly precipitate the cellulose; soak and wash several times with purified water until the pH is 6-8; take the filtered solid and test its solid content.

[0063] Everything else is the same as in Example 1.

[0064] Comparative Example 3:

[0065] S4. Prepare 100g of 10% gelatin aqueous solution; based on the alkaline solution in S1, prepare 0.4g of 12.5% ​​oxidized regenerated cellulose solution; mix the gelatin aqueous solution and the oxidized regenerated cellulose solution evenly, adjust the pH to 6-7 with 1mol / L hydrochloric acid solution, cool to form a gel, and then break it into 2-5mm gel blocks.

[0066] Everything else is the same as in Example 1.

[0067] Comparative Example 4:

[0068] S4. Prepare 50g of 40% gelatin aqueous solution; based on the alkaline solution in S1, prepare 1g of 5% oxidized regenerated cellulose solution; mix the gelatin aqueous solution and the oxidized regenerated cellulose solution evenly, adjust the pH to 6-7 with 1mol / L hydrochloric acid solution, cool to form a gel, and then break it into 2-5mm gel blocks.

[0069] Everything else is the same as in Example 1.

[0070] Comparative Example 5:

[0071] The mass ratio of S5 and EDC / NHS aqueous solution is 0.3:0.075:99.625, the mass ratio of gelatin to EDC / NHS aqueous solution is 1:40, the soaking and crosslinking time is 8 hours, the crosslinking temperature is 4℃, and after completion, it is soaked and washed several times with purified water, and the dried water content is less than 90%.

[0072] Everything else is the same as in Example 1.

[0073] Comparative Example 6:

[0074] The mass ratio of S5 and EDC / NHS aqueous solution was 0.3:0.075:99.625, and the mass ratio of gelatin to EDC / NHS aqueous solution was 1:40. The soaking and crosslinking time was 1 hour, and the crosslinking temperature was 4℃. After the process, the product was soaked and washed several times with purified water, and the moisture content was less than 90% after drying.

[0075] Everything else is the same as in Example 1.

[0076] Comparative Example 7:

[0077] S6. Prepare 25g of 2% PEG1000 aqueous solution and soak the cross-linked gel obtained in S5. After the polyethylene glycol is completely absorbed, dry it to a water content of 60% and freeze-dry it to obtain a sponge.

[0078] Everything else is the same as in Example 1.

[0079] Comparative Example 8:

[0080] S4. Prepare 100g of 10% gelatin aqueous solution; based on the alkaline solution in S1, prepare 10g of 10% oxidized regenerated cellulose solution; mix the gelatin aqueous solution and the oxidized regenerated cellulose solution evenly, adjust the pH to 6-7 with 1mol / L hydrochloric acid solution, cool to form a gel, and then break it into 2-5mm gel blocks.

[0081] Everything else is the same as in Example 1.

[0082] Comparative Example 9

[0083] S4. Prepare 100g of 10% gelatin aqueous solution, cool to form a gel, and then break it into 2-5mm gel blocks;

[0084] Everything else is the same as in Example 1.

[0085] Comparative Example 10

[0086] S6. Dry to a moisture content of 60%, then freeze-dry to obtain a sponge;

[0087] Everything else is the same as in Example 1.

[0088] Product performance testing:

[0089] (1) In vitro inverted coagulation test: The sample, anticoagulated pig blood and 0.2M calcium chloride solution were preheated at 37℃ for 5 min. 0.02g of sample and 0.4ml of anticoagulated pig blood were mixed and placed in a 37℃ water bath. The test tube was tilted every 15 seconds to observe the coagulation state and the time was recorded. The blank experimental group was 45μL of 0.2M calcium chloride solution and the control group was 0.02g of product + 45μL of 0.2M calcium chloride solution.

[0090] (2) In vitro dynamic coagulation test: Weigh 0.1g of each sample and place it in a sterile culture dish. Incubate in a 37℃ water bath for 5 min. Add 0.2ml of preheated anticoagulated pig blood (37℃) to the sample surface using a pipette to fully wet the sample. Then, add 25μL of 0.2M CaCl2 solution to each sample using a pipette and mix thoroughly. Place the culture dish in an air bath constant temperature shaker and shake thoroughly at 37℃ and 30r / min for 3 min. Add 20mL of ultrapure water to stop the reaction and continue to shake thoroughly at 80r / min to rinse out the red blood cells that were not coagulated by the hemostatic gauze. Collect the rinsing solution and place it in a centrifuge. Centrifuge at 300r / min for 5 min. After centrifugation, use a UV-Vis spectrophotometer to measure the absorbance of the test sample rinsing solution, ordinary rinsing solution (negative control group), and anticoagulated pig blood solution (blank group) at 540nm.

[0091] Calculate the in vitro coagulation index:

[0092]

[0093] Repeat the test three times and take the average value as the final BCI value. The lower the BCI value, the better the coagulation effect of the hemostatic material, and vice versa.

[0094] (3) Water absorption ratio: Take 0.5g of this product, weigh it accurately, record it as m1, and cut 15g of it. A 15cm length of 600-mesh gauze is completely immersed in water, then removed and lightly wiped dry with lint-free paper. The weight is recorded as m2. The product is wrapped in the gauze, and the weight of the rubber band is recorded as m3. The opening is secured with the rubber band. The product is placed in a 500mL beaker, and 100-300mL of purified water is added, ensuring only a portion of the product is completely immersed in the purified water at 37℃±2℃. The gauze is gently shaken to ensure the product is fully in contact with the water.

[0095] After soaking for 24±2 hours, lift the gauze out of the water. When the water droplets stop dripping, weigh and record the volume as m4. Calculate the volume using the following formula:

[0096]

[0097] AW: Swelling degree.

[0098] m4: The weight of the sample after it absorbs water, in grams.

[0099] m3: The weight of the rubber band, in grams.

[0100] m2: Weight of 600-mesh gauze, in grams.

[0101] m1: The initial weight of the sample, in grams.

[0102] (3) Porosity test: Take the S6 freeze-dried sponge and cut it into 0.5cm pieces. 0.5cm The size is 0.5cm, and its weight is recorded as m0. The sponge is fully soaked in an ethanol solution, taken out and weighed again as m1. The calculation formula is:

[0103]

[0104] (4) In vitro degradation: Weigh the sample and record the mass as m0. Immerse the sample in the solution at a ratio of 30:1 (volume of test solution (proteinase K solution prepared in PBS buffer) to sample mass (g). The volume of the test solution should not be less than 10 mL. Place the test sample in a 37±1℃ electric thermostatic water bath and change the buffer solution every 24 h. Set the degradation time to 5 time points, with at least 3 replicates at each time point, and use a separate container for each replicate. Remove the sample and dry it; record the mass at this point as m1. Continue until the mass loss reaches 100%, then end the experiment and calculate the degradation rate.

[0105] (5) In vivo degradation: Rabbits were selected as experimental animals. After anesthetizing them, the fur on both sides of their backs was removed. The paravertebral muscles on both sides were degraded in a manner roughly parallel to the spine, as follows: Figure 3 The implant is administered via intramuscular injection, with a width of 1-3 mm and a length of 10 mm. Samples are taken at 1, 2, 4, 8, and 12 weeks to observe for degradation.

[0106] (6) Cytotoxicity: The toxicity of different materials to L929 cells was assessed using the MTT assay. First, extraction buffers were prepared, and samples were dispersed in cell culture medium and extracted at 37°C for 72 h. After extraction, the samples were centrifuged and the extracts from different samples were collected. One × 10⁴ L929 cells were added to each well of a 96-well plate and cultured at 37°C for 24 h. Then, 100 μL of the extract from different samples was added to the culture medium, and the cells were cultured for another 24 h. Next, 100 μL of MTT solution (0.5 mg / mL) was added to the culture medium, and after incubation for 4 h, the MTT was removed, and 100 μL of LDMSO was added. The mixture was shaken, and the absorbance at 570 nm was read. All experimental instruments were sterilized under ultraviolet light. Cell viability calculation formula:

[0107]

[0108] (7) Hydrophilicity: Take 0.5g of this product and put it into a circular mold with a diameter of 1cm. Gently shake it to make the surface flat. Use a 1ml syringe to slowly drop a drop of water directly above the sample and observe the absorption state of the water drop.

[0109] Table 1 Performance Data

[0110]

[0111]

[0112] Table 2 In vivo degradation data

[0113]

[0114] Comparative Example 1: The concentration of microcrystalline cellulose solution exceeded 1%-6%; Comparative Example 3: The concentration of oxidized regenerated cellulose solution exceeded 1%-10%; the dissolution was incomplete, and no other corresponding parameters were selected or performance tests were conducted.

[0115] By comparing Example 1 and Comparative Example 2, the amount of anhydrous ethanol added in step S2 exceeded that in step S1 by 0.2 to 1 times, and the precipitated cellulose was consistent with that in Example 1, indicating that excess ethanol had no effect on the precipitation of cellulose.

[0116] By comparing Example 1 and Comparative Example 4, it can be seen that the concentration of gelatin affects the cross-linking effect. Excessive concentration leads to insufficient cross-linking and rapid degradation.

[0117] By comparing Example 1 and Comparative Example 7, it can be seen that the water content affects the hardness of the sponge. If the water content is too low, the sponge will be extremely hard, difficult to crush, and the resulting powder will have a high density and low water absorption.

[0118] Through Table 2 and Figure 2 The results show that the cross-linking time has a significant impact on the degradation time. Products with a cross-linking time exceeding 4-6 hours, which degrade too quickly or too slowly, do not meet the actual requirements.

[0119] By comparing Example 1 and Comparative Example 8, the acidic environment generated by excessive oxidative degradation of regenerated cellulose can kill cells and is cytotoxic, which does not meet the requirements for biomedical materials. Figure 1 ).

[0120] By comparing Example 1 and Comparative Example 9, it was found that without the addition of oxidized regenerated cellulose, the coagulation effect was significantly reduced.

[0121] By comparing Example 1 and Comparative Example 10, without the addition of polyethylene glycol, the hemostatic particles have poor hydrophilicity and exhibit slight hydrophobicity.

[0122] Unless otherwise specified, all solutions prepared are aqueous solutions.

[0123] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing gelatin-based hemostatic granules containing oxidized regenerated cellulose, characterized in that, Specifically, the steps include the following: S1. Prepare an aqueous solution of sodium hydroxide and urea, pre-cool it to obtain a mixed alkaline solution, and add microcrystalline cellulose to the mixed alkaline solution to prepare a microcrystalline cellulose solution. S2. Add anhydrous ethanol to the microcrystalline cellulose solution described in step S1 to precipitate cellulose. Soak and wash with purified water until the pH is 6-8, and filter to obtain regenerated cellulose. Take a portion of the regenerated cellulose to test its solid content. S3. The regenerated cellulose filtered in step S2 is oxidized in purified water using a TEMPO-sodium bromide-sodium hypochlorite system. The pH of the solution is adjusted to 10.5-10.

8. The oxidized regenerated cellulose is then soaked and washed with purified water until the pH is 6-8. After freeze-drying, it is ground to obtain oxidized regenerated cellulose particles. S4. Prepare a gelatin aqueous solution; based on the alkaline solution in step S1, add the oxidized regenerated cellulose particles obtained in step S3 to prepare an oxidized regenerated cellulose solution; mix the gelatin aqueous solution and the oxidized regenerated cellulose solution, adjust the pH to 6-7 with hydrochloric acid solution, cool to form a gel, and then break it into 2-5 mm gel blocks. S5. After crosslinking the gel block described in step S4 with an EDC / NHS aqueous solution for 4-6 hours, soak and wash it with purified water, and dry it until the water content is less than 90%; the mass ratio of EDC to NHS and water is 0.3:0.075:99.

625. S6. Soak the dried gel block obtained in step S5 in a polyethylene glycol aqueous solution. After the polyethylene glycol is completely absorbed, dry it to a water content of 70% to 90%. After drying, freeze dry to obtain a sponge. S7. Grind the sponge obtained in S6 to obtain hemostatic granules, place them in the outer packaging, and sterilize them.

2. The method for preparing gelatin-based hemostatic granules containing oxidized regenerated cellulose according to claim 1, characterized in that: In step S1, the mass concentration of the microcrystalline cellulose solution is 1% to 6%, and the mass ratio of sodium hydroxide to urea and water is 7:12:

81.

3. The method for preparing gelatin-based hemostatic granules containing oxidized regenerated cellulose according to claim 2, characterized in that: In step S2, the amount of anhydrous ethanol added is 0.2 to 1 times the mass of the microcrystalline cellulose solution in step S1.

4. The method for preparing gelatin-based hemostatic granules containing oxidized regenerated cellulose according to claim 3, characterized in that: In step S3, when the regenerated cellulose filtered in step S2 is added to purified water for oxidation, the solid content ratio of the TEMPO-sodium bromide-sodium hypochlorite system to the regenerated cellulose in every 200-250 ml of purified water is 0.02 g: 0.2 g: 18-36 ml: 4 g; the sodium hypochlorite is a 12% (w / w) solution, and the addition order is TEMPO, sodium bromide, regenerated cellulose, and sodium hypochlorite; the oxidation time is 3-16 hours.

5. The method for preparing gelatin-based hemostatic granules containing oxidized regenerated cellulose according to claim 1, characterized in that: In step S4, the mass concentration of the gelatin aqueous solution is 5% to 20%; the mass concentration of the oxidized regenerated cellulose solution is 1% to 10%; and the mass ratio of the gelatin aqueous solution to the oxidized regenerated cellulose is 1:0.0025 to 1:0.

05.

6. The method for preparing gelatin-based hemostatic granules containing oxidized regenerated cellulose according to claim 1, characterized in that: In step S5, the mass ratio of gelatin to EDC / NHS aqueous solution in the gel block is 1:40, the soaking and crosslinking time is 4~6h, and the crosslinking temperature is 4℃.

7. The method for preparing gelatin-based hemostatic granules containing oxidized regenerated cellulose according to claim 1, characterized in that: In step S6, the mass ratio of the dried gel block to polyethylene glycol is 1:0.025 to 1:0.1, and the molecular weight of the polyethylene glycol is one of 400, 600 or 1000.

8. The method for preparing gelatin-based hemostatic granules containing oxidized regenerated cellulose according to claim 1, characterized in that: The drying method in step S5 is vacuum drying at 37°C, and the drying method in step S6 is vacuum drying at 37°C and vacuum freeze drying.

9. The method for preparing gelatin-based hemostatic granules containing oxidized regenerated cellulose according to claim 1, characterized in that: In step S7, the hemostatic particles have a particle size of 100μm~200μm.

10. A gelatin-based hemostatic granule containing oxidized regenerated cellulose, characterized in that: It is prepared by the method for preparing gelatin-based hemostatic granules containing oxidized regenerated cellulose as described in any one of claims 1 to 9.

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