A method of preparing a hemostatic sponge

Abstract

The application discloses a preparation method of a hemostatic sponge and belongs to the technical field of preparation of high polymer medical materials. The hemostatic sponge is prepared by combining a salting-out effect and a solvent exchange strategy. The hemostatic sponge is prepared by the following steps: a preliminary structure of a loose porous structure is induced by the salting-out effect to construct a PVA / gelatin binary composite network; then, the solvent exchange strategy is adopted to replace the residual water in the preliminary structure step by step, the microstructure of the sponge is further optimized, and the sponge is dried to reach an ideal dry state, so that the hemostatic sponge is obtained. The hemostatic sponge can not only absorb blood efficiently and expand to fill a wound rapidly, but also can activate a blood coagulation mechanism to realize rapid hemostasis. The hemostatic sponge is non-toxic and harmless, and has a wide application prospect and great market potential in the field of biological medicine.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polymer medical material preparation, and particularly relates to a preparation method of a hemostatic sponge. BACKGROUND

[0002] In the modern medical field, non-compressible hemorrhage, especially the hemorrhage of torso and internal organs caused by firearms, explosions or sharp objects, is a great challenge in military injuries and accident trauma. This kind of hemorrhage is usually difficult to effectively control by traditional manual compression or tourniquet and the like, and often quickly leads to patients being in life danger. Traditional hemostatic materials, such as gauze, gelatin sponge and the like, can absorb blood and play a role in compression hemostasis to a certain extent, but the hemostatic effect on non-compressible hemorrhage is limited. Therefore, it is particularly important to develop a new type of hemostatic material which can quickly respond and effectively hemostasis. Such sponges need to be made of materials with excellent water absorption and swelling properties, which can quickly absorb water and swell when they come into contact with blood, forming a tight hemostatic barrier, thereby effectively slowing down or stopping bleeding.

[0003] Polyvinyl alcohol is a kind of polymer material with excellent water solubility, film forming property and biocompatibility. Its non-toxicity, non-irritation and good biocompatibility make polyvinyl alcohol an ideal choice for preparing biological medical materials such as hemostatic sponges. Traditional polyvinyl alcohol sponge preparation process usually involves harmful substances such as formaldehyde, which may have formaldehyde residues during use, affecting the safety of use. Chinese patent CN 111116973A provides a preparation method and application of a polyvinyl alcohol hemostatic porous material with high liquid absorption and high swelling performance and active hemostatic function. It uses a double thiol-functionalized polymer as a crosslinking agent, and carries out crosslinking reaction on the system by photo-click chemistry technology. Finally, through compression treatment and freeze-drying, a modified polyvinyl alcohol hemostatic sponge with high safety, strong liquid absorption capacity and high swelling performance is obtained. Chinese patent CN115300665A discloses an antibacterial absorbable nasal hemostatic sponge and its preparation method and application, which uses a formaldehyde-free chemical process to solve the technical problems of non-absorbable, no elasticity, poor hemostatic performance, insufficient support and high price of single-component sponges in the prior art. Although these preparation processes have made significant breakthroughs in performance without using aldehyde crosslinking agents, they undoubtedly increase the production difficulty and cost, and also pose higher challenges to industrial application due to the involvement of multiple steps and complex reaction conditions.

[0004] To solve the above problems, Chinese patent CN 117069993A discloses a preparation method of polyvinyl alcohol sponge gel, which realizes the normal temperature and pressure molding of the sponge gel by adding small molecule polyols and inorganic salts, and the prepared sponge has obvious open structure, high biocompatibility and strong liquid absorption capacity, and can be used as surgical blood suction. However, this patent does not involve the improvement of hemostatic function. At the same time, the polyvinyl alcohol sponge will harden after drying, resulting in a significant decrease in water absorption rate and expansion speed. In contrast, the wet sponge absorbs liquid faster, but if not handled properly or replaced in time during use, it may become a breeding ground for bacteria, increasing the risk of infection.

[0005] In view of the deficiencies of the prior art, the present application discloses a preparation method of a hemostatic sponge, which successfully prepares a hemostatic sponge that can rapidly expand by using salting-out effect and solvent exchange strategy. The hemostatic sponge rapidly absorbs water and expands upon contact with blood, tightly adheres to the wound, and forms effective mechanical compression, thereby rapidly stopping bleeding. At the same time, the release of hemostatic factors and pro-coagulation substances during the expansion process helps to accelerate the hemostatic process and shorten the hemostatic time. The preparation process of the present application is simple and easy to implement, and has low cost, showing broad industrial application potential. Moreover, it has the characteristics of non-toxicity, harmlessness and high efficiency, and constitutes a significant application advantage. SUMMARY

[0006] The present application aims to provide a preparation method of a hemostatic sponge, which combines salting-out effect and solvent exchange strategy to make the obtained hemostatic sponge not only rapidly expand to fill the wound, but also have excellent water absorption performance and structural stability, capable of efficiently absorbing blood and activating the coagulation mechanism to achieve rapid and effective hemostasis.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] A hemostatic sponge is composed of polyvinyl alcohol (PVA), kaolin and inorganic salt, which is specifically prepared by realizing the uniform loading and stable dispersion of kaolin in polyvinyl alcohol sponge through salting-out effect and solvent exchange strategy.

[0009] The preparation method of the hemostatic sponge comprises the following steps:

[0010] 1) First, dissolve polyvinyl alcohol and gelatin in deionized water, heat and stir until completely dissolved, to form a polyvinyl alcohol / gelatin composite solution;

[0011] 2) Add inorganic salt with salt-solubilizing effect to the obtained polyvinyl alcohol / gelatin composite solution, stir and dissolve, then slowly add pre-treated kaolin powder, continue to stir and disperse until a uniform suspension is formed;

[0012] 3) then adding small molecule polyols into the suspension obtained in step 2) and slowly adding a solution of inorganic salts with salting-out effect, stirring to form a complex emulsion;

[0013] 4) injecting the complex emulsion obtained in step 3) into a mold and standing to cure, allowing the components in the emulsion to fully interact and solidify, obtaining a sponge sample;

[0014] 5) performing solvent exchange of residual moisture and unreacted salts in the sponge sample obtained by soaking in anhydrous ethanol, and obtaining the hemostatic sponge after drying.

[0015] Further, the molecular weight of the polyvinyl alcohol in step 1) is 85000-120000. The polyvinyl alcohol with medium molecular weight has good solubility and film-forming property.

[0016] Further, the amount of gelatin in step 1) is 1%-20% of the weight of the polyvinyl alcohol used.

[0017] Further, the temperature of the heating in step 1) is 80-100°C.

[0018] Further, the concentration of polyvinyl alcohol in the complex solution obtained in step 1) is 5 wt%-20 wt%.

[0019] Further, the inorganic salt with salting-out effect in step 2) is selected from one or more of calcium chloride, magnesium chloride, zinc chloride, calcium nitrate, zinc nitrate, and magnesium nitrate, and the amount is 10%-100% of the weight of the polyvinyl alcohol used.

[0020] Further, the pre-treated kaolin powder in step 2) is kaolin powder with a purity higher than 95% pre-milled to a particle size less than 10 microns.

[0021] Further, the amount of kaolin powder in step 2) is 1%-100% of the weight of the polyvinyl alcohol used.

[0022] Further, the rotation speed in step 2) is controlled at 2000-3000 rpm.

[0023] Further, the small molecule polyol in step 3) is selected from one or more of polyethylene glycol 800, polyethylene glycol 1000, and polyethylene glycol 1500, and the amount is 100%-300% of the weight of the polyvinyl alcohol used.

[0024] Further, the concentration of the solution of inorganic salts with salting-out effect in step 3) is 1 wt%-100 wt%, and the amount is converted to 100%-500% of the weight of the polyvinyl alcohol used based on the weight of the inorganic salts with salting-out effect therein.

[0025] Further, the inorganic salt with salting-out effect is selected from one or more of potassium carbonate, potassium nitrate, zinc sulfate, and potassium citrate.

[0026] Further, the environment temperature for standing and ripening in step 4) is -20~40 ℃, and the ripening time is 1~24 hours.

[0027] Further, the solvent exchange in step 5) is performed using an ethanol solution with a concentration of 50 wt%~100 wt%.

[0028] Further, the soaking time in step 5) is 1~24 hours.

[0029] In the preparation process of the present application, the salt dissolution effect of magnesium chloride and other inorganic salts is used to increase the ionic strength of the solution to promote the uniform dispersion of kaolin; at the same time, the use of small molecule polyols such as polyethylene glycol improves the stability and flexibility of the emulsion, and the salting-out effect of inorganic salts such as potassium nitrate induces the ordered arrangement and aggregation of PVA and gelatin chains to form a composite emulsion. The obtained hemostatic sponge not only has excellent water absorption performance and structural stability, but also can rapidly expand and fill the wound to form effective mechanical compression, and the release of hemostatic factors and coagulation substances during the expansion process helps to accelerate the hemostasis process.

[0030] The present application has the following advantages:

[0031] (1) The present application realizes the stability and high efficiency of the composite emulsion by optimizing the ratio of PVA, gelatin, kaolin, inorganic salt, and small molecule polyol.

[0032] (2) The present application introduces a solvent exchange strategy, so that the prepared hemostatic sponge can rapidly absorb water and expand to form a tight hemostatic barrier, thereby effectively slowing down or stopping bleeding.

[0033] (3) The present application constructs a PVA / gelatin binary composite framework through salting-out effect, and introduces kaolin with active hemostatic function, so that the prepared sponge can release hemostatic factors and coagulation substances while rapidly expanding, accelerate hemostasis, and exhibit excellent hemostatic performance.

[0034] (4) The preparation process of the present application is simple, low in cost, and easy to industrialize, and has broad application prospects in the medical fields of surgery, dentistry, and ear-nose-throat. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 The figure shows the comparison of the prepared hemostatic sponge samples of Example 4 (left) and Comparative Example 2 (right). As can be seen from the figure, the structure of the hemostatic sponge prepared using unground kaolin is disordered and rough, and the original pore structure of the sponge is destroyed.

[0036] Figure 2 Microstructure images of the hemostatic sponge prepared for Comparative Example 1 (left) and Example 4 (right). As can be seen from the images, the obtained hemostatic sponge has an obvious open pore structure, and the kaolin is loaded on the PVA / gelatin framework in the hemostatic sponge prepared in the example.

[0037] Figure 3 Actual images of the hemostatic sponge prepared for Example 4 and Comparative Example 3 before and after absorbing methyl orange solution. As can be seen from the images, the hemostatic sponge prepared without solvent exchange swells completely in 150 s, and the central part of the sponge is not dyed; while the hemostatic sponge prepared by solvent exchange can rapidly absorb methyl orange solution in 1 s, and fully swell in 18 s, the absorption and swelling rate is significantly better than that of the hemostatic sponge without solvent exchange.

[0038] Figure 4 Water contact angle image of the hemostatic sponge prepared in Example 4. As can be seen from the image, the hemostatic sponge can quickly absorb the solution and rapidly swell.

[0039] Figure 5 Inverted coagulation experiment in vitro of the hemostatic sponge prepared in Example 4. As can be seen from the image, the blood in the hemostatic sponge is basically coagulated at 6 min, and completely coagulated at 7 min, having a good coagulation effect, which is significantly better than the blank control group.

[0040] Figure 6 Coagulation time experiment of the hemostatic sponge prepared in Example 4. As can be seen from the image, the blood in the hemostatic sponge begins to coagulate gradually at about 2-3 min, and completely coagulates at 4 min, having a good coagulation effect. DETAILED DESCRIPTION

[0041] A hemostatic sponge, the preparation of which comprises the following steps:

[0042] 1) The kaolin powder with a purity higher than 95% is pre-milled to a particle size less than 10 microns;

[0043] 2) The polyvinyl alcohol (molecular weight 85000-120000) and 1%~20% of gelatin by weight of the polyvinyl alcohol are first dissolved in deionized water, and heated and stirred at 80~100°C until completely dissolved to form a polyvinyl alcohol / gelatin composite solution, wherein the concentration of polyvinyl alcohol is 5 wt%~20 wt%;

[0044] 3) The obtained polyvinyl alcohol / gelatin composite solution is added with 10%~100% of inorganic salt by weight of the polyvinyl alcohol, which has a salt dissolving effect, and after stirring and dissolving, 1%~100% of the pre-treated kaolin powder by weight of the polyvinyl alcohol is slowly added, and the stirring and dispersion is continued at 2000~3000 rpm until a uniform suspension is formed;

[0045] 4) then add 100%~300% of the weight of polyvinyl alcohol small molecule polyols to the suspension obtained in step 3), and slowly add a 1 wt%~100 wt% concentration inorganic salt solution with salting effect (the amount is converted to 100%~500% of the weight of the inorganic salt to the weight of the polyvinyl alcohol used), and stir to form a composite emulsion;

[0046] 5) inject the composite emulsion obtained in step 4) into a mold, and stand at -20~40 ℃ for 1~24 hours to allow the components in the emulsion to fully interact and solidify, obtaining a sponge sample;

[0047] 6) soak the sponge sample obtained in a 50 wt%~100 wt% ethanol solution for 1~24 hours to exchange the residual water and unreacted salts with anhydrous ethanol, and then dry using an air flow drying method to obtain a hemostatic sponge.

[0048] In step 3), the inorganic salt with salting effect is selected from one or more of calcium chloride, magnesium chloride, zinc chloride, calcium nitrate, zinc nitrate, and magnesium nitrate.

[0049] In step 4), the small molecule polyol is selected from one or more of polyethylene glycol 800, polyethylene glycol 1000, and polyethylene glycol 1500. The inorganic salt with salting effect is selected from one or more of potassium carbonate, potassium nitrate, zinc sulfate, and potassium citrate.

[0050] In order to make the content of the present application more convenient to understand, the technical solutions of the present application will be further described below in conjunction with specific embodiments, but the present application is not limited thereto.

[0051] The kaolin powder used in the examples is pre-milled to a particle size of less than 10 microns.

[0052] Example 1

[0053] At 95 ℃, first dissolve 1 g of polyvinyl alcohol with a molecular weight of 85000 and 0.1 g of gelatin in 9 mL of deionized water; then, add 0.2 g of magnesium chloride to the mixed solution, stir and dissolve, then add 0.2 g of kaolin powder at a dispersion speed of 2000 rpm, disperse uniformly, then add 3 g of polyethylene glycol 800, and stir thoroughly; then, slowly add 5 g of a 50 wt% concentration potassium nitrate solution, and stir again to mix uniformly; finally, pour the composite emulsion into a mold and seal, place it in an environment at 20 ℃ for 1 h to cure, then soak it in a 75 wt% anhydrous ethanol solution for 24 h, and finally dry it in an oven at 60 ℃ for 12 h to obtain a hemostatic sponge.

[0054] Example 2

[0055] At 95 °C, first 1 g of polyvinyl alcohol with molecular weight of 95000 was dissolved in 10 mL of deionized water with 0.15 g of gelatin by stirring; then, 0.2 g of calcium chloride was added to the mixed solution, and after being dissolved by stirring, 0.3 g of kaolin powder was added at a dispersion speed of 2500 rpm, and after being uniformly dispersed, 2.8 g of polyethylene glycol 1000 was added and stirred thoroughly; then, 3.2 g of potassium citrate solution with a concentration of 37.5 wt% was added dropwise, and stirred again to be uniform; then, the composite emulsion was poured into a mold and sealed, and after being placed at 20 °C for 12 h for curing, it was soaked in a 75 wt% anhydrous ethanol solution for 12 h, and finally dried in an oven at 60 °C for 12 h to obtain a hemostatic sponge.

[0056] Example 3

[0057] At 95 °C, first 1 g of polyvinyl alcohol with molecular weight of 100000 was dissolved in 10 mL of deionized water with 0.05 g of gelatin by stirring; then, 0.4 g of zinc chloride was added to the mixed solution, and after being dissolved by stirring, 0.4 g of kaolin powder was added at a dispersion speed of 3000 rpm, and after being uniformly dispersed, 2 g of polyethylene glycol 1500 was added and stirred thoroughly; then, 3.2 g of zinc sulfate solution with a concentration of 37.5 wt% was added dropwise, and stirred again to be uniform; then, the composite emulsion was poured into a mold and sealed, and after being placed at 20 °C for 5 h for curing, it was soaked in a 75 wt% anhydrous ethanol solution for 1 h, and finally dried in an oven at 60 °C for 12 h to obtain a hemostatic sponge.

[0058] Example 4

[0059] At 95 °C, first 0.7 g of polyvinyl alcohol with molecular weight of 120000 was dissolved in 7 mL of deionized water with 0.077 g of gelatin by stirring; then, 0.2 g of magnesium nitrate was added to the mixed solution, and after being dissolved by stirring, 0.35 g of kaolin powder was added at a dispersion speed of 2000 rpm, and after being uniformly dispersed, 2.8 g of polyethylene glycol 1000 was added and stirred thoroughly; then, 4 g of sodium citrate solution with a concentration of 30 wt% was added dropwise, and stirred again to be uniform; finally, the composite emulsion was poured into a mold and sealed, and after being placed at 20 °C for 24 h for curing, it was soaked in a 100 wt% anhydrous ethanol solution for 24 h, and finally dried in an oven at 60 °C for 12 h to obtain a hemostatic sponge.

[0060] Example 5

[0061] At 95 °C, first 1 g of polyvinyl alcohol with molecular weight of 120000 was dissolved in 7 mL of deionized water with 0.05 g of gelatin; then, 0.3 g of zinc nitrate was added to the mixed solution, and after stirring and dissolving, 0.5 g of kaolin powder was added at a dispersion speed of 3000 rpm, and after uniform dispersion, 3 g of polyethylene glycol 800 was added and stirred thoroughly; then, 6 g of sodium chloride solution with a concentration of 20 wt% was slowly added and stirred again; finally, the composite emulsion was poured into a mold and sealed, and after being placed at 20 °C for 5 h for curing, it was soaked in a 100 wt% anhydrous ethanol solution for 24 h, and finally dried in an oven at 60 °C for 12 h to obtain a hemostatic sponge.

[0062] Comparative Example 1

[0063] At 95 °C, first 0.7 g of polyvinyl alcohol with a molecular weight of 120000 was dissolved in 7 mL of deionized water with 0.077 g of gelatin; then, 0.2 g of magnesium nitrate was added to the mixed solution, and after stirring and dissolving, 2.8 g of polyethylene glycol 1000 was added and stirred thoroughly; then, 4 g of sodium citrate solution with a concentration of 30 wt% was slowly added and stirred again; finally, the composite emulsion was poured into a mold and sealed, and after being placed at 20 °C for 24 h for curing, it was soaked in 100 wt% anhydrous ethanol for 24 h, and finally dried in an oven at 60 °C for 12 h to obtain a hemostatic sponge.

[0064] Comparative Example 2

[0065] At 95 °C, first 0.7 g of polyvinyl alcohol with a molecular weight of 120000 was dissolved in 7 mL of deionized water with 0.077 g of gelatin; then, 0.2 g of magnesium nitrate was added to the mixed solution, and after stirring and dissolving, 0.35 g of unground kaolin powder was added at a dispersion speed of 2000 rpm, and after uniform dispersion, 2.8 g of polyethylene glycol 1000 was added and stirred thoroughly; then, 4 g of sodium citrate solution with a concentration of 30 wt% was slowly added and stirred again; finally, the composite emulsion was poured into a mold and sealed, and after being placed at 20 °C for 24 h for curing, it was soaked in 100 wt% anhydrous ethanol for 24 h, and finally dried in an oven at 60 °C for 12 h to obtain a hemostatic sponge.

[0066] Comparative Example 3

[0067] First, 0.7 g of polyvinyl alcohol with a molecular weight of 120000 was dissolved in 7 mL of deionized water at 95 ℃; then, 0.2 g of magnesium nitrate was added to the mixed solution, and after being dissolved by stirring, 0.35 g of kaolin powder was added at a dispersion speed of 2000 rpm, and 2.8 g of polyethylene glycol 1000 was added after being uniformly dispersed, and fully stirred; then, 4 g of a sodium citrate solution with a concentration of 30 wt% was slowly added dropwise, and stirred again to be uniform; finally, the composite emulsion was poured into a mold and sealed, and placed at 20 ℃ for 24 h to mature, and then dried in an oven at 60 ℃ for 12 h to obtain a hemostatic sponge.

[0068] The above description is only the preferred embodiment of the present application, and any equivalent changes and modifications made within the scope of the patent application of the present application shall be within the scope of the present application.

Claims

1. A method of preparing a hemostatic sponge, characterized by: The method comprises the following steps: 1) dissolving polyvinyl alcohol and gelatin in deionized water, heating and stirring until completely dissolved to form a polyvinyl alcohol / gelatin composite solution; 2) adding inorganic salt having a salting-in effect to the obtained polyvinyl alcohol / gelatin composite solution, dissolving by stirring, then slowly adding pre-treated kaolin powder, and continuing to stir and disperse until a uniform suspension is formed; 3) then adding small-molecule polyol into the suspension obtained in step 2), and slowly adding inorganic salt solution having a salting-out effect, stirring to form a composite emulsion; 4) injecting the composite emulsion obtained in step 3) into a mold, allowing to stand and cure, so that the components in the emulsion fully interact and solidify to obtain a sponge sample; 5) performing solvent exchange on the residual moisture and unreacted salts in the sponge sample by immersing in anhydrous ethanol, and then drying to obtain the hemostatic sponge; The inorganic salt having a salting-in effect in step 2) is selected from one or more of calcium chloride, magnesium chloride, zinc chloride, calcium nitrate, zinc nitrate, and magnesium nitrate, and the amount is 10% to 100% of the weight of the polyvinyl alcohol used; the pre-treated kaolin powder is kaolin powder with a purity higher than 95% pre-milled to a particle size less than 10 microns; the amount of the kaolin powder is 1% to 100% of the weight of the polyvinyl alcohol used, and the dispersion rotation speed is controlled at 2000-3000 rpm; The small-molecule polyol in step 3) is selected from one or more of polyethylene glycol 800, polyethylene glycol 1000, and polyethylene glycol 1500, and the amount is 100% to 300% of the weight of the polyvinyl alcohol used; the concentration of the inorganic salt solution having a salting-out effect is 1 wt% to 100 wt%, and the amount is converted to 100% to 500% of the weight of the polyvinyl alcohol used based on the weight of the inorganic salt having a salting-out effect; the inorganic salt having a salting-out effect is selected from one or more of potassium carbonate, potassium nitrate, zinc sulfate, and potassium citrate.

2. A method of preparing a haemostatic sponge according to claim 1, characterised in that: The molecular weight of the polyvinyl alcohol in step 1) is 85000-120000; the amount of the gelatin is 1% to 20% of the weight of the polyvinyl alcohol used; and the concentration of the polyvinyl alcohol in the obtained composite solution is 5 wt% to 20 wt%.

3. A method of preparing a haemostatic sponge according to claim 1, characterised in that: The heating temperature in step 1) is 80-100 ℃.

4. The method of claim 1, wherein: The ambient temperature for standing and curing in step 4) is -20-40 ℃, and the curing time is 1-24 hours.

5. The method of claim 1, wherein: The concentration of the ethanol solution used for solvent exchange in step 5) is 50 wt% to 100 wt%; and the immersion time is 1-24 hours.

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