A chitosan copolymer hemostatic dressing and its preparation method

Abstract

This invention belongs to the field of hemostatic materials technology, specifically relating to a chitosan copolymer hemostatic dressing and its preparation method. The dressing comprises the following raw materials: chitosan, glycidyl methacrylate, ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate), and a photoinitiator. The weight of the glycidyl methacrylate is 5-10% of the weight of the chitosan, and the weight of the ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) is 50-150% of the weight of the chitosan. Furthermore, the weight of the ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) is at least 10 times the weight of the glycidyl methacrylate. The absorbance, clotting rate, hemostatic time, and hemostatic volume of this invention are significantly higher than those of conventional methacrylate-modified chitosan hemostatic dressings, resulting in better hemostatic effects.

Description

Technical Field

[0001] This invention belongs to the field of hemostatic materials technology, specifically relating to a chitosan copolymer hemostatic dressing and its preparation method. Background Technology

[0002] Bleeding is unavoidable in daily life, on the battlefield, and during surgery. Excessive bleeding can seriously threaten life and even lead to death. Therefore, the development of ideal hemostatic materials has always received widespread attention both domestically and internationally.

[0003] Chitosan, chemically known as polyglucosamine (1-4)-2-amino-β-D-glucose, is a natural cationic polysaccharide obtained by partial deacetylation of chitin, a naturally abundant high-molecular-weight chitin. It has attracted widespread attention due to its excellent film-forming properties, antibacterial activity, good biocompatibility, blood compatibility, biodegradability, and certain anticancer properties, and is widely used in industries such as pharmaceuticals, food, chemicals, water treatment, cosmetics, environmental protection, and biomedical engineering.

[0004] Several technologies for preparing chitosan hemostatic sponges have been disclosed. One method involves directly using chitosan as the raw material, but the resulting product has poor mechanical strength. Therefore, methods have emerged that mix chitosan with other natural polysaccharides to prepare hemostatic sponges. However, this method suffers from unsatisfactory wet stability, failing to meet clinical needs. Thus, current technologies primarily involve cross-linking chitosan with cross-linking agents to prepare hemostatic sponges. For example, patent CN03112762.2 discloses a method for preparing hemostatic sponges using glutaraldehyde or formaldehyde as a cross-linking agent; another example is patent CN104474576A, which provides a method for preparing hemostatic sponges by covalently cross-linking chitosan with 1,4-butanediol diglycidyl ether. However, the cross-linking agents used in these patents have a certain degree of toxicity, and some residues are unavoidable during the preparation process. Furthermore, these methods require a complex freezing process, which is time-consuming, energy-intensive, and costly.

[0005] To accelerate cross-linking, methods using photoinitiators have been developed. For example, CN202210367198.1 discloses a chitosan-based high-efficiency hemostatic agent with a specific structure, its preparation method, and its application. The method involves mixing chitosan methacrylate with calcium carbonate, calcium chloride, and the photoinitiator Irgacure2959, followed by photocuring and freeze-drying to obtain Janus-structured chitosan methacrylate / calcium carbonate microspheres. The photoinitiator decomposes significantly under ultraviolet light, leaving minimal residue. However, these microspheres tend to adhere to the wound site during hemostasis, and cleaning them can cause secondary damage. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a chitosan copolymer hemostatic dressing and a preparation method thereof, thereby improving its hemostatic performance.

[0007] The present invention relates to a chitosan copolymer hemostatic dressing, comprising the following raw materials: chitosan, glycidyl methacrylate, ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate), and a photoinitiator. The weight of the glycidyl methacrylate is 5-10% of the weight of the chitosan, the weight of the ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) is 50-150% of the weight of the chitosan, and the weight of the ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) is at least 10 times the weight of the glycidyl methacrylate.

[0008] Preferably, the weight of the ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) is 10-30 times the weight of the glycidyl methacrylate.

[0009] Preferably, the weight of the glycidyl methacrylate is 5% of the weight of chitosan, and the weight of the ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) is 50-150% of the weight of chitosan.

[0010] Preferably, the weight of the glycidyl methacrylate is 10% of the weight of chitosan, and the weight of the ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) is 100-150% of the weight of chitosan.

[0011] Preferably, the weight of the glycidyl methacrylate is 15% of the weight of chitosan, and the weight of the ethyl methacrylate (methyl dimethyl trifluoromethanesulfonate ammonium) is 150% of the weight of chitosan.

[0012] The structural formula of the ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) is:

[0013] Its preparation method involves reacting dimethylamine ethyl methacrylate with methyl trifluoromethanesulfonate.

[0014] Preferably, in the preparation method of ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate), the solvent is tetrahydrofuran. Preferably, methyl trifluoromethanesulfonate is added dropwise to a solution of dimethylamine ethyl methacrylate (solvent is tetrahydrofuran) under a protective atmosphere, stirred, precipitated, filtered, washed, and dried to obtain the product.

[0015] The specific reaction process is as follows:

[0016] Under ice bath conditions, 30 ml of anhydrous tetrahydrofuran and 2 ml of dimethylamine methacrylate were added to a three-necked flask and dissolved thoroughly. Under argon protection, 1.5 ml of methyl trifluoromethanesulfonate was slowly added dropwise. After the addition was complete, the mixture was heated to room temperature and stirred for 5 hours, resulting in the precipitation of a precipitate. The precipitate was filtered and washed three times with 30 ml of diethyl ether. The resulting white solid was dried under vacuum at 40 °C to constant weight, with a yield of 95%.

[0017] Preferably, the photoinitiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone.

[0018] This invention provides a method for preparing a chitosan copolymer hemostatic dressing, comprising the following steps:

[0019] Chitosan solution, glycidyl methacrylate, ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) and photoinitiator were mixed and photocured to obtain chitosan copolymer hydrogel. The hydrogel was then freeze-dried to obtain chitosan copolymer hemostatic dressing.

[0020] Preferably, the solvent for the chitosan solution is an aqueous solution of acetic acid.

[0021] Preferably, the raw materials are mixed in the dark at a temperature not lower than 50°C.

[0022] Preferably, the mixed raw materials are cooled before photocuring and then allowed to stand to defoam.

[0023] Preferably, the wavelength of the light used for photocuring is 365nm, the power is 36W, and the photocuring time is 10-30s.

[0024] Preferably, the freeze-drying method is to first freeze rapidly for 2 hours, and then freeze-dry for 24 hours.

[0025] The beneficial effects of this invention are as follows: First, the chitosan copolymer hemostatic dressing of this invention is grafted with ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate), resulting in stable hemostatic properties and high coagulation rate, making it widely applicable for wound or surgical hemostasis. Second, the preparation process combines epoxy ring-opening with photoinitiated copolymerization, achieving a one-step ammonium salting and cross-linking of chitosan, resulting in rapid gel formation. Third, the preparation of the hemostatic dressing does not require a slow, programmed freezing process, simplifying the process, reducing costs, and making it suitable for large-scale industrial production.

[0026] This invention involves ring-opening grafting of chitosan with glycidyl methacrylate, followed by UV-initiated copolymerization with ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) to obtain a chitosan copolymer hydrogel. The hydrogel is then subjected to quick-freezing and freeze-drying processes to produce a chitosan copolymer hemostatic dressing. The absorbance, clotting rate, hemostasis time, and hemostatic volume of this invention are significantly higher than those of conventional methacrylate-modified chitosan hemostatic dressings, exhibiting superior hemostatic effect. By controlling the weight ratio of glycidyl methacrylate to ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate), this invention significantly improves the hemostatic effect, achieving an absorbance of at least 38.2 and a clotting rate of at least 93.2%.

[0027] This invention utilizes the advantages of convenient photocuring and minimal residue to rapidly prepare chitosan copolymer hydrogels. The chitosan copolymer hydrogel is then rapidly freeze-dried to obtain a chitosan hemostatic sponge. This sponge exhibits rapid hemostasis and a high clotting rate at wound sites. After hemostasis, it does not adhere to the wound or cause secondary injury. Attached Figure Description

[0028] Figure 1 This is a surface SEM image of the chitosan copolymer hemostatic dressing of the present invention.

[0029] Figure 2 This is a SEM image of the bottom surface of the chitosan copolymer hemostatic dressing of the present invention.

[0030] Figure 3 It is ethyl methacrylate (dimethyltrifluoromethanesulfonate ammonium methyl methacrylate). 1 HNMR spectrum (D2O).

[0031] Figure 4 The chart shows the hemostasis time for different hemostatic materials, where a represents hemostatic dressing number 2 in Table 1, b represents hemostatic dressing number 3 in Table 1, c represents hemostatic dressing number 10 in Table 1, and d represents hemostatic dressing number 11 in Table 1.

[0032] Figure 5 The chart shows the hemostatic effects of different hemostatic materials. In the chart, a represents the hemostatic dressing with serial number 2 in Table 1, b represents the hemostatic dressing with serial number 3 in Table 1, c represents the hemostatic dressing with serial number 10 in Table 1, and d represents the hemostatic dressing with serial number 11 in Table 1. Detailed Implementation

[0033] Example 1

[0034] A method for preparing a chitosan copolymer hemostatic dressing includes the following steps:

[0035] Dissolve 2g of chitosan in 100ml of 0.6wt% acetic acid aqueous solution, then add 0.2g of glycidyl methacrylate, 1g of ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate), and 0.04g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone photoinitiator. Stir at 60℃ in the dark for 5h to mix thoroughly.

[0036] After cooling to room temperature, fill the contents into glass petri dishes and let stand for 12 hours to defoam.

[0037] Finally, the chitosan copolymer hydrogel was irradiated with a 365nm wavelength, 36W ultraviolet curing lamp for 10–30 seconds to obtain the hydrogel. This hydrogel was then rapidly frozen for 2 hours and freeze-dried for 24 hours to obtain a porous, sponge-like chitosan copolymer hemostatic dressing.

[0038] The chitosan copolymer hemostatic dressing has a thickness of 5mm-7mm and a diameter of 60mm. SEM images of its surface and bottom surface are shown below. Figure 1-2 As shown. From Figure 1-2 It can be seen that the bottom surface of the hemostatic dressing has large pores with a pore size of about 200μm, while the surface of the hemostatic dressing has a porous structure of varying sizes. The large pores in this structure facilitate blood penetration, while the small pores increase the contact area between the blood and the dressing, which is beneficial to improving the hemostasis speed and coagulation rate.

[0039] The preparation method of ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) of the present invention is as follows: Dimethylamine ethyl methacrylate is reacted with methyl trifluoromethanesulfonate. Specifically, under ice bath conditions, 30 ml of anhydrous tetrahydrofuran and 2 ml of dimethylamine ethyl methacrylate are added to a three-necked flask and dissolved evenly. Under argon protection, 1.5 ml of methyl trifluoromethanesulfonate is slowly added dropwise. After the addition is complete, the mixture is heated to room temperature and stirred for 5 hours, resulting in precipitation. The precipitate is filtered and washed three times with 30 ml of diethyl ether. The obtained white solid is dried under vacuum at 40°C to constant weight, with a yield of 95%. The structural formula of the obtained ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) is: Its NMR spectrum is as follows Figure 3 As shown.

[0040] Example 2

[0041] To experiment with the effects of different raw materials on absorbance and clotting rate, the present invention adjusted the raw materials of each material (in serial numbers 1-11, 2% chitosan aqueous solution (ml) means: 2g chitosan dissolved in 100ml of 0.6wt% acetic acid aqueous solution), and the other steps were the same as in Example 1. The absorbance and clotting rate of the dressing were tested, and the performance test table of each example is shown in Table 1.

[0042] Table 1 Performance Test Table for Each Embodiment

[0043]

[0044] Testing the hemostasis time and hemostasis volume of different materials, such as Figure 3-4 As shown, the chitosan copolymer hemostatic dressing of this application can greatly shorten the hemostasis time and reduce the amount of hemostasis.

[0045] Method for determining coagulation rate: Cut the sample into 1cm × 1cm pieces and place them in a 100ml glass beaker; then place them together in a 37℃ constant temperature incubator for 1 minute to preheat. Next, add 0.25mL of blood sample to the beaker until the blood is completely absorbed. After incubating for 1 minute, slowly add 20mL of pure water solution along the beaker wall, taking care not to affect the coagulation of the sample during pouring.

[0046] After incubating in a constant temperature incubator for 10 minutes, centrifuge the solution at 800 rpm for 5 minutes. Take the supernatant and detect the absorbance at 540 nm using a UV spectrophotometer, recording the absorbance value. Use 0.25 ml of blood dissolved in 20 ml of pure water as a 100% control.

[0047] Calculate using the following formula: BCR = (1-X) × 100%

[0048] In the formula: BCR is the coagulation rate of the product, and X is the ratio of the absorbance value of the test sample to the absorbance value of the control sample.

[0049] Method for testing hemostatic volume:

[0050] Rabbit ear artery hemorrhage model: Under sterile conditions, the hemostatic material was cut into 2cm×2cm pieces, weighed, and kept on hand.

[0051] Japanese big-eared rabbits weighing 2.5 ± 0.5 kg were selected and anesthetized by intramuscular injection of thiazide hydrochloride at a dose of 0.2 ml / kg.

[0052] After securing the rabbit's limbs, shave the fur behind its ears to expose the ear artery. Disinfect the area behind the ear with medical alcohol, then sever the ear artery, allowing blood to flow continuously from the wound. After 5 seconds of natural bleeding, wipe away the arterial blood with a sterile cotton swab and immediately apply hemostatic material to the bleeding point, starting a timer. Gently remove the hemostatic material every 30 seconds to observe if bleeding continues. If bleeding continues, continue applying pressure until the bleeding stops, recording the application time. After hemostasis is achieved, weigh the hemostatic material to calculate the rabbit's blood loss.

[0053] Comparative Example 1

[0054] Dissolve 2g of chitosan in 100ml of 0.6wt% acetic acid aqueous solution, then add 0.1g of 1,4-butanediol diglycidyl ether and 1g of chitosan quaternary ammonium salt and stir to dissolve at room temperature.

[0055] After filtration, the mixture was poured into glass petri dishes, allowed to stand for 12 hours to defoam, and then placed in a freezer. Freezer temperature control: from room temperature to 0°C and held for one hour, then to -3°C and held for one hour, then each time the temperature was lowered by 3°C and held for one hour, until it reached -18°C and held for one hour. Then, the temperature was lowered by 5°C and held for one hour each time until it reached -40°C and held for 12 hours.

[0056] Finally, the glass culture dish was placed in a freeze-drying oven and freeze-dried for 24 hours to obtain a porous sponge-like chitosan hemostatic dressing.

[0057] The performance of Comparative Example 1 was tested according to the test method of Example 2.

[0058] Adjust the content of raw materials in Comparative Example 1, test the performance of each comparative example, and obtain the performance test table of each comparative example as shown in Table 2.

[0059] Table 2 Performance Test Tables for Each Comparative Example

[0060]

[0061] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of protection of this application is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0062] One or more embodiments in this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments in this application should be included within the protection scope of this application.

Claims

1. A chitosan copolymer hemostatic dressing, characterized in that it comprises: The following raw materials are used: chitosan, glycidyl methacrylate, ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate), and a photoinitiator, wherein the weight of glycidyl methacrylate is 5-10% of the weight of chitosan, the weight of ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) is 50-150% of the weight of chitosan, and the weight of ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) is at least 10 times the weight of glycidyl methacrylate.

2. The chitosan copolymer hemostatic dressing as described in claim 1, characterized in that, The weight of the glycidyl methacrylate is 5% of the weight of chitosan, and the weight of the ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) is 50-150% of the weight of chitosan; or the weight of the glycidyl methacrylate is 10% of the weight of chitosan, and the weight of the ethyl methacrylate (dimethyl-trifluoromethanesulfonate) is 100-150% of the weight of chitosan.

3. The chitosan copolymer hemostatic dressing as described in claim 1, characterized in that, The weight of the glycidyl methacrylate is 5% of the weight of chitosan, and the weight of the ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) is 150% of the weight of chitosan.

4. The chitosan copolymer hemostatic dressing according to any one of claims 1-3, characterized in that, The structural formula of the ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) is: Its preparation method is to react dimethylamine ethyl methacrylate with methyl trifluoromethanesulfonate to obtain it.

5. The chitosan copolymer hemostatic dressing according to any one of claims 1-3, characterized in that, The photoinitiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone.

6. A method for preparing a chitosan copolymer hemostatic dressing as described in any one of claims 1-5, characterized in that, Includes the following steps, Chitosan solution, glycidyl methacrylate, ethyl methacrylate (N,N,N-trimethyl-trifluoromethanesulfonate) and photoinitiator were mixed and photocured to obtain chitosan copolymer hydrogel. The hydrogel was then freeze-dried to obtain chitosan copolymer hemostatic dressing.

7. The preparation method according to claim 6, characterized in that, The solvent for the chitosan solution is an aqueous solution of acetic acid.

8. The preparation method according to claim 6, characterized in that, The raw materials are mixed in the dark at a temperature not lower than 50°C.

9. The preparation method according to claim 6, characterized in that, Before photocuring, the mixed raw materials are cooled and then allowed to stand to defoam.

10. The preparation method according to claim 6, characterized in that, The light used for photocuring has a wavelength of 365nm and a power of 36W, and the photocuring time is 10-30s; the freeze-drying method is to first freeze rapidly for 2 hours, and then freeze-dry for 24 hours.

Images