An analgesic and hemostatic material and its preparation method

Abstract

This invention relates to the field of hemostatic materials, and more particularly to an analgesic hemostatic material and its preparation method. The analgesic hemostatic material provided by this invention comprises a hydrogel and an analgesic drug loaded on the hydrogel; the hydrogel is a three-dimensional network gel formed by crosslinking biguanide chitosan and polyvinyl alcohol. The analgesic hemostatic material provided by this invention, while possessing hemostatic function, also has analgesic and wound-healing-promoting functions, overcoming the drawbacks of using analgesic drugs and hemostatic materials separately in existing technologies, and is suitable for trauma treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hemostatic materials, in particular to a pain-relieving hemostatic material and a preparation method thereof. BACKGROUND

[0002] Hemostatic material refers to a kind of medical product specially designed for rapid control of bleeding. Common local hemostatic materials can be divided into biological sources, such as fibrinogen, thrombin, etc.; chemical synthesis, such as acrylic acid, polyethylene glycol, etc.; inorganic compounds, such as zeolite, kaolin, etc. hemostatic materials; polysaccharides, such as chitosan, cellulose, alginate, etc. These hemostatic materials are all aimed at quickly sealing the wound and promoting coagulation to prevent excessive blood loss. Although the above-mentioned materials can effectively stop bleeding, they cannot have the functions of pain relief and wound healing promotion at the same time. SUMMARY

[0003] Therefore, the present application aims to provide a pain-relieving hemostatic material with the functions of hemostasis, pain relief and wound healing promotion.

[0004] To achieve the above-mentioned application purpose, the present application provides the following technical solutions:

[0005] The present application provides a pain-relieving hemostatic material, which comprises a hydrogel and a pain-relieving drug loaded on the hydrogel; the hydrogel is a three-dimensional network gel formed by cross-linking of a biguanide-based chitosan and polyvinyl alcohol.

[0006] Preferably, the drug loading rate of the pain-relieving hemostatic material is 30-35%.

[0007] Preferably, the pain-relieving drug comprises flurbiprofen.

[0008] The present application provides a preparation method of the pain-relieving hemostatic material described in the above-mentioned solution, which comprises the following steps:

[0009] Mixing an aqueous solution of polyvinyl alcohol, an aqueous acetic acid solution of biguanide-based chitosan and a cross-linking agent solution, carrying out cross-linking reaction and repeatedly freezing and thawing until a hydrogel is formed;

[0010] Adding a dissolved solution of a pain-relieving drug to the hydrogel, freeze-drying to obtain the pain-relieving hemostatic material.

[0011] Preferably, the mass ratio of polyvinyl alcohol to biguanide-based chitosan is 1-2:1.

[0012] Preferably, the mass concentration of polyvinyl alcohol in the aqueous solution of polyvinyl alcohol is 5-10%.

[0013] The mass concentration of biguanide-based chitosan in the aqueous acetic acid solution of biguanide-based chitosan is 2-2.5%, and the mass concentration of acetic acid in the aqueous acetic acid solution is 1-2%.

[0014] Preferably, the crosslinking reaction includes sequential stirring and standing, wherein the stirring time is 1-3 hours and the standing time is 48-72 hours.

[0015] Preferably, the solvent of the analgesic drug solution is anhydrous ethanol and PBS solution, the volume ratio of anhydrous ethanol to PBS solution is 2-3:1, and the concentration of the analgesic drug in the analgesic drug solution is 30-40 mg / mL.

[0016] Preferably, the repeated freeze-thaw cycles involve repeatedly freezing and thawing; each freezing cycle is performed at a temperature of -20 to -40°C for 12-24 hours; and each thawing cycle is performed at a temperature of 20-40°C for 6-12 hours.

[0017] Preferably, the preparation method of the biguanide chitosan includes the following steps: dissolving chitosan in hydrochloric acid solution to obtain a chitosan solution; mixing the chitosan solution with dicyandiamide to carry out a modification reaction; precipitating the formed biguanide chitosan and then separating the solid and liquid phases to obtain the biguanide chitosan.

[0018] This invention provides an analgesic and hemostatic material, comprising a hydrogel and an analgesic drug loaded on the hydrogel; the hydrogel is a three-dimensional network gel formed by crosslinking biguanide chitosan and polyvinyl alcohol. In this invention, the hydrogel has a sponge-like three-dimensional network structure, which endows it with good tissue compatibility, allowing it to serve as a carrier for the analgesic drug and improving its stability. Furthermore, the hydrogel can expand after absorbing liquid; when applied to wounds, this expansion property helps to seal the wound, forming a physical barrier and reducing bleeding. The biguanide chitosan structure in the hydrogel effectively promotes wound healing. This invention loads the analgesic drug onto the hydrogel, and the hydrogel drug delivery system can control the release rate of the analgesic drug in the body, achieving sustained release. This is particularly important for analgesics that require maintaining a stable drug concentration, reducing the frequency of administration, improving patient compliance, and reducing potential side effects. The analgesic and hemostatic material provided by this invention has both hemostatic and analgesic effects, overcoming the drawbacks of using analgesics and hemostatic materials separately in existing technologies, and is suitable for trauma treatment.

[0019] This invention provides a method for preparing the analgesic and hemostatic material described above, which is simple in steps and easy to industrialize. Attached Figure Description

[0020] Figure 1 Infrared spectra of biguanidin chitosan and chitosan;

[0021] Figure 2 The drug release curve of the analgesic and hemostatic material prepared in Example 1;

[0022] Figure 3 The graph shows the results of the cytotoxicity test, where "***" represents p < 0.0001, indicating a highly significant difference.

[0023] Figure 4 This is a graph showing the results of analgesia experimental tests;

[0024] Figure 5 The images show photos from a liver hemorrhage experiment. "*" indicates p < 0.05, meaning the difference was statistically significant.

[0025] Figure 6 The graph shows the blood loss statistics. "*" represents p < 0.05, indicating a significant difference, and "**" represents p < 0.01, indicating a significant difference.

[0026] Figure 7 The chart shows the statistical values ​​of hemostasis time. In the chart, "*" represents p < 0.05, indicating a significant difference, and "**" represents p < 0.01, indicating a significant difference.

[0027] Figure 8 Photos of wound repair;

[0028] Figure 9 This is the result of an antibacterial experiment. Detailed Implementation

[0029] The present invention provides an analgesic and hemostatic material, comprising a hydrogel and an analgesic drug loaded on the hydrogel; the hydrogel is a three-dimensional network gel formed by crosslinking biguanide chitosan and polyvinyl alcohol.

[0030] In this invention, the drug loading rate of the analgesic and hemostatic material is preferably 30-35%, and in a specific embodiment, it is 31.4%. In this invention, the analgesic drug preferably includes flurbiprofen. In this invention, the drug loading rate is calculated as (mass of the analgesic drug / mass of the lyophilized hydrogel) × 100%.

[0031] In this invention, the encapsulation rate of the analgesic and hemostatic material is preferably 70-75%, and in a specific embodiment it is 73%.

[0032] Currently, hemostatic materials and analgesics for external injuries are usually used separately. This separate approach has several inconveniences. First, it requires carrying multiple different products, increasing the burden of carrying them. Second, in emergency situations, different products need to be used separately, increasing the time and complexity of treating the injury. Furthermore, if the injury causes severe pain, the process of applying hemostatic materials may cause the injured person additional suffering. This invention loads analgesics onto a hydrogel, resulting in a hemostatic and analgesic material that combines hemostasis and analgesia, overcoming the drawbacks of using analgesics and hemostatic materials separately.

[0033] Furthermore, existing hemostatic materials do not possess the function of promoting wound healing. This invention, however, constructs a hydrogel using biguanide chitosan, utilizing the antibacterial, tissue regeneration-promoting, and immunomodulatory functions of the biguanide structure to endow the analgesic and hemostatic material with the function of promoting wound healing. The specific mechanisms of action include:

[0034] Antibacterial properties: Biguanide chitosan can effectively inhibit bacterial growth and reduce the risk of infection, which is a crucial step in the wound healing process. Effective infection control provides a more favorable environment for wound healing.

[0035] Moist environment: Biguanide chitosan helps maintain a moist environment at the wound site, which promotes cell migration and proliferation, and facilitates the regeneration of epithelial cells and other cells. This is crucial for accelerating the wound healing process.

[0036] Biocompatibility and low cytotoxicity: Biguanidin chitosan has good biocompatibility and low cytotoxicity, and is well compatible with human tissues without causing significant immune responses or other side effects.

[0037] Promoting tissue regeneration: By regulating cellular behaviors such as fibroblast proliferation and migration, biguanidin chitosan can support and promote tissue regeneration. This provides important support for wound healing, especially the healing of complex wounds.

[0038] Immune regulation: Biguanidin chitosan may play a role in regulating the immune response, helping to reduce inflammation and thus supporting the healing process.

[0039] In this invention, the hydrogel possesses a three-dimensional network structure similar to a sponge. This structure endows it with excellent tissue compatibility, allowing it to be used as a carrier for analgesic drugs (effectively encapsulating both locally acting and systemically acting drugs, as well as hydrophilic and hydrophobic drugs), and improving the stability of analgesic drugs. The hydrogel expands rapidly upon water stimulation, enabling rapid hemostasis for various types of bleeding, including deep bleeding. Furthermore, the hydrogel's soft texture makes it more comfortable upon contact with body tissue, reducing discomfort. This is particularly important for drug carriers requiring long-term use, improving patient comfort and user experience.

[0040] This invention provides a method for preparing the analgesic and hemostatic material described above, comprising the following steps:

[0041] An aqueous solution of polyvinyl alcohol, an aqueous solution of biguanide chitosan in acetic acid, and a crosslinking agent solution are mixed, and after a crosslinking reaction, the mixture is repeatedly frozen and thawed until a hydrogel is formed.

[0042] The analgesic drug solution was added to the hydrogel, and then freeze-dried to obtain the analgesic and hemostatic material.

[0043] Unless otherwise specified, all raw materials used in this invention are commercially available products well known in the art.

[0044] The source of biguanide chitosan will be explained below.

[0045] In this invention, the biguanide chitosan is preferably obtained by self-preparation; the preparation method of the biguanide chitosan preferably includes the following steps: dissolving chitosan in hydrochloric acid solution to obtain chitosan solution; mixing the chitosan solution with dicyandiamide to carry out a modification reaction; precipitating the formed biguanide chitosan and then separating the solid and liquid to obtain the biguanide chitosan.

[0046] This invention involves dissolving chitosan in hydrochloric acid solution to obtain a chitosan solution.

[0047] In this invention, the degree of deacetylation of the chitosan is preferably ≥95%, and the viscosity is preferably 100-200 mPa·s. In this invention, the mass concentration of the hydrochloric acid solution is preferably 1%. This invention does not have special requirements on the amount of hydrochloric acid solution used, as long as it is sufficient to completely dissolve the chitosan. In an embodiment of this invention, specifically, 2 g of chitosan is dissolved in 100 mL of hydrochloric acid solution. This invention does not have special requirements on the dissolution process.

[0048] After obtaining the chitosan solution, the present invention mixes the chitosan solution with dicyandiamide to carry out a modification reaction, and after the biguanidin chitosan is precipitated, solid-liquid separation is performed to obtain the biguanidin chitosan.

[0049] In this invention, the mass ratio of chitosan to dicyandiamide in the chitosan solution is preferably 1.5-2:1, and in specific embodiments, it can be 1.5:1, 1.8:1, 1.9:1, or 2:1. The mixing preferably includes adding dicyandiamide to the chitosan solution. In this invention, the temperature of the modification reaction is preferably 90-100℃, and the time is preferably 2-6 hours. In specific embodiments, the temperature of the modification reaction can be 90℃, 95℃, or 100℃, and the time of the modification reaction can be 2 hours, 3 hours, 4 hours, 5 hours, or 6 hours. The modification reaction is preferably carried out under stirring conditions. In the modification reaction process of this invention, the cyano group (-C≡N) of the dicyandiamide reacts with the amino group (-NH2) of the chitosan to generate biguanidin-modified chitosan.

[0050] In this invention, the structural formula of the biguanidin-modified chitosan is shown in Formula 1:

[0051]

[0052] The present invention involves precipitating biguanidin-based chitosan formed by the modified reaction and then performing solid-liquid separation to obtain the biguanidin-based chitosan.

[0053] In this invention, the modified system is preferably placed in ice-cold ethanol to precipitate biguanide chitosan. In this invention, the temperature of the ice-cold ethanol is preferably -20 to -40°C.

[0054] The present invention does not have any special requirements for the solid-liquid separation method; any solid-liquid separation method well known in the art is acceptable, such as centrifugation.

[0055] After solid-liquid separation, the present invention preferably washes the obtained solid with ethanol and then vacuum dries it. The present invention does not have special requirements for the vacuum drying conditions; drying until the biguanide chitosan is completely dry is sufficient. In an embodiment of the present invention, drying is specifically carried out in a vacuum drying oven at 60°C for 24 hours.

[0056] The preparation method of analgesic and hemostatic materials is explained below.

[0057] This invention involves mixing an aqueous solution of polyvinyl alcohol, an aqueous solution of biguanide chitosan in acetic acid, and a crosslinking agent solution, followed by repeated freeze-thaw cycles to form a hydrogel.

[0058] In this invention, the polyvinyl alcohol is preferably PVA-105, and the relative molecular weight is preferably 47,000. In this invention, the mass concentration of polyvinyl alcohol in the aqueous solution is preferably 5-10%, and in specific embodiments it can be 5%, 6%, 7%, 8%, 9%, or 10%. In this invention, the aqueous solution of polyvinyl alcohol is preferably obtained by dissolving polyvinyl alcohol in hot water at 80°C.

[0059] In this invention, the mass concentration of biguanide chitosan in the acetic acid aqueous solution is preferably 2-2.5%, and the solvent is an acetic acid aqueous solution, wherein the mass concentration of acetic acid in the acetic acid aqueous solution is preferably 1-2%. Specifically, this invention involves dissolving biguanide chitosan in an acetic acid aqueous solution to obtain the acetic acid solution of the biguanide chitosan.

[0060] In this invention, the mass ratio of polyvinyl alcohol to biguanide chitosan is preferably 1-2:1, and in specific embodiments it can be 1:1, 1.3:1, 1.5:1 or 2:1.

[0061] In this invention, the mass concentration of the crosslinking agent in the crosslinking agent solution is preferably 50%; the solvent of the crosslinking agent solution is preferably water. In this invention, the crosslinking agent preferably includes one or more of glutaraldehyde, tannic acid, and oxidized dextran.

[0062] In this invention, the mass ratio of the crosslinking agent in the crosslinking agent solution to the total volume of the aqueous solution of polyvinyl alcohol and the aqueous solution of biguanide chitosan in acetic acid is preferably 0.001-2 mg:1 mL (i.e. 0.1-2% w / v), and in a specific embodiment it is 0.05%.

[0063] In this invention, the mixing of the aqueous solution of polyvinyl alcohol, the acetic acid solution of biguanide chitosan, and the glutaraldehyde solution preferably includes: first mixing and stirring the aqueous solution of polyvinyl alcohol with the aqueous solution of acetic acid of biguanide chitosan for 2 hours, and then adding the crosslinking agent solution.

[0064] In this invention, the crosslinking reaction is preferably carried out at room temperature (20-40°C), and the crosslinking reaction preferably includes: stirring and standing in sequence; the stirring time is preferably 1-3 hours, and in specific embodiments it can be 1 hour, 2 hours or 3 hours; the standing time is preferably 48-72 hours, and in specific embodiments it can be 48 hours, 56 hours, 64 hours or 72 hours.

[0065] After the crosslinking reaction is completed, the resulting product is subjected to repeated freeze-thaw cycles until a hydrogel is formed. In this invention, the repeated freeze-thaw cycles are preferably repeated freezing and thawing; the preferred freezing temperature is -20 to -40°C, and the preferred time is 12-24 hours; the preferred thawing temperature is 20-40°C, and the preferred time is 6-12 hours. In embodiments of this invention, the specific freezing temperature can be -20°C, -30°C, or -40°C, and the specific freezing time can be 12 hours, 18 hours, 20 hours, or 24 hours; the specific thawing temperature can be 20°C, 30°C, or 40°C, and the specific thawing time can be 6 hours, 8 hours, 10 hours, or 12 hours. In this invention, the hydroxyl groups of polyvinyl alcohol and the amino groups of biguanide chitosan more easily form hydrogen bonds through repeated freeze-thaw cycles. Extrusion causes the molecular chains to aggregate tightly, forming hydrogen bonds and microcrystalline regions. The microcrystalline regions of polyvinyl alcohol and the hydrogen bonds / electrostatic interactions of chitosan together stabilize the gel structure.

[0066] After obtaining the hydrogel, the present invention adds a solution of analgesic drugs to the hydrogel, freezes it, and obtains the analgesic and hemostatic material.

[0067] In this invention, the solvent for the solution of the analgesic drug is preferably anhydrous ethanol and PBS solution, with a preferred volume ratio of anhydrous ethanol to PBS solution of 2-3:1, and the pH value of the PBS solution is preferably 7.4. The PBS solution is added to dilute the anhydrous ethanol. In this invention, the concentration of the analgesic drug in the solution is preferably 30-40 mg / mL, and in specific embodiments, it can be 30 mg / mL, 33 mg / mL, 35 mg / mL, 38 mg / mL, or 40 mg / mL.

[0068] In this invention, the solution of the analgesic drug is preferably added dropwise into the hydrogel. In this invention, the hydrogel can be selected in a suitable shape as needed; in an embodiment of this invention, the hydrogel is cylindrical with a diameter of 8 mm and a height of 3 mm.

[0069] After the analgesic drug solution has been added, this invention preferably allows the solution to evaporate at room temperature, followed by rinsing with water. This invention does not have specific requirements regarding the time spent at room temperature, as long as the ethanol is completely evaporated; this can be 30 minutes or 24 hours.

[0070] The present invention does not have special requirements for the freeze-drying conditions; freeze-drying conditions well known in the art can be used.

[0071] The analgesic and hemostatic materials and their preparation methods provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0072] Example 1

[0073] 2 g of chitosan was dissolved in 100 mL of 1% hydrochloric acid and stirred continuously for 30 min at room temperature. Then, 1.06 g of dicyandiamide was added to the solution, and the mixture was stirred at 90 °C for another 2 h to carry out the modification reaction. After the reaction was complete, the concentrated solution was poured into 200 mL of ice-cold ethanol (temperature -30 °C) and centrifuged at 4000 g for 20 min to obtain biguanide chitosan. The obtained biguanide chitosan was washed several times with ethanol and finally dried in a vacuum drying oven at 60 °C for 24 h.

[0074] Polyvinyl alcohol (specifically PVA-105, preferably with a relative molecular weight of 47,000) was dissolved in hot water at 80°C to prepare a 10% polyvinyl alcohol solution. Biguanide chitosan was dissolved in a 1% aqueous acetic acid solution to prepare a 2.5% biguanide chitosan solution. 1.333 mL of polyvinyl alcohol solution and 4 mL of biguanide chitosan solution were stirred at room temperature for 2 hours, and then 5.333 μL of 50% glutaraldehyde solution was added. The mixture was stirred at room temperature for 1 hour, placed at room temperature for 72 hours, and then frozen at -20°C for 12 hours. After thawing at room temperature for 6 hours, the freeze-thaw cycle was repeated several times until a hydrogel was formed. The hydrogel was cut into cylindrical shapes with a diameter of 8 mm and a height of 3 mm using a punch, and denoted as BCS / PVA.

[0075] 1 mg of flurbiprofen (FB) was dissolved in 20 μL of anhydrous ethanol and 10 μL of PBS solution (pH 7.4), and then added dropwise into a cylindrical hydrogel. After being placed at room temperature for 24 h, the solution was rinsed with deionized water and lyophilized to obtain the analgesic and hemostatic material, denoted as BCS / PVA@FB.

[0076] Comparative Example 1

[0077] Preparation of CS / PVA:

[0078] Polyvinyl alcohol (specifically PVA-105, preferably with a relative molecular weight of 47,000) was dissolved in hot water at 80°C to prepare a 10% polyvinyl alcohol solution. Chitosan was dissolved in a 1% acetic acid aqueous solution to prepare a 2.5% chitosan solution. 1.333 mL of polyvinyl alcohol solution and 4 mL of chitosan solution were stirred at room temperature for 2 hours, and then 5.333 μL of 50% glutaraldehyde solution was added. The mixture was stirred at room temperature for 1 hour, placed at room temperature for 72 hours, and then frozen at -20°C for 12 hours. After thawing at room temperature for 6 hours, the freeze-thaw cycle was repeated several times until a hydrogel was formed. The hydrogel was cut into cylindrical shapes with a diameter of 8 mm and a height of 3 mm using a punch, and denoted as CS / PVA.

[0079] Comparative Example 2

[0080] Preparation of BCS / PVA:

[0081] Polyvinyl alcohol (specifically PVA-105, preferably with a relative molecular weight of 47,000) was dissolved in hot water at 80°C to prepare a 10% polyvinyl alcohol solution. Biguanide chitosan was dissolved in a 1% aqueous acetic acid solution to prepare a 2.5% biguanide chitosan solution. 1.333 mL of polyvinyl alcohol solution and 4 mL of biguanide chitosan solution were stirred at room temperature for 2 hours, and then 5.333 μL of 50% glutaraldehyde solution was added. The mixture was stirred at room temperature for 1 hour, placed at room temperature for 72 hours, and then frozen at -20°C for 12 hours. After thawing at room temperature for 6 hours, the freeze-thaw cycle was repeated several times until a hydrogel was formed. The hydrogel was cut into cylindrical shapes with a diameter of 8 mm and a height of 3 mm using a punch, and denoted as BCS / PVA.

[0082] Infrared characterization

[0083] Infrared characterization was performed on biguanide chitosan (BCS) and chitosan (CS), and the results are shown in the figure. Figure 1 .Depend on Figure 1 It can be seen that BCS is at 1515 and 1615cm. -1 The appearance of a new peak indicates the presence of C=N, signifying the formation of biguanidolated chitosan.

[0084] Hydrogel drug delivery

[0085] The analgesic and hemostatic material prepared in Example 1 was immersed in PBS solution (pH 7.4) for 24 hours. The flurbiprofen content in the solution at different time points was measured using a UV spectrophotometer, and the drug release was calculated. The results are shown in [Figure 1]. Figure 2 .Depend on Figure 2 It can be seen that the analgesic and hemostatic material prepared in Example 1 has a drug release time of about 20 hours and a cumulative drug release rate of about 55%, indicating that the analgesic and hemostatic material of the present invention can achieve continuous release of analgesic drugs, reduce the frequency of administration, and help improve patient medication compliance.

[0086] Cytotoxicity

[0087] The analgesic and hemostatic material prepared in Example 1 was subjected to MTT assay to evaluate its cytotoxicity in NIH3T3 cells (mouse embryonic fibroblast cell line). Before the test, all lyophilized hydrogels (BCS / PVA and BCS / PVA@FB) were extracted in a 37°C shaker for 24 h at a hydrogel volume ratio of 1:5 to DMEM complete medium to obtain hydrogel extracts. These extracts were then diluted with DMEM complete medium to obtain different concentrations (25%, 50%, 75%, and 100% by volume). NIH3T3 cells were seeded at a density of 3000 cells / well in 100 μL of DMEM medium and pre-cultured at 37°C for 12 h. Different concentrations of hydrogel extracts were then added, and the cells were cultured for another 24 h. Cell counting was used to assess the cytotoxicity of the foam. The results are shown in [Figure number missing]. Figure 3 .Depend on Figure 3 It can be seen that all concentrations of the unloaded hydrogel BCS / PVA are non-toxic, and the drug-loaded group BCS / PVA@FB at concentrations up to 50% is non-toxic. Figure 3 A concentration of 0 represents the blank group cultured in complete DMEM medium.

[0088] Analgesia Experiment

[0089] Mice were first anesthetized with chloral hydrate, then their backs were shaved and 8mm diameter wounds were made. They were then divided into a blank control group, a BCS / PVA group, an FB group, and a BCS / PVA@FB group for treatment. The blank control group received only 100μL PBS. The BCS / PVA group received BCS / PVA hydrogel applied to the wound. The FB group received a solution of FB with the same drug loading in a small amount of ethanol (20μL) and 10μL PBS, which was then applied to the wound and covered with a medical surgical dressing. The BCS / PVA@FB group received BCS / PVA@FB analgesic and hemostatic material.

[0090] The hot plate test was used to evaluate the responses of mice to thermal pain stimuli. The temperature of the thermostatic intelligent hot plate apparatus was set to a constant 55 ± 0.2 °C. Once the hot plate reached the set temperature, the acrylic glass cover was removed, and the mice were quickly placed on the apparatus. The time from the moment the mouse's hind paw came into contact with the hot plate until any of the following behaviors occurred—lifting, withdrawing, licking, or struggling—was recorded as the hind paw withdrawal time, also known as PWL. This index serves as an indicator for assessing the thermal pain threshold in mice. The maximum time was set to 60 seconds (critical value) to prevent burns to the mouse paw tissue. Each mouse underwent two repeated measurements, with a 10-minute interval between each measurement, and the average value was taken. The thermal pain threshold latency was measured for each mouse one day before modeling as the baseline thermal pain threshold. The thermal pain threshold was measured at 0.5, 1.5, 2, 3.5, 5, 7, and 9 hours post-surgery. The %MPE (percentage increase in pain threshold) for each mouse was calculated using the following formula 2: %MPE = [(LR - BR) = (MR - BR)] × 100% (Formula 2), where LR, MR, and BR represent the measured, maximum (60 seconds), and baseline (~5 seconds) response times, respectively. Test results are shown in […]. Figure 4 .from Figure 4 It can be seen that the analgesic effect of the BCS / PVA@FB group is higher than that of other groups, and the 9h BCS / PVA@FB group is significantly higher than that of the BCS / PVA group, indicating that the analgesic effect of the hydrogel loaded with flurbiprofen is better than that of other groups.

[0091] hemostasis experiment

[0092] Mice (n=16) used in the liver hemorrhage experiment were randomly divided into four groups: Blank, Gauze, CS / PVA, and BCS / PVA@FB. The liver of each mouse was exposed via an abdominal incision. To ensure accurate estimation of the blood weight obtained from the hemostatic sample, perihepatic serous fluid was carefully removed. A pre-weighed filter paper was placed between a plastic film and the liver. The liver was punctured at a 30° angle using a 16G needle with a diameter of 1.6 mm and a consistent puncture depth of 2 mm. Gauze, CA / PVA, and lyophilized BCS / PVA@FB were promptly applied to the bleeding site, and the hemostasis time and blood loss were recorded. Photographs were taken at 0, 30, 60, and 90 seconds at the bleeding site (see [link to relevant documentation]). Figure 5 Record the hemostasis time for each group; results are shown below. Figure 7 .from Figure 7It can be seen that the BCS / PVA@FB group had the shortest hemostasis time, showing a significant difference compared to the gauze group and the control group, as well as a significant difference between the CS / PVA group and the control group. The hemostasis effect of the flurbilov-loaded BCS / PVA@FB group was superior to other groups. The hemostasis time in the BCS / PVA@FB group was only 131.5±29.8s, which was shortened by approximately 58%, 42%, and 13% compared to the control, gauze, and CS / PVA groups, respectively. Furthermore, the blood loss in the BCS / PVA@FB group was 28.2±9.8mg, which was approximately 69%, 39%, and 39% lower than that in the control, gauze, and CS / PVA groups, respectively (see...). Figure 6 ).

[0093] wound healing effect

[0094] Mice were first anesthetized with chloral hydrate, then their backs were shaved, and 8mm diameter wounds were made. They were then divided into four groups: a control group, a BCS / PVA group, a FB group, and a BCS / PVA@FB group. The control group received only 100μL PBS. The BCS / PVA group received BCS / PVA hydrogel applied to the wound. The FB group received a solution of FB with the same drug loading in 20μL ethanol, then 10μL PBS, which was applied to the wound and covered with a surgical dressing. The BCS / PVA@FB group received BCS / PVA@FB analgesic and hemostatic material. Wound size was observed and photographed at 0, 7, 9, 12, and 15 days after wound creation. Results are shown in the table below. Figure 8 .Depend on Figure 8 It can be seen that, compared with other groups, the BCS / PVA@FB group had the fastest wound healing speed.

[0095] Antibacterial test

[0096] The bacteria were cultured overnight in Luria-Bertani medium at 37°C in a shaker. Then, 100 μL of the bacterial suspension was diluted with 400 μL of deionized water and added to CS / PVA, BCS / PVA, and BCS / PVA@FB hydrogels, respectively. The solutions were then incubated in a shaker at 37°C for 12 h. Afterward, the bacterial solutions were diluted with deionized water, and 100 μL of each dilution was inoculated onto LB agar plates. Results were obtained after 24 h of incubation. Figure 9 .

[0097] Depend on Figure 9 It is known that BCS / PVA and BCS / PVA@FB have better antibacterial effects than CS / PVA, which may be attributed to the fact that the biguanide group (such as -[NH-C(=NH)-NH-]) is highly protonated under physiological conditions, which significantly increases the molecular positive charge density, adsorbs the bacterial membrane more strongly, destroys the membrane integrity, and leads to leakage of contents and bacterial death.

[0098] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An analgesic hemostatic material, characterized by, The analgesic material comprises a hydrogel and an analgesic drug loaded on the hydrogel; the hydrogel is a three-dimensional network gel formed by cross-linking of a biguanide-based chitosan and polyvinyl alcohol; the preparation method of the biguanide-based chitosan comprises the following steps: dissolving chitosan in a hydrochloric acid solution to obtain a chitosan solution; mixing the chitosan solution with dicyandiamide for a modification reaction, and then performing solid-liquid separation after precipitating the formed biguanide-based chitosan to obtain the biguanide-based chitosan; the mass ratio of chitosan to dicyandiamide in the chitosan solution is 1.5-2:1; and the analgesic drug comprises flurbiprofen.

2. The analgesic and hemostatic material according to claim 1, characterized in that, The drug loading rate of the analgesic hemostatic material is 30-35%.

3. The preparation method of the analgesic hemostatic material according to any one of claims 1-2, comprising the following steps: mixing an aqueous solution of polyvinyl alcohol, an aqueous acetic acid solution of biguanide-based chitosan and a cross-linking agent solution, and then repeatedly freezing and thawing until a hydrogel is formed after cross-linking reaction; adding a dissolved solution of an analgesic drug into the hydrogel, and then freeze-drying to obtain the analgesic hemostatic material.

4. The production method according to claim 3, characterized by, The mass ratio of polyvinyl alcohol to biguanide-based chitosan is 1-2:

1.

5. The production method according to claim 3 or 4, characterized by, The mass concentration of polyvinyl alcohol in the aqueous solution of polyvinyl alcohol is 5-10%; The mass concentration of biguanide-based chitosan in the aqueous acetic acid solution of biguanide-based chitosan is 2-2.5%, and the mass concentration of acetic acid in the aqueous acetic acid solution is 1-2%.

6. The production method according to claim 3 or 4, characterized by, The cross-linking reaction comprises stirring and standing in sequence, the stirring time is 1-3 h, and the standing time is 48-72 h.

7. The preparation method according to claim 3, characterized in that, The solvent of the dissolved solution of the analgesic drug is anhydrous ethanol and PBS solution, the volume ratio of the anhydrous ethanol and PBS solution is 2-3:1, and the concentration of the analgesic drug in the dissolved solution of the analgesic drug is 30-40 mg / mL.

8. The preparation method according to claim 3, characterized in that, The repeated freezing and thawing is repeatedly freezing and thawing; the temperature of each freezing is -20 to -40℃, and the time is 12-24 h; the temperature of each thawing is 20-40℃, and the time is 6-12 h.

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