Cefradine supramolecular composite graded gel as well as preparation method and application thereof

Abstract

The invention discloses cefradine supramolecular composite graded gel and a preparation method and application thereof, cefradine and glycosaminoglycan are used as raw materials, and self-assembly of cefradine is controlled through an interface template to form supramolecular hydrogel. And cross-linking and compounding with glycosaminoglycan gel to obtain the double-network supramolecule-polymer graded composite gel. The graded composite gel prepared by the invention has excellent swelling property, tissue adhesion and thixotropy and tensile property similar to that of human skin, so that the graded composite gel can accelerate healing of infected wounds, and due to excellent conductivity, real-time online monitoring of drug release and wound healing conditions can be realized.

Description

Technical Field

[0001] The invention belongs to the field of medical materials and relates to a preparation method and application of a cefradine supramolecular composite graded gel. Background Art

[0002] Every year, millions of people worldwide suffer various types of trauma, such as injuries caused by accidents and surgical incisions. Once tissue is damaged, massive bleeding and wound infection become major causes of death. Skin is one of the most vital tissues in the human body. Due to its direct contact with the external environment, it is also one of the most vulnerable. While most common skin injuries undergo a continuous repair process and effectively heal over time, various factors can lead to abnormal wound healing. For example, bacterial infection of a wound can cause a persistent inflammatory response, delaying the wound healing process. Consequently, a variety of bio-soft materials have emerged as wound dressings to promote wound repair. Among them, hydrogels are considered a promising wound dressing material due to their highly tunable physical and chemical properties and three-dimensional porous structure similar to that of the extracellular matrix. Current requirements for hydrogels used in wound dressings extend beyond a single physical covering function. Based on the complex wound types and the continuous changes in physiological parameters near the wound caused by the healing process, it is very necessary to develop smart gel dressings that can act on all stages of wound healing, and can timely monitor and manage drug release and wound healing, and ultimately achieve on-demand treatment for different patients.

[0003] Another issue to consider during wound healing is how to avoid and treat bacterial infections. There are currently a large number of reports on new antibacterial materials, but antibiotics remain the first choice for clinical treatment of wound infections due to their excellent antibacterial effects. These antibiotic drugs are usually loaded into hydrogels to prepare antibacterial wound dressings. This conventional hydrogel drug delivery system usually requires a carrier, which physically or chemically loads therapeutic molecules. Although these hydrogel systems have excellent antibacterial properties, there are still many issues to consider regarding the use of carriers, such as: their complex synthesis, drug loading capacity, biocompatibility, biodegradability and potential side effects.

[0004] Chinese patent CN119950804A discloses a hydrogel dressing for treating diabetic wound infections, which is prepared using sodium alginate, polyvinyl pyrrolidone, gelatin, carboxymethyl cellulose, chlorogenic acid and Panax notoginseng saponin. However, it requires multiple polymer raw materials and the synthesis process is complicated, which greatly increases the preparation cost.

[0005] Chinese patent CN120020164A discloses a method for preparing a polyacrylic acid-nanolignin composite hydrogel. The resulting hydrogel exhibits relatively excellent tensile properties. However, the preparation process requires the introduction of substances such as acrylic acid as UV-light initiators, which may have potential biotoxicity, limiting its application.

[0006] Therefore, designing therapeutic agents into self-delivering supramolecular hydrogels without reducing the efficacy of drugs will have broader prospects. It is very necessary to provide a preparation method for smart wound dressings that promote wound healing, sterilize and anti-inflammation. Summary of the Invention

[0007] The purpose of the present invention is to overcome the problems in the prior art and provide a cefradine supramolecular composite graded gel and its preparation method and application. By compounding cefradine supramolecular hydrogel and glycosaminoglycan hydrogel to prepare a graded double-network gel, it exhibits excellent mechanical properties, long-lasting antibacterial activity in response to multiple stimuli, and the ability to rapidly promote wound healing, and can realize in situ monitoring of drug release behavior and wound status.

[0008] In order to achieve the above object, the present invention provides a cefradine supramolecular composite graded gel, which uses cefradine and glycosaminoglycan as raw materials. The cefradine forms cefradine supramolecular nanofibers, and the cefradine supramolecular nanofibers and the glycosaminoglycans form glycosaminoglycan polymer fibers cross-linked into a network to form the cefradine supramolecular composite graded gel.

[0009] Preferably, any of the above items is that a non-water-soluble solvent is added to a supersaturated aqueous solution of cephradine, and cephradine molecules are autonomously assembled into the cephradine supramolecular nanofibers at the interface formed by the non-water-soluble solvent and water.

[0010] The present invention discovers for the first time that cefradine forms a gel structure of supramolecular nanofibers by assembling them using an interface as a template. The non-water-soluble solvent is immiscible with water and can form an interface with water. The present invention defines a non-water-soluble solvent that meets these requirements as a layering agent. The layering agent does not chemically react with the raw materials and reagents required to prepare the cefradine supramolecular composite graded gel.

[0011] Preferably, any of the above items is that the cefradine supramolecular composite graded gel comprises the following components in the following weight percentage concentrations: 0.5-5 wt% of cefradine supramolecular nanofibers and 0.5-5 wt% of glycosaminoglycan polymer fibers.

[0012] Any of the above is preferably that the cefradine supramolecular nanofibers are preferably 1-2 wt%, preferably 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 wt% and ranges therebetween.

[0013] Any of the above is preferably that the glycosaminoglycan polymer fiber is preferably 1-2 wt%, preferably 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 wt% and ranges therebetween.

[0014] The present invention also provides a method for preparing the cefradine supramolecular composite graded gel described in any one of the above, comprising the following steps:

[0015] Step 1: Add cefradine to water;

[0016] Step 2: Add acid and stir thoroughly until the cefradine is completely dissolved;

[0017] Step 3: reducing the solubility of cephradine in the solution to obtain a supersaturated solution of cephradine;

[0018] Step 4: adding a delamination agent and allowing the mixture to stand for delamination to form an interface, and continuing to stand for a period of time so that the cefradine assembles at the interface to form a gel, namely, the cefradine supramolecular nanofibers;

[0019] Step 5: Filter and wash the gel obtained in step 4 for later use;

[0020] Step 6: Add glycosaminoglycan to water and stir thoroughly to disperse;

[0021] Step 7: adding the gel obtained in step 5 to the system in step 6, and stirring and mixing them thoroughly to obtain the cefradine supramolecular composite graded gel.

[0022] Preferably, in any of the above items, in step 1, the mass ratio of cefradine to water is 1:100 to 5:100, more preferably 1:100, 2:100, 3:100, 4:100, 5:100 and ranges therebetween.

[0023] In any of the above, preferably, in step 2, the mass ratio of the amount of acid added to the amount of water added in step 1 is 0.02:100 to 1:100. More preferably, the mass ratio is 0.02:100, 0.1:100, 0.2:100, 0.3:100, 0.4:100, 0.5:100, 0.6:100, 0.7:100, 0.8:100, 0.9:100, 1:100 and ranges therebetween.

[0024] Any of the above is preferably that in step 2, the type of acid includes but is not limited to organic acids (such as acetic acid, formic acid, oxalic acid, salicylic acid, etc.) and inorganic acids (such as sulfuric acid, nitric acid, hydrochloric acid, etc.). In the present invention, the role of the acid is to completely dissolve cephradine. Therefore, the present invention is not limited to the type of acid, and any acid that can provide an acidic environment for the solution is applicable to the present invention; the present invention is also not limited to the concentration or pH of the acid, and any acid concentration or pH that can completely dissolve cephradine is applicable to the present invention.

[0025] In any of the above, preferably, in step 2, the dissolution temperature is 10 to 40° C., more preferably 10, 20, 30, 40° C. and ranges therebetween.

[0026] Preferably, in any of the above items, in step 2, the stirring rate is 100 rpm to 200 rpm, more preferably 100, 150, 200 rpm and ranges therebetween.

[0027] Preferably, in any of the above items, in step 2, the stirring time is 60 min to 120 min, more preferably 60, 80, 120 min, and ranges therebetween.

[0028] Preferably, in any of the above items, in step 3, an organic amine solvent is added and stirred thoroughly to achieve complete mixing, thereby obtaining a supersaturated solution of cephradine.

[0029] Preferably, in any of the above items, in step 3, the organic amine solution comprises at least one of isopropylamine, triethylamine, diisopropylamine, and triethanolamine.

[0030] In the present invention, the role of the organic amine is to adjust the solubility of cephradine, so that the cephradine solution obtained in step 2 becomes a supersaturated solution for assembly. Therefore, any organic amine that can reduce the solubility of cephradine and make it a supersaturated solution is suitable for the present invention, and the type of organic amine in the present invention is not limited to isopropylamine, triethylamine, diisopropylamine or triethanolamine.

[0031] Preferably, in any of the above items, in step 3, the mass ratio of the amount of the organic amine added to the amount of water added in step 1 is 0.02:100 to 1:100. More preferably, the mass ratio is 0.02:100, 0.1:100, 0.2:100, 0.3:100, 0.4:100, 0.5:100, 0.6:100, 0.7:100, 0.8:100, 0.9:100, 1:100, and ranges therebetween.

[0032] Preferably, in any of the above items, in step 3, the stirring rate is 100 rpm to 200 rpm, more preferably 100, 150, 200 rpm and ranges therebetween.

[0033] Preferably, in any of the above, in step 3, the mixing time is 10 min to 60 min, more preferably 10, 20, 40, 60 min, and ranges therebetween.

[0034] Any of the above is preferably, in step 4, the layering agent comprises at least one of cyclohexane, hexadecane, dichloromethane, normal hexane, and toluene. The interface formed by the layering agent and water acts as a soft template, allowing cephradine to undergo directed self-assembly to form a gel. Any water-insoluble solvent that can layer with water, i.e., form an interface, is suitable for the present invention, so the layering agent of the present invention is not limited to cyclohexane, hexadecane, dichloromethane, normal hexane, or toluene.

[0035] In any of the above, preferably, in step 4, the mass ratio of the amount of the delaminating agent added to the amount of water added in step 1 is 20:100 to 100:100. More preferably, the mass ratio is 20:100, 30:100, 40:100, 50:100, 60:100, 70:100, 80:100, 90:100, 100:100 and ranges therebetween.

[0036] Preferably, in any of the above items, in step 4, the standing time for stratification is 20 min to 40 min, more preferably 20, 30, 40 min, or a range therebetween.

[0037] Preferably, in any of the above items, in step 4, the assembly time is 2 hours to 10 hours, more preferably 2, 4, 6, 8, 10 hours, and ranges therebetween.

[0038] Preferably, in any of the above items, in step 5, the washing method is: washing the filtered product with a washing liquid, wherein the washing liquid is a saturated aqueous solution of cephradine.

[0039] Preferably, in any of the above items, in step 5, the mass ratio of the amount of washing liquid used to the amount of water added in step 1 is 0.2:1 to 0.6:1. More preferably, the mass ratio is 0.2:1, 0.4:1, 0.6:1 and ranges therebetween.

[0040] Any of the above is preferably that in step 6, the glycosaminoglycan is at least one of hyaluronic acid, chondroitin sulfate, and keratan sulfate. The glycosaminoglycans of the present invention include but are not limited to hyaluronic acid, chondroitin sulfate, or keratan sulfate. In the present invention, glycosaminoglycan is a high molecular weight polymer, which is dispersed in water and its polymer chains are unfolded to form polymer fibers.

[0041] Preferably, in any of the above items, in step 6, the dispersion temperature is 10-40° C. More preferably, it is 10, 20, 30, 40° C. and ranges therebetween.

[0042] Preferably, in any of the above items, in step 6, the stirring rate is 100 rpm to 200 rpm, more preferably 100, 150, 200 rpm and ranges therebetween.

[0043] Preferably, in any of the above items, in step 6, the mass ratio of the amount of glycosaminoglycan added to the amount of water added is 1:100 to 5:100, more preferably 1:100, 2:100, 3:100, 4:100, 5:100 and ranges therebetween.

[0044] In any of the above, preferably, in step 6, the mass ratio of the amount of water added in step 6 to the amount of water added in step 1 is 0.5:1 to 1:1. More preferably, it is 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1 and ranges therebetween.

[0045] Preferably, in any of the above items, in step 6, the stirring and dispersing time is 60 min to 120 min, more preferably 60, 80, 120 min and the range therebetween.

[0046] Preferably, in any of the above items, in step 7, the mixing temperature is 10-40° C. More preferably, it is 10, 20, 30, 40° C. and ranges therebetween.

[0047] Preferably, in any of the above items, in step 7, the stirring and mixing rate is 50 rpm to 500 rpm, more preferably 50, 100, 200, 300, 400, 500 rpm and ranges therebetween.

[0048] Preferably, in any of the above items, in step 7, the stirring and mixing time is 60 min to 120 min, more preferably 60, 90, 100, 120 min, and ranges therebetween.

[0049] In step 7, the cefradine supramolecular nanofibers and the glycosaminoglycan polymer fibers are entangled by hydrogen bonding to form the cefradine supramolecular composite hierarchical gel.

[0050] In a preferred embodiment of the present invention, a method for preparing the cefradine supramolecular composite graded gel is provided, comprising the following steps:

[0051] Step 1: Add cefradine to water;

[0052] Step 2: Add acid and stir the reaction thoroughly until the cefradine is completely dissolved;

[0053] Step 3: Add organic amine solvent and stir thoroughly for a certain period of time to completely mix;

[0054] Step 4: adding a layering agent and allowing the mixture to stand for layering until cefradine assembles at the interface to form a gel;

[0055] Step 5: Filter and wash the gel obtained in step 4 for later use;

[0056] Step 6: Add glycosaminoglycan to water and stir thoroughly for a certain period of time;

[0057] Step 7: adding the gel obtained in step 5 to the system in step 6, and stirring and mixing them for a period of time to obtain the cefradine supramolecular composite graded gel.

[0058] The present invention also provides use of any of the above-mentioned cefradine supramolecular composite graded gels in the preparation of medical dressings.

[0059] The present invention also provides a medical dressing comprising any one of the above-mentioned cefradine supramolecular composite graded gels.

[0060] Cefradine itself is a broad-spectrum antibacterial antibiotic with excellent performance. In the present invention, cefradine is in the form of an assembly and also has antibacterial activity. In addition, during the use of the medical dressing provided by the present invention, bacterial infection can cause the pH near the wound to change, which can promote the dissociation of the cefradine supramolecular structure, facilitate the release of cefradine into the wound in the form of a monomer, and further promote the bactericidal and anti-inflammatory effects. Therefore, the medical dressing prepared by the cefradine supramolecular composite graded gel not only has antibacterial activity at the contact surface between the dressing and the wound, but also has a sustained-release effect when used because cefradine is in the form of an assembly. The cefradine molecules assembled into the fiber are slowly released, so that the non-contact area between the dressing and the wound also has an antibacterial effect.

[0061] In the present invention, cefradine self-assembles at the interface to form supramolecular nanofibers, and glycosaminoglycans are dispersed in water to form polymer nanofibers. After the two types of fibers are mixed, the fibers entangle with each other through inter-fiber interactions to form a three-dimensional network structure, and water fills the pores to ultimately obtain a composite hierarchical gel.

[0062] The beneficial effects achieved by the present invention are:

[0063] The cefradine supramolecular composite graded gel of the present invention has a simple preparation process, a stable process, and does not require complex carrier synthesis. The prepared composite graded gel has excellent mechanical properties, stability, stretchability, long-lasting antimicrobial activity, biocompatibility, and other properties. Furthermore, the wound dressing can release cefradine or glycosaminoglycans at different stages, perfectly matching each stage of wound repair, promoting rapid wound healing and maintaining long-lasting antimicrobial properties. Its rapid response to multiple stimuli such as temperature and acidity, as well as its excellent electrical conductivity, enables in situ monitoring of drug release and wound healing, thereby achieving personalized treatment for different patients. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 This is a micro-CT image of the cefradine supramolecular composite graded gel prepared in preferred embodiment 1 of the present invention.

[0065] Figure 2 This is a graph showing the tensile properties test results of the gels prepared in preferred embodiment 1 and comparative examples 1 to 3 of the present invention.

[0066] Figure 3 This is a graph showing the test results of the skin adhesion performance of the gels prepared in preferred embodiment 1 and comparative examples 1 to 3 of the present invention.

[0067] Figure 4 This is a graph showing the test results of the conductive properties of the gels prepared in preferred embodiment 1 and comparative examples 1 to 3 of the present invention.

[0068] Figure 5 This is a graph showing the test results of the performance of the gel prepared in preferred embodiment 1 and comparative examples 1 and 2 of the present invention in promoting wound healing in infected mice. DETAILED DESCRIPTION

[0069] The present invention will be described in detail below with reference to specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by those skilled in the art to the present invention based on the contents of the present invention still fall within the scope of protection of the present invention.

[0070] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, for example, they can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0071] Example 1

[0072] A cefradine supramolecular composite graded gel and its preparation method and application, comprising the following steps:

[0073] 1.5 g of cefradine was added to 100 mL of deionized water at 20° C.; 25 μL of hydrochloric acid was added and stirred at 200 rpm for 60 min to completely dissolve the cefradine; 20 μL of triethylamine was added and stirred for 10 min to completely mix; stirring was turned off and 50 mL of hexadecane was slowly added. After 20 min, the liquid was completely separated and the whole system was allowed to stand for 4 h to allow the cefradine to fully assemble at the interface to form a gel; the gel at the interface was filtered and washed with 50 mL of a saturated solution of cefradine; 1.5 g of hyaluronic acid was added to 100 mL of deionized water at 20° C. and stirred at 200 rpm for 120 min to completely disperse the hyaluronic acid in the water; the washed cefradine supramolecular gel was added to the hyaluronic acid system at 20° C. and stirred at 200 rpm for 120 min to completely mix the two gels to prepare a graded composite gel.

[0074] The morphology, tensile strength, wound healing and other performance tests of the supramolecular composite hierarchical gel were carried out. The results are as follows Figures 1 to 5 As shown, the supramolecular composite hierarchical gel exhibits excellent hygroscopicity and thixotropy, tensile properties, adhesion properties and excellent bactericidal and wound healing effects.

[0075] Example 2

[0076] A cefradine supramolecular composite graded gel and its preparation method and application, comprising the following steps:

[0077] 5.0 g of cefradine was added to 100 mL of deionized water at 40° C.; 50 μL of oxalic acid was added and stirred at 200 rpm for 120 min to completely dissolve the cefradine; 70 μL of isopropylamine was added and stirred for 20 min to completely mix; stirring was turned off and 100 mL of dichloromethane was slowly added. After 40 min, the liquid was completely separated and the entire system was allowed to stand for 10 h to allow the cefradine to fully assemble at the interface to form a gel; the gel at the interface was filtered and washed with 60 mL of a saturated solution of cefradine; 5.0 g of chondroitin sulfate was added to 100 mL of deionized water at 40° C. and stirred at 200 rpm for 120 min to completely disperse the chondroitin sulfate in the water; the washed cefradine supramolecular gel was added to the chondroitin sulfate system at 40° C. and stirred at 500 rpm for 120 min to completely mix the two gels to prepare a graded composite gel.

[0078] The morphology, tensile strength, wound healing and other performance tests of the supramolecular composite hierarchical gel were carried out, and the results were consistent with those of Figures 1 to 5The results of Example 1 are consistent with those shown, indicating that the supramolecular composite hierarchical gel provided by Example 2 exhibits excellent hygroscopicity, thixotropy, tensile properties, adhesion properties and other properties as well as excellent bactericidal and wound healing effects.

[0079] Example 3

[0080] A cefradine supramolecular composite graded gel and its preparation method and application, comprising the following steps:

[0081] 1.0 g of cefradine was added to 100 mL of deionized water at 25°C; 20 μL of acetic acid was added and stirred at 100 rpm for 60 min to completely dissolve the cefradine; 500 μL of diisopropylamine was added and stirred for 40 min to completely mix; stirring was turned off and 42 mL of n-hexane was slowly added. After 20 min, the liquid and the liquid were completely separated, and the whole system was allowed to stand for 2 h to allow the cefradine to fully assemble at the interface to form a gel; the gel at the interface was filtered and washed with 20 mL of a saturated solution of cefradine; 1.0 g of keratan sulfate was added to 50 mL of deionized water at 25°C and stirred at 100 rpm for 60 min to completely disperse the keratan sulfate in the water; (7) the washed cefradine supramolecular gel was added to the keratan sulfate system at 25°C and stirred at 50 rpm for 60 min to completely mix the two gels to prepare a graded composite gel.

[0082] The morphology, tensile strength, wound healing and other performance tests of the supramolecular composite hierarchical gel were carried out, and the results were consistent with those of Figures 1 to 5 The results of Example 1 are consistent with those shown, indicating that the supramolecular composite graded gel provided by Example 3 exhibits excellent hygroscopicity, thixotropy, tensile properties, adhesion properties and other properties as well as excellent bactericidal and wound healing effects.

[0083] Example 4

[0084] A cefradine supramolecular composite graded gel and its preparation method and application, comprising the following steps:

[0085] 1.0 g of cefradine was added to 100 mL of deionized water at 10° C.; 1000 μL of salicylic acid was added and stirred at 200 rpm for 60 min to completely dissolve the cefradine; 260 μL of triethanolamine was added and stirred for 10 min to completely mix; stirring was turned off and 50 mL of cyclohexane was slowly added. After 30 min, the liquid was completely separated and the entire system was allowed to stand for 5 h to allow the cefradine to fully assemble at the interface to form a gel; the gel at the interface was filtered and washed with 60 mL of a saturated solution of cefradine; 1.8 g of hyaluronic acid was added to 100 mL of deionized water at 10° C. and stirred at 150 rpm for 120 min to completely disperse the hyaluronic acid in the water; the washed cefradine supramolecular gel was added to the hyaluronic acid system at 10° C. and stirred at 500 rpm for 120 min to completely mix the two gels to prepare a graded composite gel.

[0086] The morphology, tensile strength, wound healing and other performance tests of the supramolecular composite hierarchical gel were carried out, and the results were consistent with those of Figures 1 to 5 The results of Example 1 are consistent with those shown, indicating that the supramolecular composite graded gel provided by Example 4 exhibits excellent hygroscopicity, thixotropy, tensile properties, adhesion properties and other properties as well as excellent bactericidal and wound healing effects.

[0087] Example 5

[0088] A cefradine supramolecular composite graded gel and its preparation method and application, comprising the following steps:

[0089] 2.0 g of cefradine was added to 100 mL of deionized water at 40° C.; 300 μL of nitric acid was added and stirred at 150 rpm for 60 min to completely dissolve the cefradine; 1000 μL of isopropylamine was added and stirred for 30 min to completely mix; stirring was turned off and 20 mL of toluene was slowly added. After the liquid was completely separated after 40 min, the entire system was allowed to stand for 3 h to allow the cefradine to fully assemble at the interface to form a gel; the gel at the interface was filtered and washed with 50 mL of a saturated solution of cefradine; 2.0 g of chondroitin sulfate was added to 80 mL of deionized water at 40° C. and stirred at 150 rpm for 90 min to completely disperse the chondroitin sulfate in the water; the washed cefradine supramolecular gel was added to the chondroitin sulfate system at 40° C. and stirred at 150 rpm for 90 min to completely mix the two gels to prepare a graded composite gel.

[0090] The morphology, tensile strength, wound healing and other performance tests of the supramolecular composite hierarchical gel were carried out, and the results were consistent with those of Figures 1 to 5The results of Example 1 are consistent with those shown, indicating that the supramolecular composite graded gel provided by Example 5 exhibits excellent hygroscopicity, thixotropy, tensile properties, adhesion properties and other properties as well as excellent bactericidal and wound healing effects.

[0091] Example 6

[0092] A cefradine supramolecular composite graded gel and its preparation method and application, comprising the following steps:

[0093] 2.0 g of cefradine was added to 100 mL of deionized water at 10° C.; 750 μL of sulfuric acid was added and stirred at 150 rpm for 90 min to completely dissolve the cefradine; 800 μL of triethanolamine was added and stirred for 10 min to completely mix; stirring was turned off and 20 mL of cyclohexane was slowly added. After the liquid and the liquid were completely separated after 30 min, the entire system was allowed to stand for 6 h to allow the cefradine to fully assemble at the interface to form a gel; the gel at the interface was filtered and washed with 20 mL of a saturated solution of cefradine; 2.0 g of chondroitin sulfate was added to 60 mL of deionized water at 10° C. and stirred at 150 rpm for 120 min to completely disperse the chondroitin sulfate in the water; the washed cefradine supramolecular gel was added to the chondroitin sulfate system at 40° C. and stirred at 50 rpm for 120 min to completely mix the two gels to prepare a graded composite gel.

[0094] The morphology, tensile strength, wound healing and other performance tests of the supramolecular composite hierarchical gel were carried out, and the results were consistent with those of Figures 1 to 5 The results of Example 1 are consistent with those shown, indicating that the supramolecular composite graded gel provided by Example 6 exhibits excellent hygroscopicity, thixotropy, tensile properties, adhesion properties and other properties as well as excellent bactericidal and wound healing effects.

[0095] Example 7

[0096] A cefradine supramolecular composite graded gel and its preparation method and application, comprising the following steps:

[0097] 5.0 g of cefradine was added to 100 mL of deionized water at 25° C.; 500 μL of formic acid was added and stirred at 150 rpm for 100 min to completely dissolve the cefradine; 100 μL of triethylamine was added and stirred for 60 min to completely mix; stirring was turned off and 40 mL of toluene was slowly added. After 20 min of complete separation of the liquid and the liquid, the entire system was allowed to stand for 3 h to allow the cefradine to fully assemble at the interface to form a gel; the gel at the interface was filtered and washed with 25 mL of a saturated solution of cefradine; 2.0 g of keratan sulfate was added to 100 mL of deionized water at 25° C. and stirred at 200 rpm for 75 min to completely disperse the chondroitin sulfate in the water; the washed cefradine supramolecular gel was added to the chondroitin sulfate system at 25° C. and stirred at 150 rpm for 100 min to completely mix the two gels to prepare a graded composite gel.

[0098] The morphology, tensile strength, wound healing and other performance tests of the supramolecular composite hierarchical gel were carried out, and the results were consistent with those of Figures 1 to 5 The results of Example 1 are consistent with those shown, indicating that the supramolecular composite hierarchical gel provided by Example 7 exhibits excellent hygroscopicity, thixotropy, tensile properties, adhesion properties and other properties as well as excellent bactericidal and wound healing effects.

[0099] Since the test results of the cefradine supramolecular composite graded gel obtained in Examples 2 to 7 are consistent with those of the cefradine supramolecular composite graded gel obtained in Example 1, it is shown that Examples 1 to 7 have the same technical effects. Therefore, Example 1 is taken as an example and compared with the single network gels in Comparative Examples 1 to 3 to highlight the advantages of the composite graded gel provided by the present invention.

[0100] Comparative Example 1

[0101] The difference from Example 1 is that Comparative Example 1 only contains hyaluronic acid hydrogel, and the hyaluronic acid hydrogel is not compounded with cefradine supramolecular gel, and the remaining steps are the same as those of Example 1. The specific steps are as follows:

[0102] At 20° C., 2.0 g of hyaluronic acid was added to 100 mL of deionized water and stirred at 200 rpm for 2 h to completely disperse the hyaluronic acid in the water.

[0103] Comparative Example 2

[0104] The difference from Example 1 is that the hyaluronic acid hydrogel that loads cephradine molecules in a conventional manner is used, and the remaining steps are the same as those in Example 1. In Comparative Example 2, cephradine is loaded in the hyaluronic acid gel pores in the form of molecules. The cephradine molecules do not form a supramolecular nanofiber structure, which is a simple physical filling. Comparative Example 2 only forms a gel skeleton structure with hyaluronic acid. The specific steps are as follows:

[0105] 2.0 g of cefradine was added to 100 mL of deionized water at 20° C.; 30 μL of hydrochloric acid was added and stirred at 200 rpm for 1 h to completely dissolve the cefradine; 2.0 g of hyaluronic acid was added to the aqueous solution of cefradine and stirred at 200 rpm for 2 h to completely disperse the hyaluronic acid.

[0106] Comparative Example 3

[0107] The difference from Example 1 is that Comparative Example 3 only includes cefradine supramolecular hydrogel and does not include glycosaminoglycan, and the remaining steps are the same as those of Example 1. The specific steps are as follows:

[0108] 2.0 g of cefradine was added to 100 mL of deionized water at 20° C.; 30 μL of hydrochloric acid was added and stirred at 200 rpm for 1 hour to completely dissolve the cefradine; 70 μL of isopropylamine was added and stirring was continued for 10 minutes to completely mix; stirring was turned off, and after the liquid and the liquid were completely separated, the mixture was allowed to stand for 4 hours to allow the cefradine to assemble into a gel; the gel was filtered and washed to obtain a cefradine supramolecular gel.

[0109] Performance testing:

[0110] 1) Morphology of Cefradine Supramolecular Composite Graded Gels: The gels prepared in Examples 1 to 7 were freeze-dried at -55°C for 12 hours using a freeze dryer. The freeze-dried samples were then cut into rectangular parallelepipeds of uniform size. The internal structures of the hydrogels in Examples 1 to 7 were determined using micro-CT.

[0111] Figure 1 The microCT images of the cefradine supramolecular composite hierarchical gel in Example 1 show that the cefradine supramolecular composite hierarchical gel skeleton is composed of highly tough polymer fibers, and the structure contains numerous pores of uneven size. This allows the pores to rapidly expand when the hydrogel absorbs water and rapidly contract when it loses water, demonstrating that the cefradine supramolecular composite hierarchical gel has excellent hygroscopicity and thixotropy. The microCT images of the cefradine supramolecular composite hierarchical gels in Examples 2 to 7 are the same as those in Example 1.

[0112] 2) Tensile Properties: The gels obtained in Examples 1 to 7 and Comparative Examples 1 to 3 were prepared into strips of 3 cm in length, 0.6 cm in width, and 200 μm in thickness. Uniaxial tensile tests were performed on the gels using an electronic universal testing machine to obtain the maximum tensile strength and elongation at break of the gels. Figure 2 shown.

[0113] Depend on Figure 2 The results show that the gel of Example 1 exhibited excellent tensile properties, and its ultimate tensile stress was close to that of human skin (~85kPa). This property makes it suitable for applications in close contact with human skin, such as wound repair materials. The cefradine supramolecular composite graded gels of Examples 2 to 7 had the same tensile properties as Example 1.

[0114] 3) Adhesion performance: Pig skin was used to test the adhesion of the gel material to the skin. The pig skin was evenly cut into strips of 1 cm x 3 cm. 500 μL of the gels of Examples 1 to 7 and Comparative Examples 1 to 3 were evenly applied to the outer surface of the skin. Another layer of skin was placed on the hydrogel to make the bonding area 1 cm x 1 cm. The bonded skin was subjected to a lap shear test on an electronic universal testing machine. The results are shown in the figure below. Figure 3 shown.

[0115] Depend on Figure 3 The results show that Comparative Example 3 barely adhered to the skin, exhibiting the lowest adhesion strength. Comparative Examples 1 and 2 exhibited moderate adhesion to the skin. In comparison, the gel of Example 1 exhibited significant superior adhesion to the skin, providing strong support for its application in wound care. The cefradine supramolecular composite graded gels of Examples 2 to 7 exhibited the same adhesion properties as Example 1.

[0116] 4) Conductive properties: The gels of Examples 1 to 7 and Comparative Examples 1 to 3 were pressed into uniform rectangular strips. Excess water on the surface of the hydrogels was removed with filter paper. The conductivity of the hydrogels was measured using a digital 4-probe conductivity tester. Figure 4 shown.

[0117] Depend on Figure 4 As can be seen from the results, Comparative Example 1 has the lowest conductivity. Cephradine acts as an ampholyte, so Comparative Example 3 has the highest conductivity. Furthermore, after loading with cephradine, the conductivity of Example 1 and Comparative Example 2 was also significantly improved. This excellent conductivity will facilitate the transmission of electrical signals during the wound repair process, accelerating wound healing. Furthermore, this excellent conductivity will facilitate the use of electrical signals to detect physiological environmental parameters of wounds, enabling remote diagnosis of wounds.

[0118] The cefradine supramolecular composite graded gels of Examples 2 to 7 have the same conductive properties as that of Example 1.

[0119] 5) Promoting wound healing performance: All rats were randomly divided into 3 groups, each with 9 rats, namely control group, comparative example 1 group, comparative example 2 group, and example 1 group. The rats were anesthetized by intraperitoneal injection of chloral hydrate (0.3 mg / kg) using standard anesthesia procedures. A 10 mm circular skin wound was made on the back of the rat using a biopsy punch, and Staphylococcus aureus (S. aureus) (10 6 CFU / mL, 50 μL) was inoculated into the back wound of rats. After the infection wound model was successfully established, 100 μL of PBS (pH 7.4) was added to the wound of the control group, and then the wound was bandaged with Tegaderm film. The wounds of the rats in the other groups were respectively added with 100 μL of the hydrogels of Examples 1 to 7 and Comparative Examples 1 to 3. The wound dressing was changed every day, and the wounds of the rats were photographed and monitored to evaluate the wound healing. The results of the investigation are as follows: Figure 5 shown.

[0120] Depend on Figure 5 As a result, the wounds of mice in all groups gradually became smaller as the administration time was prolonged. After 10 days of administration, the wound healing degrees of the comparative example 1 group, the comparative example 2 group and the embodiment 1 group were significantly higher than those of the control group. And after 14 days of administration, the wound of the hydrogel group was basically completely healed, while the control group had just started to close. Among them, the wound healing area of ​​the embodiment 1 group was significantly different from that of other groups only after 3 days of administration, and the wound healing rate of this group of mice was 100%. Therefore, the cefradine supramolecular graded composite gel also shows more excellent sterilization and the effect of promoting wound healing. The cefradine supramolecular graded composite gel of embodiment 2 to embodiment 7 has the same performance of promoting infection wound healing as embodiment 1.

[0121] The above embodiments are provided for illustrative purposes only and are not intended to limit the scope of implementation. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to provide an exhaustive list of all implementations. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A cephradine supramolecular composite graded gel, using cephradine and glycosaminoglycan as raw materials, characterized in that: The cefradine forms cefradine supramolecular nanofibers, and the cefradine supramolecular nanofibers and the glycosaminoglycan polymer fibers formed by the glycosaminoglycans are cross-linked to form a network, thereby forming the cefradine supramolecular composite graded gel.

2. The cefradine supramolecular composite graded gel according to claim 1, wherein A non-water-soluble solvent is added to a supersaturated aqueous solution of cefradine, and cefradine molecules are autonomously assembled into the cefradine supramolecular nanofibers at the interface formed by the non-water-soluble solvent and water.

3. The cefradine supramolecular composite graded gel according to claim 2, wherein The cefradine supramolecular composite graded gel comprises the following components in weight percentage concentrations: 0.5-5wt% of cefradine supramolecular nanofibers and 0.5-5wt% of glycosaminoglycan polymer fibers.

4. A medical dressing, characterized in that: The invention comprises the cefradine supramolecular composite graded gel according to any one of claims 1 to 3.

5. The method for preparing the cefradine supramolecular composite graded gel according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: Add cefradine to water; Step 2: Add acid and stir thoroughly until the cefradine is completely dissolved; Step 3: reducing the solubility of cephradine in the solution to obtain a supersaturated solution of cephradine; Step 4: adding a delamination agent and allowing the mixture to stand for delamination to form an interface, and continuing to stand for the mixture to allow the cefradine to assemble at the interface to form a gel, i.e., cefradine supramolecular nanofibers; Step 5: Filter and wash the gel obtained in step 4 for later use; Step 6: Add glycosaminoglycan to water and stir thoroughly to disperse; Step 7: adding the gel obtained in step 5 to the system in step 6, and stirring and mixing them thoroughly to obtain the cefradine supramolecular composite graded gel.

6. The preparation method according to claim 5, wherein In step 1, the mass ratio of cefradine added to water is 1:100 to 5:100; in step 2, the mass ratio of the amount of acid added to the amount of water added in step 1 is 0.02:100 to 1:100; the dissolution temperature is 10 to 40° C.; the stirring rate is 100 rpm to 200 rpm; and the stirring time is 60 min to 120 min.

7. The preparation method according to claim 5, wherein In step 3, an organic amine is added to reduce the solubility of cephradine in the solution; the organic amine solution includes at least one of isopropylamine, triethylamine, diisopropylamine, and triethanolamine; the mass ratio of the amount of the organic amine added to the amount of water added in step 1 is 0.02:100 to 1:100; the stirring rate is 100 rpm to 200 rpm; and the mixing time is 10 min to 60 min.

8. The preparation method according to claim 5, wherein In step 4, the stratification agent includes at least one of cyclohexane, hexadecane, dichloromethane, n-hexane, and toluene; the mass ratio of the added amount of the stratification agent to the added amount of water in step 1 is 20:100 to 100:100; the static stratification time is 20 min to 40 min; and the assembly time is 2 h to 10 h.

9. The preparation method according to claim 5, wherein In step 6, the glycosaminoglycan is at least one of hyaluronic acid, chondroitin sulfate, and keratan sulfate; the dispersion temperature is 10 to 40°C; the stirring rate is 100 rpm to 200 rpm; the mass ratio of the amount of glycosaminoglycan added to the amount of water added is 1:100 to 5:100, and the mass ratio of the amount of water added in step 6 to the amount of water added in step 1 is 0.5:1 to 1:1; the stirring and dispersion time is 60 min to 120 min; in step 7, the mixing temperature is 10 to 40°C, the stirring mixing rate is 50 rpm to 500 rpm, and the stirring mixing time is 60 min to 120 min.

10. Use of the cefradine supramolecular composite graded gel according to any one of claims 1 to 3 in the preparation of medical dressings.

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