A highly moisture-absorbing and highly moisture-retaining drug-loaded medical dressing and its preparation method

Abstract

The present invention provides a medical dressing with high water absorption, high moisture retention, drug-loading function and good mechanical properties, and a preparation method thereof. The medical dressing includes a fiber skeleton and a hydrogel film. The fiber skeleton is loaded with drug components, and calcium alginate hydrogel forms the hydrogel film on the surface of the fiber. The drug components loaded on the fiber skeleton are embedded by the hydrogel film, and the drugs are filled in the voids or grooves on the fiber surface. After embedding, the original voids of the fiber skeleton are retained, and the hydrogel film forms a honeycomb structure. The fiber skeleton of the present invention provides the required mechanical properties for the dressing and serves as a carrier for drug components, having the remarkable advantages of wide adaptability to drug components and large drug loading capacity. The hydrogel film swells in water, and the drugs are continuously released. The hydrogel and fiber porous structure provide excellent moisture absorption and retention properties for the dressing. It can be designed into a gauze type, a porous foam type, a patch type, etc. according to needs, and has wide adaptability.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and particularly to a drug-loaded medical dressing. Background Art

[0002] The dressing should provide a moist healing environment for the wound surface, maintain water absorption and breathability, absorb wound exudate in a timely manner, promote the synthesis and secretion of growth factors, and accelerate the wound healing rate. Drug loading can help prevent infection of the wound surface, eliminate inflammatory reactions, and improve the healing rate and quality.

[0003] Dressings are generally fibrous fabrics such as gauze and non-woven fabrics. The composite of hydrogel and gauze endows the dressing with both good mechanical properties and the advantages of high moisture absorption and anti-adhesion. Chinese invention patent CN202111467950.1 discloses a preparation method of a hydrogel gauze for preventing blood adhesion, which not only retains the characteristics of gauze but also has the advantages of hydrogel for preventing blood adhesion. Chinese invention patent CN202111143272.3 provides a surface-hydrophilic modified chitosan porous gel hemostatic gauze, on which chitosan gel is deposited, and the provided hemostatic gauze has good mechanical strength, stability and can stop bleeding quickly.

[0004] Hydrogel can carry drugs, endowing the dressing with antibacterial, anti-inflammatory or therapeutic functions. Chinese utility model patent CN201821034714.4 discloses a leak-proof hydrogel composite gauze. Drug-loaded gel particles are placed between two layers of gauze, and a broken fiber layer is used to prevent the leakage of gel particles. The dressing has antibacterial functions, but the drug is separated from the wound by broken fibers and gauze, making it difficult for the drug to be released to the wound. Chinese utility model patent CN201720989627.3 provides an anti-adhesion, highly moisture-absorbing and antibacterial gauze, on the surface of which a gel layer is laid. The gel layer contains antibacterial liquid medicine, and the gel layer and the gauze are bonded through a polymer binder.

[0005] In the prior art, the following problems mainly exist in drug loading in the gel layer:

[0006] 1. More than 97% of the hydrogel colloid is water. After the hydrogel layer is freeze-dried into a film, a thin-walled mesh pore structure is formed. Since the pore wall is extremely thin, only a dozen micrometers, if the drug content is high or unevenly dispersed, it will cause the drug to precipitate, adhere to the surface of the thin wall, and cannot be embedded, resulting in the contact of the drug components with the external environment, and problems such as shedding, volatilization, oxidation and deterioration will occur during the storage of the dressing.

[0007] 2. The drug is dissolved or dispersed in a polymer material matrix to form drug-loaded microspheres, which can effectively protect the drug. The drug-loaded microspheres are dispersed in the gel. After film formation, the microspheres adhere to the pore wall or are semi-embedded in the pore wall, and the drug content in the microspheres is between 1% and 15%. However, the preparation process of the drug-loaded microspheres is complex, and the drug entrapment efficiency (the ratio of the drug content in the microspheres to the drug dosage) generally does not exceed 50%, which greatly increases the manufacturing cost.

[0008] 3. Directly mixing the drug or drug-loaded microspheres into the gel will affect the film-forming property of the gel. Currently, the drug content in the gel film for drug loading generally does not exceed 1% of the gel film. The drug loading is low, and the half-life of the effective concentration released to the wound surface is short, and a continuous and stable therapeutic effect cannot be formed. Summary of the Invention

[0009] The object of the present invention is to overcome the deficiencies in the prior art and provide a medical dressing with high hygroscopicity, high moisture retention, high drug loading and long-acting drug release.

[0010] To achieve the above object, the present invention provides a medical dressing, including a fiber skeleton and a hydrogel film. The fiber skeleton is loaded with drug components, and calcium alginate hydrogel forms the hydrogel film on the surface of the fiber skeleton. The drug components loaded on the fiber skeleton are embedded by the hydrogel film, and the drug is filled in the voids or grooves on the fiber surface. The original voids of the fiber skeleton are retained after embedding. The hydrogel film forms a honeycomb structure.

[0011] Preferably, the mass percentage of the calcium alginate hydrogel to the fiber skeleton is 10-22%.

[0012] Preferably in any of the above, the film thickness of the calcium alginate hydrogel formed on the surface of the fiber skeleton is 8-14 μm, and the content of the drug component is less than 25% of the weight of the fiber skeleton.

[0013] Preferably in any of the above, the porosity of the fiber skeleton is 90%-95%, and the average pore diameter of the fiber skeleton is between 35 and 100 μm.

[0014] In the present invention, the fiber skeleton is a skeleton material of the dressing composed of fibers.

[0015] Preferably in any of the above, the material of the fiber skeleton is selected from gauze and / or non-woven fabric.

[0016] Preferably in any of the above, the fiber component of the fiber skeleton is preferably at least one of cotton fiber, hemp fiber and viscose fiber.

[0017] Preferably, the fiber skeleton is in the form of gauze; preferably, the fiber skeleton is non-woven fabric; preferably, the gauze is degreased cotton medical gauze; preferably, the non-woven fabric is spunlace non-woven fabric; the fibers of the spunlace non-woven fabric are further preferably biomass cellulose fibers such as cotton fibers, hemp fibers, and rayon viscose fibers. Cellulose fibers have excellent water absorption and biocompatibility; cotton fibers and hemp fibers have rich microporous structures, and the surface of viscose fibers has grooves. The micropores or grooves on the fiber surface provide volume for drug loading and are ideal carriers for drug components. Preferably, the areal density of the spunlace non-woven fabric is between 30-80 g / m 2 2, and its porosity is within 90%-95%, and the average pore diameter is between 35-72 μm.

[0018] In the present invention, the fiber skeleton serves as a carrier for loading drug components. The drug components are attached to the surface of the fibers through physical adsorption without forming chemical bond combinations, so as to facilitate drug release. The drug content generally does not exceed 25% of the fiber weight. If the drug content is too high, it is not conducive to the complete embedding of the drug by the hydrogel film.

[0019] In the present invention, calcium alginate hydrogel forms a gel film on the fiber surface. The drug components loaded on the fiber skeleton are embedded, and the original voids of the fiber skeleton are retained, and the gel film forms a honeycomb structure.

[0020] In the present invention, the mass percentage of calcium alginate to the fiber skeleton is controlled between 10-22%, and the film-forming thickness of the calcium alginate hydrogel on the fiber surface is controlled between 8-14 μm, ensuring that the drug can be effectively embedded and the flexibility of the dressing can be maintained.

[0021] When the medical dressing provided by the present invention is used, calcium alginate combines with sodium ions in body fluid to generate sodium alginate gel with high water absorption and high moisture retention characteristics. Sodium alginate swells, the macromolecular spacing increases, and the embedded drug migrates and penetrates in the gel and continuously releases to the wound surface. Preferably, when in use, a solution containing sodium ions (such as normal saline) can be sprayed on the medical dressing in advance to achieve drug release.

[0022] The medical dressing provided by the present invention can be laminated and combined to make a conformable dressing, and its structure is: the bottom layer is the medical dressing described in the present invention, and the upper layer is a soft and fluffy fiber fabric.

[0023] The present invention also provides a preparation method of the medical dressing described in any one of the above, including the following steps:

[0024] Step 1: Prepare hydrogel; dissolve sodium alginate powder in deionized water, stir until completely dissolved, and remove air bubbles to obtain an aqueous sodium alginate solution;

[0025] Step 2: Selection of the form of the fiber skeleton (gauze or non-woven fabric) and the fiber material;

[0026] Step 3: Drug loading treatment of the fiber skeleton;

[0027] Step 4: Composite of hydrogel and fiber skeleton: Place the drug-loaded fiber network obtained in Step 3 on the transfer device, and spray the sodium alginate aqueous solution obtained in Step 1 onto the drug-loaded fiber network by a nozzle; after the sodium alginate solution fully infiltrates the surface of the drug-loaded fiber network, the drug-loaded fiber network is removed from the transfer device and then immersed in a calcium chloride aqueous solution; sodium alginate crosslinks and solidifies with calcium ions to form water-insoluble calcium alginate, forming an embedding film on the surface of the drug-loaded fiber network; after solidification, wash with water to remove reaction by-products; blow dry to control the moisture content;

[0028] Step 5: Drying: Use freeze-drying process for drying.

[0029] Preferably, in Step 1, the mass concentration of the sodium alginate aqueous solution is 1-3%, the solution viscosity should be less than 1000 mPa·s; the dissolution temperature is 22-50 °C; the M / G mass ratio of sodium alginate is 2.5-3.10.

[0030] Preferably in any of the above, in Step 2, the material of the fiber skeleton is selected from gauze and / or non-woven fabric.

[0031] Preferably in any of the above, in Step 2, the fiber component of the fiber skeleton is preferably at least one of cotton fiber, hemp fiber, and viscose fiber.

[0032] Preferably in any of the above, in Step 3, the drug is a water-soluble drug, and the treatment steps are as follows: Step a: Dissolve the water-soluble drug in deionized water, and load the drug onto the fiber skeleton by padding process or spraying method to obtain a drug-loaded fiber network. Further preferably, in Step 3, a drying step is also included; preferably, in Step 3, the drug is a heat-stable water-soluble drug, and the drug-loaded fiber network obtained in Step a is dried by a heat drying method. After drying, the moisture content (percentage of water weight to the wet weight of the drug-loaded fiber network) of the drug-loaded fiber network is controlled at 18-25%; preferably, in Step 3, the drug is a water-soluble drug that is volatile when heated, and the drug-loaded fiber network obtained in Step a is dried by a freeze-drying method. After drying, the moisture content of the drug-loaded fiber network is controlled at 18-25%.

[0033] Preferably in any of the above, in Step 3, the drug is an oil-soluble drug, and the treatment steps are as follows: Step b: Select an oil-in-water type surfactant, add the oil-in-water type surfactant and the oil-soluble drug to deionized water, and stir at high speed to form an oil-in-water emulsion; load the oil-in-water emulsion onto the fiber skeleton by padding process or spraying method.

[0034] Preferably in any of the above, in step 4, the time for the drug-loaded fiber mesh to move from the position of the sodium alginate aqueous solution nozzle to being removed from the transfer device is 25 - 35 s; the mass concentration of the calcium chloride aqueous solution is 6 - 12%, and the setting time of the drug-loaded fiber mesh in the calcium chloride aqueous solution is 5 - 8 minutes.

[0035] Preferably in any of the above, in step 5, the freeze-drying temperature is -20°C to -30°C, and the time is 24 h.

[0036] In a preferred embodiment of the present invention, in step 1, the preparation method of the hydrogel solution is preferably: dissolving sodium alginate powder in deionized water at a temperature in the range of 22 - 50°C. Stir until completely dissolved and remove bubbles to obtain a sodium alginate solution.

[0037] Preferably, the mass concentration of the sodium alginate aqueous solution is 1 - 3%, and the solution viscosity should be less than 1000 mPa·s.

[0038] The raw material for preparing the hydrogel of the present invention is sodium alginate. Sodium alginate is a natural polysaccharide composed of β-D-mannuronic acid (M sugar) and α-L-guluronic acid (G sugar). Sodium alginate combines with calcium ions to form a cross-linked structure of calcium alginate gel. When it comes into contact with the pus and blood of the wound, sodium ions in the human body exchange with calcium alginate ions. As sodium ions enter, water-insoluble calcium alginate is converted into water-soluble sodium alginate, and a large amount of water enters the medical dressing to form a colloid, forming a moist hydrogel, providing a moist healing environment for the wound surface and good conditions for cell growth.

[0039] Sodium alginate is stable in nature, does not reduce the activity of drugs, has safety and biocompatibility, has good film-forming properties, and the formed film has good softness.

[0040] In the present invention, sodium alginate is preferably a sodium alginate gel with a high M / G ratio, and the preferred M / G mass ratio is in the range of 2.5 - 3.10. The hydrogel prepared from sodium alginate within this M / G range is relatively soft and has a strong creep recovery ability.

[0041] In a preferred embodiment of the present invention, in step 2, the preferred solution for the fiber skeleton material is: selecting the fiber skeleton material according to the application requirements of the dressing: preferably gauze or non-woven fabric; preferably a fiber material, further preferably a natural cellulose fiber, and further preferably at least one of cotton fiber, hemp fiber, and viscose fiber. Cotton fiber and hemp fiber have a rich microporous structure, and viscose fiber has grooves on its surface, which are ideal carriers for drug components. Cellulose fiber has excellent water absorption and biocompatibility.

[0042] In a preferred embodiment of the present invention, in step 3, the preferred drug loading treatment scheme for the fibrous skeleton material is as follows:

[0043] As needed, the drugs in the drug loading treatment are selected from at least one of antibacterial drugs, cytokines, hemostatic drugs, anti-inflammatory drugs, and analgesic drugs.

[0044] In step 3, the preferred scheme for loading water-soluble drugs is as follows:

[0045] Dissolve the water-soluble drug in deionized water, and the solution concentration is determined according to the drug solubility and drug loading requirements.

[0046] The drug is loaded onto the fibrous skeleton material through a padding process to obtain a drug-loaded fiber web. The number of padding times is greater than or equal to once, and multiple padding can increase the drug loading amount. Preferably, the spraying method is used to load the drug onto the fibrous skeleton. Preferably, heat-stable drugs can be dried by heat; preferably, heat-volatile drugs are freeze-dried; preferably, the moisture content of the drug-loaded fiber web after drying is controlled at 18-25%.

[0047] In step 3, the preferred scheme for loading oil-soluble drugs is as follows:

[0048] Select an oil-in-water (O / W) type surfactant, add the oil-in-water type surfactant and the oil-soluble drug to deionized water, and stir at high speed to form a stable oil-in-water (O / W) emulsion. The oil-in-water type surfactant can help disperse the oil in water to form an oil-in-water emulsion system, where the oil is the internal phase and the water is the continuous external phase.

[0049] The benefits of forming an oil-in-water emulsion system are as follows: 1) Cellulose fibers have good water absorption, and the oil-in-water (O / W) emulsion can be evenly adsorbed on the fiber surface; 2) It is beneficial for the subsequent formation of a film of sodium alginate aqueous solution on the fiber surface; 3) The present invention overcomes the defects of the prior art by using the oil-in-water emulsion system. If an organic solvent is used to dissolve the oil-soluble drug, after the drug is loaded onto the fiber, the solvent needs to be volatilized and removed, increasing the processing cost and causing environmental hazards.

[0050] Preferably, the oil-in-water type surfactant is preferably Span 80, Wacker E1049, food and drug industrial silicone oil emulsion, poloxamer F127aeo-9 emulsifier, polyethylene glycol (PEG) 200-6000, etc. The above oil-in-water type surfactants have no peculiar smell and good biocompatibility. The use of the oil-in-water type surfactant in the present invention is widely applied in the medical field, which is beneficial to improving the solubility and absorption rate of drugs, thereby enhancing the drug effect.

[0051] In a preferred embodiment of the present invention, in step 4, the preferred scheme for the composite of the hydrogel and the fibrous skeleton is as follows:

[0052] In step 3, the drug-loaded fiber web is placed on the conveyor roller 1, and the conveyor roller 1 rotates to spread the drug-loaded fiber web on the conveyor belt 3. The conveyor roller 1 and the mobile platform (conveyor belt 3) run at the same speed to achieve tension-free conveyance of the fiber web.

[0053] A horizontal row of nozzles 4 is arranged above the conveyor belt, and the sodium alginate aqueous solution prepared in step 1 is sprayed onto the drug-loaded fiber mesh through the nozzles 4 .

[0054] According to the set final content of hydrogel and the square meter gram weight of fiber mesh, the mass concentration of sodium alginate aqueous solution (in the range of 1-3%), the nozzle flow rate, and the movement speed of the drug-loaded fiber mesh are regulated. The nozzle flow rate is controlled to control the mass percentage of the calcium alginate hydrogel and the fiber skeleton contained in the final medical dressing to be 10-22%; the movement speed of the fiber mesh is controlled so that the time from the nozzle 4 position to the removal of the drug-loaded fiber mesh from the conveyor belt is controlled to be 25-35s, preferably 30s, to ensure that the sodium alginate solution is fully infiltrated on the fiber surface.

[0055] After the drug-loaded fiber web moves out of the conveyor belt 3, it enters the curing bath 5 under the action of gravity. The curing bath 5 contains a calcium chloride aqueous solution. Sodium alginate and calcium ions are cross-linked and cured to form water-insoluble calcium alginate, forming an embedding film on the surface of the drug-loaded fiber web.

[0056] Preferably, the mass concentration of the calcium chloride aqueous solution is 6-12%; preferably, the solidification time of the drug-loaded fiber mesh in the solidification bath 5 is 5-8 minutes. The solidification bath 5 is provided with a liquid outlet and an inlet to keep the calcium ion concentration constant.

[0057] When the set solidification time is reached, the take-up roller 14 is operated to transfer the fiber web to the washing tank 9 to remove the reaction byproducts of chloride ions and sodium ions.

[0058] The washed drug-loaded fiber web passes through the airflow nozzle 12 of the blowing device to control the moisture content of the fiber web and ensure that there are no water drops when the fiber web is rolled up.

[0059] The process of the present invention realizes the continuous production of composite solidification of fiber mesh and hydrogel, and the fiber mesh is not subjected to tensile tension and mechanical extrusion before being removed from the solidification bath 5, thereby ensuring that the drug loaded on the mesh surface does not penetrate into the sodium alginate aqueous solution.

[0060] In a preferred embodiment of the present invention, in step 5, the drying is preferably a freeze-drying process, and freeze-drying is performed after cross-linking and curing. The use of freeze-drying can prevent the drug components from being damaged by high-temperature drying. Preferably, the freeze-drying temperature is -20°C to -30°C; preferably, the time is 24 hours.

[0061] In a preferred embodiment of the present invention, the preparation method of the present invention further includes step 6, a post-treatment step:

[0062] Preferably, the medical dressing after drying in step 5 is subjected to flatness and softness finishing as needed, sterilized, and packaged.

[0063] Preferably, the medical dressing is adhered to a film to form a patch-type dressing.

[0064] Preferably, the medical dressing is laminated with hot air cotton. The hot air cotton is a highly fluffy and soft heat-meltable fiber material, and is thermally bonded to the above-mentioned dressing in a dot matrix by laser to form a sponge-type dressing.

[0065] By selecting sodium alginate as the preparation material of the hydrogel, the present invention ensures the safety and biocompatibility of the medical dressing while not reducing the activity of the drug, has good film-forming properties, and the formed film has good softness. At the same time, the present invention loads the drug on the fiber skeleton, embeds the drug inside the gel layer, and effectively protects the drug. At the same time, by controlling the drug loading amount, the type of hydrogel, and the ratio of the hydrogel to the skeleton fiber, it is ensured that the drug loaded on the skeleton fiber does not flow out during the gel coating process and the drug is effectively released during use.

[0066] The significant advantages and beneficial technical effects of the present invention are as follows:

[0067] 1. Using the fiber aggregate as the skeleton material provides excellent mechanical properties for the dressing. Through reasonable design of the skeleton material, the dressing can have the required mechanical properties, such as strength, elasticity, softness, and bulking property.

[0068] 2. The fiber skeleton as a drug carrier has a wide adaptability to the components of the drug, is suitable for water-soluble and oil-soluble liquids, has a large drug loading capacity, and the drug loading is increased by more than 10 times compared with the water-soluble gel film.

[0069] 3. The hydrogel endows the dressing with excellent water absorption and moisture retention properties, greatly improving the water absorption and moisture retention properties of the dressing.

[0070] Compared with traditional gauze, the moisture content is increased by 111.19%, and the moisture retention time is increased by 418.18%.

[0071] 4. The drug components are isolated from the outside by a dense polymer film, effectively protecting the drug components from volatilization, oxidation, and deterioration, and greatly extending the shelf life of the dressing.

[0072] 5. When the dressing encounters body fluid, the hydrogel turns into sol, and the drug is released stably and durably.

[0073] 6. The dressing of the present invention can be laminated, rolled, or formed into a ball like traditional gauze, and is used for wound hemostasis and dressing. It can be made into a dressing, a facial mask, and a foam dressing, with a wide range of applications.

[0074] 7. The present invention realizes the continuous production of the composite curing of the fiber web and the hydrogel. Before the fiber web enters the curing bath, it is not affected by tensile expansion and mechanical extrusion pressure, ensuring that the drug loaded on the surface of the web does not penetrate into the sodium alginate aqueous solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 It is a structural diagram of the preferred medical dressing of the present invention.

[0076] Figure 2 It is the process and technology of the composite of the preferred hydrogel and the fiber skeleton of the present invention.

[0077] Figure 3 The moisture release curve of the dressing in the preferred Example 4 of the present invention.

[0078] Figure 4 It is the drug release curve of the dressing in the preferred Example 4 of the present invention.

[0079] Figure 5 It is a schematic cross-sectional view of the drug-loaded retroperitoneal fiber in the preferred Example 1 of the present invention.

[0080] Marks in the drawings: 1 conveying roller, 2 guiding roller, 3 conveyor belt, 4 spray head, 5 curing bath, 6 guiding roller, 7 guiding roller, 8 guiding roller, 9 water washing tank, 10 guiding roller, 11 guiding roller, 12 air nozzle, 13 guiding roller, 14 winding roller. DETAILED DESCRIPTION OF THE INVENTION

[0081] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0082] As Figure 1 shown is a structural diagram of a medical dressing provided by the present invention. Figure 5 Shown is a schematic cross-sectional view of the drug-loaded retroperitoneal fiber.

[0083] The fiber skeleton serves as a carrier for loading drug components. The drug components are physically adsorbed on the surface of the fiber without forming a chemical bond, which is beneficial to drug release; as Figure 1 shown in a is the drug-loading of the fiber web. Figure 1 The enlarged diameter of a single fiber in a is 20 microns.

[0084] Calcium alginate hydrogel forms a gel film on the surface of the fiber. The drug components loaded on the fiber skeleton are embedded, and the original voids of the fiber skeleton are retained. The gel film forms a honeycomb structure, as Figure 1 shown in b is the embedding of the drug on the fiber surface by the hydrogel.Figure 1 The magnification of a single fiber in b is 21 microns.

[0085] The medical dressing provided by the present invention can be laminated and combined. For example, Figure 1 As shown in c, a sponge-like dressing is made of the medical dressing and hot air cotton.

[0086] Figure 2 The figure shows the process and process schematic diagram of the composite of the hydrogel and the fiber skeleton of the present invention. In the preferred embodiment of the present invention, according to Figure 2 The process flow shown in step 4 is used for the composite process of the hydrogel and the fiber skeleton:

[0087] The drug-loaded fiber web obtained in step 3 is placed on the conveying roller 1. The conveying roller 1 rotates to spread the drug-loaded fiber web on the conveyor belt 3. The conveying roller 1 and the moving platform (conveyor belt 3) run at the same speed to achieve tension-free conveying of the fiber web.

[0088] A horizontally arranged nozzle 4 is provided above the conveyor belt. The sodium alginate aqueous solution prepared in step 1 is sprayed onto the drug-loaded fiber web through the nozzle 4.

[0089] According to the set final content of the hydrogel and the gram weight per square meter of the fiber web, the mass concentration of the sodium alginate aqueous solution (within the range of 1-3%), the flow rate of the nozzle, and the movement speed of the drug-loaded fiber web are regulated. The flow rate of the nozzle is controlled to ensure that the mass percentage of the calcium alginate hydrogel and the fiber skeleton contained in the finally obtained medical dressing is 10-22%; the movement speed of the fiber web is controlled so that the time for the drug-loaded fiber web to move from the position of the nozzle 4 to the exit of the conveyor belt is controlled within 25-35 s, preferably 30 s, to ensure sufficient infiltration of the sodium alginate solution on the fiber surface.

[0090] After the drug-loaded fiber web exits the conveyor belt 3, it enters the curing bath 5 under the action of gravity. The curing bath 5 contains a calcium chloride aqueous solution. Sodium alginate cross-links and cures with calcium ions to form water-insoluble calcium alginate, forming an embedding film on the surface of the drug-loaded fiber web.

[0091] Preferably, the mass concentration of the calcium chloride aqueous solution is 6-12%; preferably, the solidification time of the drug-loaded fiber web in the curing bath is 5-8 minutes. A liquid outlet and an inlet are provided in the solidification bath 5 to keep the calcium ion concentration constant.

[0092] When the set solidification time is reached, the winding roller 14 rotates to transfer the fiber web to the washing tank 9 to remove the reaction by-products chloride ions and sodium ions.

[0093] The washed drug-loaded fiber web passes through the air nozzle 12 to control the water content of the fiber web.

[0094] Figure 2In the process, guide rollers 2, 6, 7, 8, 10, 11 and 13 control the running direction of the drug-loaded fiber web.

[0095] Example 1

[0096] Embodiment 1 provides a preferred medical dressing of the present invention, which is composed of the following components:

[0097] Fiber skeleton: 100% viscose spunlace nonwoven fabric, weight 40g / m 2 ;

[0098] Drug ingredients: Tea polyphenols, polyphenols have antibacterial, antioxidant, anti-inflammatory characteristics, and have good biological safety. Tea polyphenols solution 2.65%, room temperature.

[0099] Embodiment 1 The preferred preparation method is:

[0100] Prepare 2% sodium hyaluronate algae aqueous solution, heat to 50°C, stir thoroughly and eliminate bubbles.

[0101] After two dipping and two rolling by the dipping and rolling equipment, the fiber skeleton material loaded with tea polyphenol drug components was obtained, and the final content of tea polyphenols was 13.8%.

[0102] The hydrogel and the fiber skeleton are compounded by the process of the present invention (step 4). The time from the fiber skeleton from the nozzle to the conveyor flat belt is 32 seconds. The curing time in the curing bath is 6 minutes, and the appropriate concentration of calcium chloride in the curing bath is 8%.

[0103] According to step 5, the freeze-drying process is used for drying, and the freeze-drying is carried out at -20°C for 24 hours.

[0104] Perform post-processing according to step 6, including flatness and softness finishing, sterilization, packaging, etc.

[0105] Example 2

[0106] Embodiment 2 provides a preferred medical dressing of the present invention, which is composed of the following components:

[0107] Fiber skeleton: medical absorbent cotton gauze.

[0108] Drug ingredients: Lemon essential oil. Lemon essence has significant antibacterial, anti-inflammatory and antipyretic effects. The limonene in it is particularly beneficial for whitening, astringency, and balancing oil secretion.

[0109] Surfactant: Methyl silicone oil, also known as ordinary silicone oil, has good chemical stability and insulation properties.

[0110] Prepare a cinnamon oil emulsion with the ratio of cinnamon oil to methyl silicone oil being 1:3, and the cinnamon oil content in the emulsion is 2%. Stir at 1200 r / min for 10 hours at room temperature to form a stable oil-in-water emulsion.

[0111] Prepare a 1% aqueous sodium alginate solution, heat it to 50 °C, and stir well.

[0112] The composite of hydrogel and fiber skeleton is realized through the process described in the present invention (step 4). The time for the fiber skeleton to move from the nozzle to the transfer flat belt is 35 seconds. The curing time in the curing bath is 8 minutes, and the appropriate concentration of calcium chloride in the curing bath is 8%.

[0113] According to step 5, freeze-dry at -20 °C for 24 hours, and perform post-treatment according to step 6.

[0114] Example 3

[0115] In Example 3, a sponge-type dressing is made from the medical dressing obtained in Example 2 and hot air cotton. The dressing obtained in Example 2 is layer A, and the hot air cotton is layer B. As shown in Figure 1 Figure c is the structure of the sponge-type dressing. The hot air cotton is a fluffy and soft fiber mesh made of ES fiber, and the selected specification is a gram weight of 80 g / m 2 . Laser dot matrix thermal bonding is carried out between the two layers.

[0116] Example 4

[0117] In Example 4, performance tests are carried out on the obtained medical dressings:

[0118] 1) Comparison of water absorption rate and moisture retention performance

[0119] Measure the moisture content after the material is completely wetted, and place it in a humid environment at room temperature of 22.5 °C and relative humidity of 60% to obtain a moisture release curve, as shown in Figure 3 Figure.

[0120] The water absorption rate of the medical gauze and sodium alginate composite system (sodium alginate content 22.96%, preparation method similar to that in Example 1 or 2) prepared by the method of the present invention is 677.37%, the time for moisture release to reach a moisture content of 18.02% is 285 minutes, the water absorption rate of the same specification gauze is 320.74%, the time for moisture release to reach a moisture content of 14.16% is 55 minutes, the moisture content increases by 111.19%, and the moisture retention time increases by 418.18%.

[0121] The water absorption rate of the composite system of viscose fiber non-woven fabric prepared by the method of the present invention and sodium alginate (sodium alginate content 34.11%) is 711.45%, and the time for moisture release to reach a moisture content of 20.93% is 450 minutes. The water absorption rate of viscose fiber non-woven fabric of the same specification is 484.26%, and the time for moisture release to reach a moisture content of 23.33% is 90 minutes. The moisture content increases by 46.91%, and the moisture retention time increases by 449%.

[0122] 2) Testing of drug loading rate and drug release rate

[0123] When preparing the sample of Preparation Example 1, 100% viscose hydroentangled non-woven fabric with a grammage of 40 g / m 2 , was washed, dried, weighed as G0, and weighed after drying to obtain G. The drug loading rate was obtained according to (G - G0) / G, and the test result was 13.8%.

[0124] When preparing the sample of Preparation Example 2, medical absorbent cotton gauze was washed, dried, weighed as G0, and weighed after drying to obtain G. According to (G - G0) / G and the ratio of the drug to the surfactant, the drug loading rate was obtained, and the test result was 7.8%.

[0125] The samples obtained in Example 1 and Example 2 were respectively placed in a PBS buffer solution (pH 7.2), placed on a constant temperature shaker at 37°C, and a quantitative solution was taken away at fixed time intervals to measure the absorbance value of the liquid by UV-Vis. Then the same volume of PBS buffer solution was added, and the measurement was repeated to calculate the drug release rate. Figure 4 It shows that for the sample of Example 1, the drug release reached equilibrium in 24 hours, and the release rate was 77%. In the range of 0 to 24 hours, the release rate was stable and balanced. For the sample of Example 2, the drug release reached equilibrium at about 20 hours, and the release rate was 80%. In the range of 0 to 20 hours, the release rate was stable and balanced.

[0126] The above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A medical dressing, comprising a fibrous skeleton and a hydrogel film, characterized in that, The fiber skeleton is loaded with a drug component, and a calcium alginate hydrogel forms the hydrogel film on the surface of the fiber skeleton. The drug component loaded on the fiber skeleton is embedded by the hydrogel film. The drug component is filled in the voids or grooves on the fiber surface. After embedding, the original voids of the fiber skeleton are retained, and the hydrogel film forms a honeycomb structure. The drug is a water-soluble drug. The water-soluble drug is dissolved in deionized water, and the drug is loaded onto the fiber skeleton by a padding process or a spraying method to obtain a drug-loaded fiber web. Or, the drug is an oil-soluble drug. An oil-in-water surfactant is selected, and the oil-in-water surfactant and the oil-soluble drug are added to deionized water and stirred at a high speed to form an oil-in-water emulsion. The oil-in-water emulsion is loaded onto the fiber skeleton by a padding process or a spraying method to obtain a drug-loaded fiber web.

2. The medical dressing according to claim 1, characterized in that, The mass percentage of the calcium alginate hydrogel to the fiber skeleton is 10-22%.

3. The medical dressing according to claim 2, characterized in that, The film-forming thickness of the calcium alginate hydrogel on the surface of the fiber skeleton is 8-14 μm, and the content of the drug component is less than 25% of the weight of the fiber skeleton.

4. The medical dressing according to claim 3, wherein The porosity of the fiber skeleton is 90%-95%, or the average pore diameter of the fiber skeleton is between 35-100 μm.

5. The preparation method of the medical dressing according to any one of claims 1-4, comprising the following steps: Step 1: Prepare a hydrogel. Sodium alginate powder is dissolved in deionized water, stirred until completely dissolved, and air bubbles are removed to obtain a sodium alginate aqueous solution. Step 2: Select the material of the fiber skeleton. Step 3: Treat the fiber skeleton with the drug. When the drug is a water-soluble drug, the treatment step is Step a: The water-soluble drug is dissolved in deionized water, and the drug is loaded onto the fiber skeleton by a padding process or a spraying method to obtain a drug-loaded fiber web. Or, when the drug is an oil-soluble drug, the treatment step is Step b: An oil-in-water surfactant is selected, and the oil-in-water surfactant and the oil-soluble drug are added to deionized water and stirred at a high speed to form an oil-in-water emulsion. The oil-in-water emulsion is loaded onto the fiber skeleton by a padding process or a spraying method. Step 4: Composite the hydrogel and the fiber skeleton. The drug-loaded fiber web obtained in Step 3 is placed on a transmission device, and the sodium alginate aqueous solution obtained in Step 1 is sprayed onto the drug-loaded fiber web by a nozzle. After the sodium alginate solution is fully infiltrated on the surface of the drug-loaded fiber web, the drug-loaded fiber web is removed from the transmission device and then immersed in a calcium chloride aqueous solution. Sodium alginate crosslinks with calcium ions to form water-insoluble calcium alginate, forming an embedding film on the surface of the drug-loaded fiber web. After curing, wash with water to remove reaction by-products. Control the moisture content by blowing air. Step 5: Dry. A freeze-drying process is used for drying.

6. The preparation method according to claim 5, characterized in that, In Step 1, the mass concentration of the sodium alginate aqueous solution is 1-3%, the solution viscosity should be less than 1000 mPa·s, the dissolution temperature is 22-50 °C, and the M / G mass ratio of sodium alginate is 2.5-3.

10. In Step 2, the material of the fiber skeleton is selected from gauze and / or non-woven fabric.

7. The preparation method according to claim 6, characterized in that, Step 3 also includes a drying step; in step 3, the drug is a heat-stable water-soluble drug, and the drug-loaded fiber mesh obtained in step a is subjected to a heat drying method. After drying, the moisture content of the drug-loaded fiber mesh is controlled to be 18-25%; or, in step 3, the drug is a water-soluble drug that is easily volatile when heated, and the drug-loaded fiber mesh obtained in step a is subjected to a freeze-drying method. After drying, the moisture content of the drug-loaded fiber mesh is controlled to be 18-25%.

8. The preparation method according to claim 5, characterized in that, In step 4, the time for the drug-loaded fiber mesh to be removed from the nozzle position of the sodium alginate aqueous solution to the transmission device is 25-35 seconds; the mass concentration of the calcium chloride aqueous solution is 6-12%, and the coagulation time of the drug-loaded fiber mesh in the calcium chloride aqueous solution is 5-8 minutes.

9. The preparation method according to claim 5, characterized in that, In step 5, the freeze-drying temperature is -20°C to -30°C, and the time is 24 hours.

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