JPH0560943B2 - - Google Patents

Description

BACKGROUND OF THE INVENTION Technical Field The present invention relates to wound dressings. More specifically, when the skin is damaged due to a wound, burn, etc., the present invention is temporarily applied to the damaged skin area, softens and protects the damaged skin area without drying it out, suppresses pain, and eliminates bacteria. The present invention relates to a wound dressing that prevents infection and promotes healing. (Prior art) As a wound dressing temporarily applied to an affected area for the purpose of protecting the affected area and promoting healing due to diseases or wounds such as burns, skin harvest wounds, skin abrasion wounds, traumatic skin loss wounds, etc. Conventionally, gauze, absorbent cotton, etc. have been used, but these have low ability to prevent bacterial infection and are subject to deterioration due to exudate, requiring frequent replacement.In addition, they tend to dry the wound surface in order to absorb exudate quickly. This caused pain and bleeding when removed. Ointments and the like have also been used together, but in this case, the exudate is not sufficiently absorbed and the wound surface becomes excessively moist. Alternatively, artificial materials such as silicone gauze, silicone rubber membranes, and synthetic fiber sheets such as nylon and Teflon with a velour-like surface structure can be used as alternatives, especially when the wound surface is extensive. Coating films made of biological materials such as freeze-dried pigskin, fibrin membranes, plasma solidified membranes, collagen membranes, mucopolysaccharide-coated collagen membranes, and the like are also known.
However, among these, coatings made of artificial materials have various problems in terms of adhesion to the affected area, water vapor permeability, cracking, etc., while coatings made of biological materials have problems such as biocompatibility. However, many of them are antigenic and have drawbacks such as bacterial infection and deterioration due to exudate, and furthermore, raw materials are difficult to obtain and expensive. More recently, a composite membrane consisting of a collagen-treated nylon mesh and a silicone membrane has been developed and put into practical use, and although it adheres well to the wound surface and has moderate moisture permeability, it also adheres to the wound surface and covers the granulation tissue. It had the disadvantage of penetrating into the coating. Due to these shortcomings, wound dressings are generally used to: 1) Adhere to the wound properly to prevent infection and pain; 2) Provide appropriate moisture to the wound.
Has moderate water vapor permeability and exudate absorption,
3) Does not stick to the wound surface, minimizes scarring, and heals the wound surface cleanly; 4) Can be easily removed from the wound surface without causing pain or bleeding; 5) Prevents leakage of protein components in body fluids. , 6) The components in the exudate form a fibrin film layer on the wound surface to soften and protect the wound surface, and 7) It is desirable that the raw materials are easily available, easy to manufacture, and inexpensive. However, at present, a wound dressing that satisfies these conditions has not yet been obtained. OBJECTS OF THE INVENTION The present invention therefore aims to provide a new wound dressing. The present invention also has appropriate water vapor permeability, adheres appropriately to prevent infection and pain, does not stick to the wound surface, can be easily peeled off when exfoliated, and prevents leakage of protein components in body fluids. It is an object of the present invention to provide a wound dressing material that prevents the wound healing, promotes healing by forming a fibrin film layer with components in the exudate, and is inexpensive and easy to manufacture.
A further object of the present invention is to provide a wound dressing with excellent transparency. The above objects are a wound dressing having a support layer that contacts a wound on one side, and a moisture permeation regulating layer formed on a surface of the support layer opposite to the surface that contacts the wound. , the support layer is made of a nonwoven fabric, woven fabric, or knitted fabric of a hydrogel-forming water-absorbing material made of a partially crosslinked carboxymethylcellulose polymer; A wound dressing material characterized in that each fiber constituting the knitted fabric is coated with a biocompatible water-repellent substance to the extent that the water absorption by the hydrogel-forming water-absorbing substance is not completely inhibited. This is achieved by The invention further provides a wound dressing in which the biocompatible water-repellent material is selected from the group consisting of polyurethane, silicone rubber, styrene-butadiene-styrene copolymers and ethylene-propylene-diene terpolymers. . The present invention also provides a wound dressing in which the moisture permeation control layer is polyurethane. The present invention further provides a water vapor transmission rate (JIS) of 0.1 to 200 mg/cm ² hr.
This shows a wound dressing. The invention furthermore provides a wound dressing in which the water absorption capacity of the support layer is between 50 and 500% by weight of its own weight. The present invention also provides a wound dressing in which the moisture permeation regulating layer has a thickness of 5 to 200 μm. Specific Structure of the Invention The present invention will be described in more detail below based on embodiments. FIG. 1 is an enlarged cross-sectional view showing the microstructure of one embodiment of the wound dressing of the present invention. As shown in FIG. 1, the wound dressing 1 of the present invention includes a support layer 3 that contacts the wound on one surface, and a support layer 3 formed on the surface opposite to the surface that contacts the wound of the support layer 3. The support layer 3 is made of a nonwoven fabric, woven fabric, or knitted fabric made of a hydrogel-forming water-absorbing substance, and each fiber constituting the nonwoven fabric, woven fabric, or knitted fabric is It is coated with a biocompatible water-repellent material 2 to the extent that the water absorption by the hydrogel-forming water-absorbing material is not completely inhibited. Here, the water-repellent substance 2 and the support layer 3 are considered to be biocompatible because when the wound dressing 1 is applied to the wound, almost no foreign body reaction occurs by living organisms, and the wound surface is It has good compatibility with the wound dressing material 1, and the wound dressing material 1 has good compatibility with the wound surface due to exudates from the living body.
This is because there is no risk of the material becoming stuck. Furthermore, coating the fibers made of the hydrogel-forming water-absorbing material constituting the support layer 3 with the water-repellent material 2 allows the support layer 3 to absorb exudate moderately without excessively absorbing it. This is because it has been found that the shape of the support layer 3 can be maintained. Furthermore, by providing the moisture permeation regulating layer 4 on the opposite side of the support layer 3 from the part that can come into contact with the wound, appropriate water vapor permeation is achieved, preventing exudate from accumulating on the wound surface and keeping the wound surface moist. This will allow the tissue to sag, while preventing protein components in the exudate from leaking out to the outside, providing an extremely favorable environment for tissue repair. Furthermore, surprisingly, by providing the moisture permeation regulating layer 4, the adhesion of the wound dressing 1 to the wound surface and bleeding and pain when the wound dressing 1 is peeled off from the wound surface are suppressed. It turned out that it was possible. Furthermore, when the wound dressing 1 having such a configuration is applied to a wound, a uniform fibrin layer is formed on the wound surface, which protects the tissue and accelerates the healing of the wound. It was also discovered that when material 1 was removed, the grown epithelium did not peel off, and the wound surface healed cleanly without leaving any scars. Examples of the biocompatible water-repellent material 2 that coats the surface of the fibers of the hydrogel-forming material constituting the support layer 3 include polyurethane, silicone rubber, styrene-butadiene-styrene block copolymer (SBS), and ethylene-propylene diethylene chloride. There are enterpolymers (EPDM), etc.
Particularly desirable are segmented polyurethane and silicone rubber, which have good biocompatibility. Such water-repellent material 2 coats the surface of the fibers of the hydrogel-forming material constituting the support layer 3 to the extent that it does not completely inhibit water absorption by the hydrogel-forming water-absorbing material. On the other hand, as the hydrogel-forming substance constituting the support layer 3, a partially crosslinked carboxymethyl cellulose polymer is used. Even if the support layer 3 is composed of such a partially crosslinked polymer that has previously combined with a certain amount of water to form a hydrogel state, there will be no problem as long as the support layer 3 exhibits sufficient water absorption ability. Alternatively, the partially crosslinked polymer may not yet bind to water and form a hydrogel. Here, "biocompatible hydrogel-forming property" means that when a polymer comes into contact with water, it does not dissolve in water but absorbs water and swells, forming a hydrogel, that is, it combines with water as a dispersion medium and solidifies. state,
It means something that can show biocompatibility. Moreover, this property of not dissolving in water is advantageous because it does not cause any inconvenience such as a part of the support layer being dissolved by exudate and being incorporated into the wound site. A support layer 3 made of fibers of a hydrogel-forming water-absorbing material coated with a water-repellent material 2
The water absorption capacity of is 50-500% by weight of its own weight, preferably
It has 100-300% by weight. The moisture permeation regulating layer 4 formed on the opposite side of the support layer 3 from the part that can come into contact with the wound may be a thin film made of a material with relatively high water vapor permeability, such as polyurethane. Although it depends on the water vapor permeability of the material, the film thickness is usually about 5 to 200 μm. Further, the moisture permeation regulating layer 4 is not limited to a dense membrane made of a material with high water vapor permeability such as the above-mentioned polyurethane, but may be a porous membrane showing a similar water vapor permeability. Among these, a dense thin film of polyurethane is particularly desirable from the viewpoint of adequate water vapor permeability and excellent ability to inhibit protein leakage and bacterial invasion. Although the water vapor permeability (JIS) of the wound dressing 1 of the present invention differs slightly depending on its intended use, it is because the moisture regulating layer 4 is formed.
It shows a value of about 0.1 to 200 mg/cm ² hr. The wound dressing 1 having such a structure is sterilized if necessary, and then brought into contact with the wound part of the patient and fixed to the wound part using an adhesive tape or the like if necessary. Peeling off the wound dressing 1 from the wound site is easy because the wound dressing 1 is not adhered to the wound surface, and is not accompanied by pain or bleeding. When the dressing 1 is moistened to swell and soften the biocompatible hydrogel-forming substance of the wound dressing 1, it can be peeled off more easily. The wound dressing of the present invention can be easily manufactured, for example, as follows. That is, first, at least the lower surface of a nonwoven, woven, or knitted fabric made of fibers of partially crosslinked carboxymethylcellulose polymer is coated with a biocompatible water-repellent material such as the silicone rubber described above. The biocompatible water-repellent material is in the form of a solution, emulsion, or prepolymer containing a hardening agent, preferably in the form of a non-aqueous solvent solution, and is applied by spraying, dipping, etc., dried, and further coated as necessary. The substrate is then heat treated and coated onto the support layer. For example, when silicone rubber is used as the biocompatible water-repellent material, a silicone rubber-hexane solution is applied, and then dried to coat the support layer with silicone rubber. Next, a solution, emulsion, or prepolymer containing a hardening agent of a water vapor permeable material such as polyurethane as described above is spread on a substrate such as silicone release paper to form a film, so that the film remains sticky. In this state, the support layer coated with the water-repellent material obtained in the above step is placed so that its upper surface is attached to the membrane, dried, and heat treated if necessary to form the membrane. harden,
A moisture permeation regulating membrane is attached to the upper surface of the support layer. For example, when polyurethane is used as the water vapor permeable material, a polyurethane-tetrahydrofuran/dimethylformamide mixed solution is spread on a substrate, a support layer is placed on top of this wet layer immediately after spreading, and after being left to stand, it is dried and a polyurethane thin film is formed. Attach the support layer to. Finally, the composite layer film is peeled off from the substrate to obtain the desired wound dressing. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 A commercially available nonwoven fabric made of carboxymethyl cellulose sodium salt (manufactured by Asahi Kasei Kogyo Co., Ltd.) was mixed with 2% silicone Niver dispersion (manufactured by Toray Silicone Co., Ltd.).
The sample was immersed in a hexane solution of SD8001 Dispersion (manufactured by SD8001) for 1 minute and left at room temperature for 30 minutes. Next, a mixed solution of 20% polyether-type urethane (Leathermin P-2045R, manufactured by Dainichiseika Kaisha, Ltd.) in tetrahydrofuran (THF)/dimethylformamide (DMF) was applied onto the silicone release paper using a precision coating tool (applitter). A film was formed. Immediately after coating, place the above nonwoven fabric on top of the wet layer and let it stand at room temperature.
After standing for 10 minutes, at 60℃ for at least 1 hour.
Cured in oven. The water absorption capacity of the wound dressing thus obtained was 192% of its own weight. Comparative Examples 1 to 7 For comparison, a commercially available cellulose nonwoven fabric (Comparative Example 1), a commercially available nonwoven fabric made of carboxymethylcellulose sodium salt used in Example 1 (Comparative Example 2),
Similarly, a commercially available nonwoven fabric made of carboxymethyl cellulose sodium salt used in Example 1 was coated with silicone rubber as described in Example 1 (Comparative Example 3), a commercially available freeze-dried pork skin (Mitsui Pharmaceutical Co., Ltd.
Metaskin Co., Ltd.) (Comparative Example 4), a commercially available composite membrane consisting of a collagen-treated nylon mesh and a silicone membrane (Utsudrou MFG Co., Ltd.) (Comparative Example 4);
Incorporated (WOODROOF MFG.,
(Comparative Example 5), a commercially available cellulose nonwoven fabric coated with silicone rubber (Comparative Example 6), and the wound-resistant surface layer was made of a nonporous polyurethane sheet (film thickness of about 30 μm). Structure in which a polyurethane sheet is lined with a water-absorbing nonwoven fabric sheet (note that this nonwoven fabric sheet has a portion that protrudes from the outer periphery of the polyurethane sheet)
(Comparative Example 7) was prepared. Comparative Example 8 The same procedure as in Example 1 was performed except that polyvinyl alcohol gel (hydrous gel of Denka Poval K-05 (degree of polymerization 2000) manufactured by Denki Kagaku Kogyo Co., Ltd.) was used instead of the nonwoven fabric made of carboxymethyl cellulose sodium salt. , a wound dressing was prepared. Comparative Example 9 In Example 1, a polyacrylate foam (AT-510 (manufactured by Nippon Pure Chemical Industries, Ltd.) with a viscosity of
A wound dressing was prepared in the same manner, except that 700 cps) was cast and dried. Evaluation using experimental animals The skin on the back of a female Hartley guinea pig (weighing 300-400 g) was peeled off in a size of 2 x 3 cm to create a full-thickness skin defect wound. After stopping the bleeding, Example 1 and Comparative Example Samples 1 to 7 were each placed on the wound site, sterile gauze was placed on top of the wound area, and the animals were fixed using elastic tape and kept for 72 hours with ad libitum water and food. After 72 hours, under anesthesia, the back The sample was peeled off from the wound surface and the following items were evaluated. was pulled in the vertical direction and the stress at that time was measured.The evaluation value was based on the following criteria: 0: The sample does not stick to the wound surface less than 1 g 1: The tension at the time of peeling is 1 to 10 g 2: 〃 10 to 20 g 3 : 〃 20 to 30 g 4: 〃 30 g or more B Bleeding during peeling The wound surface and sample after sample peeling were visually observed to determine the presence or absence of bleeding.The evaluation value was based on the following criteria: 0: Upon sample peeling No bleeding. 1: There is slight bleeding when the sample is peeled off. 2: There is considerable bleeding when the sample is peeled off. C. Presence or absence of fibrin film layer formation After sample peeling, the wound surface was observed with the naked eye and a uniform fibrin layer was observed. It was investigated whether or not it was formed on the wound surface. D. Moisture permeability The moisture permeability of the wound surface at the time of sample removal and the sample were observed.The evaluation value was based on the following criteria. 1: No moisture permeates at all. 2: Water permeability is insufficient and exudate accumulates on the wound surface. 3: Appropriate moisture permeability. 4: Water permeates very well and the wound surface E. Dry residue in gauze Measure the dry weight of the sterile gauze placed on the sample in advance, and after peeling off the sample, place the sterile gauze placed on the sample at 60℃ overnight. Dry and measure the weight. From the difference in weight before and after, the adhesion residue derived from the exudate in the sterile gauze was determined, and the amount of solid matter per 1 cm ² of wound area was determined. The evaluation value was determined according to the following criteria. 0: Adhesive residue 0 to 5 mg/cm ² 1: 〃 5 to 10 mg/cm ² 2: 〃 10 to 15 mg/cm ² 3: 〃 15 to 20 mg/cm ² 4: 〃 20 mg/cm ² or more Table 1 shows the results of the evaluation values obtained for the items.

[Table] Moisture permeability test Regarding the wound dressings of Example 1 and Comparative Example 4, the method of Ohara et al. , Vol.16, No.2, P617～
See 624 (1982). ). In other words, pour 70ml of physiological saline into a 90mm diameter sieve, 7cm (vertical) x 7cm (horizontal) x 1.5cm (takasa).
Soak a sponge the size of. A sponge was sufficiently soaked with physiological saline, and a 6 cm x 6 cm sample was coated on its surface, and two sheets of 5 cm x 5 cm sterile gauze (manufactured by Kawamoto Notai, K-Pine) were placed on top of it. After pressing with the lid of a shear dish, it was left at constant temperature (temperature 25°C, humidity 48%). The weight of the gauze was measured before the test and 72 hours after the start of the test, and the difference was calculated to determine the amount of permeated water based on the change in weight of the gauze. The results are shown in Table 2. Table 2 Permeated water content (average value ± SD) [mg] Example 1 1483 ± 133 Comparative example 4 920 ± 107 Evaluation using experimental animals After shaving the back of the rat, a dermatome (surgical skin harvesting tool) was used to remove the rat. /1000 inch (approx. 0.25 mm) depth (equivalent to partial loss of epidermis and dermis) approximately 2 x 2
A wound surface with a size of cm was created, each sample of Example 1 and Comparative Examples 6 to 9 was applied thereto, and the surrounding area was compressed and fixed. Animals were sacrificed over time and necropsied.
Then, the epidermalization rate, adhesion strength, bleeding upon peeling, water permeability, and histological evaluation were performed. In addition,
The epidermal conversion rate is determined by measuring the width of the epidermis using a micrograph using a specimen tissue section.
(manufactured by KOIZUMI Co., Ltd.) and determined by the ratio to the width of the injured area. The results obtained are shown in Table 3.

[Table] Example 9 Many
As shown in Table 3, the sample of Example 1 according to the present invention did not adhere to the wound surface over time after the surgery, but naturally peeled off as the skin regenerated. On the other hand, in Comparative Examples 6 to 9, the samples were taken into the dermis exposed on the wound surface, inhibiting re-epidermis, and in some cases, clusters of inflammatory cells were observed. Specific Effects of the Invention As described above, the wound dressing of the present invention includes a support layer that contacts the wound on one side, and a support layer that is formed on the surface of the support layer that is opposite to the surface that contacts the wound. A wound dressing material having a water permeation regulating layer, wherein the support layer is made of a nonwoven fabric, woven fabric, or knitted fabric of a hydrogel-forming water-absorbing material made of a partially crosslinked carboxymethyl cellulose polymer, and the nonwoven fabric or woven fabric Alternatively, each fiber constituting the knitted fabric is coated with a biocompatible water-repellent substance to the extent that the water absorption by the hydrogel-forming water-absorbing substance is not completely inhibited. Therefore, when applied to affected areas due to diseases or wounds such as burns, skin harvest wounds, skin abrasion wounds, and traumatic skin defect wounds, the wound surface should be properly coated to have appropriate water vapor permeability and exudate absorption. It adheres closely to the wound while keeping it moisturized to prevent infection and pain, and since the area in contact with the wound surface is biocompatible, there is no risk of foreign body reactions caused by living organisms or the dressing will stick to the wound surface and cause bleeding when removed. , does not cause any pain, etc., and also prevents the leakage of protein components in body fluids, and forms a fibrin layer between the wound surface and the dressing, making the wound surface soft and protected. As described above, in synergy with keeping the wound surface under an appropriate moisturized state, this promotes healing of the wound area and regenerates cleanly without leaving any scars. In addition, each substance constituting the wound dressing of the present invention is easily and stably available, and is inexpensive.
The wound dressing is economically superior. Furthermore, these properties make it possible for biocompatible water repellent materials to be used in polyurethane, silicone rubber, and styrene.
Butadiene-styrene block copolymers and ethylene-propylene-diene terpolymers are even better when the moisture permeation control layer is polyurethane;
Since both substances are stable against exudates, the coating material will not deteriorate due to exudates. Furthermore, by selecting highly transparent materials such as silicone rubber as the biocompatible water-repellent material and polyurethane as the moisture permeation regulating layer, the resulting wound dressing material will have high transparency. This allows the state of the wound to be observed without removing the dressing.

[Brief explanation of the drawing]

FIG. 1 is an enlarged cross-sectional view showing the microstructure of an embodiment of the wound dressing of the present invention. DESCRIPTION OF SYMBOLS 1... Wound dressing material, 2... Biocompatible water-repellent material, 3... Support layer, 4... Moisture permeation regulating layer.

Claims (1)

[Claims] 1. A wound dressing having a support layer that contacts the wound on one side and a moisture permeation regulating layer formed on the opposite side of the support layer to the surface that contacts the wound. The supporting layer is made of a nonwoven fabric, woven fabric, or knitted fabric of a hydrogel-forming water-absorbing material made of a partially crosslinked carboxymethylcellulose polymer, and each fiber constituting the nonwoven fabric, woven fabric, or knitted fabric is 1. A wound dressing characterized by being coated with a biocompatible water-repellent material to the extent that water absorption by the hydrogel-forming water-absorbing material is not completely inhibited. 2 The biocompatible water-repellent material is polyurethane,
A wound dressing according to claim 1, which is selected from the group consisting of silicone rubber, styrene-butadiene-styrene block copolymer and ethylene-propylene-diene terpolymer. 3. The wound dressing material according to any one of claims 1 to 2, wherein the moisture permeation regulating layer is polyurethane. 4 Water vapor transmission rate (JIS) 0.1 to 200 mg/cm ²・hr
The wound dressing according to any one of claims 1 to 3. 5. The wound dressing according to any one of claims 1 to 3, wherein the support layer has a water absorption capacity of 50 to 500% by weight of its own weight. 6. The wound dressing material according to any one of claims 1 to 4, wherein the water permeation regulating layer has a thickness of 5 to 200 μm.