JPH0442020B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wound covering and protection material, and more particularly to a protection material preferably used for skin damage such as burns, dermabrasion wounds, abrasion wounds, and traumatic dermabrasion wounds. This invention relates to a protective material for skin damage made of a porous chitin molded body.

BACKGROUND OF THE INVENTION Conventionally, preferable treatments for skin defects such as burns and skin extraction wounds have been a major issue in the fields of plastic surgery and dermatology, and many materials have been investigated as wound covering and protective materials. For example, nylon, polyester,
Special fabrics such as polypropylene and rayon (single fibers with a diameter of several hundred microns protrude from the surface in the form of loops or fluff.) Laminated products of these fabrics and silicone sheets, formalized vinyl alcohol sponge, ethylene oxide and polyester There are gelatinized block copolymers with oxypropylene glycol and "Sofuratyur" gauze (Nippon Lucelle) impregnated with antibiotic-containing ointment, and products made from biological materials such as fibrin membranes, plasma membranes, and even collagen. There are non-woven fibers (product name: Meipatsuku, sold by Meiji Seika) and Poshinskin, which is made by sterilizing and freeze-drying the dermal layer of the pig's back.

However, these materials were not necessarily satisfactory as protective materials for cortical defects. In other words, the general function of a wound covering material is to prevent the loss of biological components from the wound surface until new skin is formed, prevent infection, and assist in the formation of granulation and epithelium. properties, water absorption and exudate adsorption, moisture permeability,
It is necessary to have properties such as histocompatibility, non-antigenicity, and ability to promote new skin. However, conventional synthetic materials have poor water absorption, exudate adsorption, moisture permeability, etc., while natural products have poor strength, exudate adsorption, etc.
Particularly in the case of deep wounds, it had the disadvantage that it would become mushy within a few days after treatment. Therefore,
When wounds were protected with these conventional synthetic or natural products, granulation, epithelial formation, etc. did not occur sufficiently as a result. For example, when it comes to burns, they are classified into degree burns, superficial degree burns, deep degree burns, and degree burns, depending on the degree of damage. Conventional burns are limited to the treatment of superficial degree burns, that is, mild burns. Furthermore, the treatment of skin harvest wounds after skin grafting also had the drawback of being limited to intermediate-thickness skin grafting.

The present inventors have found favorable granulation, which has good adhesion to the affected area and adsorption of exudate, does not accumulate exudate in the affected area, and does not dissolve or damage until healing occurs.
As a result of intensive research aimed at developing a wound covering material in which epithelium is formed, it was discovered that a porous molded article made of chitin is excellent as a wound covering material, and the present invention was thus achieved.

That is, the present invention is a wound covering protection material made of a porous chitin molded article produced by a wet molding method.

In the present invention, chitin refers to poly(N-acetyl-D-glucosamine) obtained by treating the exoskeleton of crustaceans and insects with hydrochloric acid and caustic soda to separate and purify protein and calcium. ) or their derivatives. Examples of chitin derivatives include those in which acetylglucosamine groups are partially deacetylated, etherified products, esterified products, carboxymethylated products, hydroxyethylated products, o-ethylated products, etc. Preferred specific examples include poly[N -acetyl-6-O-
(2'-hydroxyethyl)-D-glucosamine],
Examples include poly[N-acetyl-6-O-(ethyl)-D-glucosamine].

The porous chitin molded body obtained from these chitins has a porosity measured in a dry state (B/A x 100%; B: volume of pores contained in a porous molded body per unit weight,
A: Means a molded product whose total volume per unit weight of the porous molded product is 90% or more, such as a wet-formable molded product such as a sheet, rod, or fiber shape.

Such porous chitin molded bodies can be produced, for example, by the following method.

The purified chitin is added to a known chitin solvent such as a mixture of dimethylacetamide and lithium chloride, a mixture of N-methylpyrrolidone and lithium chloride, a mixture of trichloroacetic acid and a halogenated hydrocarbon at a concentration of about 0.5 to 15% by weight. Dissolve to obtain dope. A water-soluble polymer that is solid at room temperature, such as polyvinyl alcohol, polyethylene glycol, polypropylene glycol, agar, water-soluble starch, protein, etc., preferably polyvinyl alcohol or agar, is uniformly dispersed in this dope. At that time, the ratio of chitin dope to water-soluble polymer is preferably selected from the range of 1/5 to 5/1 (weight ratio). The chitin dope mixed with a water-soluble polymer is solidified in a coagulating liquid while maintaining a desired shape by pouring into a form or extruding from a slit die. As the coagulating liquid, for example, water, alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, and butyl alcohol, or ketones such as acetone are preferably used. After the solvent has been sufficiently removed and coagulation has been completed, the coagulated product is treated with water or an aqueous solution. In general, water-soluble polymers are difficult to remove from the coagulated material at low temperatures, so treatment at a high temperature of 60° C. to 125° C. is preferred, and the treatment time is preferably 30 minutes or more. The molded product that has been thoroughly washed after processing has a sponge-like shape with a high moisture content. To obtain a dried product from this state, ordinary room temperature drying may be performed, but freeze-drying is preferably used. be done. That is, it is preferable to freeze the molded product at a temperature of about -40°C while containing water, and then freeze-dry it at a temperature of 10°C.

The porous chitin molded article in the present invention includes:
A porous chitin molded article obtained as described above treated in an alkaline solution is preferably used. Preferred conditions for carrying out the alkali treatment are, for example, using a 5 to 60 W/V% aqueous solution of caustic soda at a temperature of 10 to 120° C. for one minute or more. In the present invention, the porous chitin molded article particularly preferably used is one that does not dissolve when it is neutralized after treatment and immersed in a 2V/V% acetic acid aqueous solution at 25°C.

The porous chitin molded article according to the present invention is used as a wound covering material after sterilization, and it is particularly preferable to have a wet strength of 1 g/mm ² or more. Materials with such high wet strength are preferable as wound covering and protective materials, and are particularly effective in treating burns, skin-grafted wounds after skin grafting, and the like. In other words, when used as a wound dressing for skin defects, it has good adsorption of exudate, reduces accumulation of exudate in the affected area, prevents dissolution by body fluids even after long-term use, and leaves the affected area moderately moist. This has the revolutionary effect of ensuring good regeneration of new skin.

The wound dressing of the present invention can be used not only for superficial burns and intermediate-thickness skin graft wounds, but also for deep burns and thick split-thickness skin grafts that cannot be treated with conventional wound dressings. It can be used extremely effectively as a protective material for skin harvest wounds.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Chitin powder (manufactured by Kyowa Yushi Co., Ltd.) was ground into 100 meshes, treated with 1N-HCl at 4°C for 1 hour, heated in 3% NaOH solution for 3 hours at 90-100°C, and washed with water. Dry repeatedly. The obtained chitin was dissolved at room temperature in a dimethylacetamide solvent containing 8% by weight of lithium chloride to a concentration of 2% by weight to obtain a clear liquid, which was then filtered under pressure using a 1480 mesh stainless steel net. Then, defoaming was performed under reduced pressure while stirring to obtain a chitin dope.

100g of this chitin dope and Poval UF-170GS
(manufactured by Unitika Chemical Co., Ltd.; degree of polymerization 170, degree of saponification 95% or more) was added and stirred for 1 hour in a beaker equipped with a stirring blade to prepare a uniform dispersion. This dispersion was cast onto a glass plate to a thickness of 1 mm, and then immersed in water at about 25°C to sufficiently coagulate and wash to obtain a sheet. Next, this sheet was immersed in water and then treated in a boiling state for 5 hours to obtain a sheet-like chitin molded article. This molded body is −40
After freezing at 10°C, freeze-drying was performed at 10°C to obtain a porous chitin molded body. The porosity of this molded body is
99.2%, and the wet strength was 4.5 g/mm ² .

This sheet (length 120mm, width 120mm, thickness 0.8
mm) was sterilized and used as a wound dressing.

Specifically, two of these porous sheets were applied to the affected area of a 30-year-old man who had extensive burns on his back skin and were determined to be deep burns, and the upper part was covered with cotton gauze. Protected.

After 6 days, the sheet remained undamaged and remained in its original state, adsorbed exudates from the body, and became moist, some of which had reached the cotton gauze layered on the sheet. Furthermore, there was little accumulation of exudate on the affected area and it maintained an appropriate moist state.
After 12 days of continued treatment, the sheet became dry and could be easily peeled off from the affected area, and normal new epidermis was formed on the affected area, indicating that the treatment had been sufficiently performed.

Example 2 The chitin powder obtained in Example 1 was dissolved at 1% by weight in a dimethylacetamide solution containing 8% by weight of lithium chloride, and filtered and defoamed to obtain a transparent chitin dope. A mixed solution was prepared by adding 100 g of agar powder to 100 g of this dope. Pour this liquid 15cm tall,
The mixture was poured into a mold with a width of 15 cm and a depth of 1 mm, solidified with methanol, and the solvent contained therein was removed to obtain a sheet. After immersing this sheet in water and treating it in an autoclave at 121℃ for 1 hour,
After autoclaving with 40% caustic soda solution at 121℃ for 1 hour, thoroughly neutralize and wash with water, freeze at -40℃ while still containing water, and freeze-dry at 10℃. Finally, wet strength
A porous chitin sheet with a weight of 6.5 g/mm ² and a porosity of 99.2% and a thickness of 0.8 mm was obtained.

This porous chitin sheet was sterilized and used as a protective material for a skin harvest wound after thick split-thickness skin grafting. Specifically, the patient was a 37-year-old woman who had a skin harvest wound on her back.
Two 12mm pieces were attached, and the upper part was protected with cotton gauze. After 6 days, a lot of exudate was observed on the surface of the protective material, and less exudate was observed in the affected area, and granulation was observed. After 14 days, new skin was formed, indicating that the affected area was healing well.

Claims (1)

[Scope of Claims] 1. A wound covering protection material comprising a porous chitin molded article produced by a wet molding method. 2 The porous chitin molded body has a wet strength of 1 g/mm ²
The wound covering protection material according to claim 1, which is as described above. 3. The wound covering protection material according to claim 1, wherein the porous chitin molded body is subjected to alkali treatment after wet molding.