JP2001017531A - Wound dressing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize the possibility of infection by bacteria from the outside and lengthen the effective life by including a nonwoven fabric layer made up of a hydrophobic fiber and an absorptive fiber, a nonwoven fabric layer consisting of a hydrophobic fiber, and a hyaluronic acid sponge layer. SOLUTION: A wound dressing includes a nonwoven fabric layer 11 made up of hydrophobic fibers and absorptive fibers, a nonwoven fabric layer 12 consisting of hydrophobic fibers and a hyaluronic acid sponge layer 13. The laminated nonwoven fabric layer 12 reduces effectively fuzzing up of the nonwoven fabric layer 11 and adjusts effectively the flexibility of the wound dressing. The hyaluronic acid as a biological material, obtains a fine environment highly hydrated on a wound in the wound healing process. When applied to an organism, as the covering fuses and degrades easily, in a material that is required to have a form retaining property for a relatively long period, by forming into a sponge after introducing chemical crosslinking into the hyaluronic acid by a crosslinking agent, the form retaining property is improved and adhesion to the wound is improved at the same time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wound dressing. More specifically, it is applied to a wound surface that exudes a large amount of wound fluid during the healing process, and is suitable for use in promoting wound healing.

[0002]

2. Description of the Related Art Conventionally, as a method for treating a wound caused by a burn, pressure sore (bed sore) or other trauma, a method of applying a remedy to a wound, covering the wound with gauze, and fixing with a covering material. Has been taken. In such a case, since the gauze is directly applied to the wound surface, the exudate from the wound surface is directly absorbed by the gauze, but the gauze does not have a high water absorbing ability, and the exudate is stored. This storage, on the contrary, promotes the generation of bacteria and makes early healing difficult. In particular, on a wound surface with a large amount of exudate from the wound, the ointment or cream of the therapeutic agent mixes with the exudate to form a muddy state. Therefore, it is necessary to frequently change the coating material and reapply the ointment or cream. If the dressing is changed frequently, the amount of medicine to be used increases, and the pain of the patient when changing the dressing increases. There is also a problem that the doctor's labor required for changing the covering material cannot be ignored.

[0003] Films of synthetic materials and the like have been used as a part of the covering material in order to prevent invasion of dirt and bacteria from the outside. However, these materials have a poor function of evaporating moisture. However, there is a drawback that exudate tends to accumulate between the wound surface and the dressing material, thereby delaying wound healing.

Further, from the viewpoint of good affinity with the wound surface and promotion of healing, materials derived from living bodies, for example, glucosaminoglycans such as hyaluronic acid, collagen and the like, are used in the medical field such as wound dressing materials. It has come to be taken up by. However, hyaluronic acid easily melts and decomposes when applied to a living body, and is unsuitable as it is for a material for a wound dressing material that requires relatively long-term shape retention. Collagen is abundantly contained in the dermis, tendons, bones, fascia, etc. of animals, and even if it is derived from a heterologous animal, it can be produced in large amounts because it can reduce immunogenicity when it is converted into atelocollagen by enzymatic treatment. Although it is a useful material that can be obtained relatively inexpensively, it re-fibrils under physiological conditions, and thus requires various hydrophilic treatments and cross-linking treatments. Introducing chemical cross-linking with a cross-linking agent improves shape retention, but there is a problem in that biocompatibility, which can be said to be a characteristic of collagen, is significantly impaired.

[0005]

[0003] Wound dressings must have several requirements in order to facilitate wound healing. For example, wound dressings must be highly absorbent and have a high rate of fluid uptake to remove exudate from the wound surface. And it must prevent the absorbed liquid from leaking from the wound dressing and soiling the bedding. The wound dressing must also be breathable so that the wound can breathe and minimize the potential for bacterial infection from the outside to keep the wound as sterile as possible. However, it cannot be said that these requirements have been sufficiently satisfied by the wound dressing materials conventionally used.

[0006] It is therefore an object of the present invention to minimize the possibility of external bacterial infection, to absorb a significant amount of exudate oozing from the wound surface, and to ensure that the Wound dressing that can extend the useful life of the wound dressing by transferring the contained moisture through the wound dressing within the desired rate to the outer surface of the wound dressing and evaporating this moisture into the surrounding environment Is to provide. Further, it is another object of the present invention to provide a wound dressing material having good affinity with a wound surface and having a healing promoting effect on the wound surface.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, completed the present invention. The present invention is as follows. (1) A wound dressing comprising a nonwoven fabric layer composed of a hydrophobic fiber and a highly absorbent fiber, a nonwoven fabric layer composed of a hydrophobic fiber, and a hyaluronic acid sponge layer. (2) The wound dressing according to (1), wherein the basis weight of the nonwoven fabric layer composed of the hydrophobic fiber and the highly absorbent fiber is 30 to 300 g / m ² . (3) The basis weight of the nonwoven fabric layer made of hydrophobic fibers is 5 to 10
The wound dressing of (1) or (2) above, which is 0 g / m ² . (4) Laminating a nonwoven fabric layer made of hydrophobic fibers on both sides of a nonwoven fabric layer made of hydrophobic fibers and superabsorbent fibers (1)
The wound dressing according to any one of (1) to (3). (5) The wound dressing according to any one of (1) to (4), wherein the hyaluronic acid sponge layer is formed by crosslinking hyaluronic acid with an epoxy compound.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As one embodiment of the present invention, FIG.
The structure shown in FIG. That is, the nonwoven fabric layer 11 composed of the hydrophobic fiber and the highly absorbent fiber can absorb a large amount of wound exudate released from the wound surface, and can reduce the moisture contained in the exudate at a desired speed. Has the ability to be transferred through the wound dressing to the exterior surface of the wound dressing to allow this moisture to evaporate into the surrounding environment.
In this way, by allowing the water vapor from the absorbed liquid to escape into the atmosphere, the frequency of replacement of the wound dressing can be reduced.

As the highly absorbent fiber used in the present invention, wood pulp, natural fiber of cotton, rayon, regenerated fiber of cupra, semi-synthetic fiber such as acetate and the like are used. As the hydrophobic fiber, polyester, nylon, acrylic,
Synthetic fibers such as polypropylene and polyethylene are preferred. Particularly, the hydrophobic fiber and the superabsorbent fiber are 6: 4 by weight.
When used in a ratio of 8: 2, the hydrophobic fibers receive water from the highly absorbent fibers that have absorbed the exudate, and serve to evaporate the water in the outer air layer, which is particularly preferable. The thickness of the fiber constituting the nonwoven fabric layer 11 composed of the hydrophobic fiber and the highly absorbent fiber is about 0.3 to 10 denier (d), preferably 0.5
It is desirable that the thickness be about 5 d.

[0010] As a method for producing a nonwoven fabric, it can be produced by a known method, for example, the following method. A wet process in which a short fiber layer (web) is made with water, impregnated with resin, and dried and hardened, just as paper is made. A dry method in which a web is made mechanically without using water and bonded with resin or adhesive fibers. A needle punch method in which a web of the same type as the dry type is pierced with a pierced needle to mechanically entangle the fibers. Spunlace method in which fibers are entangled with a high-pressure water stream on a web of the same type as the dry type. A web with a uniform thickness by arranging a large number of continuous yarns in all directions like a spider web while simultaneously blowing out the melted raw resin from many small holes (nozzles) before forming fibers Spunbonding method, where yarns are naturally and mechanically attached to each other.

The above-mentioned nonwoven fabric layer 11 can also be made by these known methods or by a combination of these methods. . Since the nonwoven fabric used in the present invention must have elasticity, a nonwoven fabric having a relatively large elongation is used. The elongation is length 60cm width 6c
m when a load of 1500 g is hung on a nonwoven fabric
m is expressed as a percentage of the original length.
The nonwoven fabric used in the present invention is preferably 30 to 200
%, More preferably 40 to 150%. The thickness of the nonwoven fabric layer 11 is preferably about 1 to 20 mm in consideration of flexibility, durability, workability, absorbability, and the like.
More preferably, it is about 1 to 10 mm.

The basis weight of the nonwoven fabric layer 11 is preferably from 30 to 300 g / m ² from the viewpoint of the retention of exudate.
More preferably, those having 50 to 200 g / m ² are suitable.

It is more preferable to use a composite nonwoven fabric layer in which a nonwoven fabric layer 12 made of a hydrophobic fiber is further laminated on the nonwoven fabric layer 11 made of a hydrophobic fiber and a highly absorbent fiber. The nonwoven fabric layer 12 made of hydrophobic fibers is effective in suppressing the fluffing of the nonwoven fabric layer 11 made of hydrophobic fibers and superabsorbent fibers, and at the same time, adjusting the flexibility of the wound dressing.

Further, the nonwoven fabric layer 12 made of hydrophobic fibers
Is advantageous in that the physical strength and durability of the hyaluronic acid sponge can be further improved.

Examples of the hydrophobic fiber material used for the nonwoven fabric layer 12 include polyester, polypropylene, polyethylene, nylon, and thermoplastic elastomer.
Among these hydrophobic fiber materials, a thermoplastic elastomer is a preferable material as a wound dressing material because it exhibits rubber elasticity at room temperature and is highly elastic. Among the thermoplastic elastomers, polyolefin-based, polyurethane-based, and polyester-based elastomers are particularly preferred because they are soft and rich in elasticity. As the hydrophobic fiber material, a commercially available product or an improved product thereof can be used.

The thickness of the fibers constituting the nonwoven fabric layer 12 is preferably about 0.3 to 10 d, more preferably 0.5 to 10 d.
It is desirable to have one of about 5d.

As a method of laminating the nonwoven fabric layer 12 on the nonwoven fabric layer 11, the nonwoven fabric layer 11 and the nonwoven fabric layer 12 are separately prepared by the above-mentioned method, and these two nonwoven fabric layers are brought into close contact with each other by heating. The non-woven fabric layer is bonded by using a thermoplastic resin or an adhesive fiber to form a non-woven fabric layer, and the above-mentioned hydrophobic fiber material, which is a raw material of the non-woven fabric 12, is directly spun into a web shape on one surface of the non-woven fabric layer 11. 1
2, a spunbonding method or the like. In the case where the nonwoven fabric layer 12 and the nonwoven fabric layer 11 are bonded via a thermoplastic resin, if the thermoplastic resin is applied to the entire surface, the function of transmitting exudate from the wound surface is impaired. It is good to make partial adhesion to the extent that it does not.

The thus prepared nonwoven fabric layer 12
Has both water permeability and smoothness, so that the adhesiveness to the wound surface is good, and the exudate from the wound surface passes through the hydrophobic and water-permeable nonwoven fabric layer 12 to form a hydrophobic fiber. There is a feature that the nonwoven fabric layer 11 made of a highly absorbent fiber is easily absorbed.

One purpose of the nonwoven fabric layer 12 is to suppress the fluffing of the nonwoven fabric layer 11 and to adjust the flexibility of the wound dressing material. Therefore, the thinner and softer the better, the better. The basis weight of the nonwoven fabric layer 12 is 5 to 100 g / m
² is preferred. The nonwoven fabric layer 12 made of hydrophobic fibers may be laminated on only one side of the nonwoven fabric layer 11 made of hydrophobic fibers and superabsorbent fibers.
May be laminated on both sides of the nonwoven fabric layer 11 composed of hydrophobic fibers and superabsorbent fibers.

When the nonwoven fabric layer 12 composed of hydrophobic fibers is laminated on both sides of the nonwoven fabric layer 11 composed of hydrophobic fibers and superabsorbent fibers, the nonwoven fabric layer 1 on the side (inside) in contact with the wound surface is formed.
2 may be provided with a hyaluronic acid sponge layer. In this case, the nonwoven fabric layer 12 on the opposite side (outside) in contact with the wound surface is uniform and denser than gauze or cotton cloth, and thus prevents invasion of bacteria from the outside while maintaining water vapor permeability. It is more preferable because it also has a barrier function of performing

Another object of the present invention is to provide a wound dressing having a healing promoting effect on a wound surface by using hyaluronic acid as a biomaterial.
That is, hyaluronic acid provides a highly hydrated microenvironment to the wound surface during the wound healing process. In such a microenvironment, it is known that adhesion and detachment between a cell membrane and a substrate when various cells move on a wound surface are controlled, and cell migration is facilitated, so that wound healing is promoted. I have. However, hyaluronic acid easily melts and decomposes when applied to a living body, and is unsuitable as it is for a material for a wound dressing material that requires a relatively long-term shape retention. Therefore, by introducing a chemical cross-linking agent into the hyaluronic acid by using a cross-linking agent and forming it into a sponge shape, the shape retention and the adhesion to the wound surface were improved at the same time.

As the hyaluronic acid to be crosslinked, for example, those having a molecular weight of preferably 500,000 to 3,000,000, more preferably 1.8 to 2.2 million are used. Further, as the crosslinking agent, a water-soluble polyfunctional epoxy compound can be used. As polyfunctional epoxy compounds,
For example, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, glycerol diglycidyl ether,
Examples include glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, sorbitol polyglycidyl ether, diglycidyl succinate, and diglycidyl adipate.

The crosslinking reaction is generally carried out at 0.2 to 2.0% by weight of hyaluronic acid, preferably at 0.5 to 1% by weight.
An aqueous solution is prepared and the pH of the solution is 4-7, preferably about 5
After adjusting to ~ 6, the reaction is carried out using a reaction solution in which the epoxy compound is added in an amount of 1/20 to 1/2 mol, preferably about 1/10 mol, based on the repeating unit of hyaluronic acid. Can be. As the solvent, in addition to the above water,
An alcohol-water system can be used.

The reaction temperature may be, for example, about 20 to 80 ° C., preferably about 40 to 60 ° C., and the reaction time is preferably 2 to 10 hours, more preferably 4 to 6 hours.

After the completion of the above crosslinking reaction, the temperature is from -20 ° C to -10
Hyaluronic acid sponge may be produced by quenching and freeze-drying in a freezer at 0 ° C, preferably -40 to -80 ° C, or -30 to -50 ° C in a freeze dryer.
Alternatively, it may be manufactured by freezing gradually, followed by vacuum drying. Examples of the method for forming the sponge-like sheet include the freeze-drying method as described above, but are not limited thereto, and those skilled in the art can employ an appropriate method.

The degree of cross-linking of hyaluronic acid is determined by the type, proportion, and reaction conditions of the epoxy compound used for the cross-linking reaction. Therefore, the degree of cross-linking should be appropriately selected according to the application site of the wound dressing and the purpose of use. Generally, after being implanted in a living body (for example, subcutaneously of Wistar rats) and allowed to stand for one week, 5
It is preferable to use a hyaluronic acid sponge in which about 30% by weight remains.

The thickness of the hyaluronic acid sponge layer may be arbitrarily set depending on the purpose of use of the wound dressing material and the site to be applied, but is preferably about 1 to 20 mm, more preferably about 2 to 10 mm.

Each of the constituent members of the wound dressing according to the present invention,
It is preferable that an antibacterial agent is blended in any of the constituent members of the nonwoven fabric layer and the hyaluronic acid sponge layer, or all of the constituent members. As the antibacterial agent, any antibacterial agent such as a sulfa drug, penicillin, nalidixin, silver sulfadiazine, polymyxin sulfate, and gentamicin sulfate can be used. The use of silver sulfadiazine. The content of antibacterial agent depends on the type of drug,
It may be determined according to the purpose of use and application site of the wound dressing. When silver sulfadiazine is used, the content or application amount of the wound dressing is 20 to 500 μg / cm ² ,
Preferably it is 50 to 400 μg / cm ² . With such a content, the growth of bacteria on the wound surface can be suppressed, and at the same time, the growth of cells inside the wound dressing that has absorbed the exudate can be effectively suppressed. The wound dressing of the present invention is used so that the hyaluronic acid side is in contact with the wound surface, but may be used in an arbitrary shape such as a bandage shape or a pad shape of several cm square to several tens cm square. It can be appropriately selected and used depending on the degree and depth of the wound, the area of the wound surface, and the like.

[0029]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the effects of the present invention will be specifically described. However, the present invention is not limited to the following Examples.

Example 1 Production of Nonwoven Fabric Layer (Wound Dressing Material for Control Experiment) A nonwoven fabric layer 11 composed of a hydrophobic fiber and a highly absorbent fiber was
After mixing polyester fiber having an average fineness of 1.5 d and rayon fiber of 2.0 d in a weight ratio of 70:30, an extremely thin fiber layer (web) is formed, and the web is superposed to obtain a basis weight of 100 g /. after so composed in m ^2,
The web layer was stuck with a pierced needle, and the fibers were mechanically entangled with each other (needle punch method).

In order to measure the absorbency of the nonwoven fabric layer thus prepared, the measured nonwoven fabric layer is immersed in water, taken out, allowed to drip for 30 seconds, and weighed again to determine the water absorption. It was measured. This nonwoven fabric layer was found to have an extremely high absorption capacity of 17 g / g. Therefore, it is suitable as a member of a covering material when there is a large amount of exudate from the wound surface.

On the other hand, the nonwoven fabric layer 12 is formed by a spun bond method using a hydrophobic polyester-based thermoplastic elastomer (trade name: Perprene, manufactured by Toyobo Co., Ltd.) on a release paper, and has a basis weight of 30 g / m2. m ² . The nonwoven fabric layer 11 and the nonwoven fabric layer 12 were pressed by a hot press, and then the release paper was removed.

The nonwoven fabric layer was coated with silver sulfadiazine as an antibacterial agent so as to have a concentration of 50 μg / cm ² .

Example 2 Production of Wound Dressing Material Hyaluronic acid having a molecular weight of 2,000,000 produced by fermentation method
% Aqueous solution (pH = 6), ethylene glycol diglycidyl ether as a cross-linking agent was added so as to be 1/10 mol of the molecular weight of the repeating unit of hyaluronic acid.
100 ml of this mixture is placed in a polystyrene container (10 cmx
10 cm). Next, the nonwoven fabric layer produced in Example 1 was cut so as to have a size of 10 cm × 10 cm, and the nonwoven fabric layer 12 composed of hydrophobic fibers was placed below, and immersed in the above-described aqueous solution of hyaluronic acid at 50 ° C.
Was allowed to stand for 5 hours in a dryer set to perform an intermolecular crosslinking reaction. This was taken out, quenched and frozen in a freezer at −80 ° C., and vacuum dried to form a hyaluronic acid sponge layer.

Example 3 Animal Experiment The wound dressings obtained in Examples 1 and 2 were sterilized with ethylene oxide gas, and then subjected to the following experiment.
That is, under anesthesia, both backs of a Japanese white rabbit (3 months old) were shaved, disinfected with isodine, and a circular full-thickness skin defect wound with a diameter of 55 mm was created on both backs of the rabbit, and the right back The wound dressing material laminated with the hyaluronic acid sponge layer produced in Example 2 was applied to the same, and the wound dressing material not laminated with the hyaluronic acid sponge layer produced in Example 1 was applied to the left back as a control experiment. Gauze was put on the top and fixed with elastic adhesive tape. One week later, the dressing was removed under anesthesia, the condition of the wound surface was observed, and the wound area was disinfected with isodine.
A wound dressing laminated with a hyaluronic acid sponge layer and a control dressing were applied, and gauze was applied thereto and fixed with an elastic adhesive tape. Thereafter, a new wound dressing material was replaced every week, and the state of the wound was observed over time.

When a wound dressing having a hyaluronic acid sponge layer laminated thereon was applied, almost all of the hyaluronic acid was decomposed and absorbed when it was removed in one week. Further, the exudate was sucked up by the nonwoven fabric layer, and no accumulation of exudate occurred under the coating material.

In the right back to which the wound dressing laminated with the hyaluronic acid sponge layer was applied, granulation tissue formation and shrinkage from around the wound were promoted, and at the third week of application of the wound dressing,
The diameter of the skin defect wound became about 10 mm.

On the other hand, on the left back side to which the coating material containing no hyaluronic acid was applied, the exudate was not observed under the coating material at the third week of application of the coating material, but the diameter of the skin defect wound was smaller. It was about 20 mm.

Judging comprehensively, the wound dressing having the hyaluronic acid sponge layer laminated thereon can appropriately absorb the exudate due to the presence of the nonwoven fabric layer, so that no exudate is stored under the dressing. The effect of promoting healing by hyaluronic acid was observed.

[0040]

As described above, the wound dressing according to the present invention has the following effects. Since the nonwoven fabric layer 11 is composed of the hydrophobic fiber and the high-absorbency fiber, it can absorb a large amount of wound exudate released from the wound surface, and can remove water contained in the exudate into a desired amount. The exudate is stored between the wound and the wound dressing because it has the ability to evaporate this moisture into the surrounding environment by passing through the wound dressing at a rate to the outer surface of the wound dressing. Nothing. Therefore, the frequency of changing the wound dressing can be reduced, so that the complexity of the operation is reduced, and the labor of the healer can be greatly reduced. When the nonwoven fabric layer 11 made of hydrophobic fiber is laminated on both sides of the nonwoven fabric layer 12 made of hydrophobic fiber and high-absorbency fiber, the dense nonwoven fabric layer 12 is provided on the outer surface of the wound dressing material. This prevents dirt and bacteria from entering the wound surface and prevents the absorbed body fluid from leaking from the wound dressing and soiling the bedding. By incorporating the hyaluronic acid sponge layer, which is a biomaterial, into the wound dressing, wound healing can be promoted. By crosslinking hyaluronic acid, the effect of hyaluronic acid on promoting wound healing can be maintained.

[Brief description of the drawings]

FIG. 1 shows one embodiment of a wound dressing according to the present invention.

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Claims (5)

[Claims] 1. A wound dressing comprising: a nonwoven fabric layer composed of a hydrophobic fiber and a highly absorbent fiber; a nonwoven fabric layer composed of a hydrophobic fiber; and a hyaluronic acid sponge layer. 2. The wound dressing according to claim 1, wherein the basis weight of the nonwoven fabric layer composed of the hydrophobic fiber and the superabsorbent fiber is 30 to 300 g / m ² . 3. The wound dressing according to claim 1, wherein the basis weight of the nonwoven fabric layer made of hydrophobic fibers is 5 to 100 g / m ² . 4. The wound dressing according to claim 1, wherein a nonwoven fabric layer made of a hydrophobic fiber is laminated on both sides of a nonwoven fabric layer made of a hydrophobic fiber and a highly absorbent fiber. 5. The wound dressing according to claim 1, wherein the hyaluronic acid sponge layer has crosslinked hyaluronic acid with an epoxy compound.