JPS63115563A - Wound cover material - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a dressing for the purpose of treating burns, external injuries, wounds, etc., and particularly to a dressing that has good adhesion to the wound surface, The present invention relates to a wound dressing that prevents the accumulation of exudate during treatment and promotes healing.

(Prior Art) A variety of dressings have been developed for use in treating a wide range of skin damage caused by burns, trauma, wounds, etc. These dressings can be broadly classified into the following three types: It is classified as In other words, (1) tissue pieces such as homogeneous split-thickness cortex pieces, heterogeneous skin pieces, and human amniotic membrane; (2) reconstituted biomaterials such as collagen membranes (nonwoven fabrics) and fibrin membranes; (3) silicone membranes and nylon knitted membranes. It is a synthetic polymer material represented by a layered structure.

(Problems to be Solved by the Invention) However, although the tissue piece (1) is excellent in controlling insensible excretion and preventing leakage of body fluids, it has a strong immunological rejection reaction, and can be covered for a short period of time. Collagen, which can be stably supplied, is mainly used as the reconstituted biomaterial in (2), but this is because it is quickly degraded and absorbed in the body even if antigenicity can be reduced by enzyme treatment. It is not suitable for long-term coating, and since the synthetic polymer material (3) is non-degradable and absorbable in vivo, it has low antigenicity and can be stably supplied and sterilized, but it has poor affinity with living organisms. It has the disadvantage of being generally low.

In order to improve the drawbacks of these dressings for treating skin damage, the present invention is made of polyamino acids with excellent tissue affinity and has a sponge layer and a membrane layer, thereby reducing exudate from the wound surface. It is designed to have the effect of promoting treatment by allowing the absorption of the exudate and its invasion into the tissue, preventing the exudate from accumulating between the dressing and the wound surface, and preventing the invasion of bacteria etc. from the outside. .

(Means for Solving the Problems) That is, the gist of the present invention is to create a sponge layer with a pore size of 20 to 500 μm and a thickness of 1 to 10 mm using polyamino acids, and a sponge layer with a pore size of 20 μm or less and a thickness of 0.5 μm. It concerns a wound dressing formed by providing a membrane layer of ~5μ in a polymeric manner.

The polyamino acids used in the present invention include poly(L
-Leucine), poly(T-benzyl-glutamate), copoly(L-lysine-L-leucine), and copoly(L-lysine-L-glutamic acid), which have excellent tissue affinity. It is more preferable that it can be dissolved in a solvent that can be freeze-dried.

The wound dressing according to the present invention is formed of a sponge layer and a membrane layer using these polyamino acids.

The sponge layer has a pore diameter of 20 μm to 500 μm and a thickness of 1 μm.
It consists of ~10 cranes and is the part that is attached to the wound surface. Therefore, the pores are formed as open cells from the wound side to the side that will be polymerized with the membrane layer, and the pore diameter will be smaller from the wound side to the side that will be polymerized with the membrane layer. is preferred. If the pore diameter is less than 20 μm, tissue penetration and exudate absorption will be poor, while if it is more than 500 μm, the adhesion to the wound surface will be poor and exudate will be likely to stagnate, which is unfavorable for wound healing. In addition, if the thickness is less than 1 inch, tissue penetration and exudate absorption will be insufficient.
If it is 10 mm or more, the handleability becomes poor, which is not preferable in any case.

The membrane layer has a pore diameter of 20 μm or less and a thickness of 0.5 μm to 5 μm. The membrane layer is the outer surface of the present wound dressing, and primarily has the role of preventing bacteria from entering the wound from outside.

Therefore, if the pore size is 20 μm or more and the thickness is 0.5 μm or less, the function will not be sufficient, and if the thickness is 5 μm or more, the water vapor permeability, oxygen permeability, etc. to the wound area will tend to be insufficient, which is not preferable.

The wound dressing according to the present invention can be produced by, for example, injecting a poly-α-amino acid solution into a predetermined container, gelling it at room temperature, drying the surface with warm air, and then rapidly cooling and freezing it. By vacuum drying, a wound dressing material having a membrane layer on the surface and a sponge layer on the surface in contact with the inner layer and the bottom of the container is obtained.

This wound dressing material obtained in this way absorbs exudate, forms fibrin, and obtains primary biological adhesion with the wound surface, followed by secondary biological adhesion due to the invasion of fibroblasts and capillaries. This contributes to early healing.

(Example) The present invention will be further explained below based on Examples.

Example 1 N-carboxylic anhydride of L-leucine is dissolved in benzene and polymerized using triethylamine as an initiator. A benzene solution of poly (L-leucine) (concentration 0.5 g) was obtained by dissolving this poly (L-leucine) in a benzene solution.
/j) 30ml/t was poured into a 10cm x 15cm aluminum container. Since the polymer solution becomes solid at room temperature, it was heated to 70° C. and injected as a homogeneous polymer solution. After gelling the polymer solution at room temperature, only the surface of the polymer gel was dried with warm air at about 50°C. After increasing the polymer concentration in the gel by evaporation of benzene, it was rapidly cooled and frozen at -30°C, and the wound dressing material according to the present invention was obtained by freeze-vacuum drying. This wound dressing is composed of a sponge layer and a membrane layer, and the thickness of the sponge layer is approximately 2.4 V.
In case a, the pore diameter is 300 to 400 on the outer surface on the wound side.
The area in contact with the membrane layer is approximately 50 to 100 μm.
The present wound dressing was evaluated using rats aged 6-8 weeks. A full-thickness skin lesion (3 cm x 2.5 cm) was surgically created on one side of the rat's back, a wound dressing was sutured, gentamicin ointment was applied to the surrounding area, a telefaft was sutured, and it was bandaged with an elastic band. did.

When the wound surface was covered and protected for 4 weeks, the covering material and the surrounding tissue were excised together, and histological examination using 10% hematoxylin and eosin staining revealed that tissue had invaded the sponge. , the appearance of foreign body giant cells was weak, and good biological adhesion was observed. In addition, new tissue enriched with capillaries was formed in the lower layer of the sponge. The coating was removed to reveal a good tissue surface with slight bleeding.

The surface of the covering material was in a slightly dry state, and it is judged that control of unnatural excretion was maintained.

Example 2 30n aqueous solution of copoly (L-leucine-cy-lysine)
/! , I Q cm Treated for 24 hours at °C,
After the intermolecular crosslinking reaction, a water-insoluble sponge was prepared by thoroughly washing with acetone and sterilized with ethylene oxide gas to obtain a wound dressing according to the present invention.

The thickness of the sponge layer of this wound dressing material is approximately 2 mm, and the pore diameter is approximately 300 to 400 μm on the outer surface facing the wound and approximately 50 to 100 μm in the portion in contact with the membrane layer. Similar to No. 1, the pore size decreased from the wound side to the membrane layer.

Further, the thickness of the film layer was approximately 10 μm.

Regarding the wound dressing material according to this example, an intermolecularly crosslinked sponge (area 1 (7 nm, thickness 3 nm)) was implanted subcutaneously on the back of a 5-week-old rat, and evaluated based on the presence or absence of a biological reaction after 4 weeks. A tissue specimen was prepared in the same manner as in Example 1, and when the cross section was observed after staining, no encapsulation of general tissue was observed at the edge of the sponge, and fibroblasts and capillaries appeared at the bottom of the sponge. was.

Example 3 Poly(γ-benzyl monoglutamate) in dioxane solution (concentration 0.5 g/a>30nj!) in 10×15
The wound dressing material according to the present invention was obtained in the same manner as in Example 1 by injecting the solution into a ca+ aluminum container. The thickness of the sponge layer of this wound dressing is approximately 3 μm, and the pore diameter is approximately 300 to 450 μm on the outer surface, which is the wound side, and 50 μm on the part in contact with the membrane layer.
The thickness of the film layer was approximately 15 μm.

This wound dressing material was also evaluated using rats in the same manner as in Example 1.

When this wound dressing was applied to a full-thickness defect in the back skin of a rat for 10 days, the structure of the adhesion to tissue and the outer surface of the sponge were observed using a scanning electron microscope, and it was found that tissue had invaded the inside of the sponge. A fibrin structure was observed on the outer surface.

Comparative Example 1 Using the benzene solution of poly(L-leucine) used in Example 1, a wound dressing was prepared in the same manner as in Example 1, except for drying the surface with warm air at approximately 50°C. Created. This wound dressing had no membrane layer and was entirely made of a sponge layer. The thickness was 2.51 m, and the pore diameter on the wound side was 300 to 400 μm ◇ Comparative Example 2゜The benzene solution of poly(L-leucine) used in Example 1 was cast into an aluminum container. After gelation at room temperature, the whole was dried with warm air at about 50°C.

After drying, rapidly freeze to -30°C, freeze-vacuum dry,
A wound dressing was obtained. This wound dressing had no sponge layer and was entirely formed from a membrane layer. The thickness was 11.

Example 1 was also applied to the wound dressings obtained in Comparisons 1 and 2.
When evaluation was conducted using rats in the same manner as in Comparative Example 1, it was found that the covering material of Comparative Example 1 was able to capture the upper surface more easily.
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In addition, the covering material of Comparative Example 2 does not have biological adhesion;
Exudate remained and no new tissue was observed.

This is thought to be due to the lack of a sponge layer, which prevents tissue from penetrating, resulting in poor adhesion to the living body, and poor absorption of bodily fluids, resulting in the fluids remaining on the wound surface.

(Effects of the Invention) As explained above, the wound dressing material according to the present invention has a sponge layer with a predetermined pore size and a predetermined thickness, so that exudate can be effectively absorbed and primary biological contact with the wound surface can be achieved. In addition, the membrane layer has a predetermined pore size and thickness to control insensible evaporation through the permeation of water vapor and to prevent external infiltration. It has the characteristics of preventing the invasion of bacteria and effectively contributing to early healing.

Claims (1)

[Claims] 1. A sponge layer with a pore size of 20 to 500 μm and a thickness of 1 to 10 mm and a membrane layer with a pore size of 20 μm or less and a thickness of 0.5 to 5 μm are formed in a polymerized manner using polyamino acids. wound dressing.