IE50513B1

IE50513B1 - Covering device for skin treatment based on a gel-type polymer

Info

Publication number: IE50513B1
Application number: IE2367/80A
Authority: IE
Original assignee: Hoechst Ag
Priority date: 1979-11-17
Filing date: 1980-11-14
Publication date: 1986-04-30
Also published as: DE2946553A1; NO803437L; EP0031018A1; ATE6344T1; IE802367L; JPS5683355A; EP0031018B1; NO152319C; NO152319B; DE3066719D1

Abstract

1. Covering device for skin treatment, in particular for the treatment of burns, wounds and skin lesions, comprising a selectively permeable membrane layer with an adjoining watercontaining gel formed from a polymer, wherein a flat membrane tube which is permeable to water vapour and gases and is sealed at its ends and has pores an average size from 3 x 10**-4 to 10 mu m, contains in its cavity a readily deformable and readily flowable mass of a polymer gel, which has a high content of water relative to its total weight.

Description

The present invention pertains to a covering device for skin treatment, and more especially to a covering device for use in treating burns, wounds and skin lesions. This skin covering device is based on a gel-type polymer.

For the therapy of large-area wounds, for example in the case of serious burns, there are extremely diverse and in part contradictory properties and characteristics demanded from the covering material. The hitherto known devices possess these properties and characteristics only to an inadequate extent. For example, the covering material should, on the one hand, be suitable for the absorption of the fluids exuded from the wound, but should, on the other hand, keep the water losses or protein losses of the patient at a minimum. It should permit heat exchange and gas exchange with the skin, but at the same time prevent access of bacteria and viruses. It should be possible to change it with as little pain as possible; however, it should stimulate 2o granulation of the skin by means of a moist medium and make it possible to dilute exuded material and toxins by supplying water. Furthermore, it is necessary that me'di'canfeii't'S can be applied epicutaneously.

For this reason, natural materials, such as pig skin cr autologous transplants are generally used in practice for the treatment of wounds, for example, in the case of severe burns, although only after removal of the necrotic tissue. Although transplants are preferred to pig skin, they are likewise not applicable in the first phase of wound sanitation, namely, for cleaning the wound. Moreover, they are usually not available in the required amount.

For the treatment of wounds and in dermatology it is also known to use crosslinked, gel-type polymers, that is to say, water-containing polymer compositions, such as, for example, crosslinked polyacrylamide gel or agar gel. These polymer compositions are, however, very difficult to prepare in a continuous manner in the form of layers or film-like structures and, additionally, they have serious defects in clinical use since they can only be handled with complications.

It is therefore an object of the present invention to provide an improved skin covering device.

It is a further object of the invention to provide an additional, improved agent, based on gel-type polymers, for skin treatment, in particular for the treatment of burns, wounds and also skin lesions and dermatological problems.

It is a particular object of the invention to provide such a skin covering which enables the treatment of certain skin injuries, for which the conventional covering devices are less suitable.

In accomplishing the foregoing objects, there has been provided in accordance with the present invention a covering device for skin treatment, including treatment of burns, wounds and skin lesions, comprising a selectively permeable membrane in the form of a tube sealed at its ends, said membrane being permeable to water vapour and gases and -4 Having an average pore size of 3 x 10 to 10 wn, and a readily deformable and readily flowable mass of a polymer 0513 gel, which has a high content of water relative to its total weight contained in the cavity of the tube. In one preferred embodiment, the device further comprises a film of material adjacent to the membrane in such a way that the membrane, together with the film, forms a cavity which is adapted to receive a therapeutically active agent.

Further objects, features and advantages of the invention will become apparent from the detailed description of preferred embodiments which follows, when considered together with the attached drawing.

A covering device based on a gel-type polymer is provided for skin treatment, in particular, in the case of burns and wounds. This device comprises a gel-type polymer which is completely enclosed by a membrane which is permeable to water vapour and gas.

The term gel-type polymer is hereby defined as a dimensionally stable, readily deformable mass of polymer which has a high content of water relative to its weight.

The membrane which is permeable to water vapour and gas, is a membrane having an average pore size in -4 the range from about 3 x 10 to 10 pm and comprises, for example, regenerated cellulose (e.g., described in German Auslegeschrift No. 2,736,569) or an asymmetrical plastic membrane of polyamide (e.g., described in German Auslegeschrift No. 2,751,910) or a polycarbonate (e.g., described in German Offenlegungsschrift No. 2,510,337).

These membranes have hitherto been used for dialysis -3 -2 (pore size 10 to 10 um) or hemofiltration, and they have a thickness from about 10 to 150 nm. The membrane has a two-dimensional form. It possesses the form of flattened tubing which is sealed or closed at its ends, for example, in the form of a bag which surrounds all of the gel-type polymer.

The gel-type polymer is readily deformable or capable of flow (semi-solid), in contrast to the self-supporting polymers or gels hitherto uses in the treatment of wounds. The solid or non-liquid portion thereof consists, for example, of a cellulose ether or a starch ether, in particular of hydroxyethylcellulose, carboxymethylcellulose or methylcellulose or a corresponding starch derivative. Other suitable cellulose ethers are alkyl hydroxyalkyl ethers, alkyl carboxymethyl ethers, hydroxyalkyl carboxymethyl ethers and alkylhydroxyalkyl carboxymethyl ethers.

Examples of further suitable gel-type polymers are gels based on acrylic acid and methacrylic acid or derivatives of these, and on polyvinylpyrrolidone, polyvinyl alcohol, agar or agarose.

It is, however, also possible to use chemically modified cellulose ethers, such as are described in German Offenlegungsschriften No. 1,912,740, No. 2,357,079, No. 2,358,150 and No. 2,519,927.

Cellulose ethers modified with compounds containing monovalent, divalent or trivalent ions are also suitable gel-type polymers.

Depending on the intended use, the layer thickness of the gel-type polymer can vary within wide limits, but it is advantageously from about 1 to 5 mm. When a device with a transparent gel-type polymer and a transparent membrane is used for the treatment of skin injuries, the healing process can advantageously be monitored and checked visually.

In a further embodiment, the membrane is con10 nected to a reservoir for medicaments. This reservoir is formed, for example, by a liquid-tight film which covers the membrane on the side remote from the skin to be treated and, together with this membrane, forms a cavity. The surface of the membrane adjacent to this cavity is optionally covered with a liquid-tight film having apertures or predetermined break points, which are opened only immediately before use of the covering device. For.example, a bactericidal or therapeutically active solution is filled into this cavity, and this solution passes through the membrane into the gel-type polymer, from which it reaches the skin area which is to be treated. This reservoir thus makes it possible to rapidly fill and/or to continuously replenish the covering device with liquid and medicaments. The dosage rate is here controlled by the nature and pore size of the membrane. It is also possible to mix the gel-type polymer with the therapeutically active solution already at the time when it is filled into a membrane tubing.

The covering device according to the invention achieves the initially stated objects. It can also be produced in an economical manner and is simple to handle in clinical use.

The invention is explained with reference to a drawing conprising three figures. In the figures of the drawing particular embodiments of the invention are schematically shovn in section.

Figure 1 shows a particularly preferred embodiment of the invention consisting of a membrane tubing 1 and a water-swollen gel-type polymer 2.

Figure 2 shows another embodiment of the inven5 tion for special applications, having a reservoir for a therapeutically active solution and consisting of a membrane tubing 1, a water-swollen gel-type polymer 2, an impermeable barrier film 3 and a therapeutically active solution 4.

Figure 3 depicts a further embodiment for special applications, having a reservoir for a therapeutically active solution and consisting of a membrane tubing 1, a water-swollen gel-type polymer 2, an impermeable barrier film 3, a therapeutically active solution 4 and a liquid-tight film 5 with predetermined break points.

Claims

CLAIMS:

1. A covering device for skin treatment, including treatment of burns, wounds and skin lesions, comprising a selectively permeable membrane in the form 5 of a tube sealed at its ends, said membrane being permeable to water vapour and gases and having an average pore size of 3 x 10 to 10 ym, and a readily deformable and readily flowable mass of a polymer gel, which has a high content of water relative to its total weight con10 tained in the cavity of the tube.

2. A covering device as claimed in Claim 1, wherein the closed membrane tube has the shape of a tubular bag.

3. A covering device as claimed in Claim 1 or 2, wherein the material forming the tube and also the mass of polymer gel are transparent. 20

4. A covering device as claimed in any one of Claims 1 to 3, wherein the readily deformable and readily flowable mass of polymer gel comprises a polymer selected from: a carbohydrate or a derivative thereof, polyvinylpyrrolidone, polyvinyl alcohol or polyacrylic or polymethacrylic acid 25 or a derivative thereof.

5. A covering device as claimed in any preceding Claim, further comprising a film of material adjacent to said membrane in such a way that the membrane, 30 together with the film, forms a cavity which is adapted to receive a therapeutically active agent. S0513

6. A covering device according to Claim 1, substantially as hereinbefore described with reference to and as illustrated in figures 1 to 3 of the accompanyind drawing.