WO2003101360A1

WO2003101360A1 - Bandage which is adhesive in moist conditions

Info

Publication number: WO2003101360A1
Application number: PCT/EP2003/005745
Authority: WO
Inventors: Karl-Heinz Woeller
Original assignee: Beiersdorf Ag
Priority date: 2002-06-01
Filing date: 2003-06-02
Publication date: 2003-12-11
Also published as: DE10224420C1; AU2003242603A1

Abstract

The invention relates to a bandage which self-adheres to moist wounds and is based on a polymer film consisting of polyvinyl alcohol and polyacrylic acid. Said bandage based on a polymer film which is self-adhesive in moist conditions comprises a homogeneous mixture of polyvinyl alcohol having a mean molecular weight of between 20,000 and 100,000 g/mol, preferably between 28,000 and 40,000 g/mol, and a hydrolysis degree of between 80 and 95 %, preferably between 85 and 90 %, and polyacrylic acid having a mean molecular weight of between 450,000 and 4,000,000 g/mol, preferably between 1,300,000 and 4,000,000 g/mol, the weight ratio of polyvinyl alcohol to polyacrylic acid in the polymer film being between 10:1 and 1:1. The inventive bandage loses its adhesive force once the wound has healed and thus dried, and then automatically and painlessly detaches itself from the skin.

Description

description

Moist adhesive wound dressing

The invention relates to a wound dressing which is self-adhesive on moist wounds and is based on a polymer film consisting of polyvinyl alcohol and polyacrylic acid. After the wound has healed and the wound has dried out, the wound dressing loses its adhesive force and then detaches itself from the skin without pain.

Films and foils are often used in plasters and wound dressings because of their impermeability to water, their impermeability to germs, their conformability and their high tolerance. However, it is known that a moist wound environment is essential for wound healing and therefore the wound dressings should be permeable to air and water vapor.

Known wound dressings generally consist of a carrier material which is provided on one side with a self-adhesive layer. In most cases, a wound covering is applied to this self-adhesive coating. To ensure easy handling, the self-adhesive coating is also covered with a protective layer, for example a sealing paper. Then individual wound dressings or plasters are punched out of a roll in different shapes and sealed in paper. The punched-out shapes are geometrically regular shapes such as rectangles or circles.

DE 43 14 834 A1, for example, discloses a film-based dressing material which is covered on one side with a backing material which is the same size as the film and has at least one grip strip and which on the other side has a self-adhesive strip. adhesive layer is provided. Such a plaster with polyurethane film is commercially available under the name "Aqua Protect" ® from Beiersdorf. Modern wound care products such as hydrocolloids (see, for example, "Hydrocolloids" by R. Lipmann in "Medical Device & Diagnostic Industry, June 1999), developed for colostomy and professional wound care applications are increasingly used.

Wound care products based on hydrocolloids have advantages over conventional plasters. These generate a moist wound healing environment that does not allow the wound to dry out and creates an optimal environment for rapid wound healing. Further advantages are the unobtrusiveness during use, secure adherence, absorbency of exudate, good cushioning effect and the painless removability.

Contoured wound dressings with an adhesive layer consisting of swellable hydrocolloids and water-insoluble, viscous constituents, for example polyisobutylene, rubber, silicone or polyurethane elastomers, are the subject of WO 92/05755. A problem in the manufacture of these wound dressings is the introduction of polar active ingredients into the mostly non-polar polymer matrices. As a result, preferred active ingredients can sometimes be incorporated into the polymer matrix only poorly or only in a limited concentration. Furthermore, there is a risk that, due to the different polarity and insolubility of the active substances in the polymer matrix, the active substances crystallize out of the polymer system over time. Long-term stability is not guaranteed.

In addition, there is the problem of incorporating substances that promote wound healing into polymer matrices. Since these substances, such as dexpanthenol, inhibit the crosslinking reaction of, for example, polyurethane, it is not possible to incorporate the substances into the polyurethane matrix. As a consequence, these substances are introduced into the ^polyurethane matrix in complex downstream process steps. Foam wound dressings, such as those available from S & N under the names Cutinova ® thin and Cutinova ® hydro, are described in DE 42 33 289 A1, DE 196 18 825 A1 and WO 97/43328, among others.

The flat polyurethane foam with a thickness of 1 to 6 mm is covered on one side by a polyurethane film. Patches of the appropriate size are punched out of the bale goods. The wound dressing produced in this way surprisingly completely detackifies when absorbing wound fluid and does not show the tendency to disintegration with strong swelling known from hydrocolloids, which can lead to residues of the hydrocolloid remaining in the wound.

Other commercially available polymer films for wound covering / treatment are applied in dissolved form and then have to dry on the wound to form a film. These wound dressings are so-called spray plasters. It is disadvantageous that the polymer solution of the spray plaster can smear and / or stick together with clothing or other parts of the body during the drying process. Another disadvantage is that many of the existing polymeric wound covers have to be dissolved in organic solvents for spray application. These solvents cause a subjectively more or less severe burning sensation in the open wound.

Finally, conventional plasters for wound care should be mentioned (for example, the Hansaplast ® classic tissue plaster from Beiersdorf). The low elasticity and the tendency for the backing material to roll up at the edges of the plaster prove to be disadvantageous in the case of mechanical stress with a longer wearing period. In addition, the plaster is heavily moistened with daily personal care or hand washing and loses its adhesive power. Conventional plasters are visually very noticeable, hinder movements or, for example, impair wearing comfort in the shoe.

All known wound dressings based on foils are strongly adhesive on the skin and / or are detackified on a moist surface.

Polymer films are also known which are produced by active polymerization using organic material such as albumin. Such polymer films are all common ^¬ known, such as in WO 00/44808 and references cited therein Druckschrif- These polymer films are produced in bioreactors and are very complex and the feed materials are correspondingly expensive. A particular disadvantage here is the high technical effort involved in production.

Films made from polyvinyl alcohol and polyacrylic acid are also known for packaging purposes. From DE 3148931, films made of polyvinyl alcohol and polyacrylic acid are known which are suitable for packaging purposes and are therefore transparent and mechanically resistant. In order to achieve the properties of the film desired for packaging purposes, polyvinyl alcohol with an average molecular weight of 10,000 to 50,000 g / mol and a degree of hydrolysis of 85 to 90% and polyacrylic acid with a molecular weight of 30,000 to 400,000 g / mol are used. These films are then water-soluble and not sticky.

It is also known that polyvinyl alcohol (PVA) is not fully compatible with most other polymers and therefore does not form completely homogeneous mixtures with such polymers. It is therefore difficult to produce transparent, mechanically resistant and especially sticky films using polyacrylic acid.

It is therefore the task of providing a wound dressing based on film, which adheres to moist ground, in particular to moist wounds, is permeable to air and water vapor, is detackifying on dry ground, is simple and inexpensive to produce and has no unpleasant side effects, such as burning during application or pain caused by redetachment.

This bundle of tasks is surprisingly solved by a wound dressing according to the main claims. The subclaims relate to advantageous embodiments of the wound dressing according to the invention. The invention further comprises the method for producing the dressing and its use.

It was surprising and unforeseeable for the person skilled in the art that a wound dressing based on a self-adhesive polymer film comprising a homogeneous mixture of polyvinyl alcohol with an average molecular weight of 20,000 to 100,000 g / mol, preferably 28,000 to 40,000 g / mol, and one Degree of hydrolysis from 80 to 95%, preferably 85 to 90%, and polyacrylic acid with an average molecular weight of 450,000 to 4,000,000 g / mol, preferably 1,300,000 to 4,000,000 g / mol, the weight ratio of polyvinyl alcohol to polyacrylic acid in the polymer film in the range 10 : 1 to 1: 1 lies, the tasks completely solved.

The wound dressing according to the invention does not have the disadvantages of known wound dressings with polymer films for wound covering / treatment described above. It is a solvent-free matrix system made of the synthetic polymers polyvinyl alcohol and polyacrylic acid, which only adheres to the moist wound area, which, after the wound has healed, can be removed independently and painlessly and is inexpensive to produce using simple technical means. Furthermore, the wound dressing is permeable to air and water vapor.

Wound dressings in which the weight ratio of polyvinyl alcohol to polyacrylic acid in the film is in the range from 5: 1 to 3: 1 have proven particularly suitable.

The moist self-adhesive polymer film can also be equipped with disinfectants or other active substances for wound treatment. For better wound healing, the wound dressing can therefore be doped with pharmaceutical and / or cosmetic active ingredients for continuous release into the wound. Dexpanthenol, chlorhexidine, lidocaine and urea may be mentioned as preferred pharmaceutical active substances, and the groups of flavonoids and sericosides may be mentioned as preferred cosmetic active substances. The proportion of active substances in the wound dressing is advantageously 0.01 to 10% by weight. The active ingredient is introduced into the polymer matrix during polymer formation by known methods.

In the simplest embodiment, the wound dressing can be thin. Foil for physical coverage and / or infection protection can be applied to superficial wet wounds. Due to the transparency of the film, the wound healing process can be observed over time without removing the wound covering without the pain-intensive detachment of the dressing being necessary, as with conventional wound dressings, and a new wound dressing having to be applied. The polymer film can be embossed on one or both sides to increase the internal strength of the wound dressing. Likewise, the polymer film can be made reinforced by an inserted mesh made of synthetic or natural fabric. Suitable fabrics are, for example, cotton mesh fabrics with a mesh size of 1 to 2 mm or a perforated fleece made of 67% viscose and 33% polyester.

In a further embodiment, the polymer matrix is covered on one side with a carrier material (fabric, nonwovens, foams, plastics, etc.) and applied as a composite film. Depending on the carrier material used, the water vapor permeability, the strength of the wound covering, the padding against pressure and other physical properties of the wound covering can be controlled.

The co-decisive advantage of the polymer film is its self-adhesive property on moist ground, which makes an additional application of an adhesive layer on the matrix, for fixing the wound dressing in the area of the skin, superfluous. This leads among other things for an inexpensive and simple production method.

The special property of the moist adhesive property of the wound dressing according to the invention can be explained by the finely divided incorporation of the hydrophilic polyacrylic acid into an only moderately hydrophilic polyvinyl alcohol network. Because of their carboxylate function, polyacrylates according to the invention have a strong charge affinity for water. In the case of superficial injuries to the skin, this moisture, which is necessary for the adhesive properties, is present in the form of exudate and blood, and the wound dressing is thus sucked onto the wound with gel formation. The much lower hydrophilicity of the polyvinyl alcohol ensures an even distribution of moisture in the polymer matrix. Due to the poor gel formation capacity of the polyvinyl alcohol, the strength of the matrix is retained. As soon as sufficient moisture is no longer supplied from the wound due to progressive healing, the proportion of polyacrylic acid gel dries out and the matrix loses its adherence.

Polyacrylates which are advantageous according to the invention are acrylate-alkyl acrylate copolymers, in particular those which belong to the group of the so-called carbomers or carbopoles (car- bopol® is actually a registered trademark of the BF Goodrich Company). In particular, the acrylate-alkyl acrylate copolymers which are advantageous according to the invention are distinguished by the following structure:

R 'represents a long-chain alkyl radical and x and y numbers which symbolize the respective stoichiometric proportion of the respective comonomers.

According to the invention, particular preference is given to acrylate copolymers and / or acrylate-alkyl-acrylate copolymers which are available from the BFGoodrich Company under the trade names Carbopol® 1382, Carbopol® 981 and Carbopol® 5984; polyacrylates from the group of are preferred Carbopole types 980, 981, 1382, 2984, 5984 and particularly preferably Carbomer 2001. The invention also includes conventional wound dressings, the surface of which is equipped with the polymer film described according to the invention. The adhesive / detackifying behavior of the wound dressings of commercially available plasters can thus be controlled. For the production, a corresponding commercially available wound dressing is soaked with the polymer mixture, which still contains water, and only then dried.

In a further embodiment, the optionally active substance-containing polymer matrix can be located between a cover layer firmly anchored to it, also named as a carrier layer, and a removable separating layer. The removable release layer serves to secure the adhesive layer, to improve transport and storage stability and is removed before application to the skin. The polymer matrix can be applied to a carrier layer or film, as is known from the prior art. The carrier film consists of an air and water vapor permeable but water impermeable polymer layer with a thickness of approx. 10 to 100 μm. The possibly flexible carrier film preferably consists of polymers of polyurethane, PE, PP, polyamide, polyester or polyether-ester.

The wound dressing according to the invention, usually in the form of a plaster, comprises a moist self-adhesive polymer matrix according to the invention, an optionally active substance-impermeable backing layer and a removable protective layer which is removed on the skin before application. Additional ingredients such as fillers, stabilizers, enhancers and / or cosmetic additives can be incorporated in the matrix in order to adapt the dressing to the different areas of application and to provide a user-friendly dressing. Finally, the matrix can be covered with an adhesive-repellent carrier material, such as siliconized paper, or can be provided with a wound dressing or padding. On its moist, self-adhesive side, which later turns towards the skin, the dressing according to the invention is usually covered over its entire width with an adhesive-repellent backing material until use. This protects the self-adhesive layer from the matrix, which is well tolerated by the skin and which has preferably been applied using the transfer process, and additionally stabilizes the entire product. The cover can be formed in one piece or preferably in two parts in a known manner.

To produce the moist adhesive film, a film-forming polymer of high cohesiveness, such as Polyvinyl alcohol (Mowiol 18/88; Hoechst) with an average molecular weight of 20,000 to 100,000 g / mol, preferably 28,000 to 40,000 g / mol, and a degree of hydrolysis of 80 to 95%, preferably 85 to 90%, with a gel-forming polyacrylic acid polymer, such as Carbopol 980 from Goodrich, with an average molecular weight of 450,000-4,000,000 g / mol, preferably 1,300,000 to 4,000,000 g / mol, the weight ratio of polyvinyl alcohol to polyacrylic acid being in the range from 10: 1 to 1: 1 ,

Both polymers are dissolved in water as a solvent at 60 to 90 ° C in an agitator, e.g. a kneader, dissolved or swollen and mixed homogeneously with each other. The resulting viscous mass is then spread flat and then dried to form a film.

To change the physical properties of the film, such as the elasticity, appropriate additives such as polyethylene glycol (Lutrol E400; from BASF) etc. can be incorporated during the kneading process. Disinfectants such as chlorhexidine solutions or salts can additionally be incorporated into the matrix as pharmaceutical / cosmetic active ingredients, and dexpanthenol and / or other substances into the matrix as wound healing agents. Thermally sensitive active ingredients, which do not allow incorporation into the matrix at 60 to 90 ° C, can be incorporated by first producing and drying the matrix without an active ingredient. These temperature-sensitive active ingredients can then be dissolved in a hydrophilic medium and absorbed through the matrix. The matrix is then dried again by evaporation of the solvent at room temperature or in a freeze dryer. To adjust a particularly skin-friendly pH value of the moist adhesive polymer film and / or to influence the gel properties of the moist polyacrylic acid, corresponding pH value corrections such as trometamol, triethanolamine etc. can also be incorporated into the matrix.

As an option for production in a kneader, the polymer film can also be produced continuously in an extruder.

Examples

5 (1-V) wound dressings were produced in accordance with the above production method.

The wound dressings based on foils I to III show with increasing proportion of polyacrylic acid with constant cohesiveness and visual appearance an increasingly higher adhesion on moist surfaces. In contrast to the wound dressings I to III, the wound dressings IV and V are additionally doped with disinfectant and wound healing-promoting active ingredients, but they have the same visual appearance, as well as analogous adhesive properties in comparison to wound dressing I. Wound dressing V is additionally equipped with a proportion of plasticizer and therefore , with similar other properties, more flexible to use as a wound dressing IV.

Claims

claims:

1. Wound dressing based on a moist self-adhesive polymer film comprising a homogeneous mixture of

Polyvinyl alcohol with an average molecular weight of 20,000 to 100,000 g / mol and a degree of hydrolysis of 80 to 95% and

Polyacrylic acid with an average molecular weight of 450,000 - 4,000,000 g / mol, the weight ratio of polyvinyl alcohol to polyacrylic acid in the polymer film being in the range from 10: 1 to 1: 1.

2. Wound dressing according to claim 1, characterized in that the weight ratio of polyvinyl alcohol to polyacrylic acid in the film is in the range 5: 1 to 3: 1

3. Wound dressing according to claim 1 or 2, characterized in that the film polyvinyl alcohol with an average molecular weight of 28,000 to 40,000 g / mol and a degree of hydrolysis of 85 to 90% and polyacrylic acid with an average molecular weight of 1,300,000 to 4,000 Includes 000 g / mol.

4. Wound dressing according to one of the preceding claims, characterized in that the film is doped with pharmaceutical and / or cosmetic active ingredients.

5. Wound dressing according to claim 4, characterized in that the film is doped with dexpanthenol.

6. Wound dressing according to one of the preceding claims, characterized in that the film is embossed on one or two sides.

7. Wound dressing according to one of the preceding claims, characterized in that the film is reinforced with an inserted mesh made of synthetic and / or natural tissue.

8. Wound dressing according to one of the preceding claims, characterized in that the film is covered on one side with a carrier material consisting of fabric, nonwovens, foams and / or plastics.

9. wound dressing comprising a conventional wound dressing and optionally an adhesive layer, characterized in that a moist self-adhesive polymer film according to one of claims 1 to 5 is applied to the wound dressing or the wound dressing is impregnated with the homogeneous polymer mixture according to one of claims 1 to 5.

10. Process for the production of a polymer film which is self-adhesive on a moist base by mixing polyvinyl alcohol with an average molecular weight of 20,000 to 100,000 g / mol, preferably 28,000 to 40,000 g / mol, and a degree of hydrolysis of 80 to 95%, preferably 85 to 90%, and polyacrylic acid with an average molecular weight of 450,000 - 4,000,000 g / mol, preferably 1,300,000 to 4,000,000 g / mol, the weight ratio of polyvinyl alcohol to polyacrylic acid being in the range from 10: 1 to 1: 1, in water until homogeneous, then spread and dry.

11. The method according to claim 8, characterized in that the additional pharmaceutical and / or cosmetic active ingredients are introduced into the mixture.

12. The method according to claim 9, characterized in that dexpanthenol is introduced into the mixture.

13. wound dressing based on a moist self-adhesive polymer film obtainable from a process according to any one of claims 9 to 10.

14. Use of a moist self-adhesive polymer film comprising a homogeneous mixture

Polyvinyl alcohol with an average molecular weight of 20,000 to 100,000 g / mol and a degree of hydrolysis of 80 to 95% and Polyacrylic acid with an average molecular weight of 450,000 - 4,000,000 g / mol, the weight ratio of polyvinyl alcohol to polyacrylic acid in the polymer film being in the range from 10: 1 to 1: 1 as a wound dressing.

15. Use of a polymer film according to claim 12, characterized in that the film is additionally doped with pharmaceutical and / or cosmetic active ingredients.