CS233752B1 - Absorbing wound cover - Google Patents

Abstract

used to cover heavily exuding infectious wounds, such as affected areas in the case of skin and tissue infections. The wound dressing should be non-toxic and compatible with tissues, well adaptable to the shape of the wound and easy to remove, should protect against infection, accept in addition to exudate also bacteria, fungi, toxins, proteins and inflammatory mediators, should be sterilizable and additionally sterilizable as well as should support granulation and epithelialization. The absorbent wound dressing consists of spherical particles of regenerated cellulose with a diameter of 0.05 to 0.5 mm, which are optionally impregnated with therapeutically active substances, then dried while maintaining the macroporous structure, optionally sterilized with gamma rays and applied to the wound in a layer 2 to 5 mm thick. The possibilities of using the invention are in the field of healthcare.

Description

The present invention relates to an absorbent wound cover which is used to cover heavy wet-wound infectious wounds, as well as affected areas in skin and tissue diseases, and to a method for its manufacture.

In the aforementioned problems and in recent years, in addition to the powders established in many years of pharmaceutical practice, composite powders have been found to be particularly suitable, consisting mainly of bactericidal, possibly bacteriostatically active substances and a base such as talc, lactose, starch and the like. i synthetic polymers and copolymers, among others chitin and chitose (KIT Ses Grant Rap. MITSG 1978, Proc. Int. Conf. Chitin / Chitoean 1977,

Col. (belg. Patent 856,603), cross-linked dextrans (e. G. S. Jacobason et al., Scand J. Plast. Reconetr. Surg. 10 (1976) pp. 65-72); derivatives (e.g., hol. p. 6,807,540), polypropylene (Sv. Patent 472,894), soft polyurethane foams (e.g. H. Bohmert, Med. Welt 28 (1977) P. 826-831, S. Klene, Dt. Gesundh.-Wesen 34 (1979) pp. 2,010-2,014, W. Kothe et al., Medizin ektuell-10 (1979) pp. 452-453), cellulose-acrylic acid copolymers (British Pat. 1). 141 271) as well as copolymers of vinyl esters and unsaturated carbonic acids (DOS 2 653 135) · They are used either alone or as carriers with active substances, e.g. They also recommend the treatment of Acne vulgaris and Fsoriasis.

Among the materials used mainly in the absence of the active substance, crosslinked dextrans and soft polyurethane foams, the latter in particular as so-called synthogrefts, have proved to be suitable. These nontoxic and tissue-tolerant and biologically inert materials have a relatively coarse porous structure which makes them capable of receiving water in an amount corresponding to several times their own weight.

When applied to wet infectious wounds, they exert an excellent effect on their cleansing and reduction of infection, removing exudate, bacteria, fungi, inflammatory mediators, toxins and their degradation products from the wound surface. Since these materials can absorb proteins, including the cleavage products of the fibrin-fibrinogen system, simultaneous scab formation is avoided. On the other hand, granulation and epithelization are promoted.

Against the positive effects of crosslinking dextrans and polyurethane soft foams, some of their drawbacks that limit their use need to be considered. So for water absorption, resp. Exudate occurs relatively slowly in cross-linked dextrans. They swell on the gel-like layer, inside which the gas permeability is reduced.

Covers made of polyurethane soft foam must be trimmed according to the shape of the wound, as otherwise they do not adhere sufficiently and as a result the wound cleaning is severely reduced: there must be no interference with the healthy wound area. In addition, covers of this kind must also be replaced very often, preferably every twelve hours, since otherwise the granulations will ingrow into the material and can only be separated from it by bleeding on large areas accompanied by pain.

It is an object of the present invention to provide a wound dressing which exhibits the beneficial effects of crosslinked dextrans and polyurethane soft foams, while at the same time overcoming the aforementioned drawbacks, in particular a non-toxic tissue-friendly dressing.

- in addition to clean coverage and thus protection against infection, removes exudate rapidly and with respect to the patient from heavily wet wounds Gently, in addition to exudate, it also removes bacteria, fungi, toxins, proteins and inflammatory mediators,

- when absorbing water or exudate, it does not swell onto the gel-like layer, is sterilizable and additionally sterilizable, promotes granulation and epithelization

The object of the invention is to provide a cellulose-based wound dressing which is biologically inert, i.e. non-toxic and tissue-tolerant, and exhibits the aforementioned properties.

The present invention provides an absorbent wound cover comprising spherical particles of regenerated cellulose. These spherical particles preferably have a diameter of 0.05 to 0.5 mm, in particular 0.05 to 0.3 mm. The spherical particles preferably have a mecroporous structure which already exhibits apparent pores in the dry state.

The absorbent wound dressing of the present invention is prepared by drying spherical portions of regenerated cellulose to less than 1.5 mL of water / g to maintain dry wicking, then collecting a 0.05 to 0.5 mm particle size fraction and removing with mechanical impurities.

The cellulose particles are preferably additionally impregnated with the therapeutically active agents in dissolved form, then preferably packaged in containers and sterilized by gamma rays.

The classification is carried out, for example, by sieving, for example a shaking, oscillating or vibrating screen. Mechanical impurities can be removed by air separators or magnetically in drum separators. Suitable containers are glass, plastic or metal containers.

For the production of the absorbent wound cover according to the invention, regenerated celluloses produced according to U.S. Pat. No. 172 640 (pearl cellulose).

The porous structure ensures that the wound cover can absorb secretions from the wound in an amount of 1.5 to 5 g HgO / g dry matter: while the granular microstructure remains largely preserved, so that the material applied to the wound in the form of a powder is 2 to 5 mm thick. especially 2 to 3 mm, can be rinsed again with no water and almost painless.

While the aqueous exudate is mainly absorbed into the macropores in the cellulose particles, the capillary forces acting in the space between the particles also remove bacteria, fungi, toxins, proteins and inflammatory mediators from the wound surface. The exudate is absorbed more rapidly than cross-linked dextrans, since the cellulose particles do not have to swell.

In the following, the invention is illustrated by the following examples, which describe the manufacture of a wound dressing and its impregnation with an active agent.

Example 1 »

100 g of pearl cellulose (regenerated cellulose in the form of spherical particles produced _from by MS. AA. 172640, is classified to an oscillating or vibrating sieve fraction of particle size 0.05 to 0.3 mm is freed sifter or magnetically in a drum mechanical impurities separator, airtight closes in a container of glass, plastic or metal and sterilizes the rays of gema.

Example 2 g of bead cellulose according to example 1 are washed successively with 500 ml of a 1% ethanolic bacitracin solution and 500 ml of diethyl ether and dried under vacuum at room temperature to constant weight. In this process, an antibiotic on porous bead cellulose in an amount of 45 mg / g dry matter, i.e. 2,300 international units, is eliminated.

Claims (4)

An absorbent wound cover, characterized in that it consists of spherical particles of regenerated cellulose with a diameter of 0.05 to 0.5 mm, preferably 0.05 to 0.3 mm, having a macroporous structure. OF THE INVENTION 2. A method according to claim 1, wherein the spherical portion of the regenerated cellulose is dried to maintain its absorbency in a dry state with a flow rate of less than 1.5 ml of water / g, whereupon a particle size fraction of 0.05-0. 5 mm and get rid of mechanical impurities. 3. The method of claim 2, wherein the cellulose particles are additionally impregnated with the therapeutically active agents in dissolved form. 4. A method according to claims 2 and 3, characterized in that the cellulosic particles are wrapped in containers and sterilized by gamma rays;