WO2012122956A1

WO2012122956A1 - Antimicrobial mixture and a covering supporting wound healing, having an antimicrobial activity

Info

Publication number: WO2012122956A1
Application number: PCT/CZ2012/000021
Authority: WO
Inventors: Zuzana Valentova; Sarka DUSKOVA; Michal ZAVADIL; Veronika HEKRLOVA; Vladimir Velebny; Lubos Sobotka
Original assignee: Contipro Pharma A.S.
Priority date: 2011-03-11
Filing date: 2012-03-01
Publication date: 2012-09-20
Also published as: JP3196712U; DE212012000057U1; FR2972355A3; DK201300152Y3; FR2972355B3; DK201300152U1; ITMI20120370A1; BR112013023201A2; AT13850U1; CZ22394U1; HU4499U; RU149063U1; AR088721A4

Abstract

The invention relates to an antimicrobial mixture for healing of superficial wounds based on a physiologically acceptable hyaluronic acid salt, optionally with one or more other polysaccharides, and a compound having an antimicrobial activity, which can be used for healing of superficial wounds, especially chronic wounds, for example varicose ulcers, and to a covering which contains said mixture.

Description

Antimicrobial mixture and a covering supporting wound healing, having an antimicrobial activity

Field of the Invention

The invention relates to a mixture for healing of superficial wounds based on a physiologically acceptable hyaluronic acid salt, optionally with one or more other polysaccharides, and a compound having an antimicrobial activity, which can be used for healing of superficial wounds, especially chronic wounds, for example varicose ulcers, and to a covering which contains said mixture.

Background of the Invention

Wound healing, especially anomalous wound healing, is a complicated process, which can be supported by a covering providing adequate healing conditions and/or containing active compounds. Anomalous wound healing includes conditions of excessive wound healing (such as fibrosis, adhesions and contractures), or, what is more frequent, insufficient wound healing (such as chronic varicose ulcers or diabetic wounds). Despite many recent significant advances in the field, anomalous wound healing still represents the cause of high costs, sickness rate and mortality; This all stresses out the importance of providing an optimal environment for wound healing which can positively influence the healing process (Stephanie R. Goldberg, Robert F. Diegelmann: Wound Healing Primer, Surgical Clinics of North America, Volume 90, Issue 6, December 2010, p. 1133-1146).

A brief review of the literature dealing with the topic of wound healing is presented for example in the publication of James R. Hanna, Joseph A. Giacopelli: A review of wound healing and wound dressing products, The Journal of Foot and Ankle Surgery, Volume 36, Issue 1, January-February 1997, p. 2-14. The authors discuss especially the importance of an appropriate wound covering which ensures the optimal environment for wound healing. It is described that modern coverings visually consist of more than one layer and that the contact layer has the greatest influence oh healing.

There are lots of commercial products on the market nowadays which, however, do not sufficiently fulfill the important requirements imposed on wound coverings or the production costs are high, and therefore, the mass employment is limited. Usually, various gel-forming natural or synthetic substances which are able tb regulate moisture are used. But these substances mostly only regulate the moisture within the wound and do not support self- regeneration ability of the body. Moreover, the application of such substances reduces gas permeability, and therefore, the respiration of the wound is blocked. Infections are eliminated by applying disinfecting agents before the bandage is applied, which means that the disinfecting effect is only for a short-term. These wound coverings cannot be applied to chronic wounds because there is the risk that the moist environment can promote infection multiplication and thereby significantly deteriorate the condition of the patient.

Many patents and publications describe the application of hyaluronan as the main component of wound coverings but due to the expensiveness these formulations are not commercially used very much. Therefore, the practical use of hyaluronan remains aimed only at intra-somatic (intra-articular injections), optionally at special applications (ophtalmology, eye drops for eye surface humectation for patients with contact lenses).

Commercial application of hyaluronan is illustrated by the preparation based on hyaluronan combined with another active substance described by U.S. Patent 4736024'. The product is designated especially ^; foV ophtalmology^* and the pharmacolbjgieall ¹ active substances used include for example¹ kariamycin, neomycin';¹ tetracycline,

combinations thereof.

^{1 ; : , ;} U:S. Patent 5128136 'de^cribeis a¹ preparation'' ¹ used ⁰ for prevention of wound dehydration and infection, i:e:'fbr a similar purpose as uie'pfesented preparation. However; in the contrary to the preparaii0h÷accdrdirig to the invention" ^' it contains soluble coll gen as the main component which does' hot¹ affect' the wound healing, and it does not contain hyamrc c acid or salts thereof. The disadvantage' of the U.S. Patent 5128136 is that collagen can' cause undesirable reactions, such as inflammation. Another disadvantage is that after the application the liquid transforms its phase' into a solid gel which blocks the gas permeability¹.' '

Subiect-matter of the Ιη ΐ¾6'η \

| - ^ ^' T ^ the existing' cbm Ositions^' S^

fieialihl ' are 'eliminated by the mixture according to the invention, comprising a physiologically¹ acceptable H alu ohic^ substance' ¾el8cteir from the⁾ group ' comprising octen½^ benzalc0 urrf¹ nldfid^, benzalcdhium bromide, ^; ' ' chlorhexidirie, hibitane,^'■

catbethbpendecinium bromidey cetylfrimethylammoriiun ' · bromide and a rhix^iire 'thereof ^! iri aiiy ratios. The mixture can further' comprise one or rriore' polysacchsirideS selected ir the group dmprisirig native dr modified polysaccharide^'s ^ahyalw^

'chifd^'San,¹ ^ttc^e,''dg^^_>'^^o∞_>^-^Ll--3-glucane ai d^'a riixture thereof; and optionalIy also an adjuvant increasing antimicrobial effect, for example a chelating agent such as EDTA, bet^iine and 2-phenoxyemanoJ>¾¾¾e i¾ijixture_. can optionally comprise also a saccharide selected from the group comprising¹; glucose, fructose and saccharose, and/or an electrolyte selected from the group comprisingySfidium chloride, ¾¾fesjium chloride, potassium iodide, magnesium chloride, sodium- : hydrogen phosphate, sodium dihydrogen phosphate, zinc sulphate, and/or a plant extract i^* another natural product selected from the group comprising bee propolis, olive oil, tea tre;eKoil, extract from oak tte§,rjcalendula, mint or citruses, or a mixture of any combination of said substances.

The mixture according; 'to the invention preferably comprises hyaluronan and octenidine dihydrochloride as the antimicrobial substance, preferably in the weight ratio of 500:1.

mixture is preferably a layer of polysaccharide fibres coifiairiing an antimicrobial substance in the structure thereof.

Furthermore, the invention "relates to the covering' for supporting the wound healing which is in the form of a single-layer or multi-layer formation. The multi-layer formation comprises layers arranged in the following manner in the direction from the wound: the contact layer (K), which is provided^ on one side which is 'to be in contact with the wound, with the coating (P) made of polysaccharides with an antimicrobial substance, i.e. made of the above-mentioned mixture accordin Ϊ6 the invention (file' chemical or the physical mixture), then one or more absorption layers Pand the surface layer (R). Therefore, the lower, contact layer (K) contains at one (lower) side' destined to be contacted with the wound, the coating (P) made of the mixture of polysaccharides with an antimicrobial substance, and the other (upper) side is abutted by one or more absorption layers (A, of ^;¾ Ty A-2 etc.). The upper side of the last upmost absorption layer which is the most distant from the wound abuts to the surface layer (R). All layers can be welded together at the edges, forming the so-called tea bag having the dimensions of for example 10 x 0 cm. In case of the one-layer covering, the formation consists only of the contact 'layer (K) having the coating (P) made of the mixture of polysaccharides with an antimicrobial substance, wherein the contact layer (K) can be composed of fabric with a high^' absorption capacity (it can be a superabsorbent too). The contact layer is preferably made from woven or knitted fabric made of polyamide (PAD) monofilaments, optionally . of staple fibers; from non-woven fabric or a porous membrane, polyurethane, polyester, viscose, mixtures of said fibers or other materials, for example synthetic fibres like polypropylene. The coating (P): can be preferably in the form of a lyophilizate or a dried coating_s more specifically in the form of a lyophilized or dried layer of the chemical mixture or a layeri of the physical mixture. The absorption layer or absorption layers (A) are preferably made /from materials selected from the group comprising polyester, viscose, polyamide, polyethylene,¹ polypropylene, polysaccharide, for example xanthan or cellulose derivative, superabsorption material, a combination of woven or non-woven textile fibres and superabsorbents, or , a mixture of said materials. In case of more absorption layers (A), it is preferred to arrange; them in such a way that the absorption capacity gradient increases in the direction from th ;¾ound, e.g. the absorption layer (A-l) close to the wound is made from 100% polyester and the absorption layer (A-2) further from the wound is made from polyester and viscose mixture 1 :1. The surface layer (R), preferably prepared from non- woven polyester fabric, can optibiially have an antimicrobial modification by means of impregnation by a suitable antirnibrobial substance or . by means of antimicrobial fibres content, for example obtained from bamboo, or by means of silver micro-particles content.

The coating (P) can be composed of a layer of precipitated fibres of polysaccharide, coated with a layer of an antimicrobial substance solution, wherein the amount of the polysaccharide coating is at least 0.1 mg/m² and the amount of antimicrobial substance coating is at least 0.0001 mg/m . If hyaluronan is used as the polysaccharide and octenidine dichloride is used as the antimicrobial substance, then the' amount of the hyaluronan coating is within the range from 1 to 50 g/rn² arid the amount of the Octenidine dihydrochloride coating is within the range from 0.001 t ^* .5 g/m². The most preferred amount of the hyaluronan coating is within the range i from 5 to 20 g/m² and the amount of the octenidine dihydrochloride coating is withift ttie raiige from 10 to 40 mg/m².

The contact layer (K) arid the surface layer (R) can be attached together by the borders thereof, in order to close the abspi tion layer or absorption layers (A) between the contact layer (K) and the surface layer (R), e.g. the borders of the contact layer (K) and the surface layer (R) can be welded together.

Brief Description of the Drawings

Figure 1 represents a cross Election of the covering, the lower side being the contact layer K composed of 100% polyamide with the coating P of the mixture of polysaccharides and the antimicrobial substance, then the first absorption layer A-l composed of 100% polyester, the second absorption layer A-2 composed of a mixture of 50 % polyester and 50 % viscose and over this, the surface layerR composed of 100% polyester. The layers K and R are welded together like a "tea bag", inside of which there are absorption layers instead of tea.

Figure 2 represents a view of the covering area from the direction from the polysaccharide coating. The border S is formed by a weld (the layers marked as K a R in Figure 1 are welded), part N is the coating composed of the mixture of the polysaccharides and the antimicrobial substance.

Figure 3 represents a graph showing the effectivity of wound healing on a healthy rat model, where the healed area of the wound was measured versus the healing time, using the covering of Example 1 and using a bandage consisting of a gauze without any preparation

time, u^ft g me-c vering ¾f Exa ple l⁵ a¾!d usin a ebn1rol¾ana¾^

made tfW same* ' abric n¾ateriais,^ubut^! 'without^''^

6f t ^e^^¾ iti h-^'6f^^im lie 1 and the control bandage (see the description relating to Figure 4 ori a Miiiature 'pig'model.

n^: Fig ire^' represents a graph showing the antimicrobial¹ effect^' preparation¹ of Example T and the control ftaridage ^"(see the descriptiori* efatiiig 16 Figure 4) ^soh^! rtfds h'¾ miniature pig model.

Examples

Example 1

Covering ith^'hyaluroriah,

l bphilized

Octenidine dihydrochloride (10 mg) is dissolVe^'d iri 1 ml of absolute etha¾0l,^c theri 30 j l^cof this solution is takeh' to 10 till^' with sterile waters for injections. Sbdium hyalurpnafl (150 mg) with molecular Weight 1 650 000 g/mol is gradually added to this solution while stirring 'and is stirred for 12 hoUrSi The resulting viscods 'solution is uniforml applied ½ΐη^ a template having the width of mm and the hole of 10 x 1Ό Cm on the Βηρρϋή ^ήο (οόήίΑά layer)' having the dimension of 13 x 13 cm, the support fabric being a 40 g/m² knitted lattice made of monofilaments of 22 dtex polyamide "M". The contact layer with the applied coating attached to a suitable support, is immediately freezed . to -70°C and then transferred into Iyophilizer (the coating must stay frozen) and lyophilized. The resulting spongy porous elastic lyophilizate of white colour firmly sticks to the contact layer, partly it is within the material of the fabric, but the major part of the deposited material is on one side of the fabric. The contact layer is placed in such a manner that the lyophilizate is in contact with the base where it lies, for example with the table or the frame on which the fabric is stretched (i.e. the major part of the coating is directed towards the base), and a square of 10 x 10 cm of a 140 g/m² non- woven fabric made of polyester (the first absorption layer) is placed thereon. On the first absorption layer, the second absorption layer is placed (a square of 10 x 10 cm of a 140 g/m²non- woven fabric made of polyester and viscose 1:1). On the second absorption layer, the surface layer made of 30 g/m non-woven polyester, having the dimensions of 13 x 13 cm, is placed. The covering is completed by wel'd g the contact and the, surface layers in a suitable distance from the absorption layers to present their damage by!heat. The final product, a square of approximately 11 x 11 cm is then produced by cutting the' excess boarders of the surface and contact layers.

The resulting square cohering is applied on the ound with the contact layer towards the wound and then fixed by % secondary covering. On a highly exudative wound, a dry covering is applied. On slightly exudative wounds, the contact layer is moisturized by 5 to 10 ml of physiological solution, sterile Water or drinking water prior to application. On dry wounds it is always necessary¹ ΐό' moisturize the covering by 10 ml of a suitable liquid (examples mentioned above). This covering can be left on the wound for up to 3 or 4 days, then it is re-bandaged. In case 6f massive exudation only the secondary covering is changed as often as necessary, the primary covering is not changed. The absorption capacity of the secondary covering can be increased; by using any commercially available superabsorbent or another appropriate system.

Example 2

Covering with hyaluronan, octcnidine dihydrochloride and two different absorbent layers, dried

Octenidine dihydrochloride (10 mg) is dissolved in 1 ml of absolute ethanol and 30 μΐ of this solution is taken to 10 ml with sterile water for injections and isopropanol 1:1 (i.e. 50% solution of isopropanol). Sodium hyaluronan (150 mg) with the molecular weight 1 650 000 g/mol is gradually added to thisisblution while stirring and is stirred for 30 minutes. The resulting viscous solution is uniformly applied using a template having the width of 1 mm and the hole of 10 x 10 cm on the support fabric (contact layer) having the dimension of 13 x 13

I ; ; - .' . ·^{■■■ " '}. - cm, the support fabric being a 40. g/m knitted lattice made of monofilaments of 22 dtex polyamide "M". The contact layer with the deposited solution attached to a suitable support is oven dried at 40°C for 2.5 hours, or a suitable drying profile is used (e.g. drying at 40°C for 60 minutes, heating to 70°C for 30 minutes, delay at 70°C for 15 minutes and then cooling to 40°C). The resulting glassy elastic clear (colourless) film firmly sticks to the contact layer, partly it is within the material of the fabric, but the major part of the deposited material is on one side of the fabric and has the same structure as the surface of the support to which the fabric was fixed; if the support is smooth, the film is smooth too; a more preferred is a relief with slight depressions. The contact layer is placed in such a manner that the coating is in contact with the base (i.e. the major part of the coating is directed towards the base), and a square of 10 x 10 cm of a 140 g7m hort- woven fabric made of polyester (the first absorption layer) is placed thereon. On the first absorption layer, the second absorption layer is placed which is a square of 10 x 10 cm of a 140 g/m² non^wpven fabric made of polyester and viscose 1 :1. On the second absorption layer, the surface' layer made of 30 g/m non-woven polyester, having the dimensions ' of 13 x 13 cm is placed. The covering is completed by welding of the contact and surface ; layers in a suitable distance from the absorption layers to prevent damage by heat. The final' product (a square oF approximately 11 x 11 cm) is then produced by cutting excess boarders of the surface and contact layers. < ^■■

The resulting covering is'applied on the wound With the contact layer directed towards

the covering.

Example 3

Covering with ^'hydiiiOhan,^J08tem¾ e '

two different absorbent layers, fibrous ^{: :}

solution is stirred for 12 hours. The resulting viscous solution is filled into a syringe and is extruded into the precipitating bath, which is composed of 400 ml of concentrated acetic acid (about 98%) and 100 ml of isopropanol (about 99%). The resulting fibre is left in the bath and the length thereof can be modified for example by quickly rotating knives (e.g. in a machine similar to the common mixer). The solution of shorter fibres is then filtred through the contact fabric and a suitable porous diaphragm (e.g. a solid panel with bored holes, on which the fabric is placed) to form a layer of fibres having the capacity of about 15 g/m . Optionally, the coating of fibres can be prepared on a porous diaphragm and then it is transferred (e.g. by "reprint" on the contact layer). The fibres layer on the contact fabric is washed with a suitable liquid, e.g. a mixture of isopropanol and water (the concentration of isopropanol must be higher then 60% to ensure that the fibres do not dissolve). The washed layer is then pressed in

ftbfes¹ i¾^;c¾riii(¾ieAti ¾0¾fi^^;in_; ^'imcll a way that a sq&arBo ζάΐ ^&&^ ά

and the attachment of the fibres'to the contact fabric). 'ίή ¾his wa^, octenidine dichioride, the" a timicrobial substance, penetrates into the polysaccharide fibres stnicture'and a^; physical mixture of polysaccharide(s)' and antimicrobial substarice^is formed. The contact layer, with fibres-coating attached to a suitable support is oven dried at 40°C for 2.5 hours or a suitable drying profile is used (e.g. drying at 40°C for 60 mmStbsj^' heating to 70°C for 30 minutes, delay at 70°C for 15 minutes and' men cooling to 40°C). Further processing to obtain the Wound covering and the use thereof is the same as iii Ex iple 1. The fibre coating is^!rho e porous than the film prepared iri Example 2, but at the same time, the structure of the pores is different from that of the lybp ilikaie described in Example 1. The properties of the covering with the fibres coating are more* similar to those of the iybphtilizate than to those of the film.

Example 4

Substitution of part of hyalurorian by another substance or mixture of substances

Example 5

Substitution of octenidine dihydrochloride by another substance or mixture of substances

An analogous process⁵ is used as in Examples 1, 2, 3 or 4, but octenidine dihydrochloride is replaced by: another suitable antimicrobial substance in a suitable concentration (here calculated pei -area of 10 x 10 cm) Hor example, 1.5 mg of benzalconium chloride can be used; 3.5 mg of chlorohexidine; 0.5 mg of PHMB; or a mixture of any combination various amounts of said substances with' ctenidine dihydrochloride, optionally without octenidine dihydrochloride.

Example 6

Evaluation of the efficiency of the preparation (tests of antimicrobial efficiency, preclinical assessment)

Models used, brief description

The antimicrobial effectivity was tested in vitro. The samples were tested batch- wise in several days. The samples were transferred by sterile forceps into sterile glass tubes (in case of solid coverings), liquid mixtures were transferred into tubes by a pipette. 15 ml of culture medium BHI (Brain Heart Infusion Broth; Hi-Media) were added to each tube and samples were inoculated by the following microorganisms: Staphylococcus aureus subsp. aureus CCM 4516 (gram-positive coccus), Escherichia coli CCM 4517 (gram-negative rod), Pseudomonas aeruginosa CCM 1961 (gram-negative non-fermenting rod), Bacillus subtilis subsp. spizizenii CCM 1999 (sporulating gram-positive rod), Aspergillus niger CCM 8222 (fungus). The growing properties of the culture medium were tested. The tubes were capped with a metallic cover and transferred for cultivation into a constant-temperature chamber. Liquid samples were cultivated for 24 and 48 hours, solid covering samples were cultivated for one week at the temperature within the range from 30 to 35 °C and the following week at 20 to 25°C. After the said period, the presence or absence of cloudiness was examined. Clouded samples were plated by sterile inoculating loop to Petri dishes with blood agar KA (Merck) for cultivation verification ^Jbf the present ''microorganisms. TTieir irictibatioii proceeded for 5 days at 30 to 15°C '

T healing effect was' assessed b

ZDF rats). Wounds 2 x 2 cm were prepared and the healing was measured twice a week based bn the wound contraction using c0mput0r evaluation of photographic recording of the Wound; { I v . ^u;i Also, the healing effect was assessed by minnesVtk type rhiniature pig mod61 witn- 5 deep ful profile excisions of 2 X 25 irmi on each side; prepared ίη anesthesia by the' method described by Van Dorp Verhoeven MC, Koerten HK, ^an Der Nat-Van Der Mei TH Van Blitterswijk¹ CA, Vonec M ¹ Derrnai

wounds i Yucdta miniature pigs using a biodegraddbl copolymer, Wound 'Repair Regen, 1998; 6(6)356-68: The wounds were then covered 'with a control and experimental covering until trie healing w∑is complete. ' Regular re-bandage¾ ^{; 1} fdtodocumentatiori ¹ arid scraping for ¹

exammatibri were performed twice a week. Based on the image analysis, the rate of wound a so -thS

effect of the covering on the wound m crobial colonizati was measured.

S. aureus strains, the inhibition; for E._; coli strain was 99.95 % and for P. aeruginosa strain

90 %;

A sample of the finished άογεπη£ showed an inhibition zone around the contact layer, however, in a greater distance .front the ^ venng the micrpprganisms growth was not inhibited. On the other hand, this .faGt showis evidence that the antimicrobial substance is not released from the covering to the surrounding environment^ and therefore, the patient will not be adversely affected.

Microbial efficiency of the active mixture (liquid according to Example 5)

A sample of the liquid mixture (viscous solution) used for the coating according to Example 5 showed total (i.e. 100%) inhibition of E. coli strains growth (initial suspension 1 800 CFU/ml), S. aureus (600 CFU/ml) and A. niger (6$ 0VU/m\) with the content of 16 mg of benzalconium chloride (BAC); or 40 mg of chlorhexidine or 40 mg of PHMB. When 1.6 mg of BAC was used, the inhibition was 100% only^j&t' S. aureus strains, the inhibition of E. coli strain was 16 % and inhibition oF A. nigcr strain was 89 %. When 4 mg of

chlorhexidine was used, the inhipition of E; coli growthv^as ¾l %, S. aureus 95 % and A. niger 32 %. When 4 mg of polyh£xamethylene bigua¾de ; (PHMB) was used, E. coli growth inhibition was 44 % and A. niger 57 %.

Samples of the finished coverings showed inhibition zones in a similar way as was described for the preparation of Example 1. Therefore, when a suitable quantity of a suitable antimicrobial substance is used, the coverings have similar microbial inhibition properties which are based on the overall construction and preparation process of the covering, not only on the particular antimicrobial substance.

Covering of Example 1, healing¹ effect, healthy rat model¹

When the covering of Example T was used, a significant acceleration of the wound contraction was observed, which ih^' the used model represents the scale of healing, or of healing efficiency. Compared to¾ne riot treated control wound (see Figure 3) it is clear that the' application of the covering 'according to Example 1 shortens time of wound healing especially thanks to the fact that the wound healing process starts immediately after the injury. In case of the not treated wound, the healing process starts approximately three days after the injury. The intensity of the subsequent wound healing is then similar in both cases, as can be seen in the similar slope of both functions in Figure 3. Since healthy rats were used, the efficiency on chronic wound cannot be assessed. Covering of Example 1 , healing effect, healthy miniature pig model

It was found out that the covering of Example 1 positively influenced the rate of wound closing (Figure 4) and atep the total bacteria content in the wounds decreased (Figure 5), of which especially the gram-negative bacteria were monitored (Figure 6).

Claims

1. A mixture for supporting wound healing comprising a physiologically acceptable

hyaluronic acid salt, characterized by that it further comprises an antimicrobial substance selected from the group comprising octenidine dihydrochloride, cetrimide, benzalconium chloride, benzalconium bromide, chlorhexidine, chlorhexidin bigluconate, polyhexamethylene biguanide, carbethopendecinium bromide, cetyltrimethylammonium bromide and a mixture thereof in any ratio.

2. The mixture according to claim 1, characterized by that it further comprises one or more polysaccharides selected from the group comprising native or modified polysaccharides hyaluronan, xanthan, schizofyllan, chitosane, glucane, alginate, cellulose, β-Ι-3-glucane and a mixture thereof.

3. The mixture according to claim 1 or 2, characterized by that said antimicrobial substance

¾¾c¾hidiriB ^di¾cM i¾! ^r

4. T¾ ffi¾¾¾^^ ¾^;-to¾&faS^r^

^iolbgic^Hy¹^

ffi S&hSM ii p^l ^a iaridS^fli^ ovalently bound molecule or functional group, i wnefeW!slaidiriole polysaccharide'orW dirferen¾^! <iily^ ^,rc sy^metic polyihe ^;of of' Cross-linked p'oly^acchatide e ^^ or diff re¾^:rHole¾i ie¾?

6. T¾e¾ix¾ui atc0rdifig to any of the preceding claims, characterized by that it further

surface layer (R), wherein all layers are arranged in the following order in the direction from the wound: contact layer (K), which contains on the side to be contacted with the

^! wound or on both sides, a coating (P) made of the mixture of any one of claims 1 to 10; one or more absorption layers (A) and a surface layer. (R).

13. The covering according to' any o¾e; of claims 11 or If, ' characterized by that the contact layer is preferably made from a woven or knitted fabric rhade of polyamide (PAD) monofilaments, optionally of staple fibers; from ηοη όνεη fabrics or porous membrane, polyurethane, polyester, viscose;/ mixtures of said fibers or from other materials, for example from synthetic fibres such as polypropylene ^{p: '}

14. The covering according to any' one of claims 11 to 13 characterized by that the coating (P) made of the mixture of any one of claims 1 to 10 can be in the form of a lyophilizate or a dried coating.

15. The covering according to any one of claims 11 to 14, characterized by that the coating (P) is a lyophilized or dried layer of the chemical mixture according to claim 9 or a layer of the physical mixture according to claim 10.

16. The covering according to alny one of claims 12 to 15, characterized by that it comprises one or more absorption layers (A) prepared from materials selected from the group comprising polyester, viscose; polyamide, polyethylene, polypropylene, polysaccharide of the xanthan type or cellulose; deriyate, superabsorptiott material, a combination of woven or non-woven fabric fibres and superabsorbents, or a mixture of said materials.

17. The covering according to any one of claims 12 to 16, characterized by that it comprises more absorption layers (A) arranged in such a way that the absorption capacity gradient increases in the direction frohi the wound.

18. The covering according to claim 17, characterized by that it comprises absorption layers (A-l) and (A-2), wherein the absorption layer (A-l)^' is closer to the wound and is made of 100% polyester and the absorption layer (A-2) is further from the wound and is made of a 1 : 1 mixture of polyester and viscose.

19. The covering according to any one of claims 12 to 18, characterized by that the surface layer (R) is preferably made from a non- woven polyester fabric which can optionally be antimicrobial treated by means of impregnation by a suitable antimicrobial substance or by means of antimicrobial fibres_; content, obtained fpr example from bamboo, or by means of silver microparticles content.

20. The covering according to an one of claims 11 to 19, characterized by that the coating (P) is composed of precipitated polysaccharide fibres layer, on which layer a layer of antimicrobial substance solution is applied, wherein the amount of the polysaccharide coating is at least 0.1 mg/m and the amount of antimicrobial substance coating is at least 0.0001 mg/m².

21. The covering according to claim 20, characterized by that the polysaccharide is

hyaluronan and the polysaccharide coating quantity s i within the range from 1 to 50 g¼n², and the antimicrobial substariceas octeriidine dichloride and the quantity of octenidine dihydrochloride coating is witfiifi -^'the range from 0.001 to 0.5 g/m².

22. The covering according to claim 21 , characterized by that the quantity of hyaluronan coating is within the range from 5 to 20 g/m² and the quantity of octenidine

dihydrochloride coating is within the range from 10 to 40 mg/m².

23. The covering according to any one of claims 12 to 22, characterized by that the contact layer (K) and the surface layer (R) are attached together by the edges thereof in order to close the absorption layer or absorption layers (A) between the contact layer (K) and the surface layer (R).