Wound dressing with a bacterial adsorbing composition and moisture holding system

Abstract

The invention herein relates to a wound dressing product, combining a hydrophobic fabric, which is to be placed towards the wound, and is capable of binding unwanted microorganisms, and a moisture carrying matrix such as a gel or a foam. The product of the invention is ideal for treatment of drier wounds. It protects the wound and reduces the number of pathogenic microorganisms, without using antimicrobial substances and at the same time adds or traps moisture to the wound both supporting the hydrophobic functioning of the pad and healing in general by keeping the wound moist.

Claims

1. A dressing for a wound consisting essentially of: a first layer, wherein the first layer is a hydrophobic layer that binds microorganisms when the dressing is placed on the wound, and wherein the first layer has been treated with a compound that contains hydrophobic groups and the compound is selected from the group consisting of a dialkyl carbamoyl chloride and an alkyl ketene dimer; and a second layer comprising a foam that is attached to the first layer, wherein, when the dressing is applied to the wound, the first layer is between the second layer and the wound, and a surface of the first layer is configured to be in direct contact with the wound, wherein moisture is trapped by the foam and supports hydrophobic functioning of the dressing that helps bind microorganisms to the first layer without the use of antimicrobial compounds, and wherein the foam consists of a polyether foam, polyester foam, or polyurethane foam.

2. The dressing of claim 1, wherein the foam is a polyether foam.

3. The dressing of claim 1, wherein the hydrophobic layer is bonded to the foam.

4. The dressing of claim 1, wherein the hydrophobic layer is bonded to the foam with an adhesive.

5. The dressing of claim 1, wherein the hydrophobic layer comprises a woven or non-woven fabric.

6. The dressing of claim 1, wherein the hydrophobic layer comprises a hydrophilic fabric.

7. The dressing of claim 1, wherein the hydrophobic layer is made of cellulose acetate and the compound is dioctadecyl carbamoyl chloride, and wherein the dioctadecyl carbamoyl chloride is applied to the cellulose acetate.

8. The dressing of claim 1, wherein the compound is a dialkyl carbamoyl chloride selected from the group consisting of dihexadecyl-carbamoyl chloride and dioctadecyl-carbamoyl chloride.

9. The dressing of claim 1, wherein the foam is a polyurethane foam.

10. A dressing for a wound consisting essentially of: a hydrophobic layer that binds microorganisms when the dressing is placed on the wound, wherein the hydrophobic layer has been treated with a compound selected from the group consisting of a dialkyl carbamoyl chloride and an alkyl ketene dimer; and a foam layer attached to the hydrophobic layer, wherein, when the dressing is placed on the wound, a surface of the hydrophobic layer is configured to be in direct contact with a surface of the wound, and wherein moisture is trapped by the foam layer and supports hydrophobic functioning of the dressing that helps bind microorganisms to the hydrophobic layer without the use of antimicrobial compounds.

11. The dressing of claim 10, wherein the foam layer is selected from the group consisting of polyether, polyester, and cellulose.

12. The dressing of claim 10, wherein the foam layer comprises a polyurethane foam.

13. The dressing of claim 10, wherein the hydrophobic layer is bonded to the foam layer with an adhesive.

14. The dressing of claim 10, wherein the hydrophobic layer comprises a woven or non-woven fabric.

15. The dressing of claim 10, wherein the hydrophobic layer is made of cellulose acetate and the compound is dioctadecyl carbamoyl chloride, and wherein the dioctadecyl carbamoyl chloride is applied to the cellulose acetate.

16. The dressing of claim 10, wherein the compound is a dialkyl carbamoyl chloride selected from the group consisting of dihexadecyl-carbamoyl chloride and dioctadecyl-carbamoyl chloride.

17. The dressing of claim 10, wherein the foam consists of a polyether foam, polyester foam, or polyurethane foam.

18. A dressing for a wound consisting essentially of: a fabric layer, wherein the fabric layer comprises at least one hydrophobic fabric that binds microorganisms, wherein the at least one hydrophobic fabric is a fabric comprising a compound that contains hydrophobic groups, and wherein the compound is selected from the group consisting of a dialkyl carbamoyl chloride and an alkyl ketene dimer; and a foam layer that is attached to the fabric layer, wherein, when the dressing is applied to the wound, a surface of the fabric layer is configured to be in direct contact with a surface of the wound.

19. The dressing of claim 18, wherein the at least one hydrophobic fabric is a cellulose acetate fabric treated with a compound that contains hydrophobic groups.

20. The dressing of claim 18, wherein the foam layer comprises a polyurethane foam.

21. The dressing of claim 18, wherein the foam layer is selected from the group consisting of polyether, polyester, and cellulose.

22. The dressing of claim 18, wherein the foam layer traps moisture and aids in the binding of microorganisms to the at least one hydrophobic fabric.

23. The dressing of claim 18, wherein the dressing does not include an antimicrobial compound.

24. The dressing of claim 18, wherein the fabric layer is bonded to the foam layer with an adhesive.

25. The dressing of claim 18, wherein the foam consists of a polyether foam, polyester foam, or polyurethane foam.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1a-1c show the gel-based product. The figures are schematic drawings of a cross-sectional side view of the invention as it may be used. In FIG. 1a, the product is shown above a wound surface, on which there are bacteria schematically shown, before placement of the product on the wound. In FIG. 1b, the product is shown on the wound surface. In FIG. 1c, the product is shown upon removal from the wound.

(2) FIGS. 2a-2c show the foam-based product. The figures are schematic drawings of a cross-sectional side view of the invention as it may be used. In FIG. 2a, the product is shown above a wound surface, on which there are bacteria schematically shown, before placement of the product on the wound. In FIG. 2b, the product is shown on the wound surface. In FIG. 2c, the product is shown upon removal from the wound.

DETAILED DESCRIPTION OF THE INVENTION AND

Preferred Embodiments Thereof

(3) The product of the invention is ideal for treatment of drier wounds. It protects the wound, absorbs exudate and reduces the number of pathogenic microorganisms, without using antimicrobial substances and adds moisture to the wound both supporting the hydrophobic functioning of the pad and healing in general by keeping the wound moist. The product of the invention consists basically of two layers: a moisture carrying matrix, such as a gel or a moisture trapping matrix such as a foam and a hydrophobic cellulose acetate fabric which binds microorganisms.

(4) The SORBACT method is based on the effect that pathogenic microorganisms displays a cell surface hydrophobicity. By using a fabric or similar structure treated to become hydrophobic, this surface will then bind to the unwanted microorganisms, making it possible to remove them from a wound when the pad with the treated fabric is removed. This removal of unwanted microorganisms will be made without any development of resistance or other side-effects such as allergies or cytotoxicity,

(5) Also wounds with low secretion of wound fluids and dry wounds have many times a too high level of unwanted microorganisms for proper wound healing and there is also a concern for various infections. To be able to use the safe and effective means of the SORBACT method to remove microorganisms from surfaces such as wounds also in drier conditions, we have in the invention herein incorporated a SORBACT pad with specifically developed hydrogels or foams or the like. The gel contains water which is donated to the wound surface when the product of the invention is applied. The foam contains no water or to only a small extent, but the foam helps trapping the small amounts of moisture secreted from the skin, helping the hydrophobic interaction between the SORBACT pad and the wound surface. The gel or the foam, when adding or trapping moisture to the surface also helps in the healing of the wound and further reduces the risk of the pad sticking to the wound surface and thereby aid in it's removal.

(6) The Gel Based Product

(7) Referring to the figures, FIGS. 1a-1c are a schematic representation of the use of the invention to bind microorganisms, showing the holding material 10, hydrophobic layer 14, and a gel layer 16, above a wound area 18, on which bacteria 20, are depicted, showing sequentially before, during and after application to a wound, respectively.

(8) The hydrophobic layer 14 is coated with a moisture-carrying layer of gel 16. Since the gel layer 16 is fluid it gets integrated with the hydrophobic layer 14. The product is held in place over the wound by the holding material 10, being cotton gauze, various band-aid, wound dressings or the like.

(9) The hydrophobic material may comprise, for example, a hydrophobic fabric or hydrophobic non-woven fabric, or a hydrophilic fabric or non-woven fabric which has been rendered hydrophobic by a special treatment, or a hydrophobic, perforated foil. Hydrophobic woven and non-woven fabrics may be produced from synthetic fibers or the type polyamide, polypropylene and polytetrafluoroethylene fibers, or from carbon fibers. In order to obtain a hydrophobic material from a woven or non-woven hydrophilic fabric, such as woven or non-woven cotton fabric, the fabric may be treated chemically for example, in a known manner, with a compound containing hydrophobic groups, for example with a DACC such as dihexadecyl-carbamoyl chloride or dioctadecyl-carbamoyl chloride or an AKD.

(10) A preferred hydrophobic layer of the invention is made of green cellulose acetate to which dioctadecyl carbamoyl chloride is applied as discussed in the examples.

(11) The gel can be based on for example Carboxymethyl cellulose, Polysaccharides, Polymers, NaCl and Glycerin.

(12) The Foam Based Product

(13) FIGS. 2a-2c are a schematic representation of the use of the invention to bind microorganisms, showing the holding material 10, foam layer 12, and a hydrophobic layer 14, above a wound area 18, on which bacteria 20, are depicted, showing sequentially before, during and after application to a wound, respectively.

(14) In the foam product, the hydrophobic layer 14 is placed between the foam layer 12 and the wound site 18. The product is hold in place over the wound by the holding material 10, being cotton gauze, various band-aid, wound dressings or the like. The hydrophobic material may comprise, for example, a hydrophobic fabric or hydrophobic non-woven fabric, or a hydrophilic fabric or non-woven fabric which has been rendered hydrophobic by a special treatment, or a hydrophobic, perforated foil. Hydrophobic woven and non-woven fabrics may be produced from synthetic fibers or the type polyamide, polypropylene and polytetrafluoroethylene fibers, or from carbon fibers. In order to obtain a hydrophobic material from a woven or non-woven hydrophilic fabric, such as woven or non-woven cotton fabric, the fabric may be treated chemically for example, in a known manner, with a compound containing hydrophobic groups, for example with a DACC such as dihexadecyl-carbamoyl chloride or dioctadecyl-carbamoyl chloride or an AKD.

(15) A preferred hydrophobic layer of the invention is made of green cellulose acetate to which dioctadecyl carbamoyl chloride is applied as discussed in the examples.

(16) The hydrophobic material is bonded to foam layer with the aid of a suitable adhesive, for example Disponal 70 (Limgrossisten AB, Norrkoping, Sweden). Other adhesives known in the art could also be used.

(17) The bonded hydrophobic layer of the Cellulose Acetate is attached to a moisture-trapping layer of foam. The foam can be based on for example Polyether, Polyester and Cellulose.

(18) The microorganisms will be removed from the wound when the dressing is changed. Hence, the number of microorganisms decreases over time to a number which the body can control and the wound can heal. Since microbes adhere to the dressing by hydrophobic interactions, spread of microorganisms to the environment during changing of dressings is limited. The combined bacteria-binding capacity and absorption of wound secretion, pus and debris provide optimal cleansing of the wound. With this method, the bacterial load in the wound surface is reduced rapidly and effectively. The body's own defense mechanism can then take over, and the natural healing process can continue. The use of a hydrophobic layer, even without systemic antibiotic therapy, decreases the number of infecting microorganisms but does not eliminate all bacteria which is an advantage since a small number of microorganisms stimulate wound healing. The invention replaces the use of topical antibiotics, and hence reduces the spread of antibiotic resistant organisms.

(19) Since the products of the invention have an integrated moisture-holding matrix such as a gel or foam, the products of the invention are ideal for treatment of drier wounds. The products protect the wound, absorb exudate and reduce the number of pathogenic microorganisms, without using antimicrobial substances and adds moisture to the wound both supporting the hydrophobic functioning of the pad and healing in general by keeping the wound moist.

(20) An alternative method to lift the microbes from the wound and still keep the wound moist is the electrostatic solution (such as described in U.S. Patent application 2006/0163149) used in layer 14 together with foam or gel. A further method to lift the microbes and still keep the moist, is to use the hydrophobic method in combination with the electrostatic method together with gel or foam.

(21) Other objects and features of the inventions will be more fully apparent from the following examples and appended claims.

Example 1

Manufacture of Wound Dressing Product with Gel as the Moisturizing Matrix

(22) In this example we manufacture a gel based wound dressing based on the invention in the following manner:

(23) Materials: (from Inside-Out See FIG. 1a)

(24) TABLE-US-00001 COMMERCIAL LAYER PRODUCT NAME SUPPLIER 1. Moisturizing gel Syntalen K Vendiko Chemical AB Malm 2. Hydrophobic layer Green Cellulose Acetate ABIGO Medical AB woven prepared according Sweden to U.S. Pat. No. 4,617,326

(25) The hydrophobic layer is preferably produced according to U.S. Pat. No. 4,617,326 by applying to a cellulose acetate fabric an amount of dioctadecyl carbamoyl chloride as disclosed in this patent making a covalent bond between the materials. The acetate fabric is on rolls at a width of 1 m, and taken as such to the next step.

(26) A packaging-film which also serves as a carrier-film during the production is used. This film is preferably made of an aluminum foil, and most preferably of foil having a plastic layer on both sides, such as a Polyethylene terephthalate laminated aluminum foil and with a polyethylene surface on the inside for welding the packaging, for example, PET70/ALU6,35/PE70 (by Stenqvist AB, SE-260 50 Billesholm, Sweden). One further option is to have foil of peel-open type, as known in the industry, for easier use by the final user. 1. The foil is placed in an assembling machine where the lower foil of the package is fed on a continuous line over a surface for the assembly. 2. On the foil is firstly the gel placed by pumping and distributing the gel evenly over an area of 75150 mm on the foil. The amount of gel used is preferably 11-17 gram for this size of the product, but can be varied between 3-30 grams. 3. The hydrophobic layer of acetate fabric is cut into suitable size pieces for the final product, which in this example is 75150 mm. The cut pieces are placed on top of the gel area on the foil. 4. Over the now assembled product with a bottom packaging foil, layer of gel and the acetate fabric, is now a top foil placed of the same type as the bottom foil. The package foil is then welded to create the finished and packaged product.

(27) The now completely assembled dressing, is finally sterilized (Isotron Gamma Irradiation, Netherlands) and then packed.

Example 2

Manufacture of Wound Dressing Product with Foam as the Moisturizing Matrix

(28) In this example we manufacture a foam based wound dressing based on the invention in the following manner:

(29) Materials: (from Inside-Out See FIG. 2a)

(30) TABLE-US-00002 COMMERCIAL LAYER PRODUCT NAME MANUFACTURER 1. Hydrophobic layer Green Cellulose Acetate ABIGO Medical AB woven prepared according Sweden to U.S. Pat. No. 4,617,326 2. Adhesive Disponal 70 Limgrossisten AB, Norrkping, Sweden 3. Moisturizing foam Bulpren S 31062, about 75 ABC Eurosoft AB, ppi (pore per inch) Bjuv, Sweden

(31) The hydrophobic layer is preferably produced according to U.S. Pat. No. 4,617,326 by applying to a cellulose acetate fabric an amount of dioctadecyl carbamoyl chloride as disclosed in this patent making a covalent bond between the materials. The acetate fabric is on rolls at a width of 1 m, and taken as such to the next step.

(32) The adhesive component, Disponal 70 (Limgrossisten AB, Norrkoping, Sweden), is applied to the foam material by using a slot applier, spraying or roll coating, such as reverse roll, direct roll, 5-roll multi-roll, 3-roll offset, offset gravure, die, pressure, saturators, rod, and Meyer rod coating as a very thin layer at an amount of <10 g/m.sup.2 preferably <8 g/m.sup.2 and then laminated with the foam layer, (Bulpren S 31062), between two rollers for the final bonding.

(33) The now bonded hydrophobic layer and foam layer is cut into suitable size pieces for the final product, in this case 30 mm30 mm. The completely assembled dressing, is finally sterilized (Isotron Gamma Irradiation, Netherlands) and then packed in cartons.

(34) While the invention has been described with reference to specific embodiments, it will be appreciated that numerous variations, modifications, and embodiments are possible, and accordingly, all such variations, modifications, and embodiments are to be regarded as being within the spirit and scope of the invention.