Absorbent wound dressing containing a hydrogel layer
View Patent ↗A wound dressing comprising: a liquid-permeable top sheet having a wound facing surface and a back surface, said top sheet being adapted to block or restrict passage of liquid from the back surface to the wound facing surface; and an insoluble hydrogel layer adjacent to the back surface of the top sheet.
1. A wound dressing comprising: a liquid-permeable top sheet having a wound facing surface and a back surface, said top sheet having greater permeability to the flow of liquid away from the wound facing surface than to the flow of liquid towards the wound facing surface, thereby blocking or restricting passage of liquid from the back surface to the wound facing surface; a hydrogel layer adjacent to and bonded to the back surface of the top sheet; and an absorbent layer adjacent to the hydrogel layer, on the opposite side of the hydrogel from the back surface of the top sheet; wherein the top sheet is formed from a liquid-impermeable sheet material provided with tapered capillaries, each capillary having a base substantially in the wound facing surface of the top sheet and an apical opening remote from the wound facing surface of the top sheet; wherein the capillaries are substantially in the form of truncated cones; and wherein the hydrogel layer is apertured in register with apertures in the top sheet, wherein said wound dressing maintains a suitably moist wound environment.
2. A wound dressing according to claim 1 , wherein the absorbent layer comprises a layer of hydrophilic foam, a superabsorbent, or a combination thereof.
3. A wound dressing according to claim 1 , wherein the absorbent layer further comprises a medicament.
4. A wound dressing according to claim 1 , wherein the dressing further comprises a substantially liquid-impermeable backing layer over the absorbent layer.
5. A wound dressing according to claim 4 , further comprising a layer of adhesive on the surface of the backing layer facing the top sheet.
6. A wound dressing according to claim 5 , wherein the backing layer extends beyond at least one edge of the absorbent layer to provide an adhesive-coated margin adjacent to said edge for adhering the dressing to a surface.
7. A wound dressing according to claim 1 , wherein the top sheet comprises a porous, substantially hydrophobic, non-woven fabric.
8. A wound dressing according to claim 1 , wherein the capillaries have a base opening dimension from 0.15 mm to 6 mm, and an apical opening dimension of from 0.1 to 2.5 mm.
9. A wound dressing according to claim 8 , wherein the capillaries have a base opening dimension of from 0.5 mm to 1.5 mm, and an apical opening dimension of from 0.1 to 0.5 mm.
10. A wound dressing according to claim 1 , wherein the capillaries have an average angle of taper of from 10 to 60 degrees.
11. A wound dressing according to claim 1 , wherein the hydrogel layer has a dry basis weight from 10 to 200 g/m 2 .
12. A wound dressing according to claim 1 , wherein the hydrogel layer comprises a hydrogel material selected from polyurethane gels, biopolymer gels, carboxymethyl cellulose gels, hydroxyethyl cellulose gels, hydroxypropyl methyl cellulose, modified acrylamides and mixtures thereof.
13. A wound dressing according to claim 1 , wherein the hydrogel layer comprises a hydrogel material selected from gels formed from vinyl alcohols, vinyl esters, vinyl ethers and carboxy vinyl monomers, meth(acrylic) acid, acrylamide, N-vinyl pyrrolidone, acylamidopropane sulphonic acid, plutonic (block polyethylene glycol, block polypropylene glycol)polystyrene maleic acid, NN-dimethylacrylamide, diacetone acrylamide or acryloyl morpholine.
14. A wound dressing according to claim 1 , wherein the hydrogel layer comprises an emollient.
15. A wound dressing according to claim 14 , wherein the emollient is selected from the group consisting of white soft paraffin, yellow soft paraffin, liquid paraffin, urea creams, lanolin, sodium pyrrolidone carboxylate, evening primrose extract (gamma linolenic acid), soya oil, tea tree oil, coconut oil, almond oil, camomile extract, cod liver oil, peanut oil, emu oil, aloe vera, sunflower oil, avocado oil, jojoba oil, cocoamide, and mixtures thereof.
16. A wound dressing according to claim 1 , wherein the hydrogel layer comprises an active therapeutic agent or an antimicrobial agent.
17. A wound dressing according to claim 16 , wherein the hydrogel layer comprises a silver compound.
18. A wound dressing according to claim 1 , further comprising one or more protective cover sheets over the wound facing surface of the top sheet.
19. A wound dressing according to claim 1 , wherein the dressing is sterile and packaged in a microorganism-impermeable container.
20. A method of treating a wound comprising the step of applying a wound dressing comprising a liquid-permeable top sheet having a wound facing surface and a back surface, said to sheet having greater permeability to the flow of liquid away from the wound facing surface than to the flow of liquid towards the wound facing surface, thereby blocking or restricting passage of liquid from the back surface to the wound facing surface; a hydrogel layer adjacent to and bonded to the back surface of the top sheet; and all absorbent layer adjacent to the hydrogel layer, on the opposite side of the hydrogel from the back surface of the top sheet; wherein the top sheet is formed from a liquid-impermeable sheet material provided with tapered capillaries, each capillary having a base substantially in the wound facing surface of the top sheet and an apical opening remote from the wound facing surface of the top sheet; wherein the capillaries are substantially in the form of truncated cones; and wherein the hydrogel layer is apertured in register with apertures in the to sheet, wherein said wound dressing maintains a suitably moist wound environment, to the wound with said top sheet contacting said wound.
21. A wound dressing according to claim 1 , wherein the hydrogel layer has a dry basis weight of form 10 to 100 g/m 2 .
22. A wound dressing according to claim 1 , wherein the hydrogel layer is bonded to the back surface of the top sheet.