Abstract: A wound treatment device comprising a water-impermeable envelope having at least one aperture, wherein the envelope contains a therapeutic substance, and wherein the at least one aperture in the envelope is blocked by a material that breaks down in the presence of one or more active components of wound fluid thereby permitting the therapeutic substance to contact the wound fluid. Preferably, the aperture is blocked by a material that is a substrate for an enzyme present in wound fluid, such as a protease.

Abstract: A wound dressing comprising an elongate spiral roll of a polyurethane foam. Also provided is a method of preparing such dressings comprising the steps of: providing a foaming mixture comprising an isocyanate-capped prepolymer and a foaming agent; casting the foaming mixture into a sheet; and rolling up the sheet into a spiral roll before curing of the polyurethane is complete.

Abstract: The invention provides wound dressings, in particular wound dressings of low- or non-exuding wounds a bleeding wounds. The wound dressings are of the island type, having as adhesive-coated backing sheet (6) and an absorbent island (9) supported on the backing sheet. The island (9) comprises a layer (2) of liquid absorbent material enclosed in an envelope of textured perforated thermoplastic film. The film (3) at one side of the island (9) presents a ribbed or embossed perforated surface having low adherency to the wound. The film island an the rear surface of the envelope is perforated and smoothed to provide good attachment to the backing sheet (6) and controlled water vapor transmission rate. The invention also provides a method of manufacture of the wound dressings according to the invention, according to which the absorbent layer (2) is wrapped in a textured perforated thermoplastic film, and the film on the rear face of the envelope is then preferably smoothed by blowing hot air onto it.

Abstract: The invention provides a method of forming a polyurethane foam suitable for use as a wound-contacting layer, said method comprising: mixing 1 part by weight of an isocyanate-capped prepolymer having from 0.5 to 4.8 meq. NCO groups/g with from 0.4 to 1.0 parts by weight of water and an effective amount of a nonvolatile pharmaceutically acceptable acid to form a prepolymer mixture; allowing said prepolymer mixture to cure to form a foamed product; followed by drying the foamed product. The invention also provides acidified polyurethane foams obtainable by this method, and wound dressings comprising such foams.

Abstract: The invention provides a wound dressing (1) comprising a wound contacting sheet (4) laminated to one side of an absorbent layer (3) of water-swellable absorbent material such as a polyurethane. A liquid water-impermeable backing layer (2) is laminated to the other side of the absorbent layer (3). The wound contacting sheet is provided with one or more slits (5) therein. Expansion of the absorbent layer (3) due to absorption of wound exudate causes the slits (5) in the wound contacting sheet (4) to expand, thereby allowing passage of high flow rates of wound exudate. If the flow of exudate falls, then the slits close, thereby avoiding excessive drying of the wound surface.