Abstract: A wound dressing comprising: a therapeutic agent selected from the group consisting of antimicrobial substances, pain relieving substances, protease inhibitors, and mixtures thereof; and a barrier layer for initially separating the therapeutic agent from a wound fluid in use, wherein the barrier layer comprises a substrate for an enzyme selected from the group consisting of proteases, kallikrein and tissue-plasminogen activator. Preferably the substrate comprises a substrate for elastase or a collagenase. The barrier layer breaks down in infected or chronic wounds, thereby releasing the therapeutic substance selectively into such wounds.

Abstract: A wound dressing comprising: a therapeutic agent selected from the group consisting of antimicrobial substances pain relieving substances, protease inhibitors, and mixtures thereof; and a barrier layer for initially separating the therapeutic agent from a wound fluid in use, wherein the barrier layer comprises a substrate for an enzyme selected from the group consisting of proteases, kallikrein and tissue-plasminogen activator. Preferably the substrate comprises a substrate for elastase or a collagenase. The barrier layer breaks down in infected or chronic wounds, thereby releasing the therapeutic substance selectively into such wounds.

Abstract: A wound dressing comprising: a wound contacting sheet having a wound facing surface and a back surface opposite the wound facing surface, and having apertures therein that open or enlarge in the presence of wound exudate; and a plurality of particles comprising one or more therapeutic agents located behind the back surface of the back sheet, wherein the particles are able to pass through the apertures to the wound facing surface of the sheet when the apertures are opened or enlarged in the presence of said wound exudate.