Abstract: A substance transfer device for topical or transdermal drug delivery to a living body or collection of fluids from a living body, comprises a layer of skin or wound surface compatible adhesive having a surface for contacting the body, and channels therethrough which provide liquid communication with depots of drug or collection means. These channels form discrete, exposed areas of drug composition or drug delivery means, surrounded by the adhesive. The drug contained in the device does not need to pass through the layer of adhesive before contacting the underlying skin. In one arrangement, particularly suitable for delivery of macromolecular drugs, the channels extend through the entire thickness of the adhesive layer, and communicate with reservoirs of drug.

Abstract: Condensation copolymers such as polyesters are rendered photodegradable, by subjecting them to conditions under which they undergo ester interchange effectively causing polymer chain scission, in the presence of a keto carbonyl containing compound having chemical groups reactive with the condensation polymer products formed by the ester interchange. The compound reacts chemically with the polymer products to reform the high molecular weight condensation copolymer, but with the keto carbonyl groups chemically linked into the polymer chains to confer photodegradability thereon.