Patent ID: 7037526

Claim:
A process for the production of a polymer-based preparation in film form, for biphasic release of substances contained therein to liquid surroundings, the preparation comprising at least two polymer matrix layers which differ in terms of their construction from polymers, with release taking place rapidly from one of the layers, and release taking place slowly from at least one other layer, said matrix of the rapidly releasing layer comprising a polyvinyl alcohol or a polyvinyl alcohol-containing polymer mixture, and said matrix of the slowly releasing layer(s) comprising at least one polymer selected from the group consisting of cellulose ethers, polyurethane, polymethacrylates, poly(methyl methacrylates) and derivatives or copolymers thereof, said process comprising the following steps: a) providing a polymer solution suitable for the rapidly releasing layer, comprising the substances to be released; b) coating of the polymer solution onto an inert substrate by knife or roller application or spraying processes and subsequent drying to form the rapidly releasing film layer; c) providing a polymer solution suitable for the slowly releasing layer, comprising the substances to be released; and d) coating of this solution onto the rapidly releasing film layer by knife or roller application or spraying processes or printing and subsequent drying to form the slowly releasing film layer.