EP0598309A2 — Multilayer matrix systems for the controlled release of active principles

USPTO Abstract

This invention concerns systems for the release of active principles which are capable of releasing active principle(s) into an aqueous medium at a controlled rate. More precisely, the invention concerns a monolithic system for the controlled release of active principles, consisting of: a) at least one swelling layer containing one or more active principles, in a matrix of swellable, hydrophilic polymers; b) at least one erodible and/or soluble layer comprising excipients and/or water soluble polymers, possibly containing one or more active principles, either the same or different from those present in the layer a), the said erodible and/or soluble layer being in contact with the swelling layer(s) a).