| abstract |
Novel devices for the controlled release of active materials especially pharmaceutical are formed from at least two interpenetrating pieces. The male piece is water swellable and swells to disengage the female piece. The female piece is preferably formed from a thermoplastic, e.g. LDPE or from a soluble material such as gelatin which is rendered impermeable by an external coating of a hydrophobic material such as PVC. The devices find particular application as oral dosage forms for use in man. |