A drug delivery for administering drug to an aqueous body environment at a substantially constant rate. The devices consist essentially of a mixture of drug of specific average particle size dispersed in a polymer of specific water permeability, tensile strength, and Young's modulus in specific volume...http://www.google.com.au/patents/US4177256?utm_source=gb-gplus-sharePatent US4177256 - Osmotic bursting drug delivery device
