Water absorption, swelling and rupture of osmotic tablets containing a water swellable polymer

摘要

Baker (1) invented controlled release delivery of drugs by an osmotic bursting mechanism. This system consists of a water-permeable membrane surrounding a core of an active agent capable of creating an osmotic pressure and additional osmotic agnet(s), if needed. When this device is placed in an aqueous medium, osmotically drawn water swells the core, distends the membrane and eventually ruptures it, releasing the contents of the core to the environment. The lag-time between the time the tablet is placed in the aqueous environment and when it bursts can be of enormous value for several applications within pharmaceutical and agricultural industries and can be controlled by modifying the osmotic pressure of the core.