Controlled release delivery system by an osmotic bursting mechanism
First Claim
1. A water actuated osmatic type active agent dispenser including a means for dispensing a dosage of active agent into an aqueous fluid or humid environment comprising (1) a fluid permable membrane defining at least a part of a walled enclosure, said enclosure containing therein an active agent which exhibits an osmatic pressure upon exposure of the enclosure to the environment, the thickness and permibility of said membrane comprising a means for controlling the water diffusion therethrough until the osmotic pressure in the enclosure is sufficient to distort, stretch and finally rupture the enclosure resulting in release of the agent to the environment.
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Abstract
An osmotic dispenser comprised of (1) a water permeable membrane forming part or all of the walls of an enclosure surrounding (2) an active agent, and in some cases (3) an additional compound known as an osmotic attractant which together exhibits an osmotic pressure against water. When placed in an aqueous environment water is osmotically drawn into the enclosure by the combined action of the agents (2) and (3) which distends and swells the enclosure until the membrane or some other part of the enclosure wall reaches the point of ultimate elongation and a portion of the wall yields and ruptures releasing the contents of the enclosure to the environment.
165 Citations
14 Claims
- 1. A water actuated osmatic type active agent dispenser including a means for dispensing a dosage of active agent into an aqueous fluid or humid environment comprising (1) a fluid permable membrane defining at least a part of a walled enclosure, said enclosure containing therein an active agent which exhibits an osmatic pressure upon exposure of the enclosure to the environment, the thickness and permibility of said membrane comprising a means for controlling the water diffusion therethrough until the osmotic pressure in the enclosure is sufficient to distort, stretch and finally rupture the enclosure resulting in release of the agent to the environment.
Specification