| 摘要 |
An osmotic active agent dispenser is comprised of (1) a first compartment of relatively impervious material containing an active agent and provided with an aperture for releasing said active agent to the exterior of the dispenser; (2) a second compartment of controlled permeability to water containing a solution of an osmotically effective solute which exhibits an osmotic pressure gradient against water; and (3) a movable barrier member separating the first from the second compartment. The barrier member is slidably responsive to an increase in volume in the second compartment via absorption of water therein; whereby as water flows by osmosis into the compartment (2) of the dispenser in a tendency towards osmotic equilibrium with its environment, corresponding pressure is exerted behind the barrier (3) driving it into and diminishing the volume of the compartment (1), in turn continuously ejecting active agent thereout at an osmotically controlled rate over a prolonged period of time. In a specific embodiment, the dispenser is comprised of a plurality of capsule half shells one of which compartmentalizing and being free to move within the device, thereby defining a closure for both the active agent compartment and the solution compartment.
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