Patent ID: 6939556

Claim:
An osmotic delivery system comprising: a capsule, said capsule having an interior for holding a beneficial agent, said interior having an interior surface; an osmotic agent located in said interior; a semipermeable body in liquid communication with said capsule for permitting liquid to permeate through said semipermeable body to said osmotic agent; and a piston having a length to total diameter ratio of about 1.1:1 and a core-diameter-to-overall-diameter ratio of about 0.9:1 located within said interior of said capsule, being movable with respect to said interior surface of said capsule, defining a movable seal with said interior surface of said capsule that separates said osmotic agent from said beneficial agent; said osmotic agent located between said piston and said semipermeable body, said osmotic agent for imbibing fluid from a surrounding environment through said semipermeable body to cause said piston to move and, in turn, cause delivery of said beneficial agent from said capsule.