Osmotic delivery system semipermeable body assemblies that control the delivery
rate of a beneficial agent from an osmotic delivery system incorporating one of
the semipermeable body assemblies are provided. A semipermeable body assembly or
plug includes a semipermeable body which is positionable in an opening of an osmotic
delivery system. The semipermeable body has a hollow interior portion having a
size selected to obtain a predetermined liquid permeation rate through the semipermeable
body. Because the beneficial agent in the osmotic delivery system is delivered
at substantially the same rate, the osmotic agent imbibes liquid which has permeated
through the plug from a surrounding environment, and the liquid permeation rate
through the plug controls the delivery rate of the beneficial agent from the osmotic
delivery system. The liquid permeation rate through a semipermeable body may be
varied to control the delivery rate of beneficial agent from an osmotic delivery
system by changing the thickness of the semipermeable body or by changing an amount
of surface area of the semipermeable body that is exposed to liquid when the osmotic
delivery system is located in a liquid environment of use.
