Osmotic device for delayed delivery of agent

DETAILED DESCRIPTION The present invention is directed to a fluid-imbibing dispensing device for the initially delayed delivery of an active agent to a fluid environment of use.
The dispenser comprises a housing open at one end to provide outlet means therefor, at least a portion of the housing proximate the end opposite the outlet means permitting passage of fluid from the environment to the interior of the housing; one active agent unit comprising a container containing an active agent formulation, at least the open end of the active agent unit being disposed within the housing in slidably telescoping arrangement with the outlet means; and, a fluid-activated driving member within the housing in fluid-transmitting relationship with the fluid-passing portion of the housing proximate the end of the housing opposite the outlet means, for separating apart the housing and the active agent unit after exposure to the environment of use.
Optionally, the dispenser also comprises a partition layer between the driving member and the open end of the active agent unit.
The invention also is directed to a method for delaying the initial delivery of an active agent to a fluid environment of use, the method comprising placing the dispensing device of the invention into the environment of use, allowing fluid to be imbibed through at least a portion of the housing of the dispensing device for causing the expansion means to expand and exert pressure on the slidably connected housing and active agent unit, and delivering the active agent from the dispensing device by the expansion means increasing in volume, thereby pushing apart and separating the housing and the active agent unit and exposing the active agent formulation to the environment.