Osmotic system having laminated wall comprising semipermeable lamina and microporous lamina

An osmotic therapeutic system for the controlled dispensing of a beneficial drug formulation to a biological fluid environment of use comprising:

• (a) a shaped laminated wall comprising:
• a semipermeable lamina that is formed of a material permeable to the passage of an external fluid, substantially impermeable to the passage of drug, and essentially maintains its physical and chemical integrity in the biological environment of use, said semipermeable lamina in laminar arrangement with a lamina formed of a material that forms in the environment of use a microporous lamina having a plurality of micropores with paths through the lamina, said laminated wall surrounding and forming:
• (b) a compartment containing a beneficial drug formulation;
• (c) a passageway in the laminated wall communicating with the compartment and the exterior of the system for dispensing drug formulation from the system;
• and,
• (d) wherein in operation, when the system is in the environment of use, fluid from the environment is imbibed through the laminated wall into the compartment in a tendency towards osmotic equilibrium at a rate determined by the permeability of the laminated wall and the osmotic pressure gradient across the laminated wall, thereby forming a solution containing the drug formulation that is dispensed through the passageway at a controlled rate over a prolonged period of time.