Osmotic pump drug delivery system semipermeable membrane

In the OROS system, solid drug—present alone or with an osmotic driving agent—is surrounded by a semipermeable membrane having one delivery orifice (Figure 9). During pump operation, water from the environment is continuously imbibed across the semipermeable membrane, by osmosis, to produce the fluid drug formulation. The membrane s structure does not allow expansion of the tablet s volume ... 

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