ABSTRACT
Osmotically controlled tablets use osmosis, the natural movement of water through a membrane, to control drug delivery within the gastrointestinal tract. An implantable osmotic injector capable of delivering fluid at a constant rate for weeks was first proposed in 1955 by Rose and Nelson [1]. ALZA Corporation (Mountain View, CA) pioneered the solid tablet osmotic dosage form (the Oros system) [2-4] in the 1970s, various configurations of which have been marketed since 1983 generating sales of about $1.5 billion in 1999. Currently, more than 10 products using Oros technology are marketed for the treatment of various conditions (Table 1).
