Abstract: An oral sustained release composition for slightly soluble pharmaceutically active agents comprising a core, a wall around said core, and a bore through said wall connecting said core and the environment outside of said wall; wherein said core comprises a slightly soluble active agent, optionally a crystal habit modifier, at least two osmotic driving agents, at least two different (or two different grades of) hydroxyalkyl celluloses, and optionally lubricants, wetting agents, and carriers; said wall being substantially impermeable to said core components and permeable to water and gastro-intestinal fluids. The composition is most especially adapted for administering carbamazepine.

Abstract: An osmotic dispensing delivery system suitable for oral administration, containing a pharmaceutically acceptable active agent for the controlled continuous release of about 50 to about 90 percent by weight of said active agent into the gastrointestinal tract at a rate of about 5 to about 12 percent by weight of said agent per hour consisting essentially of:(a) a shaped solid core containing an osmotically active composition comprising an effective amount of a pharmaceutically acceptable active agent, alone or in combination with a pharmaceutically acceptable binder, an osmotically active driving agent, or tabletting lubricant, or mixtures thereof;(b) said core being substantially evenly coated with a discrete layer of a water-soluble, or water-dispersible, and water permeable substantially non-osmotically active solid polymeric binder, said binder layer being present in an amount between about 0.