Abstract: A drug delivery capsule from which the delivery of the drug is driven by the osmotic infusion of moisture by the capsule from a physiological environment is provided with a delivery orifice which opens intermittently to achieve a pulsatile delivery effect. The wall in which the orifice is formed is constructed of an elastic material, preferably an elastomer, which stretches under a pressure differential caused by the pressure rise inside the capsule as the osmotic infusion progresses. The orifice is small enough that when the elastic wall is relaxed, the flow rate of drug through the orifice is substantially zero, but that when the elastic wall is stretched due to the pressure differential across the wall exceeding a threshold, the orifice expands sufficiently to allow the release of the drug at a physiologically beneficial rate.

Abstract: An osmotically driven syringe (20, 60) is disclosed which can be used to deliver a beneficial agent such as a drug, at varying pre-determined rates over multiple periods of time. The syringe (20, 60) is driven by an osmotic engine (10) having a shaped wall (12) containing an osmotic agent (17) and/or a gas generating means (19), such as an effervescent couple. The wall (12) is composed of a semipermeable and/or microporous material which is permeable to an external liquid (e.g., water) but which is substantially impermeable to the osmotic agent (17) and the gas generated by the gas generating means (19). The wall (12) has a passageway (13) therethrough to provide a flow path for the driving fluid generated by the engine (10). The osmotic agent(s) (17) and/or the gas generating means (19) are placed in the engine (10) in such a way as to drive engine (10) at different pumping rates (R.sub.1, R.sub.2) over sequential periods of time (t.sub.0 to t.sub.1 and t.sub.1 to t.sub.2).

Abstract: A method of preventing sensitization in transdermal drug delivery by the inclusion of a corticosteroid, which will be coextensively coadministered with the sensitizing agent.