Osmotically driven delivery devices with pulsatile effect

An osmotically driven device for placement in an aqueous environment for pulsatile delivery of a beneficial agent to said environment, said device comprising:

• an elongate enclosure having a longitudinal axis, first and second ends, an inner wall surface and an orifice at said first end, at least a portion of said enclosure adjacent to said second end being permeable to moisture;
• a partition dividing the interior of said enclosure into first and second compartments adjacent to said first and second ends, respectively, for retention of said beneficial agent and an osmotically active agent, respectively, said partition comprised of first and second members joined to each other by compressible means, said first member positioned closest to said first end of said enclosure and said second member positioned closest to said second end of said enclosure;
• a plurality of stop means on said inner wall surface, spaced longitudinally thereon;
• said stop means offering a first resistance to passage of said first member, and said inner wall surface between said stop means offering a second resistance to passage of said first member, said second resistance substantially less than said first resistance, and said stop means and said inner wall surface offering substantially less resistance to passage of said second member than to the passage of said first member.