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Osmotic device having microporous reservoir

  • US 3,977,404 A
  • Filed: 09/08/1975
  • Issued: 08/31/1976
  • Est. Priority Date: 09/08/1975
  • Status: Expired due to Term
First Claim
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1. An osmotic device for the continuous dispensing of an active agent to an environment of use, said device comprising:

  • a. a shaped wall formed of a semipermeable material that maintains its integrity during the dispensing period and is characterized as permeable to the passage of an external fluid in the environment of use and substantially impermeable to the passage of the active agent with the wall surrounding in at least a part;

    b. a reservoir formed of a material having a plurality of micropores with the reservoir containing an active agent that is soluble in the external fluid and exhibits an osmotic pressure gradient across the wall against the fluid;

    c. a passageway for dispensing agent from the device, said passageway consisting of at least one micropore that communicates with the reservoir and the exterior of the device; and

    d. wherein in operation with the device in the environment of use, external fluid is continuously imbibed through the wall into the reservoir in a tendency towards osmotic equilibrium at a rate determined by the permeability of the wall and the osmotic pressure gradient across the wall, thereby continuously dissolving the agent which is dispensed from the reservoir through the microporous passageway to the exterior of the device at a controlled rate over a prolonged period of time.

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