Osmotic dispenser with means for dispensing active agent responsive to osmotic gradient
Patent 3995631 Issued on December 7, 1976. Estimated Expiration Date: 
December 7, 1993. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
December 7, 1993. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 2962023 3468308 3496937 3556992 3561644 3604417 3641237 3732865 3760984 InventorsApplicationNo. 291686 filed on 09/25/1972US Classes:604/892.1, Osmotic or diffusion pumped device or system222/95, With wall-collapsing means424/427, Ocular424/430Vaginal, urethral, uterineExaminersPrimary: Medbery, Aldrich F.Attorney, Agent or FirmForeign Application Priority Data1972-01-11 ILAbstractAn osmotic active agent dispenser is comprised of a chamber having controlled permeability to an external fluid, i.e., water, and containing an osmotically effective solute which, in solution, exhibits an osmotic pressure gradient against said external fluid, said chamber housing a flexible bag of relatively impervious material containing an active agent and provided with means or dispensing head for releasing said active agent to the exterior of the dispenser. The flexible bag is disposed within the said housing chamber such that as the, e.g., water permeates from the external environment through the permeable walls of the chamber and migrates or diffuses by osmosis into the solution contained therein, same increases in volume thereby generating mechanical compressing or deflating force on the flexible bag, which force in turn ejects the active agent out of the apparatus at an osmotically controlled rate over a prolonged period of time.Other References
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