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US 4,874,388 AGranted
Multi-layer delivery system
AssigneeAlza Corporation
InventorsPatrick S. L. Wong, Felix Theeuwes, James B. Eckenhoff
Life of this patent
Estimating the term…
Abstract
A dispenser for use in a fluid environment having a rigid housing containing a fluid activated driving member, a plurality of drug containing layers and an outlet means by which drug is dispensed to the environment. The housing adjacent to the layers is fluid impermeable and the housing adjacent to the driving member is fluid permeable or has an open area by which fluid can contact the driving member. O048743884
Claims26
A drug dispenser for use in a fluid-containing environment comprising, in combination:
- a. a rigid housing having an outlet at one end thereof;
- b. a fluid activated driving member within a portion of said housing proximate the end of said housing opposite to said outlet and in contact with said housing, at least that portion of the housing contacting the driving member having a predetermined permeation rate to the environmental fluid;
- c. a first set of drug layers longitudinally disposed within said housing between said driving means and said outlet;
- d. a second set of layers longitudinally disposed within said housing and alternating with said first drug layers;
- and
- e. an expansion chamber defining an empty volume within said housing between the drug layer most proximate the outlet and the outlet;
- whereby said drug layers must be displaced through the expansion chamber by said driving means after exposure of said dispenser to the fluid environment.
4 more elements
Dependencies are inferred from the claim text.