US4350271A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Water absorbing fluid dispenser
Assignee: Alza Corp
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Filing: 1980-08-22
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Granted: 1982-09-21
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Expires: 2000-08-22
Abstract
Abstract A fluid dispenser that operates by absorbing water is disclosed. The dispenser includes a rigid water permeable housing; a water insoluble, water swellable composition that fills a segment of the space within the housing, a lipophilic fluid charge that fills the remainder of the space within the housing and that is immiscible in the water-swellable composition, and an outlet through the housing that communicates with the fluid charge. In operation the water swellable composition absorbs water, expands, and in piston-like fashion displaces the fluid charge from the dispenser via the outlet.
Inventors
- 👤 James B. Eckenhoff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:59
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/0002; A61K9/0004; A61M; A61M31/00; A61M31/002
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
79 words
Fluid dispenser for use in a water containing environment comprising: (a) a rigid, water permeable housing; (b) a water insoluble, water swellable composition filling a portion of the space within the housing and being in contact with the housing; (c) a fluid lipophilic composition filling the remainder of the space within the housing, said fluid composition being substantially immiscible in the water swellable composition; and (d) fluid composition outlet means in the housing that communicates with the fluid composition.
Claim 2
Dependent Claim
79 words
Fluid dispenser for use in a water containing environment comprising: (a) a rigid, water permeable housing; (b) a water insoluble, water swellable composition filling a portion of the space within the housing and being in contact with the housing; (c) a fluid lipophilic composition filling the remainder of the space within the housing, said fluid composition being substantially immiscible in the water swellable composition; and (d) fluid composition outlet means in the housing that communicates with the fluid composition.
Claim 3
Dependent Claim
26 words
The dispenser of claim 1 wherein said lipophilic composition and said water swellable composition form therebetween a substantially contiguous interface extending substantially completely across said container.
Claim 4
Dependent Claim
45 words
The dispenser of claim 1 or 2 wherein the outlet means is a plurality of micropores in the housing that permit passage of the fluid composition when hydraulic pressure is applied to the fluid composition and do not permit passage of the water swellable composition.
Claim 5
Dependent Claim
18 words
The dispenser of claim 1 or 2 wherein the outlet means is a single orifice in the housing.
Claim 6
Dependent Claim
30 words
The dispenser of claim 1 or 2 wherein the water swellable composition is comprised of polyethylene oxide having a molecular weight in the range of about 100,000 to about 4,000,000.
Claim 7
Dependent Claim
47 words
The dispenser of claim 1 or 2 wherein said housing is tubular and provided with rigid ends resistant to the hydraulic pressure generated within said housing, said water swellable composition fills one end of said dispenser and said fluid lipophilic composition fills the other of said ends.
Claim 8
Dependent Claim
19 words
The dispenser of claim 6 wherein the outlet means is an orifice in said other end of said housing.
References Cited (Backward Citations)
US3865108A
Cited
US4203439A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-09-20 | 1986-03-22 | 1986-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-09-20 | 1990-03-22 | 1990-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-09-20 | 1994-03-22 | 1994-09-21 | $7700.00 | Window Closed / Lapsed |