Patent US4816262A successfully refreshed from Google Patents.
US4816262A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Controlled release tablet
Assignee: University of Montreal
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Filing: 1986-08-28
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Granted: 1989-03-28
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Expires: 2006-08-28
Abstract
Abstract The disclosure herein describes a controlled release tablet which includes a core formed of a solid mixture having a hydrophilic releasable agent; the core has a central hole and is coated, on all faces except that bordering the hole with a hydrophobic material. The thickness of the core gradually increases from the hole to the outer border, this being a factor in the rate of release of the mixture through the hole. One application of such a tablet is for the controlled release of a therapeutic agent in the field of drug delivery systems.
Inventors
- 👤 Jean N. McMullen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:20
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/20; A61K9/2072
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
87 words
A pharmaceutical tablet comprising: a body having a disc-like configuration with a cylindrical hole extending centrally therethrough, said body including: a core formed of a compressed mixture of a therapeutic agent and of a biocompatible polymeric material, said core being defined by centrally tapering upper and lower annular faces and by inner and outer cylindrical faces; and a coating of impermeable material covering said upper and lower annular faces and said outer cylindrical face; said agent being released from said hole at a biological site of absorption.
Claim 2
Dependent Claim
87 words
A pharmaceutical tablet comprising: a body having a disc-like configuration with a cylindrical hole extending centrally therethrough, said body including: a core formed of a compressed mixture of a therapeutic agent and of a biocompatible polymeric material, said core being defined by centrally tapering upper and lower annular faces and by inner and outer cylindrical faces; and a coating of impermeable material covering said upper and lower annular faces and said outer cylindrical face; said agent being released from said hole at a biological site of absorption.
Claim 3
Dependent Claim
35 words
A pharmaceutical tablet as defined in claim 1, wherein said coating on said upper and lower annular faces defines flat upper and lower surfaces extending in a plane subtantially parallel to that of said body.
Claim 4
Dependent Claim
26 words
A pharmaceutical tablet as defined in claim 1 or 2, wherein said annular faces define an angle of 30° relative to the plane of said body.
Claim 5
Dependent Claim
26 words
A pharmaceutical tablet as defined in claim 1 or 2, wherein said annular faces define an angle of 20° relative to the plane of said body.
References Cited (Backward Citations)
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US2312381A
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US3113076A
Cited
US3146169A
Cited
US3279995A
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GB1372040A
Cited
US4218433A
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US4663147A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-27 | 1992-09-26 | 1993-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-27 | 1996-09-26 | 1997-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-27 | 2000-09-26 | 2001-03-28 | $7700.00 | Window Closed / Lapsed |