US4851233A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sustained release formulations
Assignee: Warner Lambert Co LLC
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Filing: 1986-10-06
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Granted: 1989-07-25
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Expires: 2006-10-06
Abstract
Abstract A new drug delivery system, which gives sustained release properties is made by combining certain cellulosic polymers with cellulose in a binder system.
Inventors
- 👤 Sadath U. Khan
- 👤 Reginald Phillips
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:04
CPC Classifications
A; A61; A61K; A61K31/00; A61K31/185; A61K31/19; A61K31/195; A61K31/21; A61K31/215; A61K31/235; A61K31/24; A61K31/245; A61K9/00; A61K9/20; A61K9/2004; A61K9/2022; A61K9/205; A61K9/2054
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
92 words
A compressed tablet binder system mixture consisting essentially of: (a) about 60-90 wt % of procainamide hydrochloride or sodium meclofenamate, (b) about 5-20 wt % of a Type "H" hydroxy ethyl cellulose, and (c) about 5-15 wt % of microcrystalline cellulose, which is further coated by the hydroxy ethyl cellulose; said hydroxy ethyl cellulose rapidly hydrating to a transient gel state which persists long enough to provide a sustained dissolution with drug release occurring via a slow diffusion and matrix erosion; said tablet being completely disintegrated at the end of drug dissolution.
Claim 2
Dependent Claim
92 words
A compressed tablet binder system mixture consisting essentially of: (a) about 60-90 wt % of procainamide hydrochloride or sodium meclofenamate, (b) about 5-20 wt % of a Type "H" hydroxy ethyl cellulose, and (c) about 5-15 wt % of microcrystalline cellulose, which is further coated by the hydroxy ethyl cellulose; said hydroxy ethyl cellulose rapidly hydrating to a transient gel state which persists long enough to provide a sustained dissolution with drug release occurring via a slow diffusion and matrix erosion; said tablet being completely disintegrated at the end of drug dissolution.
Claim 3
Dependent Claim
10 words
The composition of claim 1 wherein (a) comprises procainamide hydrochloride.
Claim 4
Dependent Claim
10 words
The composition of claim 1 wherein (a) comprises sodium meclofenamate.
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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) | 1992-07-24 | 1993-01-23 | 1993-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-24 | 1997-01-23 | 1997-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-24 | 2001-01-23 | 2001-07-25 | $7700.00 | Window Closed / Lapsed |