US4704284A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Long-acting matrix tablet formulations
Assignee: Pfizer Inc
•
Filing: 1982-08-12
•
Granted: 1987-11-03
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Expires: 2002-08-12
Abstract
Abstract A pharmaceutical tablet which releases an initial burst of therapeutic agent and thereafter releases the agent at an essentially constant rate comprising an acid soluble therapeutic agent in an insoluble matrix, the tablet containing an acid insoluble, base soluble pharmaceutically acceptable component selected from polymers and fatty acids, a pharmaceutically acceptable organic acid and at least one pharmaceutically acceptable excipient, the component and the acid each being present in an amount of from about 1-25 percent by weight of the total composition.
Inventors
- 👤 Morgan L. Beatty
- 👤 Wayne A. Boettner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:21
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/20; A61K9/2072; A61K9/2077; A61K9/2004
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
126 words
A pharmaceutical tablet which releases an initial burst of therapeutic agent and thereafter releases said agent at an essentially constant rate comprising an acid-soluble therapeutic agent, an acid-insoluble, base-soluble pharmaceutically acceptable polymeric acid phthalate, and a pharmaceutically acceptable polycarboxylic acid in an insoluble matrix consisting of ethyl cellulose, hydrogenated vegetable oil or mixtures thereof, said phthalate being present in an amount of from about 1 to 25 percent by weight of said tablet, said acid being present in an amount of from about 7 to 20% by weight of said tablet, said matrix components being present in an amount of from about 2-10% by weight of said tablet and said therapeutic agent being present in an amount of from about 25-75% by weight of said tablet.
Claim 2
Dependent Claim
126 words
A pharmaceutical tablet which releases an initial burst of therapeutic agent and thereafter releases said agent at an essentially constant rate comprising an acid-soluble therapeutic agent, an acid-insoluble, base-soluble pharmaceutically acceptable polymeric acid phthalate, and a pharmaceutically acceptable polycarboxylic acid in an insoluble matrix consisting of ethyl cellulose, hydrogenated vegetable oil or mixtures thereof, said phthalate being present in an amount of from about 1 to 25 percent by weight of said tablet, said acid being present in an amount of from about 7 to 20% by weight of said tablet, said matrix components being present in an amount of from about 2-10% by weight of said tablet and said therapeutic agent being present in an amount of from about 25-75% by weight of said tablet.
Claim 3
Dependent Claim
18 words
The tablet of claim 1 wherein said phthalate is hydroxypropyl methylcellulose phthalate and said acid is citric acid.
Claim 4
Dependent Claim
19 words
The tablet of claim 2 wherein said phthalate is present in an amount of from 3-15 percent by weight.
Claim 5
Dependent Claim
11 words
The tablet of claim 1 wherein said therapeutic agent is trimazosin.
Claim 6
Dependent Claim
31 words
The tablet of claim 1 comprising about 40-60 weight % trimazosin, about 4-5 weight % ethyl cellulose, about 12-15 weight % citric acid and about 3-7 weight percent hydroxypropyl methylcellulose phthalate.
Claim 7
Dependent Claim
14 words
The tablet of claim 5 which also contains from about 7-8 weight percent zein.
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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) | 1990-11-02 | 1991-05-04 | 1991-11-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-02 | 1995-05-04 | 1995-11-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-02 | 1999-05-04 | 1999-11-03 | $7700.00 | Window Closed / Lapsed |