Patent US4351825A successfully refreshed from Google Patents.
US4351825A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the preparation of tablets with retarded liberation of the active agent is predetermined
Assignee: Orion Oyj
•
Filing: 1980-01-14
•
Granted: 1982-09-28
•
Expires: 2000-01-14
Abstract
Abstract A process for the preparation of matrix-type tablets with retarded liberation of the active agent. The liberation of the active agent from the tablets takes place at a speed that has been adjusted precisely in advance. In the granulation process, polymethacrylate plastics insoluble in neutral or slightly acid water either as dissolved in an organic solvent or as a water dispersion are used as the retarding matrix substance. Before the tablets are compressed, an ester of a large-molecule fatty acid or a product obtained from same by means of hydrogenation is mixed into the grain mix in order to adjust the rate of liberation of the active agent.
Inventors
- 👤 Gunnar A. Sothmann
- 👤 Esko V. Marttila
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:09
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/20; A61K9/2004; A61K9/2013; A61K9/2022; A61K9/2027
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
121 words
Process for the preparation of controlled release tablets containing an active agent comprising: (a) granulating the active agent with an organic solvent solution or a water dispersion of a copolymerizate of acrylic and methacrylic acid esters containing quaternary ammonium groups or an anionic copolymerizate of methacrylic acid and methyl ester of methacrylic acid; (b) mixing the granules with an ester of a fatty acid containing 10 to 30 carbon atoms, said ester being present in an amount less than 15% of the total weight of the mixture whereby the granules are coated with said ester; and (c) compressing the resulting mixture into tablets whereby the tablets release the active agent at a rate which is substantially independent of the compression pressure.
Claim 2
Dependent Claim
121 words
Process for the preparation of controlled release tablets containing an active agent comprising: (a) granulating the active agent with an organic solvent solution or a water dispersion of a copolymerizate of acrylic and methacrylic acid esters containing quaternary ammonium groups or an anionic copolymerizate of methacrylic acid and methyl ester of methacrylic acid; (b) mixing the granules with an ester of a fatty acid containing 10 to 30 carbon atoms, said ester being present in an amount less than 15% of the total weight of the mixture whereby the granules are coated with said ester; and (c) compressing the resulting mixture into tablets whereby the tablets release the active agent at a rate which is substantially independent of the compression pressure.
Claim 3
Dependent Claim
36 words
A process as claimed in claim 1, characterized in that a water dispersion of a copolymerizate of methyl and ethyl esters of acrylic and methacrylic acid with neutral character is used as the retarding matrix substance.
Claim 4
Dependent Claim
25 words
A process as claimed in claims 2 or 1, characterized in that the fatty acid ester is hydrogenated castor oil or hydrogenated cotton seed oil.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-09-27 | 1986-03-29 | 1986-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-09-27 | 1990-03-29 | 1990-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-09-27 | 1994-03-29 | 1994-09-28 | $7700.00 | Window Closed / Lapsed |