US4025613A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Timed-release aspirin
Assignee: Hitachi Ltd
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Filing: 1975-06-25
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Granted: 1977-05-24
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Expires: 1995-06-25
Abstract
Abstract A method for making multi-layer aspirin tablets including a timed-release layer by coating particles of standard aspirin prior to tabletting with an organic solvent solution containing cellulose acetate phthalate and a plasticizer and pressing together separate layers of the thus-coated aspirin and standard uncoated aspirin into a double-layer tablet.
Inventors
- 👤 Michael G. Guy
- 👤 Richard G. Powers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:22
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/20; A61K9/2095; A61J; A61J3/00; A61J3/10; A61K31/00; A61K31/60; A61K9/2072; A61K9/2086; A61K9/209; A61K9/48; A61K9/50; A61K9/5005; A61K9/5021; A61K9/5036; A61K9/5042
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
157 words
A method for making a multi-layer aspirin tablet including at least one layer having timed-release characteristics comprising: (a) mixing uncoated particles of standard 80 mesh U.S.P. aspirin with a non-aqueous solution comprised of about 5 to about 18 weight % cellulose acetate phthalate, a pharmaceutically acceptable plasticizer and a pharmaceutically acceptable solvent, the amount of said solution being sufficient to coat and impregnate each of the particles with said solution; (b) forming the resultant mixture into discrete granules; (c) drying said granules to remove substantially all of said solvent therefrom; (d) reducing the resultant granules to a size whereby they can pass through a 20 mesh screen; (e) homogenizing said reduced granules by mixing; (f) forming a first layer of said reduced granules containing no tabletting excipients; (g) forming a second layer of standard U.S.P. aspirin particles adjacent said first layer; and (h) compressing said layers together in a tabletting press to form said multi-layer aspirin tablet.
Claim 2
Independent Claim
157 words
A method for making a multi-layer aspirin tablet including at least one layer having timed-release characteristics comprising: (a) mixing uncoated particles of standard 80 mesh U.S.P. aspirin with a non-aqueous solution comprised of about 5 to about 18 weight % cellulose acetate phthalate, a pharmaceutically acceptable plasticizer and a pharmaceutically acceptable solvent, the amount of said solution being sufficient to coat and impregnate each of the particles with said solution; (b) forming the resultant mixture into discrete granules; (c) drying said granules to remove substantially all of said solvent therefrom; (d) reducing the resultant granules to a size whereby they can pass through a 20 mesh screen; (e) homogenizing said reduced granules by mixing; (f) forming a first layer of said reduced granules containing no tabletting excipients; (g) forming a second layer of standard U.S.P. aspirin particles adjacent said first layer; and (h) compressing said layers together in a tabletting press to form said multi-layer aspirin tablet.
Claim 3
Dependent Claim
21 words
A method according to claim 1 wherein the amount of cellulose acetate phthalate in said solution is about 15 weight %.
Claim 4
Dependent Claim
31 words
A method according to claim 1 wherein said solvent is selected from the group consisting of acetone, methyl ethyl ketone, methanol, ethanol, isopropanol, methylene chloride, ethylene dichloride, chloroform and mixtures thereof.
Claim 5
Dependent Claim
12 words
A method according to claim 3 wherein said plasticizer is diethyl phthalate.
Claim 6
Dependent Claim
21 words
A method according to claim 4 wherein the amount of said diethyl phthalate in said solution is about 3 weight %.
Claim 7
Dependent Claim
39 words
A method according to claim 3 wherein the amount of said cellulose acetate phthalate contained in each of said granules after drying is about 0.5 to about 5.0 % by weight, based on the total weight of said granule.
Claim 8
Dependent Claim
11 words
A multi-layer aspirin tablet produced by the process of claim 1.
References Cited (Backward Citations)
US3115441A
Cited
US3488418A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-23 | 1980-11-22 | 1981-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-23 | 1984-11-22 | 1985-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-23 | 1988-11-22 | 1989-05-24 | $7700.00 | Window Closed / Lapsed |