US4218433A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Constant-rate eluting tablet and method of producing same
Assignee: Nippon Kayaku Co Ltd
•
Filing: 1978-02-27
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Granted: 1980-08-19
•
Expires: 1998-02-27
Abstract
Abstract A tablet formed with a hollow or hollows in its surface and containing a water-soluble component is coated with a coating agent which is insoluble in water but has water permeability, thereby to obtain a constant-rate eluting medicinal tablet. A process of producing such tablet is also disclosed.
Inventors
- 👤 Yoshida Kooichi
- 👤 Shozi Eitoshi
- 👤 Ootaki Hiroshi
- 👤 Terada Takashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:59
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/20; A61K9/2072
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
139 words
A method of producing a constant-rate eluting tablet comprising the steps of molding a medicinal composition containing a water-soluble substance or substances with a pestle having a convexity or convexities to form a tablet having a hollow or hollows, and then coating this tablet with a coating agent which is insoluble in water but has water permeability, said hollow measuring 0.1 to 1.0 mm in width, 0.1 to 0.4 mm in depth and greater than 0.1 mm in length, and as for the area less than 1/6 of the overall surface area of the tablet, wherein the coating agent insoluble in water but having water permeability is a methacrylic acid--methacrylic acid ester copolymer, ethyl cellulose, cellulose acetate, polyvinyl acetate, cellulose acetate phthalate or hydroxypropyl cellulose phthalate, and wherein the coating thickness is within the range of 30 to 150μ.
Claim 2
Independent Claim
139 words
A method of producing a constant-rate eluting tablet comprising the steps of molding a medicinal composition containing a water-soluble substance or substances with a pestle having a convexity or convexities to form a tablet having a hollow or hollows, and then coating this tablet with a coating agent which is insoluble in water but has water permeability, said hollow measuring 0.1 to 1.0 mm in width, 0.1 to 0.4 mm in depth and greater than 0.1 mm in length, and as for the area less than 1/6 of the overall surface area of the tablet, wherein the coating agent insoluble in water but having water permeability is a methacrylic acid--methacrylic acid ester copolymer, ethyl cellulose, cellulose acetate, polyvinyl acetate, cellulose acetate phthalate or hydroxypropyl cellulose phthalate, and wherein the coating thickness is within the range of 30 to 150μ.
Claim 3
Dependent Claim
126 words
A constant-rate eluting tablet made in accordance with the method of claim 1 by coating a bare tablet having a hollow or hollows in its surface and containing a water-soluble component with a coating agent which is insoluble in water but has water permeability, said hollow measuring 0.1 to 1.0 mm in width, 0.1 to 0.4 mm in depth and greater than 0.1 mm in length, and as for the area less than 1/6 of the overall surface area of the tablet, wherein the coating agent insoluble in water but having water permeability is a methacrylic acid--methacrylic acid ester copolymer, ethyl cellulose, cellulose acetate, polyvinyl acetate, cellulose acetate phthalate or hydroxypropyl cellulose phthalate, and wherein the coating thickness is within the range of 30 to 150μ.
Claim 4
Dependent Claim
15 words
A constant-rate eluting tablet of claim 1, wherein the water-soluble component is a water-soluble medicine.
Claim 5
Dependent Claim
21 words
A constant-rate eluting tablet of claim 1, wherein the water-soluble material is composed of a water-soluble medicine and a water-soluble excipient.
Claim 6
Dependent Claim
23 words
A constant-rate eluting tablet of claim 1, wherein the water-soluble component consists of a water-soluble medicine and a difficultly water-soluble or water-insoluble excipient.
Claim 7
Dependent Claim
23 words
A constant-rate eluting tablet of claim 1, wherein the water-soluble component consists of a difficultly water-soluble or water-insoluble medicine and a water-soluble excipient.
References Cited (Backward Citations)
US216107A
Cited
FR442266A
Cited
US3113076A
Cited
US3146169A
Cited
US3279995A
Cited
US3775537A
Cited
GB1372040A
Cited
US3845770A
Cited
US3917813A
Cited
US4083949A
Cited
US4096238A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-08-19 | 1984-02-18 | 1984-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-08-19 | 1988-02-18 | 1988-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-08-19 | 1992-02-18 | 1992-08-19 | $7700.00 | Window Closed / Lapsed |