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Patent US4223109A successfully refreshed from Google Patents.
US4223109A
Expired / Lapsed
US
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Calcium salts of divinyl ether--maleic anhydride copolymer
Assignee: Pharmacia and Upjohn Co
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Filing: 1979-02-22
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Granted: 1980-09-16
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Expires: 1999-02-22
Abstract
Abstract The calcium salts of the solid cyclic copolymers of divinyl ether and maleic anhydride, soluble in water, have been found to be as effective in treating tumors and viruses as the prior art alkali metal salts (e.g., the sodium salt) but much less toxic. These copolymers are characterized by containing divinyl ether and maleic anhydride in a mole ratio of about 1:2, having a molecular weight of from about 2000 to about 100,000 and from about 5% to about 70% of its carboxylic acid groups converted to calcium salts.
Inventors
- 👤 Richard L. Wolgemuth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:13
CPC Classifications
C; C08; C08F; C08F8/00; C08F8/44; Y; Y10; Y10S; Y10S260/00; Y10S260/47
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
31 words
The calcium salt of a solid, cyclic copolymer of divinyl ether and maleic anhydride, soluble in water and containing divinyl ether and meleic anhydride in a mole ratio of about 1:2.
Claim 2
Dependent Claim
31 words
The calcium salt of a solid, cyclic copolymer of divinyl ether and maleic anhydride, soluble in water and containing divinyl ether and meleic anhydride in a mole ratio of about 1:2.
Claim 3
Dependent Claim
46 words
The calcium salt of claim 1 where the solid cyclic copolymer has a molecular weight, as determined by gel permeation chromatography, of from about 2000 to about 100,000 and from about 5% to about 70% of its carboxylic acid groups are converted to the calcium salt.
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) | 1983-09-16 | 1984-03-17 | 1984-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-16 | 1988-03-17 | 1988-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-16 | 1992-03-17 | 1992-09-16 | $7700.00 | Window Closed / Lapsed |