US3629237A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Compositions useful as enteric coatings and method for preparing acid phthalates of cellulose ethers for them
Assignee: Shin-Etsu Chemical Co Ltd
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Filing: 1969-09-02
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Granted: 1971-12-21
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Expires: 1989-09-02
Abstract
Abstract ACID PHTHALATE OF CELLULOSE ETHERS REPRESENTED BY THE GENERAL FORMULA: R1MR2NA WHERE R1 IS A HYDROXYALKYL GROUP OF 3 OR 4 CARBON ATOMS, R2, HYDROGEN OR AN ALKYL GROUP OF 1 OR 2 CARBON ATOMS, M AND N ARE POSITIVE INTEGERS, AND A IS RESIDUAL CELLULOSE STRUCTURE WHICH ETHERS ARE READILY SOLUBLE IN WEAK ALKALINE SOLUTION, BESIDES POSSESSING HIGH SOLUBILITY IN ORGANIC SOLVENTS AND EXCELLENT RESISTANCE TO WATER; THEY ARE USEFUL AS ENTERIC COATINGS, AND DRUGS COATED WITH THEM CAN STAND LONG STORAGE AND ARE READILY SOLUBLE UPON PASSING INTO THE INTESTINES, THEREBY ENHANCING THE EFFECT OF THE DRUGS.
Inventors
- 👤 Shunichi Koyanagi
- 👤 Kinya Ogawa
- 👤 Akira Yamamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:04
CPC Classifications
C; C08; C08B; C08B11/00; C08B11/02; C08B11/04; C08B11/08; A; A61; A61K; A61K9/00; A61K9/20; A61K9/28; A61K9/2806; A61K9/2833; A61K9/286; A61K9/2866; C08B11/193; C08B13/00; C08B3/00; C08B3/12
Claims Analysis
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-20 | 1975-06-21 | 1975-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-20 | 1979-06-21 | 1979-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-20 | 1983-06-21 | 1983-12-21 | $7700.00 | Window Closed / Lapsed |