Patent US2693435A successfully refreshed from Google Patents.
US2693435A
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Vitamin a ester composition and process of preparing vitamin a ester
Assignee: Pfizer Inc
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Filing: 1952-02-01
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Granted: 1954-11-02
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Expires: 1972-02-01
Abstract
No abstract record available.
Inventors
- 👤 William E Stieg
- 👤 Axel T Nielsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 09:27
CPC Classifications
A; A61; A61K; A61K31/00; A61K31/59
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
40 words
A PROCESS FOR THE PREPARATION OF A MIXTURE OF EDIBLE OIL FATTY ACID ESTERS OF VITAMIN A, WHICH PROCESS COMPRISES CONTACTING A LOWER ALKANOIC ACID ESTER OF VITAMIN A WITH AN EDIBLE OIL IN THE PRESENCE OF AN ALKALINE CATALYST.
Claim 2
Dependent Claim
40 words
A PROCESS FOR THE PREPARATION OF A MIXTURE OF EDIBLE OIL FATTY ACID ESTERS OF VITAMIN A, WHICH PROCESS COMPRISES CONTACTING A LOWER ALKANOIC ACID ESTER OF VITAMIN A WITH AN EDIBLE OIL IN THE PRESENCE OF AN ALKALINE CATALYST.
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) | 1957-11-01 | 1958-05-03 | 1958-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-11-01 | 1962-05-03 | 1962-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-11-01 | 1966-05-03 | 1966-11-02 | $7700.00 | Window Closed / Lapsed |