US2804476A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for separating tetracycline and chlortetracycline
Assignee: Pfizer Inc
•
Filing: 1954-04-14
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Granted: 1957-08-27
•
Expires: 1974-04-14
Abstract
No abstract record available.
Inventors
- 👤 Virgil V Bogert
- 👤 Chester J Walsh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:38
CPC Classifications
C; C07; C07C; C07C233/00; Y; Y10; Y10S; Y10S435/00; Y10S435/8215; Y10S435/822; Y10S435/886; Y10S435/889
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
79 words
A PROCESS FOR SEPARATING TETRACYCLINE FROM AQUEOUS SOLUTIONS CONTAINING THE SAME AND APPRECIABLE QUANTITIES OF CHLORTETRACYCLINE, WHICH COMPRISES ADJUSTING THE SAID SOLUTION TO A PH BETWEEN ABOUT 0.5 AND 3.5, EXTRACTING THE TWO ANTIBIOTICS INTO A WATER-IMMISCIBLELOWER ALCOHOL, SELECTED FROM THE CLASS CONSISTING OF BUTANOLS, PENTANOLS AND HEXANOLS, SEPARATING THE RESULTING EXTRACT, WASHING THE SAID EXTRACT WITH WATER WHILE ADJUSTING THE PH OF THE AQUEOUS PHASE TO A PH BETWEEN ABOUT 5 AND 8, WHEREBY TETRACYCLINE CRYSTALS ARE PRECIPITATED.
Claim 2
Dependent Claim
79 words
A PROCESS FOR SEPARATING TETRACYCLINE FROM AQUEOUS SOLUTIONS CONTAINING THE SAME AND APPRECIABLE QUANTITIES OF CHLORTETRACYCLINE, WHICH COMPRISES ADJUSTING THE SAID SOLUTION TO A PH BETWEEN ABOUT 0.5 AND 3.5, EXTRACTING THE TWO ANTIBIOTICS INTO A WATER-IMMISCIBLELOWER ALCOHOL, SELECTED FROM THE CLASS CONSISTING OF BUTANOLS, PENTANOLS AND HEXANOLS, SEPARATING THE RESULTING EXTRACT, WASHING THE SAID EXTRACT WITH WATER WHILE ADJUSTING THE PH OF THE AQUEOUS PHASE TO A PH BETWEEN ABOUT 5 AND 8, WHEREBY TETRACYCLINE CRYSTALS ARE PRECIPITATED.
References Cited (Backward Citations)
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Cited
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-08-26 | 1961-02-25 | 1961-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-08-26 | 1965-02-25 | 1965-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-08-26 | 1969-02-25 | 1969-08-27 | $7700.00 | Window Closed / Lapsed |