US3013074A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tetracycline purification process
Assignee: Pfizer Inc
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Filing: 1960-05-23
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Granted: 1961-12-12
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Expires: 1980-05-23
Abstract
No abstract record available.
Inventors
- 👤 Joseph A Kardys
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:44
CPC Classifications
C; C07; C07C; C07C233/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
96 words
THE PROCESS OF PURIFYING TETRACYCLINE WHICH COMPRISES CRYSTALLIZING SAID ANTIBIOTIC FROM AN IMPURE SOLUTION THEREOF IN AQUEOUS ALCOHOL BY MAINTAINING THE PH OF SAID SOLUTION BETWEEN ABOUT 2.5 AND 9.5, SAID ALCOHOL BEING SELECTED FROM THE GROUP CONSISTING OF ALKANOLS HAVING UP TO 3 CARBON ATOMS AND ETHYLENE GLYCOL MONOALKYL ETHERS HAVING A TOTAL OF 3 TO 4 CARBON ATOMS, SAID SOLUTION HAVING DISSOLVED THEREIN A CITRATE SELECTED FROM THE GROUP CONSISTING OF CITRIC ACID, ALKALI METAL CITRATES, AND AMMONIUM CITRATES AT A CONCENTRATION OF AT LEAST ABOUT 3 MILLIMOLES PER GRAM OF TETRACYCLINE BASE ACTIVITY.
Claim 2
Dependent Claim
96 words
THE PROCESS OF PURIFYING TETRACYCLINE WHICH COMPRISES CRYSTALLIZING SAID ANTIBIOTIC FROM AN IMPURE SOLUTION THEREOF IN AQUEOUS ALCOHOL BY MAINTAINING THE PH OF SAID SOLUTION BETWEEN ABOUT 2.5 AND 9.5, SAID ALCOHOL BEING SELECTED FROM THE GROUP CONSISTING OF ALKANOLS HAVING UP TO 3 CARBON ATOMS AND ETHYLENE GLYCOL MONOALKYL ETHERS HAVING A TOTAL OF 3 TO 4 CARBON ATOMS, SAID SOLUTION HAVING DISSOLVED THEREIN A CITRATE SELECTED FROM THE GROUP CONSISTING OF CITRIC ACID, ALKALI METAL CITRATES, AND AMMONIUM CITRATES AT A CONCENTRATION OF AT LEAST ABOUT 3 MILLIMOLES PER GRAM OF TETRACYCLINE BASE ACTIVITY.
Claim 3
Dependent Claim
115 words
THE PROCESS OF PURIFYING TETRACYCLINE WHICH COMPRISES CRYSTALLIZING SAID ANTIBIOTIC FROM AN IMPURE SOLUTION THEREOF IN AQUEOUS ALCOHOL BY MAINTAINING THE PH OF SAID SOLUTION BETWEEN ABOUT 2.5 AND 9.5, SAID ALCOHOL BEING SELECTED FROM THE GROUP CONSISTING OF ALKANOLS HAVING UP TO 3 CARBON ATOMS AND ETHYLENE GLYCOL MONOALKYL ETHERS HAVING A TOTAL OF 3 TO 4 CARBON ATOMS, SAID SOLUTION HAVING DISSOLVED THEREIN A CITRATE SELECTED FROM THE GROUP CONSISTING OF CITRIC ACID, ALKALI METAL CITRATES, AND AMMONIUM CITRATES AT A CONCENTRATION BETWEEN ABOUT 3 AND ABOUT 20 MILLIMOLES PER GRAM OF TETRACYCLINE BASE ACTIVITY, AND UREA AT A CONCENTRATION BETWEEN ABOUT 1 AND ABOUT 6 MILLIMOLES PER GRAM OF TETRACYCLINE BASE ACTIVITY.
Claim 4
Dependent Claim
115 words
THE PROCESS OF PURIFYING TETRACYCLINE WHICH COMPRISES CRYSTALLIZING SAID ANTIBIOTIC FROM AN IMPURE SOLUTION THEREOF IN AQUEOUS ALCOHOL BY MAINTAINING THE PH OF SAID SOLUTION BETWEEN ABOUT 2.5 AND 9.5, SAID ALCOHOL BEING SELECTED FROM THE GROUP CONSISTING OF ALKANOLS HAVING UP TO 3 CARBON ATOMS AND ETHYLENE GLYCOL MONOALKYL ETHERS HAVING A TOTAL OF 3 TO 4 CARBON ATOMS, SAID SOLUTION HAVING DISSOLVED THEREIN A CITRATE SELECTED FROM THE GROUP CONSISTING OF CITRIC ACID, ALKALI METAL CITRATES, AND AMMONIUM CITRATES AT A CONCENTRATION BETWEEN ABOUT 3 AND ABOUT 20 MILLIMOLES PER GRAM OF TETRACYCLINE BASE ACTIVITY, AND UREA AT A CONCENTRATION BETWEEN ABOUT 1 AND ABOUT 6 MILLIMOLES PER GRAM OF TETRACYCLINE BASE ACTIVITY.
References Cited (Backward Citations)
US2905662A
Cited
US2929837A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-12-11 | 1965-06-12 | 1965-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-12-11 | 1969-06-12 | 1969-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-12-11 | 1973-06-12 | 1973-12-12 | $7700.00 | Window Closed / Lapsed |