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US 5,663,415 AGranted
Process for preparing antihistamine tannates
AssigneeJame Fine Chemicals, Inc.
InventorsVilas M. Chopdekar, James R. Schleck, Vernon A. Brown, Cheng Guo
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Abstract
A process for preparing pure antihistamine tannate compositions. The antihistamine in the form of its free base is contacted with tannic acid in the presence of water for a period of time of about 5 minutes to 4 hours and at a maximum temperature such that not more than about 5 wt. % of the antihistamine tannate will be decomposed. Water is removed from the antihistamine tannate by freeze-drying.
Claims10
A process for preparing an antihistamine tannate composition which comprises the steps of:
- (a) contacting an antihistamine in the form of its free base with tannic acid in the presence of water at a maximum temperature which will not cause decomposition of the antihistamine tannate to an extent of greater than about 5 wt %, based on the weight of the antihistamine tannate;
- (b) allowing the antihistamine to remain in contact with the tannic acid in the presence of water for a period of time in the range of about 5 minutes to 4 hours at said maximum temperature;
- and
- (c) freeze-drying the antihistamine tannate resulting from step (b) at a temperature and at a reduced pressure and for such period of time that (i) at least about 90 wt. % of the water is removed from the antihistamine tannate and (ii) decomposition of the antihistamine tannate will be limited to a maximum of about 5 wt. %.
1 more element
Dependencies are inferred from the claim text.