Process for preparing antihistamine tannates

摘要

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.