Determination of Some Tetracyclines Spectrophotometrically by Flow Injection Analysis

Abstract
A spectrophotometric method for the determination of some tetracyclines is described. The suggested method is based on the reaction of the drug with sodium tungstate at pH 6 to form a yellow complex which can be determined spec trophotometrically. The complexes show absorption maxima at 380, 3385 and 390 nm for oxytetracycline hydrochloride(OTCH), doxycycline hydrochloride(DCH) and chlortetracycline hydro-chloride(CTCH), respectively. These drugs can be determined either in pure form or in pharmaceutical preparations.