Identification of the thiazide diuretic drugs

Abstract

Abstract A method for detecting and identifying ten thiazide diuretic drugs in tablets, gastric washings and urine by ultraviolet spectrophotometry and paper chromatography is described. The thiazides can be detected by absorption maxima in the region 264 to 294mμ at concentrations of 5 μg/ml or lower. Identification is by ascending high temperature reverse phase paper chromatography using tributyrin treated paper and developing for 20 min at 90° with a phosphate buffer (pH 7614). Further differentiation is obtained with the solvent system amyl alcohol—0 880 ammonia (9:1) on Whatman No. 1 paper. The thiazides are located as absorbing or fluorescent spots in ultraviolet light (2534 Å) and these are confirmed by the stable red colour given by an alkaline sodium 1,2-naphthaquinone-4-sulphonate spray reagent. Many of these diuretics are co-extracted with barbiturates and may interfere with barbiturate determinations.