A high performance liquid chromatographic method for the screening of 17 diuretics in human urine

A simple and adequate HPLC method was developed for screening of human urin e for the following 17 diuretic drugs: acetazolamide, bendrofluazide, bumet anide, canrenoic acid, chlorothiazide, chlorthalidone, clopamide, epitizide , etacrynic acid, furosemide, hydrochlorothiazide, indapamide, mefruside, p iretanide, spironolactone, torasemide, and triamterene. The assay involves extraction from two 2 mL urine samples with ethyl acetate at pH = 5, washin g with a phosphate buffer at pH = 6 and analysis by HPLC using a reversed p hase C18 column and ultraviolet detection with a diode array detector for a ll drugs (except triamterene) using two eluents consisting of water, trieth ylamine, phosphoric acid and acetonitrile at different ratios and different pH values. Triamterene is determined by direct injection of diluted urine onto the column and is measured by fluorescence detection. The recoveries o f the diuretic drugs were determined at two different concentrations and ra nged from 43-110% (median: 87%) which is sufficient to detect abuse of thes e drugs. The repeatability of the assay ranged from 1-12% (median: 5.5%).