CHROMATOGRAPHIC DETERMINATION OF DIURETICS IN URINE SAMPLES USING HYBRID MICELLAR MOBILE PHASES WITH FLUOROMETRIC DETECTION

A rapid and simple chromatographic procedure, that uses hybrid micella r mobile phases of sodium dodecyl sulphate (SDS), propanol and phospha te buffer at pH 3, and fluorimetric detection (lambda(exc)=270nm, lamb da(em)=430nm), is reported for the determination of mixtures of seven diuretics of diverse efficacy (amiloride, bendroflumethiazide, bumetan ide, furosemide, hydroflumethiazide, piretanide and triamterene), in u rine samples. The application of a sequential optimization procedure f or the resolution of the mixtures of the diuretics was problematic. Ho wever, their separation was achieved through the use of an interpretiv e optimization procedure based on the accurate description of the rete ntion. The optimum mobile phase contained 0.055 M SDS-8% propanol. The limits of detection (ng/ml) and inter-day reproducibilities (%) in th e urine samples were: amiloride (9.7, 5.7), bendroflumethiazide (10, 8 .8), bumetanide (1.4, 3.6), hydroflumethiazide (7.1, 5.6), piretanide (54, 4.1), and triamterene (1.7, 1.4). Detection of urinary excretion of the diuretics was possible at least up to 24-72 h after their inges tion. Injection of furosemide standards originated four chromatographi c peaks, which corresponded to the drug and diverse impurities. (C) 19 98 Elsevier Science B.V. All rights reserved.