ON THE RETENTION OF DIURETICS IN MICELLAR LIQUID-CHROMATOGRAPHY AND THEIR SITE OF ACTION WITHIN THE NEPHRON

The therapeutical action of diuretics has been attributed to their hyd rophobic character, among other properties. Therapeutical and physiolo gical classifications of diuretics are correlated. The site of action of high efficacy diuretics is the loop of Henle, that of intermediate efficacy diuretics is the distal tubule and that of low efficacy diure tics is the proximal and distal tubules. and the collected duct.Partit ion coefficients between water and micelles offer a scale for hydropho bicity, which leads to a further correlation between' retention in Mic ellar Liquid Chromatography (MLC), with a sodium dodecyl sulphate mobi le phase and an ODS-C18 column, and the sites of action within the nep hron. The site of action of those diuretics showing the lower retentio n in MLC is the proximal tubule (acetazolamide) and the loop of Henle (loop diuretics), for those diuretics with an intermediate retention i s the distal tubule (thiazides), and for those with a long retention i s the collecting duct (potassium sparing diuretics).