Single and multiple dose pharmacokinetics of sultosilic acid in humans

Single and multiple oral doses of Sultosilic acid were administered to four healthy volunteers. Plasma and Urine levels of unchanged Sultosilic acid (I) and its major metabolite (II) were measured. I and II were extracted from plasma and urine with chloroform after ion-pair formation and analysed by HPLC using a U.V. detector. Sultosilic acid was well absorbed and the plasma concentrations declined bioexponentially with mean half-lives of 1.9 h (fast disappearance phase, alpha) and 17.6 h (slow disappearance phase, beta) for I and 2.0 h (alpha) and 17.0 h (beta) for II. Renal clearances of I and II were 50.5 ml/min and 74.8 ml/min respectively. 60% of the administered dose was excreted in urine, 28% unchanged (I), the remainder as carboxylic derivative (II). Minimal drug concentrations in plasma in the range of those detected in steady state conditions were already found within the first day of treatment.