Metabolism of hydroxyethylrutosides (HR): metabolism of [14C]-HR in man.

1. following oral administration of a [14C]-hydroxyethylrutoside (Paroven, Venoruton) preparation (HR) to three subjects, 3.05--5.97% of the administered [14C] was excreted in urine. Unchanged urinary [14C]-hydroxyethylrutosides represented 1.57--1.96% of the total dose. 2. Significant levels of [14C] were detected in plasma within 1 h of oral administration of HR. Peak levels were observed from 2--9 h. 3. The presence in urine of [14C]-3',4',5,7-tetra-O-(beta-hydroxyethyl)rutoside, [14C]-3',4',7-tri-O-(beta-hydroxyethyl)rutoside and [14C]-4',7-di-O-(beta-hydroxyethyl)rutoside was shown by radioscanning and/or spectal methods. 4. Administration of a second oral dose of [14C]-HR to each of the three subjects following extended dosage of nonlabelled HR did not result in any increase in urinary [14C] excretion over that observed after administration of a single oral dose. 5. Observations on urinary excretion in man are compatible with the finding in experimental animals that the major route of hydroxyethylrutoside excretion is via the biliary-enteric route.