Pharmacokinetics of [14C]-ITF-296 and its metabolites, ITF-1124 and ITF-1577, were studied in dogs and monkeys after a single intravenous (2.5 mg/kg) and oral (10 mg/kg) administration. Radioactivity was measured by LSC while unchanged drug and its metabolites in plasma were assayed by an HPLC-UV method. The absorption of [14C]-ITF-296 after oral administration is practically complete both in dogs and in monkeys. The determination of unchanged drug and its metabolites shows quite a similar profile in dogs and monkeys for ITF-296 and ITF-1124 and a different time-course for ITF-1577. Elimination of radioactivity occurs mainly in urine (namely 70-80%) for both species and the recovery of the dose (higher than 90%) takes place up to 96 h after both treatments.