The pharmacokinetics of FCE 22101 were studied in rats, rabbits, Cynomolgus monkeys and dogs after intravenous administration. Pertinent pharmacokinetic parameters were determined according to a two-compartment model and correlated among species as an exponential function of body weight, thereby allowing an estimation of pharmacokinetic parameters corresponding to a 70 kg man. Allometric equations, including data on humans reported in the literature, were also established and used to study similarities and differences in the disposition of FCE 22101 among species. The pharmacokinetic profile of FCE 22101 was consistent with the principles of allometry in all animal species studied (and in man) with the exception of the Cynomolgus monkey, in which clearance of FCE 22101 was slower than expected.