Journal of Drug Metabolism & Toxicology
Open Access

Abstract

Species Differences in the Pharmacokinetic Parameters of Cytochrome P450 Probe Substrates between Experimental Animals, such as Mice, Rats, Dogs, Monkeys, and Microminipigs, and Humans

Sakai C, Iwano S, Yamazaki Y, Ando A, Nakane F, Kouno M, Yamazaki H and Miyamoto Y

To clarify species differences in the pharmacokinetic parameters of cytochrome P450 (CYP) activities between humans and experimental animals, we assessed several CYP activities in mice, rats, dogs, monkeys, and microminipigs, using the simultaneous administration of typical human CYP substrates, such as caffeine (human CYP1A2 substrate), losartan (CYP2C9), omeprazole (CYP2C19), dextromethorphan (CYP2D6), and midazolam (CYP3A), to these animals. The intrinsic clearance (CLint) of these 5 substrates was also examined using the liver microsomes of humans and the experimental animals. The high bioavailabilities (BAs) and low CLint values of caffeine in the experimental animals were similar to those in humans. Mice and monkeys had lower BAs and higher CLint values of losartan than those in humans. Mice, rats, and monkeys had lower BAs and higher CLint values of omeprazole than those in humans. The lowest BAs of dextromethorphan were observed in monkeys and microminipigs, and only the CLint in dogs was similar to that in humans. The BA of midazolam in microminipigs only was similar to that in humans, while the CLint values in the other animals were similar to that in humans. These results indicated that in vitro and in vivo experimental data obtained using multiple animals including microminipigs are useful for predicting human pharmacokinetics.