Interspecies scaling of oleanolic acid in mice, rats, rabbits and dogs and prediction of human pharmacokinetics

This study was conducted to predict the pharmacokinetics of oleanolic acid in humans based on animal data by allometry and several species-invariant time methods. Oleanolic acid was injected intravenously to mice, rats, rabbit and dogs (dose 1 mg/kg). The serum concentration-time profiles of oleanolic acid were best described by bi-exponential equation in all animal species. The average Cl, V _ss and t _1/2 were 0.065 L/h, 0.019 L and 28.7 min in mice, 0.47 ± 0.06 L/h, 0.117 ± 0.029 L and 29.7 ± 12.2 min in rats, 2.77 ± 0.88 L/h, 1.83 ± 0.60 L and 84.4 ± 16.9 min in rabbits and 14.0 ± 0.7 L/h, 9.2 ± 10.1 L and 54.5 ± 57.2 min in dogs, respectively. Based on animal data, human pharmacokinetic parameters of Cl, V _ss and t _1/2 were predicted by simple allometry. In addition, actual concentration-time profiles obtained from animals were transformed to human profiles by species-invariant times of kallynochron, apolysichron and dienetichron. The predicted human pharmacokinetic parameters of Cl, V _ss and t _1/2 by using simple allometry and species-invariant time transformation method ranged from 48.3-97.2 L/h, 49.1-92.9 L and 45.6-187.2 min, respectively. Those predicted parameters of oleanolic acid may be useful in designing dosing schedules of oleanolic acid in future clinical studies.