[Studies on the pharmacokinetics of lidamycin in mice and dogs using bioassay].

Aim: A bioassay method was established for the determination of active concentrations of lidamycin and studied its pharmacokinetics in mice and dogs.

Methods: Cytotoxicity of lidamycin in vitro was used to determine drug serum concentrations in vivo.

Results: Validity of methodology met the requirements of pharmacokinetic study. The concentration-time profile in mice after iv lidamycin of 100, 50 and 10 microg x kg(-1) was best fitted with 2-compartmental model with T1/2alpha and T1/2beta of 0.77-1.8 min and 5.6-7.2 min, respectively. The AUC were 2851.3, 887.8 and 166.4 microg x min x L(-1), respectively and increased with dose nonlinearly. There were similar trends between AUC and the potency of tumor growth inhibition. After iv lidamycin of 12 microg x kg(-1) in dogs, the concentrations of lidamycin decreased rapidly and the AUC was 16 microg x min x L(-1), which were lower and quicker than those in mice. The levels in serum after second administration at day 15, were lower than those of the first.

Conclusion: Active concentrations and pharmacokinetics of lidamycin were obtained by bioassay method successfully. There are species differences and single and multi-dosing differences in the pharmacokinetics of lidamycin.