Abstract: Aim and Methods Thepharmacokinetics and bioavailability of thedomestic and theimported astemizole tablets were studiedin 6 Chinese healthy volunteers by radioimmunoassay in a clinical trial of cross-over design.Results Themain pharmacokinetic parameters calculated by thepractical pharmacokinetics program 87 wereas follow s:For thedomestic product, Vd=5.34±1.85 L;αT_1/2=0.74±0.37 h;βT_1/2=286.10±220.11 h;CL=0.052±0.031 ng/ml;T_max=1.56±1.32 h;C_max=1.04±0.10 ng/ml;AUC=262.69±162.18 ng/ml·h^-1.For theimported product, V d=8.24±2.56 L;αT_1/2=1.16±0.98 h;βT_1/2=260.38±260.37 h;CL=0.089±0.079 ng/ml;T_max=1.37±0.82 h;C_max=0.93±0.14 ng/ml;AUC=250.66±148.05 ng/ml·h^-1.Therelative bioavailability of thedomestic tablets was 127.8 %.Conclusion No signif icant pharmacokine tic difference has been found be tw een thedomestic andimpor ted astemizole tablets.

Key words: astemizole, pharmacokinetics, radioimmunoassay, bioavailability