Single-dose pharmacokinetics of clomiphene citrate in normal volunteers

Twenty-four healthy adult female volunteers participated in a randomized, three-phase double-blind crossover trial comparing the single-dose (50 mg) pharmacokinetics of three formulations of clomiphene citrate (CC). Plasma levels of both the Z(cis) and E(trans) isomers of CC, as well as principal metabolites, were determined at periodic intervals; and no differences between formulations were observed. The active Z isomer attained peak blood levels later than the inactive E isomer and was eliminated much more slowly, significant plasma concentrations still being detected up to 1 month after treatment. The results of this study demonstrate that three commercially available formulations of CC are bioequivalent.