Pharmacokinetic fundamentals of vaginal treatment with clotrimazole.

Absorption of clotrimazole after vaginal application was estimated to be between 3 and 10%. In order to investigate the fate of clotrimazole reaching systemic circulation, pharmacokinetic studies following oral and intravenous administration were carried out. The concentrations of clotrimazole in vaginal fluid and in blood plasma after vaginal application of 200 and 500 mg were determined using a specific assay by quantitative thin-layer chromatography. Fungicidal concentrations of clotrimazole in vaginal fluid up to 3 days after application of one vaginal tablet containing 500 mg were found. In contrast, clotrimazole plasma levels were lower than 0.01 micrograms/ml, demonstrating that clotrimazole is rapidly metabolized.