Determination of the antifungal agent, ketoconazole, in human plasma by high-performance liquid chromatography.

A rapid and selective high-performance liquid chromatographic (HPLC) assay for the quantitative determination of ketoconazole, an orally active antifungal agent, in human plasma is described. After extraction of the drug from plasma, the compound is separated by HPLC using a reversed-phase column and detected by UV light at 205 nm. Quantitation is accomplished by external standardization and the determination of peak areas is performed with the aid of an integrating computer. The average recovery of ketoconazole over a concentration range of 0.1-20.0 microgram/ml was 88.2 +/- 4.07% S.D. The maximum sensitivity of the assay is less than 0.1 microgram/ml. The assay is suitable for use in pharmacokinetic studies following the administration of therapeutic doses of ketoconazole to humans.