Sensitive gas-liquid chromatographic method for the determination of oxiconazole in plasma

A specific and highly sensitive gas-liquid chromatographic method was developed for the determination of oxiconazole in rat, dog, and human plasma. The compound and its internal standard were extracted from plasma at basic pH with n-hexane-isoamyl alcohol (98:2, v/v), gas chromatographed on 3% SP-2250/Supelcoport (80-100 mesh) and quantified by means of an electron-capture detector. Oxiconazole was extracted almost quantitatively from plasma in the concentration range 10-5000 ng/ml. The sensitivity limit was about 1 ng/ml, using a 1-ml specimen. The method was applied to 13-week tolerance studies in dogs and rats in order to follow oxiconazole concentrations in plasma after oral administration of the compound. The assay was sensitive enough to measure precisely the small amounts of unchanged compound in plasma after intravaginal application of labelled oxiconazole to human volunteers.