Analytical methods for the determination of naftifine and its metabolites in human plasma and urine.

Analytical procedures have been worked out for the determination both of naftifine, the antifungal constituent of Exoderil, and its demethyl derivative in plasma, and of the metabolites p-hydroxyphenyl-, 3,4-dihydrodiol- and 7,8-dihydrodiol-naftifine and naphthoic acid in urine. For plasma a HPLC-method with UV-detection after extraction of the samples with hexane is used. In urine samples the metabolites are deconjugated, extracted with chloroform, silylated and measured by GC with flame ionization detection. The standard calibration curves for the parent compound and metabolites are linear. The detection limit for naftifine and its demethyl derivative is ca. 5 ng/ml, for naphthoic acid 1 microgram/ml and for the other metabolites 2 micrograms/ml.