Simultaneous determination of voriconazole and posaconazole concentrations in human plasma by high-performance liquid chromatography.

A simple, sensitive, and selective high-performance liquid chromatographic method for the simultaneous determination of voriconazole and posaconazole concentrations in human plasma was developed and validated. Quantitative recovery following liquid-liquid extraction with diethyl ether was achieved. Linearity ranged from 0.10 to 20.0 microg/ml for voriconazole and from 0.05 to 10.0 microg/ml for posaconazole. The intra- and interday coefficients of variation were less than 8.5%, and the lower limits of quantitation were <0.05 microg/ml.