Simultaneous determination of triazole antifungal drugs in human plasma by sweeping-micellar electrokinetic chromatography

The number of cases of invasive fungal infections (IFIs) has risen significantly in recent years; therefore, this study developed a sensitive and effective sweeping-micellar electrokinetic chromatography (MEKC) method for the simultaneous determination of the three most frequently used triazole antifungal drugs for the treatment of IFIs, which included voriconazole, itraconazole, and posaconazole. Due to the diverse lipophilicity of the tested drugs, the analytical conditions that resulted in good resolution between itraconazole and posaconazole caused the peak for voriconazole to split. The splitting phenomenon was resolved by incorporating a high-salt stacking mechanism into the sweeping-MEKC method. The optimum background electrolyte was composed of 25 mM phosphoric acid solution (pH 2.2), 100 mM sodium dodecyl sulfate, 13 % acetonitrile, and 13 % tetrahydrofuran. The best peak shape of voriconazole was obtained when the conductivity ratio between the sample matrix and background electrolyte was 2.3. Compared to the conventional MEKC mode, the enhancement factor of the sweeping-MEKC method was 66 for itraconazole, 55 for posaconazole, and 43 for voriconazole. The sweeping-MEKC method was validated in terms of precision, accuracy, linearity, specificity, selectivity, and sensitivity. The linearity ranges of the method covered the commonly used therapeutic ranges of the three drugs. The developed sweeping-MEKC method was successfully applied to the analysis of clinical samples, thus demonstrating its applicability for clinical use.