A validated LC-MS/MS method for determination of sertaconazole nitrate in human plasma

A specific and sensitive liquid chromatography electrospray ionization tandem mass spectrometric (LC-ESI-MS/MS) method for quantitative determination of sertaconazole in human plasma was developed. The analysis was performed and validated in positive ion multiple reactions monitoring mode using loratadine as an internal standard (IS). Sample preparation involved one-step liquid-liquid extraction using ether-dichloromethane (80/20, v/v). Sertaconazole and IS was separated on a C18 column using isocratic elution with a mobile phase of methanol: 0.2% formic acid aqueous solution (70:30, v/v,) at the flow rate of 0.2 mL/min. The transition monitored were m/z 439 [M+H](+)-->m/z 181 for sertaconazole and m/z 383[M+H]+ --> m/z 337 for IS. The lower limit of quantification was 0.1 ng/mL based on 500 microL of plasma, and no interferences were detected in chromatograms. Calibration curve was linear over the range of 0.1-10 ng/mL, and correlation coefficients were 0.999. Intra- and inter-day assay variations were <10%, and the accuracy values were between -0.4% and 9.0% relative error (RE). The extraction recoveries ranged from 60% to 70% across the calibration curve range. The described method provides a sensitive analytical tool to determine sertaconazole in plasma, and was successfully applied to a pharmacokinetic study in 10 healthy human subjects after administration of 300 mg vaginal suppository formulation of sertaconazole nitrate.