Development and validation of a LC–MS/MS method for the determination of viaminate in human plasma

A sensitive and specific method for determination of viaminate in human plasma by using high-performance liquid chromatography coupled with electrospray tandem mass spectrometry (LC–MS/MS) was developed in this study. The plasma samples were simply deproteinated, extracted, evaporated, and then reconstituted in 200 μl of methanol prior to analysis. Chromatographic separation was carried out on a Shimadzu VP-ODS column (250 mm × 2.0 mm, 5 μm) with a mobile phase of methanol–water (95:5, v/v) at a flow rate of 0.2 ml/min. Quantification was performed in the negative-ion electrospray ionization mode by selected ion monitoring of the product ions at m/z 164 for viaminate and m/z 109 for testosterone propionate which was used as the internal standard. The corresponding parent ions were m/z 446 and m/z 345. A linear calibration curve was observed within the concentration range of 0.10–200 ng/ml. The lowest limit of quantitation (LLOQ) was 0.1 ng/ml. The extraction-efficiency at three concentrations was 100.7, 93.6, and 99.7%. Practical utility of this new LC–MS/MS method was confirmed in pilot pharmacokinetic studies in humans following oral administration.