Development and Validation of a Quantitative Determination Method for Fluorothiazinone in Human Blood Plasma

An HPLC-MS/MS technique for quantitative determination of the new antibacterial drug fluorothiazinone in human blood plasma using an internal standard was developed and validated. The validation protocol proved the selectivity, accuracy, and precision of the method and the lack of significant carryover, matrix, and sample-dilution effects. The calibration curve was linear in the concentration range 0.1 – 300 ng/mL with a correlation coefficient r2 > 0.9990. The lower limit of quantitation was 0.1 ng/mL. The studied analyte was shown to be stable during storage in a stock solution (for 6 h at room temperature) and in plasma samples (for 6 h at room temperature, after three freeze–thaw cycles, and for 30 d at –70°C) and in an autosampler after sample preparation (for 24 h at +10°C).