Development of a LC-MS method for quantification of FK-3000 and its application to in vivo pharmacokinetic study in drug development

► FK-3000 and IS were monitored at m/z 418.45 and 256, respectively, with an ESI source in positive-ion mode in Micromass ZQ. ► Mobile phase was consisted of acetonitrile and 0.1% formic acid solution and FK-3000 was extracted with ethyl acetate. ► The LLOQ of FK-3000 in rat plasma was 10 ng/mL and calibration curve was linear from 10 to 1000 ng/mL. ► Matrix effect of FK-3000 and IS in rat plasma was absent and FK-3000 and IS was recovered consistently in rat plasma. ► Quantification method for FK-3000 in rat plasma was validated according to the guidance of FDA.