Simultaneous determination of JTT-501 and its main metabolite in human plasma by liquid chromatography–ionspray mass spectrometry

An LC–MS–MS analytical method was developed for the determination of a new antidiabetic agent, JTT-501 and its main metabolite (JTP-20604) in human plasma. The compounds were isolated from plasma by protein precipitation before analysis by HPLC with atmospheric pressure positive ionisation MS–MS detection. An isotopically labelled analog of JTT-501 was used as the internal standard. Linearity was demonstrated over the calibration range of about 5–10 000 ng/ml for both compounds. The assay was validated with respect to accuracy, precision and analyte stability. This method was used for the determination of plasma concentrations for the two compounds in a clinical tolerability study. A cross-validation exercise between two different mass spectrometers, used for the determination of clinical samples, is also reported.