Determination of LBPT in human plasma by high performance liquid chromatography–tandem mass spectrometry

A rapid and selective HPLC–MS/MS method was developed for the determination of LBPT in human plasma. The analyte was extracted from plasma samples by solid-phase extraction and then chromatographed on a C18 analytical column. The mobile phase consisted of acetonitrile-10 mM ammonium formate in 0.1% formic acid (30:70, v/v) and the flow rate was 0.2 mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer in multiple reactions monitoring (MRM) mode using positive electrospray ionization (ESI). The method was validated over the concentration range of 0.2–100 ng/mL. Inter- and intra-day precision (RSD %) were less than 9.2% and the accuracy (RE %) ranged from 0 to 11.0%. The lower limit of quantitation (LLOQ) was 0.2 ng/mL. The extraction recovery was on average 75% and the detection was not affected by the matrix. The method was successfully applied to the pharmacokinetic study of LBPT in healthy Chinese subjects.