Abstract
AIM: A rapid and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for epalrestat detection in human plasma. MATERIALS AND METHODS: A triple quadrupole tandem mass spectrometer equipped with an electrospray ionization (ESI) source was used to quantify epalrestat and the internal standard epalrestat-d(5) in the negative ion mode using multiple reaction monitoring (MRM). After acetonitrile-mediated protein precipitation, chromatographic separation was achieved using a reversed-phase C(18) column (ACQUITY UPLC BEH, 2.1 × 50 mm, 1.7 μm; Waters Corp) with acetonitrile and 2 mM ammonium acetate in water as the mobile phase through gradient elution. RESULTS AND CONCLUSION: The retention time of epalrestat was 0.92 min and the entire run time was only 2.00 min. The calibration curve was linear in the range 10.0-8.00 × 10(3) ng/mL (r ≥ 0.99). The within-run and between-run relative standard deviations (RSDs) were < 9.3%. The within-run and between-run relative errors (REs) ranged -8.4-4.2%. No significant matrix effects were observed and the recovery rate was high. The method was fully validated, including reinjection reproducibility in human plasma, and was successfully applied in a pharmacokinetic study, in which 100% incurred sample reanalysis met the criteria.