Quantification of fenoprofen in human plasma using UHPLC‐tandem mass spectrometry for pharmacokinetic study in healthy subjects

A rapid, simple and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method has been developed to quantify fenoprofen, a nonsteroidal anti-inflammatory drug in human plasma for a pharmacokinetic study in healthy subjects. Owing to high levels of protein binding, protein precipitation followed by solid-phase extraction was employed for the extraction of fenoprofen and fenoprofen-d3 (used as internal standard) from 200 muL human plasma. Separation was performed on a BEH C18 (50 x 2.1 mm, 1.7 mum) column using methanol-0.2% acetic acid in water (75:25, v/v) under isocratic elution. Electrospray ionization was operated in the negative mode for sample ionization. Ion transitions used for quantification in the selected reaction monitoring mode were m/z 241/197 and m/z 244/200 for fenoprofen and fenoprofen-d3, respectively. Under the optimized conditions, fenoprofen showed excellent linearity in the concentration range 0.02-20 mug/mL (r(2) >/= 0.9996), adequate sensitivity, favorable accuracy (96.4-103.7%) and precision (percentage coefficient of variation