Comparison of UPLC-MS/MS and HPLC-UV methods for the determination of zaltoprofen in human plasma

The aim of this study was to compare UPLC-MS/MS and HPLC-UV methods for the determination of zaltoprofen in human plasma. In HPLC-UV, zaltoprofen was separated using 1% (v/v) aqueous acetic acid (pH 2.2) and acetonitrile (ACN) mixed with methanol as a mobile phase (1% aqueous acetic acid/ACN/methanol, 36/60/4, v/v/v) by isocratic elution at a flow rate of 1.0 mL/min with a Zorbax ODS column (250 × 4.6 mm, 5 µm). Quantification of zaltoprofen was performed using a UV detector (330 nm). In UPLC-MS/MS, zaltoprofen was separated using 0.1% (v/v) aqueous formic acid containing 0.5% (v/v) of 10 mM ammonium formate (pH 3.2) buffer (pH 2.3) and ACN as a mobile phase by gradient elution at a flow rate of 0.3 mL/min with a KINETEX core–shell C18 column (50 × 2.1 mm, 1.7 µm). Quantitation of UPLC-MS/MS was performed on a triple quadrupole mass spectrometer using electrospray ionization, operating in the multiple reaction monitoring positive ion mode. The calibration ranges for zaltoprofen in HPLC-UV and UPLC-MS/MS were 0.05–20 and 0.005–10 µg/mL, respectively. The developed methods satisfied the international guidance criteria and can be successfully applied to pharmacokinetic study of an 80 mg zaltoprofen tablet after oral administration to humans.