ABSTRACT
Aim To establish a LC-MS/MS method for the determination of pirfenidone(BT)and its major metabolite 5-carboxy-pirfenidone(SBT)in human plasma.Methods Human plasma samples containing BT and SBT,as well as their corresponding deuterium-labeled internal standards pirfenidone-d5(dBT)and 5-carboxy-pirfenidone-d5(dSBT),were precipitated using methanol.Chromatographic separation was carried out on an Agilent ZORBAX SB C18(3.0 mm×100 mm,3.5 μm)column with the mobile phase of water(0.5％formic acid)and acetonitrile(50/50).The detection of analytes was performed on a tandem mass system equipped with an electrospray ionization source in positive ion mode using multiple-reaction monitoring.The MS/MS ion transitions monitored were m/z 185.958→77.1 for BT,m/z 215.944→77.0 for SBT,m/z 190.965→81.1 for dBT and m/z 220.948→99.1 for dSBT.Results There was no remarkable interference in blank solvent,plasma,and there was no mutual interference between analytes or internal standards.The proposed method showed good linearity over the concentration range of 0.020 59～25.14 mg·L-1 for BT and 0.016 73～20.42 mg·L-1 for SBT.The intra-batch and inter-batch precision and accuracy were proved to be acceptable.Human samples kept stable after 4 h at room temperature,the three freeze-thaw cycles and 10,29 and 52 days at-70 ℃,and the processed samples remained stable after 24 h in the autosampler.The average extraction recovery and matrix effect were precise,reproducible and acceptable.Conclusion Our current LC-MS/MS method is proved to be sensitive,accurate and convenient,and could be suitable for the clinical pharmacokinetic studies of BT-related preparations.
ABSTRACT
Aim To establish a LC-MS/MS method for the determination of hydroxysafflor yellow A ( QA ) in human plasma. Methods After being added into 0. 2M ammonium acetate (1∶1,V/V), QA was extrac-ted using solid-phase extraction technique, and the eluent was directly injected into LC-MS/MS systems. Agilent ZORBAX SB C18 (3. 0 × 100 mm, 3. 5 μm) column and isocratic elution system composing of meth-anol and 0. 2 mM ammonium acetate (70 ∶ 30, V/V) provided chromatographic separation of QA and internal standard isorhamnetin-3-O-neohespeidoside ( SLS) fol-lowed by detection with mass spectrometry. The mass transition ion-pair was followed as m/z 611 . 131→490. 900 for QA and m/z 623. 032→298. 800 for SLS. Results The retention time of QA and SLS was 2. 7 min and 3. 9 min respectively, with no interference in human blank plasma. The proposed method showed good linearity over the concentration range of 8. 57 ~4185 μg·L-1 for QA with a correlation coefficient≥ 0 . 9949 . The lower limit of quantitation was 8. 570 μg ·L-1 . The intra-batch and inter-batch precision and accuracy were within 7%. The average matrix effect ranged from 115. 72% to 119. 06% with RSD less than 5%. The average extraction recovery ranged from 77. 75% to 80. 76% with RSD less than 5%. Stability of human samples after 4 h at room temperature, after the three freeze-thaw cycles and after 31 days at -70℃, and post-preparative stability of the processed sam-ples after 24 h was acceptable. Plasma samples with the concentration beyond the upper quantitation limit could be accurately determined after being diluted using 6. 25 times ( V/V ) of human blank plasma. Conclusion Our current LC-MS/MS method is sensitive, accurate and convenient, and is proved to be suitable for the sys-tematic study on clinical pharmacokinetics of QA.