A liquid chromatography-tandem mass spectrometric method for the simultaneous quantitation of five components of Ixeris sonchifoliain (Bge.) Hance in rat plasma and its application to a pharmacokinetic study.

A rapid and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the simultaneous quantitation of five major active ingredients of Ixeris sonchifolia (Bge.) Hance in rat plasma has been developed and validated. After liquid-liquid extraction of 50μL plasma with ethyl acetate, analytes and internal standard (I.S.), astilbin, were chromatographed on a Zorbax SB-C18 column (150mm×4.6mm, 5μm) using acetonitrile - 10mM ammonium acetate (60:40, v/v, pH 5.6) as mobile phase. The five analytes: chicoric acid, luteolin 7-O-β-d-glucuronide, luteolin 7-O-β-d-glucopyranoside, luteolin 7-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranoside, apigenin 7-O-β-d-glucuronide and I.S., were detected by negative ion electrospray ionization followed by multiple reaction monitoring of the ions with m/z 473.0→311.0, 461.0→285.0, 447.0→285.0, 609.1→285.0, 445.1→269.0 and 449.1→150.9, respectively. The method was linear for all analytes in the concentration range 10-3000ng/mL with intra- and inter-day precision (as relative standard deviation) ≤8.99% and accuracy (as relative error) ≤4.00%. The limits of detection (LOD) were 5, 1, 5, 5, 2ng/mL for chicoric acid, luteolin 7-O-β-d-glucuronide, luteolin 7-O-β-d-glucopyranoside, luteolin 7-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranoside, apigenin 7-O-β-d-glucuronide, respectively. The method was successfully applied to a pharmacokinetic study of the five analytes in rat after a single intravenous dose of Kudiezi Injection.