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 50 μL plasma with ethyl acetate, analytes and internal standard (I.S.), astilbin, were chromatographed on a Zorbax SB-C18 column (150 mm × 4.6 mm, 5 μm) using acetonitrile – 10 mM 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 10–3000 ng/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, 2 ng/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.