Simultaneous determination of four shanzhiside methylester derivatives in rabbit plasma by liquid chromatography/tandem mass spectrometry.

A simple and sensitive high-performance liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed and validated for simultaneous determination of shanzhiside methylester and its three derivatives in rabbit plasma. The method showed good linearity and no endogenous material interfered with the marked compounds and internal standard (IS) capatol peaks. Samples were processed by acetonitrile precipitation. Chromatography was performed using a C₁₈ column (150 × 3.9 mm i.d., 4 µm). The mobile phase consisted of methanol and water (60:40, v/v) during a total run time of 7 min. The main mass parent ions and daughter ions pairs (m/z) for monitoring were: shanzhiside methylester, 429.0/267.4; 8-O-acetyl shanzhiside methylester, 470.9/411.3; loganin, 413.2/251.4; phloyoside II, 479.2/281.3; and IS 385.2/203.3. Finally, the method was applied to a pharmacokinetic study of rabbits following intravenous administration of iridoid glycosides extracted from traditional herb Lamiophlomis rotata.