Optimization of solid-phase extraction and liquid chromatography-tandem mass spectrometry for simultaneous determination of capilliposide B and its active metabolite in rat urine and feces: Overcoming nonspecific binding

• Quantification of LC-B and its metabolite, LC-A, in rat urine and feces samples.
• A SPE procedure was optimized to clean-up urinary and fecal samples.
• Samples acidified with formic acid allow a high extraction recovery.
• CHAPS was used to overcome nonspecific adsorption in urine.

Capilliposide B, a novel oleanane triterpenoid saponin isolated from Lysimachia capillipes Hemsl, showed significant anti-tumor activities in recent studies. To characterize the excretion of Capilliposide B, a reliable liquid chromatography-tandem mass spectrometry (LC–MS/MS) method was developed and validated for simultaneous determination of Capilliposide B and its active metabolite, Capilliposide A in rat urine and feces. Sample preparation using a solid-phase extraction procedure was optimized by acidification of samples at various degrees, providing extensive sample clean-up with a high extraction recovery. In addition, rat urinary samples were pretreated with CHAPS, an anti-adsorptive agent, for overcoming nonspecific analytes adsorption during sample storage and process. The method validation was conducted over the curve range of 10.0–5000 ng/ml for both analytes. The intra- and inter-day precision and accuracy of the QC samples showed ≤11.0% RSD and −10.4–12.8% relative error. The method was successfully applied to an excretion study of Capilliposide B following intravenous administration.

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