A simple LC-MS/MS method facilitated by salting-out assisted liquid-liquid extraction to simultaneously determine trans-resveratrol and its glucuronide and sulfate conjugates in rat plasma and its application to pharmacokinetic assay

A simple LC-MS/MS method facilitated by salting-out assisted liquid-liquid extraction (SALLE) was applied to simultaneously investigate the pharmacokinetics of trans-resveratrol (Res) and its major glucuronide and sulfate conjugates in rat plasma. Acetonitrile-methanol (80:20, v/v) and ammonium acetate (10mol L-1) were used as extractant and salting-out reagent to locate the target analytes in the supernatant after the aqueous and organic phase stratification, then the analytes were determined via gradient elution by LC-MS/MS in negative mode in a single run. The analytical method was validated with good selectivity, acceptable accuracy (>85%) and low variation of precision (<15%). SALLE showed better extraction efficiency of target glucuronide and sulfate conjugates (>80%). The method was successfully applied to determine Res and its four conjugated metabolites in rat after Res administration (intragastric, 50 mg kg(-1); intravenous, 10 mg kg(-1)). The systemic exposures to Res conjugates were much higher than those to Res (AUC(0-t), i.v., 7.43 mu m h; p.o., 8.31 mu m h); Res-3-O-beta-D-glucuronide was the major metabolite (AUC(0-t), i.v., 66.1 mu m h; p.o., 333.4 mu m h). The bioavailability of Res was estimated to be similar to 22.4%. The reproducible SALLE method simplified the sample preparation, drastically improved the accuracy of the concomitant assay and gave full consideration of extraction recovery to each target analyte in bio-samples.