Simultaneous determination of ginsenosides and bufadienolides in rat plasma after the oral administration of Shexiang Baoxin Pill for pharmacokinetic study by liquid chromatography tandem mass spectrometry following solid-phase extraction.

A sensitive and reliable bioanalytical method was established for quantitati\ve and pharmacokinetic investigation of nine ginsenosides and seven bufadienolides in rat plasma after the oral administration of Shexiang Baoxin Pill by liquid chromatography-electrospray ionization tandem mass spectrometry, using tinidazole and digoxin as internal standards (ISTDs). All of the analytes and ISTDs obtained satisfactory recoveries by solid-phase extraction using an Oasis HLB μElution Plate, which was eluted with methanol and ethyl acetate successively, and chromatographic separation was achieved on a Shim-pack XR-ODSIIcolumn (75 × 2.0 mm, 2.2 μm) with gradient elution using a mixture of acetonitrile-0.1% formic acid solution (v/v) as the mobile phase at a flow rate of 0.3 mL/min. Detection was carried out by a triple-quadrupole tandem mass spectrometry with positive/negative ion switching multiple reaction monitoring mode. All analytes showed good linearity over a wide concentration range (r(2)  > 0.99). The lower limit of quantification was in the range 0.625-12.5 ng/mL for bufadienolides and 2-5.5 ng/mL for ginsenosides, and the mean recoveries of all analytes were in the range 78.29-99.35%. The intra- and inter-day precisions (RSD) were in the range 0.08-12.38% with the accuracies between 86.09 and 99.40%. The validated method was then successfully applied to pharmacokinetic study of the above 16 compounds in rat plasma. Pharmacokinetic results indicated that the developed extraction and analytical method could be employed as a rapid, effective technique for pharmacokinetic study of multiple components, especially various polarity that are difficult to extract simultaneously.