Simultaneous determination of panax notoginsenoside R1, ginsenoside Rg1, Rd, Re and Rb1 in rat plasma by HPLC/ESI/MS: platform for the pharmacokinetic evaluation of total panax notoginsenoside, a typical kind of multiple constituent traditional Chinese medicine

A platform for the pharmacokinetic study of multiple constituent traditional Chinese medicine was developed and validated. An HPLC/ESI/MS method was employed for the simultaneous determination of panax notoginsenoside R1, ginsenoside Rg1, Rd, Re and Rb1 in rat plasma. After the addition of digoxin as an internal standard (IS), rat plasmas were extracted with n-butanol saturated with pure water and all analytes were separated on a reversed-phased C(18) column with a mobile phase of acetonitrile-water (0.5 mM ammonium chloride) and pumped at a flow rate of 0.2 mL/min. Analytes were determined in a single quadrupole mass spectrometer using an electrospray ionization source. HPLC/ESI/MS was performed in the selected-ion monitoring mode with the chlorinated adducts of molecular ions [M + Cl]( -) at m/z 967.75, 835.80, 981.80, 981.80, 1143.65 and 815.40 for R1, Rg1, Rd, Re, Rb1 and digoxin, respectively. The method showed excellent linearity over the concentration range 3.03-775.00 ng/mL (r(2) = 0.9994) for R1, 4.00-1025.00 ng/mL (r(2) = 0.9991, 0.9988, 0.9991) for Rg1, Rd and Re, respectively, and 2.77-710.00 ng/mL for Rb1 (r(2) = 0.9990). The low limit of quantification was 3.03, 4.00, 4.00, 4.00 and 2.77 ng/mL for R1, Rg1, Rd, Re and Rb1, respectively, with S/N > 10. The intra- and inter-day precisions were below 12.00% and the accuracy was between -2.31 and +4.43% for all analytes. The extract recoveries of analytes were from 67.47 to 94.18%. All analytes were stable in rat plasma after storage for 12 h at ambient temperature, at 4 degrees C for 12 h in the sample pool, at -20 degrees C for 4 weeks and at -20 degrees C for three thaw-freeze cycles. The HPLC/ESI/MS technique provided an excellent method for the simultaneous quantification of R1, Rg1, Rd, Re and Rb1 in rat plasma and was successfully applied to the pharmacokinetic study of a multiple-constituent traditional Chinese medicine, total panax notoginsenoside (Xuesaitong injection).