Simultaneous determination of three major bioactive saponins of <it>Panax notoginseng </it>using liquid chromatography-tandem mass spectrometry and a pharmacokinetic study

Abstract Background Panax notoginseng saponins (PNS), the main active components of Radix Notoginseng, has been used for treating atherosclerosis, cerebral infarction, and cerebral ischemia. Ginsenosides Rg1, ginsenoside Rb1, and notoginsenoside R1 are the main contributors of biological activities, determination of these three saponins is very important for the in vivo evaluation of PNS. The present study aims to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of ginsenosides Rg1, ginsenoside Rb1, and notoginsenoside R1. The use of this method was exemplified in pharmacokinetic study of beagle dog plasma after oral administration of PNS. Methods Liquid chromatography-tandem mass spectrometry (LC/MS/MS) method was combined with solid-phase extraction (SPE). This setup was used to determine simultaneously the three major PNS (ginsenoside Rg1, ginsenoside Rb1, and notoginsenoside R1) in beagle dog plasma. Tandem mass spectrometry was performed using electrospray ionization in the positive ion mode. Results The lower limits of quantification were 0.5 ng/mL for notoginsenoside R1, 0.82 ng/mL for ginsenoside Rg1, and 1.10 ng/mL for ginsenoside Rb1. The calibration curves for the three saponins were linear over the concentration ranges 2.64-264 ng/mL (r2 = 0.9967, P = 0.003), 3.6-360 ng/mL (r2 = 0.9941, P = 0.004), and 18.7-1870 ng/mL (r2 = 0.9912, P = 0.004) for notoginsenoside R1, ginsenoside Rg1, and ginsenoside Rb1, respectively. Within these concentration ranges, the relative standard deviation (RSD) of intra- and interday assays for the three PNS from beagle dog plasma samples were less than 12%. Conclusions This LC/MS/MS method in combination with SPE is useful in the pharmacokinetic study of PNS, such as the simultaneous determination of saponins in beagle dog plasma after oral administration.