Determination of ginsenoside-Rg(1) in human plasma and its application to pharmacokinetic studies following intravenous administration of 'Shenmai' injection.

'Shenmai' injection is derived from traditional Chinese medicine 'Shenmaisan' and made from Radix ginseng Rubra and Radix Ophiopogonis. Ginsenoside-Rg(1), as a major constituent of Radix ginseng Rubra, is considered responsible for the efficacy of this injection. A rapid, simple and accurate method has been established for determination of ginsenoside-Rg(1) in Shenmai injection and human plasma using LC-ESI-MS/MS, and to study the pharmacokinetics of Rg(1) in ten healthy volunteers after intravenous single dosing of 60 mL of Shenmai injection. Following solid-phase extraction (SPE), samples were separated on a C(18) column coupled with electrospray ionization mass spectrometry. The protonated analyte was quantified by multiple reaction monitoring (MRM) with a quadruple mass spectrometer in positive mode. Linearity was confirmed in the concentration range of 1 to 1000 ng/mL for Rg(1), and the lower limit of quantification (LLOQ, S/N > 10) was 1 ng/mL. The intraday and interday RSDs were within 15% and mean extraction recoveries ranged from 98.6% to 104.9%. The pharmacokinetics of Rg(1) in healthy volunteers conforms to the two-compartment open model. The main pharmacokinetics parameters were as follows: t(1/2beta), 2.09 +/- 1.89 h; CL, 0.03 +/- 0.01 L kg(-1) h(-1); AUC (0 approximately infinity), 124.4 +/- 35.9 2 ng mL(-1) h and AUC (0 approximately infinity), 127.9 +/- 37.2 ng mL(-1) h, respectively.