A Simple HPLC Assay for Ginsenoside-Rh2 in Plasma and Its Application for Pharmacokinetic Study in Rats

Ginsenoside-Rh2 (G-Rh2) is an important constituent in ginseng and has significant anti-tumor property.A simple HPLC assay was developed to study pharmacokinetics of G-Rh2 in rat plasma.The HPLC consisted of a C 18 reversed phase analytical column, a variable wavelength ultraviolet (UV) spectrophotometric detector, and a mobile phase made up of 0.005 M KH 2 PO 4 (pH 7.2): acetonitrile: methanol (23:7:70).The system was operated at ambient temperature isocratically at a flow rate of 0.5 mL/min and wavelength at 203 nm.Extraction of G-Rh2 from plasma was achieved by solid phase extraction (SPE) using 100 mg/mL C 18 SPE columns.The results showed that standard curves using 50 mL of plasma sample were linear from 0.25 to 100 mg/mL, with regression coefficient (r 2 )>0.99.The intra-and inter-assay variations over a 3-month study period were <10% and <20%, respectively.After 10 mg/kg twice daily for 4 doses by subcutaneous (sc) injection, the mean maximum plasma concentration (C max ), and time to C max (T max ) of G-Rh2 was 0.79 mg/mL and <0.5 hour, respectively.The described HPLC is readily performed in most laboratories and should have adequate sensitivity and specificity to study pharmacokinetics of G-Rh2 in rats following multiple doses.