Abstract: AIM: To establish an analytical method for determination of notoginsenoside R₁ concentration in plasma and to study its pharmacokinetic profile in dogs. METHODS: Six dogs were intravenously administration of 0.7131 mg·kg^-1 notoginsenoside R₁. Blood samples were collected at various time-points after drug administration. Analytical method based on liquid chromatography- mass spectrometry(LC-MS) was established to determine the plasma concentration of notoginsenoside R₁. Pharmacokinetic evaluation was carried out using the 3P97 program. RESULTS: The calibration curves were linear over the concentration ranged from 5 to 2 000 μg·L^-1 (γ =0.9996). The intra-day and inter-day precisions were generally good (<15 %) at low, medium and high concentrations. The overall recovery was more than 90 %. Six dogs were intravenously administration of 0.7131 mg·kg^-1 notoginsenoside R₁, and an open two compartment model best described the concentration-time profiles for notoginsenoside R₁. The half-lifes for the rapid and slow distribution phase (T_1/2α and T_1/2β) were 38.59 and 230.06 min, respectively. The total area under the plasma concentration /time curve (AUC), the volume of the central compartment (V) and plasma clearance(CL) were 67353.75 mg·min·ml^-1, 3.53 L·kg^-1 and 0.1068 L·kg^-1 ·min^-1, respectively. CONCLUSION: The analytical method is sensitive, specific, rapid and reproducible, and it is suitable for pharmacokinetic studies of notoginsenoside R₁.

Key words: notoginsenoside R₁, liquid chromatography-mass spectrometry, pharmacokinetics, Beagle dogs