Pharmacokinetics of Loganin in rat plasma after oral administration of total glycosides of Jinkuishenqi pill

To investigate the pharmacokinetics of loganin in rat plasma which is administered total glycoside (TG) of Jinkuishenqi pill with three different doses and the influence of verapamil. The three different doses (2.95 4.43 5.90 gmiddotkg^-1)of TG alone or TG(5.90 gmiddotkg^-1) in combination with verapamil (10 mgmiddotkg^-1) was administered to Wistar rats. Serial blood samples of loganin were measured by RP-HPLC. The pharmacokinetic parameters were calculated by 3p97, and its statistical comparisons were performed with the unpaired Student t-test. No statistically significant differences were obtained in the pharmacokinetic parameters among the three different doses. It was confirmed that the pharmacokinetic process of loganin is linearly and could be fitted to one-compartment mode. The mean terminal half-lives (T_1/2Ke) of loganin is 81min, time to reach maximum concentrations(T_max) is 54min, absorption rate constant(Ka) is 0.0422 min^-1, maximum concentrations (C_max) is 7271.4ngmiddotmL^-1, elimination rate constant(Ke) is 0.0087 min^-1. For TG be associated with verapamil, T_1/2Ke is 85min, T_max is 35 min, Ka is 0.0754 min^-1, Ke is 0.0081 min^-1, Cmax is 10443.1 ngmiddotmL^-1, the area under the plasma concentration-time curves (AUC_0-infinity) for the AUC_0-infinity of TG(5.90gmiddotkg^-1) is 1.7 times. The study shows that the absorbed dose, absorption rate constant of loganin should be increased obviously by verapamil, so we could improve the bioavailability of loganin by associating with P-glycoprotein inhibitor.