Comparison between the characteristics of absorption and pharmacokinetic behavior of ginsenoside Rg1 and ginsenoside Rb, of Panax notoginseng saponins / 药学学报

ABSTRACT

To compare the characteristics of absorption and pharmacokinetic behavior of ginsenoside Rg1 (Rg1) with ginsenoside Rb1 (Rb1) of panax notoginseng saponins (PNS), bile excretion of both Rg1 and Rb1 were studied after i.v. and i.g. of PNS solution. Plasma protein binding ratios were studied using equilibrium dialysis method, and referred to pharmacokinetic parameters. It shows that (61.48 +/- 18.30)% dose of Rg1 and (3.94 +/- 1.49)% dose of Rb1 were separately excreted into bile 10 hours after i.v. administration (PNS 50 mg x mL(-1)), and (0.91 +/- 0.51)% dose of Rg1 and (0.055 +/- 0.02)% dose of Rb1 were excreted into bile 12 hours after i.g. administration (PNS 1 500 mg x mL(-1)). Plasma protein binding degrees of Rg1 and Rb1 were 6.56% - 12.74% and 80.1% - 89.69%, respectively. Stomach, intestinal and hepatic throughput efficiency (F(S), F1 and F(H)) for Rg1 were 49.85%, 13.05%, 50.56%, respectively, and 25.82%, 4.18%, 65.77% for Rb1. Therefore, poor intestinal absorption is a primary reason for the low bioavailability of both Rg1 and Rb1. Rg1 possesses relatively high bile excretion and low plasma protein binding rate, in contrast, Rb1 possesses low bile excretion and high plasma protein binding rate. Membrane permeability and elimination rate of Rb1 were lower than that of Rg1, meanwhile, longer MRT and bigger AUC could be found for Rb1.