Biol. Pharm. Bull. 30(1) 1—5 (2007)

GBE possesses many constituents, and is mainly composed of flavonoids such as quercetin andrutin, and terpenoids such as bilobalide and ginkgolides A, B and C. In German pharmaceutical analysis, the quality of GBE has been standardized ascontaining 22—27% flavonoid glycosides and 6% terpenoids. In recent clinical and experimental experiments, GBE has been reported to be effective against ischemic brain injury, cerebral (or cerebrovascular) insufficiency, cognitive speed, dementia and Alzheimer’s disease, peripheral vascular disease such as arterial occlusive disease and aging damages. Actually, these effects have been recognized clinically using many double-blind studies with GBE versus placebo. The mechanisms for thebeneficial effects of GBE are considered to be due to the improvements of (a) haemodynamic disorders; (b) PAF-associated abnormalities; (c) cell damages induced by free radicals; and (d) decrease in ATP level during anoxia. GBE modulates cytochrome (CYP) P450. GBE induced markedly the activity of CYP2B, CYP3A1 and CYP3A2 in the rat liver. These results suggest that GBE attenuates the therapeutic potency of nicardipine due to the induction of the CYP3A2 level. It is still unknown whether GBE can pass through the blood-brain barrier. The endothelial productions (i.e., NO) induced by GBE application might pass through the blood-brain barrier and then would cause the vasodilation in cerebral arteries. The concentrations used in our studies are relatively higher, because the concentrations in in vitro experiments are generally higher than actual clinical serum concentrations. The pharmacological activities of GBE mainly was attributed to ginkgolides (Fig. 1). Accumulating evidence suggested that ginkgolide B(GB) shows the strongest pharmacological activity among the ginkgolides. Now, GB is being developed for treating cerebrovascular accident, but no information is available on systemic and comprehensive pharmacokinetics of GB. In this study, we report for the first time a thorough characterization of the pharmacokinetics of GB and providing large data sets that can be used to predict biological events related to pharmacokinetic behavior of GB through determining the concentrations in biological samples after intravenous administration of GB emulsion to rats.