Pharmacokinetics of ginkgolides A, B and K after single and multiple intravenous infusions and their interactions with midazolam in healthy Chinese male subjects

Ginkgo terpene lactones meglumine injection (GMI) is a novel preparation of traditional Chinese medicine that contains ginkgolides A, B and K (GA, GB, GK, respectively) as its primary components. In this study we evaluated the safety, tolerability and pharmacokinetics of these three ginkgolides after single and multiple intravenous infusions of GMI. We also investigated the effect of GMI on cytochrome P450 3A4 (CYP3A4) in healthy Chinese volunteers. In this open-label, placebo-controlled study 15 subjects were randomly assigned to receive GMI or matched placebo (4:1 ratio). All subjects first received midazolam (MDZ) on day 1, followed by a 6-day washout. On Day 8, the subjects were started on once-daily dosing of either GMI or placebo for 14 days. Lastly, on Day 22 the subjects were given second dose of MDZ + GMI or MDZ + placebo. Plasma concentrations of ginkgolides, MDZ and its metabolite 1-hydroxy midazolam were quantified. The steady-state conditions of GA, GB and GK were achieved after 6 days of daily dosing. Following a single dose of GMI (Day 8) the area under the concentration-timecurve from zero to 24 h after administration (AUC(0-24h)) of GA, GB and GK (arithmetic +/- standard deviation) was 4.10 +/- 1.06, 4.61 +/- 1.31 and 0.127 +/- 0.102 h mu g/mL, respectively; the corresponding values following multiple doses of GMI (Day 19) were 3.94 +/- 1.16, 5.00 +/- 1.55 and 0.118 +/- 0.096 h mu g/mL, respectively. The mean accumulation ratios were 0.95, 1.08 and 0.89 for GA, GB and GK, respectively. Additionally, the geometric mean [peak concentration (C-max) and AUC(0-24h)] ratios of MDZ and 1-hydroxy midazolam were all within the specified acceptance ranges in the MDZ + placebo treatment and MDZ + GMI treatment. Our results show that GMI was well tolerated during the entire study. There was no systemic accumulation and no significant effects on the pharmacokinetics of MDZ in healthy Chinese male subjects after repeated dosing of GMI.