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Purpose: 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. Methods: 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. Results: 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) of GA, GB and GK (arithmetic ± standard deviation) was 4.10 ± 1.06, 4.61 ± 1.31 and 0.127 ± 0.102 h μg/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 μg/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) and AUC] ratios of MDZ and 1-hydroxy midazolam were all within the specified acceptance ranges in the MDZ + placebo treatment and MDZ + GMI treatment. Conclusions: 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. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the pharmacokinetics and pharmacodynamics of rabeprazole (RPZ) given as successive intravenous infusion to healthy Chinese volunteers. Methods: A total of 63 subjects (33 males and 30 females) were recruited at four research centers and given a 5-day therapeutic course of RPZ (10, 20, or 40 mg) administered as single daily doses during a 30-min period. Plasma concentrations were monitored by sampling at very short intervals for the first 330, 360, or 420 min post-RPZ administration. Intragastric pH was recorded 24 h post-RPZ administration on day 1 and day 5. Results: After receiving a single and repeated doses of RPZ, the area under the plasma concentration-time curve (AUC) was 51.9 ± 22.1, 96.7 ± 27.6, and 188.4 ± 65.8 mg·min/L on day 1 and 59.3 ± 23.9, 106.7 ± 27.8, and 200.3 ± 79.0 mg·min/L on day 5 for the low-, middle-, and high-dose groups, respectively. The corresponding peak concentrations (C) were 0.64 ± 0.11, 1.30 ± 0.26, and 2.6 ± 0.54 μg/mL on day 1 and 0.76 ± 0.15, 1.39 ± 0.25, and 2.91 ± 0.53 μg/mL on day 5, respectively. Although the mean AUC and C values increased from a single dose to repeated doses in the three groups, the difference was not significant. The mean AUC and C ratios of repeated dose to single dose were 1.14, 1.10, and 1.06 on day 1 and 1.19, 1.07, and 1.12 on day 5 for the low-, middle-, and high-dose groups, respectively. After administration of a single dose, the 24-h pH value was significantly higher in the high-dose group than in the low-dose group. After repeated doses, significant increases in pH were observed in the low-, middle-, and high-dose groups; however, the between-group differences were not statistically significant. Conclusions: There is a relationship between the pharmacokinetics and pharmacodynamics of RPZ, with the latter depending in part on the duration of administration, as evidenced by a higher AUC or C and intragastric pH from repeated dosing. [ABSTRACT FROM AUTHOR]

To explore the effect of cytochrome P450 2C19 (CYP2C19) polymorphisms on the relationship between the pharmacokinetics and pharmacodynamics of omeprazole administered by intravenous successive infusions in Chinese healthy volunteers. A total of 21 subjects [7 homozygous extensive metabolizers (homEMs), 9 heterozygous extensive metabolizers (hetEMs), 5 poor metabolizers (PMs)] received a 5-day course of omeprazole (40 mg) administered as a single dose daily during a 30-min period. Plasma concentrations were monitored by sampling at very short intervals for the first 8.5 h post-omeprazole administration and at 24 h post-administration, and intragastric pH was recorded on days 1 and 5. After a single dose, both the area under the plasma concentration–time curve (AUC) and peak concentration (Cmax) were higher in PMs than in EMs. Both the mean half-life (t½) and total clearance in PMs were significantly higher and lower than those in homEMs and EMs, respectively. Mean AUC and Cmax ratios in homEMs, hetEMs, and PMs were 1.0:1.1:1.4 and 1.0:1.0:1.1, respectively. Relative to the values determined after a single dose in EMs, after repeated doses, the intragastric pH, AUC, Cmax, and t½ had increased significantly, while the total clearance had decreased significantly. Mean AUC and Cmax ratios in homEMs, hetEMs, and PMs were 1.4:1.4:1.5 and 1.2:1.2:1.3, respectively, compared to those of a single dose. The mean intragastric pH was significantly higher in PMs than in EMs after the fifth dose. There is a relationship between the pharmacokinetics and pharmacodynamics of omeprazole, with the latter depending in part on the duration of administration as evidenced by a higher AUC or Cmax and intragastric pH resulting from repeated dosing. [ABSTRACT FROM AUTHOR]