Stationary solution of master equations in the large-system-size limit.
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Journal Article↗
Biomedical subjects
Gang Hu
Publications and source records attributed to Gang Hu.
Pharmacokinetic and pharmacodynamic population modeling of orally administered rabeprazole in healthy Chinese volunteers by the NONMEM method.
The pharmacokinetic-pharmacodynamic (PK-PD) relationship of the proton pump inhibitor rabeprazole in healthy Chinese volunteers was characterized via a population approach. Healthy Chinese male volunteers were enrolled in the clinical trial. Subjects were divided into three groups by their CYP2C19 genotype. Serum concentrations of rabeprazole were determined using high performance liquid chromatography (HPLC). The intragastric pH values were monitored simultaneously. Data analysis was performed using nonlinear mixed-effects modeling as implemented in the NONMEM software package. The final PK-PD model incorporated a one-compartment PK model with one-order absorption from the gastroenteric trace, first-order elimination pathway with one fixed-effect genotype modeling, and a full sigmoidal Emax PD model (X +/- SE: E0 = 2.30 +/- 0.189; Emax = 7.32 +/- 0.662; EC50 = 51.3 +/- 2.142 ng/ml; Hill coefficient = 5.00 +/- 0.556). The time profiles for concentration and pH value, as well as the concentration-pH value relationship of rabeprazole in healthy Chinese volunteers were well described by the developed population PK-PD model.
2-Pyridinylmethylsulfinylbenzimidazoles↗
Pharmacokinetics of magnesium glycyrrhizinate following intravenous administration of magnesium glycyrrhizinate in rats.
The elimination, distribution, excretion of magnesium glycyrrhizinate (MG) after intravenous (i.v.) administration in rats, and the binding rate of MG to plasma protein were investigated. The concentrations of MG in plasma, tissue, and excretion of rats after i.v. administration of MG were measured using reversed-phase high performance liquid chromatography (RP-HPLC). The concentrations of MG in plasma declined in an apparent biexponential manner. The pharmacokinetic parameters from a two-compartment model analysis of plasma samples after i.v. administration of MG 30, 60, and 120 mg/kg-, were t(1/2beta) (min): 140, 180, and 240; AUC(0 approximately 18) (g x min x L(-1)): 10212, 15432, and 50321; CL (L x kg(-1) x min(-1)): 0.0025, 0.0039, and 0.0021, respectively. The drug administered as an iv injection, were mainly cumulated in the liver. When MG was administered to bile-duct cannulated rats, about 90% of i.v. dosed MG was excreted into bile under unchanged form within 24 h after administration. The average binding rate of MG to plasma protein was 87%. The experimental results showed that the distributional property of MG in the present rats study is beneficial to its liver protective activity and liver function improvement.
Animals↗