ABSTRACT
The present study was to estimate pharmacokinetic parameters of metformin hydrochloride in 20 Chinese healthy volunteers with a limited sampling strategy (LSS), which will provide scientific data for bioequivalence and clinical application. A single dose of metformin was administrated to 20 healthy volunteers. The concentration of metformin in whole blood was determined by validated high performance liquid chromatography (HPLC) method. Multi-linear regression analysis was performed to establish a model to estimate AUC(0-24 h) and Cmax of metformin by LSS method. The LSS models were validated by the Jackknife method. The result indicated: the linearity relationship between AUC(0-24 h) or Cmax and single concentration point was poor. Several models for metformin AUC(0-24 h) or Cmax, estimation were better (r2 > 0.9, P < 0.05). Validation tests indicated that most informative sampling points (C2, C6 for AUC(0-24 h), C1.5, C2 for Cmax) provided accurate estimations of these parameters. So, a multi-linear regression model for estimation pharmacokinetic parameters of metformin by using LSS method is feasible.
ABSTRACT
The method of simultaneous administration of several probe substrates is called “Cocktail" approaches. The objective of the article is to review the application of this technique in characterizing the activity of multiple drug-metabolizing enzymes and in clinical researches. This paper also shows Five-drug and Six-drug Cocktail set for evaluating in vivo activity of drug-metabolizing enzymes.
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Aim To study effects of different dosage regimens of gentamicin(GTM) on impairment of renal functions, plasma concentrations and pharmacokinetics in rats. Method 108 rats were divided into 6 groups: control group; chronological once-daily dose groups (N100 and D100 group, in which 100 mg?kg -1 GTM were intramuscularly administrated at 01 ∶00 or 13 ∶[KG-*3]00 respectively), and chronological twice-daily different dose groups (N90+D10, N70+D30, N50+D50 group, in which 90 mg?kg -1+10 mg?kg -1, 70 mg?kg -1+30 mg?kg -1 and 50 mg?kg -1+50 mg?kg -1 GTM were given at 1:00 and 13:00 respectively). The blood urea nitrogen (BUN) and creatinine (Cr) levels were observed, the plasma concentrations of GTM at 0.25,0.5,1, 2, 5 and 8h were determined, the C-T curves were profiled and the pharmacokinetic parameters were calculated at the 1st, the 10th, and the 20th day of administrations. Results ① Impairment of renal function. At the 10th day of administration, the Cr and BUN levels of N50+D50 group were the highest. There was a significant difference when compared those of the 10th day of administration with those of the 1st day of administration and of control group at same time respectively (P
ABSTRACT
To study the effects of astragaloside Ⅳ, which was obtained from Astragalus membranaceus Bge., on myocardiac dynamics and cardiac function on normal and cardiac depressant rat. Methods Left ventricular pressure (LVP) and differential value of dp/dt were recorded by left ventricular catherization to observe the effect of 1 mg/kg iv astragaloside Ⅳ on normal and cardiac depressant rat induced by iv 0.75 mg/kg of Propanolol. Results Astragaloside Ⅳ decreased heart rate slightly, and showed inotropic activity by increasing dp/dtmax significantly, with improvement of cardiac diastolic function. It shortened the time constant (T) and caused no obvious change on the tension time index (TTI) in normal rat. These results suggested that astragaloside Ⅳ did not increase cardiac oxygen consumption while exerting its inotropic effect. Conclusion Astragaloside Ⅳ can improve both cardiac systolic and diastolic functions, and may be used as a candidate for the treatment of cardiac disfunction.
ABSTRACT
Object To study the effects of astragaloside Ⅳ, which was obtained from Astragalus membranaceus Bge., on myocardiac dynamics and cardiac function on normal and cardiac depressant rat Methods Left ventricular pressure (LVP) and differential value of dp/dt were recorded by left ventricular catherization to observe the effect of 1 mg/kg iv astragaloside Ⅳ on normal and cardiac depressant rat induced by iv 0 75 mg/kg of Propanolol Results Astragaloside Ⅳ decreased heart rate slightly, and showed inotropic activity by increasing dp/dt max significantly, with improvement of cardiac diastolic function It shortened the time constant (T) and caused no obvious change on the tension time index (TTI) in normal rat These results suggested that astragaloside Ⅳ did not increase cardiac oxygen consumption while exerting its inotropic effect Conclusion Astragaloside Ⅳ can improve both cardiac systolic and diastolic functions, and may be used as a candidate for the treatment of cardiac disfunction
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AIM To compare the pharmacokinetics and bioequivalence of between capsule and solution of benzoylmetronidazole. METHODS Ten chinese healthy male volunteers in a randomized 2-way crossover study were given a single oral dose 960 mg capsule(test) and solution (control) respectively. The serum concentrations of metronidazole, one of the metabolites of benzoylmetronidazole, was measured by high performance liquid chromatography. RESULTS The serum concentration-time curves appeared one-compartment open model. The results of the capsule and the solution of benzoylmetronidazole showed that T max (5.10?1.60) h and (3.12?0.90) h; C max (5.32?0.87) mg?L -1 and (6.51?1.25) mg?L -1 ; T 12 (10.56?1.75) h and (10.16?1.65) h; AUC (106.96?19.62) mg?h -1 ?L -1 and (113.59?19.84) mg?h?L -1 . CONCLUTION No significant difference appears in the pharmacokinetic parameters between the two formulations except of T max and C max ( P