RESUMO
Rufloxacin is a new once-daily antibacterial fluoroquinolone with a long half-life. The aim of the present study was to evaluate the plasma and biliary kinetics and biliary and urinary excretion of rufloxacin in patients with extrahepatic cholestasis. Twelve patients with total external percutaneous transhepatic biliary drainage were given a single oral dose of 400 mg of rufloxacin. Plasma, bile, and urine samples and fractions were collected over 72 h after drug administration. Rufloxacin and its major metabolite, the N-desmethyl derivative, were measured by high-performance liquid chromatography. Maximum rufloxacin concentrations in plasma and bile (means +/- standard deviations) were 4.05 +/- 1.38 micrograms/ml and 8.24 +/- 7.16 micrograms/ml, respectively, and were reached in 4.2 +/- 3.0 h and 4.2 +/- 3.5 h, respectively. The terminal elimination half-life of rufloxacin in plasma was 45.1 +/- 13.5 h. Apparent plasma clearance was 31.3 +/- 10.5 ml/min, while biliary clearance was 0.4 +/- 0.2 ml/min and renal clearance was 12.7 +/- 6.0 ml/min. In 72 h, 0.9% +/- 0.8% of the dose given was recovered in bile and 27.2% +/- 12.0% was recovered in urine. Biliary concentrations exceeded the MICs of most common biliary tract pathogens for at least 24 h after administration. The broad antibacterial spectrum of rufloxacin and its high and prolonged biliary concentrations suggest that this drug may be useful for treatment of biliary tract infections.
Assuntos
Anti-Infecciosos/farmacocinética , Sistema Biliar/metabolismo , Colestase Extra-Hepática/metabolismo , Fluoroquinolonas , Quinolonas/farmacocinética , Administração Oral , Idoso , Bile/metabolismo , Bile/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
The metabolism of striatum dopamine (DA) was studied in mice during proestrus, estrus and diestrus. The following results have been obtained: (1) the concentration of DA is higher in diestrus than in proestrus and estrus; (2) the concentration of its metabolite, homovanillic acid (HVA), is maximum in the estrus phase; (3) the DA turnover, evaluated by measuring the DA disappearance after blocking synthesis with methyltyrosine, is faster in estrus than in the other phases. These results have been discussed in view of the possible role of dopaminergic mechanisms in the control of gonadotropin secretion.