sitafloxacin and Diarrhea

1. The aim was to compare the pharmacokinetics of sitafloxacin from a capsule formulation (dose of 500 mg sitafloxacin) and an intravenous (i.v.) formulation infused over 1 h (dose of 400 mg sitafloxacin) in healthy male and female subjects and to estimate the absolute bioavailability of sitafloxacin from the capsule formulation. 2. Following oral administration, sitafloxacin was rapidly absorbed, with a mean maximum concentration in plasma of 4.65 microgml(-1) occuring at median tmax = 1.25 h giving a mean AUC(0-infinity) = 28.1 microg h ml(-1). For the i.v. administration, a mean Cmax = 5.53 microm(-1) occurred at the end of the 1-h infusion with a mean AUC(0-infinity) = 25.4 microg h ml(-1). The mean terminal elimination half-life was 7.0 h (oral) and 6.6 h (i.v.). For the oral and i.v. formulations, the mean total plasma clearance was 296 and 263 mlmin(-1), respectively and the mean volume of distribution was 180 and 150 litres, respectively. 3. Within 48 h post-dose, approximately 61% (range 22-86%) of the administered dose was excreted unchanged in urine following capsule administration, compared with approximately 75% (range 42-101%) following the i.v. formulation. For both formulations, the renal clearance of sitafloxacin (means of 181 and 198 ml min(-1) for the capsule and i.v. doses, respectively) implies active tubular secretion of the drug. 4. The absolute bioavailability of sitafloxacin from the capsule formulation was high at 89%, with a 95% CI of 84-94%. The intersubject variability (CV%) in the sitafloxacin AUC(0-infinity) for the capsule was low at 18.6%. 5. Gender differences in the pharmacokinetics of sitafloxacin were small and would not warrant dose adjustment. 6. The findings show that the capsule formulation offers good oral bioavailability and merits further clinical evaluation of sitafloxacin as an orally effective fluoroquinolone antibacterial.

Topics: Administration, Oral; Adult; Anti-Infective Agents; Biological Availability; Capsules; Cross-Over Studies; Diarrhea; Dose-Response Relationship, Drug; Female; Fluoroquinolones; Humans; Injections, Intravenous; Male; Middle Aged; White People

The activity of DU-6859a, a new fluoroquinolone antimicrobial agent, was compared with that of ciprofloxacin by agar dilution susceptibility testing against enteric pathogens and multiresistant Escherichia coli. The results indicate that DU-6859a inhibits most of these organisms at concentrations similar to those of ciprofloxacin. DU-6859a showed increased activity compared to ciprofloxacin against Campylobacter species isolates.

Topics: Anti-Infective Agents; Ciprofloxacin; Diarrhea; Drug Resistance, Multiple; Escherichia coli; Fluoroquinolones; Gram-Negative Bacteria; Humans; In Vitro Techniques; Microbial Sensitivity Tests; Quinolones; Spiro Compounds