title: Pharmacokinetics of difloxacin in olive flounder Paralichthys olivaceus at two water temperatures.
abstract: In this study, the pharmacokinetics profiles of difloxacin in the olive flounder (Paralichthys olivaceus) were investigated following intravenous and oral administration (10 mg/kg BW) at 14 and 22 °C water temperatures. Plasma and tissue samples (muscle, liver, and kidney) were analyzed using an HPLC method. The results showed that the plasma concentration-time data for difloxacin were described commendably by two-compartment open model at the two water temperatures. The absorption half-life (t(1/2ka)) of difloxacin after oral administration were 2.08 and 1.10 h at 14 and 22 °C, respectively; whereas the elimination half-life (t(1/2β)) was 4.41 and 2.38 h, respectively. The muscle concentration of 1.35 ± 0.19 μg/g was observed at 9 h at 14 °C, and 2.11 ± 0.33 μg/g at 6 h at 22 °C, respectively. For liver, the peak concentration of difloxacin 2.43 ± 0.30 μg/g occurred at 6 h at 14 °C, which was lower than the 3.34 ± 0.24 μg/g peak that occurred at 4 h at 22 °C. The calculated bioavailability of difloxacin was 68.07% at 22 °C, which was higher than the 53.43% calculated for 14 °C. After intravenous administration, the t(1/2β) were 4.79 and 2.81 h at 14 and 22 °C, respectively. The results indicate that the peak concentrations in muscle and liver at 14 °C are approximately half of those achieved at 22 °C. However, the C(max) in kidney at 14 and 22 °C were similar. The Vd values were 1.20 and 1.75 L/kg at 14 and 22 °C, respectively. These data indicated that both temperature and drug administration had significant effects on the elimination of difloxacin, and lower temperature or oral administration resulted in lower elimination.
authors.affiliation: Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China; Fishery College, Ocean University of China, Qingdao, China.
authors.forename: M
authors.initials: M
authors.lastname: Sun
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: C L
authors.initials: CL
authors.lastname: Gai
authors.forename: Z Q
authors.initials: ZQ
authors.lastname: Chang
authors.forename: J T
authors.initials: JT
authors.lastname: Li
authors.forename: F Z
authors.initials: FZ
authors.lastname: Zhao
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000097:blood / Q000378:metabolism / Q000493:pharmacokinetics*; D002939:Ciprofloxacin / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism / Q000493:pharmacokinetics; D005432:Flounder / Q000097:blood*; D018482:Muscle, Skeletal / Q000378:metabolism; D015203:Reproducibility of Results; D013696:Temperature
chemical_list: D000900:Anti-Bacterial Agents; D002939:Ciprofloxacin; C047225:difloxacin