title: Pharmacokinetics and bioavailability of florfenicol following intravenous, intramuscular and oral administrations in rabbits.
abstract: This study examined the disposition kinetics and bioavailability of florfenicol after intravenous (i.v.), intramuscular (i.m.) and oral administration to rabbits at a dose of 30 mg/kg BW. Serial blood samples were collected through an indwelling catheter intermittently for 24 h for various routes. Plasma antibacterial concentrations were determined using a microbiological assay method with Bacillus subtilis ATCC 6633 as a reference organism. Plasma concentration-time data generated in the present study were analysed by non-compartmental methods based on statistical moment theory. Following i.v. administration, the overall elimination half-life (t1/2beta) was 1.54 h, mean residence time (MRT) was 1.69 h, mean volume of distribution at steady-state (Vdss) was 0.57 L/kg, and total body clearance (Cltot) was 0.34 L/kg/h. After i.m. and oral dosing, the terminal part of the curve should correspond to the absorption phase, instead of to the elimination phase, with terminal half-lives of 3.01 and 2.57 h, respectively. The mean absorption time (MAT) was 2.65 h for i.m. and 2.01 h for oral administration. Elimination rate constants differed with i.v., i.m. and oral administrations, suggesting a flip-flop situation. The observed mean peak plasma concentrations (Cmax obs) were 21.65 and 15.14 microg/ml achieved at a post-injection time (Tmax obs) of 0.5 h following i.m. and oral dosing, respectively. The absolute systemic availabilities were 88.25% and 50.79%, respectively, and the extent of plasma protein binding percent was 11.65%.
authors.affiliation: Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt. abdelaty44@hotmail.com
authors.forename: A M
authors.initials: AM
authors.lastname: Abd El-Aty
authors.forename: A
authors.initials: A
authors.lastname: Goudah
authors.forename: K
authors.initials: K
authors.lastname: Abo El-Sooud
authors.forename: H Y
authors.initials: HY
authors.lastname: El-Zorba
authors.forename: M
authors.initials: M
authors.lastname: Shimoda
authors.forename: H H
authors.initials: HH
authors.lastname: Zhou
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D019540:Area Under Curve; D001682:Biological Availability; D006207:Half-Life; D007273:Injections, Intramuscular / Q000662:veterinary; D007275:Injections, Intravenous / Q000662:veterinary; D011485:Protein Binding; D011817:Rabbits / Q000378:metabolism*; D013839:Thiamphenicol / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D000900:Anti-Bacterial Agents; C035534:florfenicol; D013839:Thiamphenicol