title: Pharmacokinetics of florfenicol in healthy pigs and in pigs experimentally infected with Actinobacillus pleuropneumoniae.
abstract: A comparative in vivo pharmacokinetic study of florfenicol was conducted in 18 crossbred pigs infected with Actinobacillus pleuropneumoniae following intravenous (i.v.), intramuscular (i.m.), or oral (p.o.) administration of a single dose of 20 mg/kg. The disease model was confirmed by clinical signs, X rays, pathohistologic examinations, and organism isolation. Florfenicol concentrations in plasma were determined by a validated high-performance liquid chromatography method with UV detection at a wavelength of 223 nm. Pharmacokinetic parameters were calculated by using the MCPKP software (Research Institute of Traditional Chinese Veterinary Medicine, Lanzhou, China). The disposition of florfenicol after a single i.v. bolus was described by a two-compartment model with values for the half-life at alpha phase (t(1/2alpha)), the half-life at beta phase (t(1/2beta)), the area under the concentration-time curve (AUC(0- infinity )), and the volume of distribution at steady state (V(ss)) of 0.37 h, 2.91 h, 64.86 micro g. h/ml, and 1.2 liter/kg, respectively. The concentration-time data fitted the one-compartment (after i.m.) and two-compartment (after p.o.) models with first-order absorption. The values for the maximum concentration of drug in serum (C(max)), t(1/2alpha), t(1/2beta), and bioavailability after i.m. and p.o. dosing were 4.00 and 8.11 micro g/ml, 0.12 and 3.91 h, 13.88 and 16.53 h, and 122.7 and 112.9%, respectively, for the two models. The study showed that florfenicol was absorbed quickly and completely, distributed widely, and eliminated slowly in the infected pigs, and there was no statistically significant difference between the pharmacokinetic profiles for the infected and healthy pigs.
authors.affiliation: Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China. j.liu@auckland.ac.nz
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Liu
authors.forename: Ki-Fai
authors.initials: KF
authors.lastname: Fung
authors.forename: Zhangliu
authors.initials: Z
authors.lastname: Chen
authors.forename: Zhenling
authors.initials: Z
authors.lastname: Zeng
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000189:Actinobacillus Infections / Q000188:drug therapy / Q000378:metabolism*; D016977:Actinobacillus pleuropneumoniae; D000284:Administration, Oral; D000818:Animals; D000900:Anti-Bacterial Agents / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D019540:Area Under Curve; D001682:Biological Availability; D006207:Half-Life; D007273:Injections, Intramuscular; D007275:Injections, Intravenous; D007408:Intestinal Absorption; D013552:Swine; D013839:Thiamphenicol / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; C035534:florfenicol; D013839:Thiamphenicol