Pharmacokinetics of florfenicol after intravenous and intramuscular administration in New Zealand White rabbits

• Published in: Research in veterinary science 2009-08, Vol.87 (1), p.102-105
• Main Authors: Koc, F., Ozturk, M., Kadioglu, Y., Dogan, E., Yanmaz, L.E., Okumus, Z.
• Format: Article
• Language: English
• Subjects: Animals; Anti-Bacterial Agents - administration & dosage; Anti-Bacterial Agents - blood; Anti-Bacterial Agents - pharmacokinetics; Antibiotics; Anticoagulants; Area Under Curve; Drug dosages; Drug therapy; Florfenicol; Half-Life; Injections, Intramuscular; Injections, Intravenous; Methods; Pharmacokinetic; Plasma; Rabbit; Rabbits; Thiamphenicol - administration & dosage; Thiamphenicol - analogs & derivatives; Thiamphenicol - blood; Thiamphenicol - pharmacokinetics; Veterinary medicine
• ISSN: 0034-5288; 1532-2661
• DOI: 10.1016/j.rvsc.2008.10.010

The pharmacokinetic disposition and bioavailability of florfenicol (FF) were determined after single intravenous (i.v.) and intramuscular (i.m.) administrations of 25 mg/kg b.w. to ten healthy New Zealand White rabbits. Plasma FF concentrations were determined by high-performance liquid chromatography (HPLC). The plasma pharmacokinetic values for FF were best described by a one-compartment open model. The elimination half-life ( t 1/2β) was different ( p < 0.05) however, the area under curve (AUC) was similar ( p > 0.05) after i.v. and i.m. administrations. FF was rapidly eliminated ( t 1/2β 1.49 ± 0.23 h), slowly absorbed and high ( F, 88.75 ± 0.22%) after i.m. injection. In addition, FF was widely distributed to the body tissues ( V ss 0.98 ± 0.05 L/kg) after i.v. injection. In this study the time that plasma concentration exceeded the concentration of 2 μg/mL was approximately 6 h. For bacteria with MIC of 2 μg/mL, frequent administration at this dose would be needed to maintain the concentration above the MIC. However, it is possible that rabbit pathogens may have MIC values less than 2 μg/mL which would allow for less frequent administration. Further studies are necessary to identify the range of MIC values for rabbit pathogens and to identify the most appropriate PK-PD parameter needed to predict an effective dose.