Pharmacokinetics and Distribution of Florfenicol in Bronchial Secretions of Healthy and Pasteurella multocida Infected Calves

Abstract

Florfenicol was administered intravenously and intramuscularly at a dose rate of 20 mg/kg bwt to determine its concentration in blood and bronchial secretions as well as kinetic behavior in healthy and diseased calves. Sever acute bronchopneumonia was induced via inoculating the animals with Pasteurella multocida. Following intravenous (i.v) administration, the serum concentration -time curve indicated a two compartment open model with a mean elimination half-lives (t 1/2β ) of 4.10 and 4.84 h in healthy and infected calves, respectively. The mean volumes of distribution at steady state (Vdss) were 0.68 and 0.63 L/kg and the total body clearances (C ltot ) were 0.15 and 0.11 L/kg/h with mean residence time (MRT) of 0.05 and 0.05 h, respectively. Florfenicol was slowly eliminated from serum and bronchial secretions with elimination half-lives (t 1/2el ) of (12.43 and 17.23 h) and (13.74 and 22.46 h), respectively, following intramuscular (i.m.) injection. The peak concentrations (Cmax) in serum and bronchial secretions were (3.70 and 4.06 µg/ml) and (6.88 and 7.62 µg/ml) attained at (3.07 and 3.01 h) and (1.54 and 1.70 h), respectively. The drug is extensively distributed to bronchial secretions with AUC bronchial secretion / AUC serum ratio of 1: 2.53 and 1: 2.03, respectively. The clinical and hematological parameters in calves treated intramuscularly returned to normal faster than those treated intravenously. These results suggest that i.m. injection of florfenicol could be used for treatment of acute P. multocida bronchopneumonia in calves.

3Department of Nutrition and food science, Faculty of specific education (Home Economics), Faculty of Medicine; Benha University

“…The results of hematological changes after treatment with tulathromycin agreed with (Altunok et al, 2002, andYazar et al, 2004) who reported that there was a changes in hematological parameters toward the normal limits in treatment with tulathromycin. The results of hematological changes after treatment with florfenicol agreed with (Ramadan and Abd El-Aty, 2011) who recorded that the hematological parameters returned toward normal levels after second day of intramuscular treatment of florfenicol. The results of hematology after treatment with amoxicillin agreed to (Elmajdoub et al, 2014) who concluded that amoxicillin given in the therapeutic dose twice daily to healthy Libyan sheep caused only minor inconclusive changes in the hematological parameters.…”

High-Throughput Intracellular Antimicrobial Susceptibility Testing of Legionella pneumophila

“…Interestingly, florfenicol appeared to have similar in vitro activity based on our studies (Tables 1 and 2; see also Table S1 in the supplemental material). However, florfenicol, currently approved only for veterinary use (35), is not associated with bone marrow failure, is immune to inactivation by chloramphenicol acetyltransferase (36), the most prevalent mechanism of chloramphenicol resistance, and achieves excellent penetration into bronchial secretions (37). Therefore, it is potentially worthy of further study for treatment of human pneumonia.…”

Diferencias de especie en las concentraciones plasmáticas y tisulares de florfenicol entre ovinos y conejos

“…La farmacocinética de FFC ha sido descrita en pollos (4), cerdos (7), perros (8), conejos (9), ovinos (10), y ganado bovino (11,12). Es sabido que la farmacocinética de fármacos en animales puede variar dependiendo de distintos factores, incluyendo variaciones entre especies (13).…”