Pharmacokinetics of Ceftiofur‐Related Residues in Rabbits After Single Intravenous and Intramuscular Administration

) of 0.85 L/kg, and was eliminated slowly, with a systemic clearance of 0.083 L/h/kg. The mean residence time (MRT; 9.95 h) after IM administration was not longer than that observed after IV administration (10.34 h), precluding reliable estimation of the absorption half-life. Based on PK/PD analysis assuming a minimum inhibitory concentration (MIC) of ≤ 1.0 μg/mL, the calculated time above MIC (T > MIC) values following single IV and IM administration were approximately 4 and 5 h, respectively. These results indicate that although ceftiofur is rapidly and extensively absorbed in rabbits, a single IV or IM dose of 2 mg/kg BW may be insufficient to achieve effective exposure against bacterial pathogens with MIC values ≥ 1.0 μg/mL.