Difference in the PK of ceftiofur in the presence and absence of nimesulide and implications for dose determination through PK/PD integration

Pharmacokinetic evaluation of cefquinome in febrile goats following intravenous administration

Pharmacokinetics of cefquinome was studied in febrile female goats following its intravenous (IV) administration at the dose rate of 2 mg/kg body weight. The fever was induced by administration of Escherichia coli lipopolysaccharide (lμg/kg body weight). Cefquinome concentration in plasma of goats was estimated using HPLC. The drug was detected upto 24 h in febrile goats. The disposition kinetics of the drug was described by twocompartment open model. PK-PD indices; AUC24h/MIC, Cmax/MIC, T>MIC were calculated by integrating in-vivo PK data with earlier generated MIC data against Pasteurella (P.) multocida. A favourable PK and PK-PD indices suggested that the dose of 2 mg/kg/24 h of cefquinome would be effective clinically to treat goats affected with P. multocida infections.

Implications for dosing regimen of enrofloxacin administered concurrently with dexamethasone in febrile buffalo calves

The objective of the study was to determine the influence of dexamethasone (DXM) on pharmacokinetics (PK) and pharmacodynamics (PD) of enrofloxacin (ENR) for dosage optimization following concurrent administration of ENR and DXM in febrile buffalo calves. A 2 μg/kg intravenous dosage of lipopolysaccharide derived from Escherichia coli was used to induce fever in calves. After inducing fever, ENR was administered at the dose rate of 12 mg/kg, IM followed by IM injection of DXM (0.05 mg/kg) in calves. Minor alterations in PK of ENR were observed following the administration of ENR + DXM. The PK parameters were t_1/2K₁₀ = 6.34 h, Cl/F = 0.729 L/kg/h, and MRT_0-∞ = 10.5 h. Antibacterial activity (MIC, MBC, ex vivo time-kill kinetics) of ENR for P. multocida was not affected by DXM. But MPC of ENR against P. multocida was lessened in presence of DXM. Using PK-PD-modeled AUC_0-24h/MIC values for bactericidal effect against P. multocida, daily dosages of ENR administered in combination with DXM were 4.02 mg/kg and 16.1 mg/kg, respectively, for MIC_90s of 0.125 μg/ml and 0.50 μg/ml. A dose of 5.38 mg/kg was determined for ENR for frequently occurring P. multocida infections having ≤ MIC₉₀ of 0.125 μg/ml and PK-PD modeled dose was comparable with the recommended ENR dose of 5 mg/kg for bovines for mild infections. It is suggested that a recommended dosage of 5-12.5 mg/kg of ENR can be used effectively in combination with DXM to treat P. multocida associated infections in buffalo calves without any risk of resistance amplification.