Pharmacokinetics, bioavailability and PK/PD relationship of cefquinome for Escherichia coli in Beagle dogs.

The pharmacokinetics and bioavailability of cefquinome in Beagle dogs were determined by intravenous (IV), intramuscular (IM) or subcutaneous (SC) injection at a single dose of 2 mg/kg body weight (BW). The minimum inhibitory concentrations (MIC) of cefquinome against 217 Escherichia coli isolated from dogs were also investigated. After IV injection, the plasma concentration-time curve of cefquinome was analyzed using a two-compartmental model, and the mean values of t1/2α (h), t1/2β (h), Vss (L/kg), ClB (L/kg/h) and AUC (μg·h/mL) were 0.12, 0.98, 0.30, 0.24 and 8.51, respectively. After IM and SC administration, the PK data were best described by a one-compartmental model with first-order absorption. The mean values of t1/2Kel , t1/2Ka , tmax (h), Cmax (μg/mL) and AUC (μg·h/mL) were corresponding 0.85, 0.14, 0.43, 4.83 and 8.24 for IM administration, 0.99, 0.29, 0.72, 3.88 and 9.13 for SC injection. The duration of time that drug levels exceed the MIC (%T > MIC) were calculated using the determined MIC90 (0.125 μg/mL) and the PK data obtained in this study. The results indicated that the dosage regimen of cefquinome at 2 mg/kg BW with 12-h intervals could achieve %T > MIC above 50% that generally produced a satisfactory bactericidal effect against E. coli isolated from dogs in this study.