Pharmacokinetics of cefquinome in tilapia (Oreochromis niloticus) after a single intramuscular or intraperitonealadministration

The pharmacokinetics of cefquinome was studied in plasma after a single dose (10mg/kg) of intramuscular (i.m.) or intraperitoneal (i.p.) administration to tilapia (Oreochromis niloticus) in freshwater at 30 degrees C. Ten fish per sampling point were examined after treatment. The data were fitted to two-compartment open models following both routes of administration. The estimates of total body clearance (CL/F), volume of distribution (Vd/F), and absorption half-life (T-1/2ka) were 0.049 and 0.037L/h/kg, 0.41 and 0.33L/kg, and 0.028 and 0.035h following i.m. and i.p. administration, respectively. After i.m. injection, the elimination half-life (T-1/2) was calculated to be 5.81h, the maximum plasma concentration (C-max) to be 49.40g/mL, the time to peak plasma cefquinome concentration (T-max) to be 0.14h, and the area under the plasma concentration-time curve (AUC) to be 204.6gh/mL. Following i.p. administration, the corresponding estimates were 6.05h, 44.39g/mL, 0.17h and 267.8gh/mL. The minimum inhibitory concentrations of cefquinome, determined for 30 strains of Streptococcus agalactiae isolated from diseased tilapia, ranged from 0.015 to 0.12g/mL. Results from these studies support that 10mg cefquinome/kg body weight daily could be expected to control tilapia bacterial pathogens inhibited invitro by a minimal inhibitory concentration value of 2g/mL.