Study on pharmacokinetics and bioavailability of difloxacin in chickens

Thirty healthy Avine broiler chickens were allotted to 3 groups at 10 chickens per group. Pharmacokinetics of difloxacin was investigated in the 30 healthy Avine broiler chickens following single intravenous,intramuscular and oral administration at the dose of 10 mg/ kg, respectively. Blood samples were collected at different intervals after administration and difloxacin concentrations were determined by the HPLC method with a limit of detection of 0.05 μg/mL. The difloxacin concentration-time data were fitted to a two-compartmental open model after single intravenous administration to the healthy chickens. The main pharmacokinetic parameters were as follows: t_(1/2α)=0.69 h±0.43 h,t_(1/2β)=6.11 h±1.50 h,V_(1)=1.70 L/kg±0.33 L/kg,V_(d(area))=3.10 L/kg±0.67 L/kg,Cl_(B)=0.37 L/(kg·h)±0.10 L/(kg·h),AUC=29.16 μg/(mL·h)±8.04 μg/(mL·h).The drug concentration-time data were both fitted to a one-(compartmental)model with first order absorption after single intramuscular and (oral) administration to the chickens.The main pharmacokinetic parameters after single intramuscular administration were as follows:t_(1/2Ka)=0.17 h±0.12 h, t_(1/2Ke)=5.64 h±0.74 h, t_(max)=0.86 h±0.40 h, C_(max)=2.51 μg/mL±0.36 μg/mL, AUC= 22.62 μg/(mL·h)±3.28 μg/(mL·h), F=77.00%±11.80%. The main pharmacokinetic parameters after single oral administration were as follows: t_(1/2Ka)=1.46 h±1.00 h,t_(1/2Ke)=8.20 h±3.12 h,t_(max)=4.34 h±2.40 h, C_(max)=1.00 μg/mL±0.21 μg/mL, AUC=15.82 μg/(mL·h)±3.67 μg/(mL·h), F=54.20%±(12.60%). The results of the present study showed that difloxacin was absorbed rapidly (after) intramuscular administration, distributed extensively and eliminated slowly in chickens. The drug was not absorbed completely (after) both single intramuscular and oral administration in chickens.