Pharmacokinetics of Ceftiofur Sodium in Black-bone Silky Fowl after One Single Intravenous and Intramuscular Injection

Background: Ceftiofur is a third-generation cephalosporin antibiotic developed exclusively for veterinary applications. Although not approved in China, ceftiofur is being used extensively in an extra-label manner to treat poultry infections. Black-bone silky fowl is a unique chicken breed which is different from the common chicken breeds in both morphology and other physiology. These differences may result in varied pharmacokinetic profiles. Therefore, the present study aimed to investigate the pharmacokinetics of ceftiofur (measured by ceftiofur and its active metabolites concentrations) in black-bone silky fowl following a single intravenous or intramuscular injection of ceftiofur sodium. Methods: Ceftiofur sodium was intravenously and intramuscularly given to six healthy black-bone silky fowl at the dose of 10 mg/kg body weight. A derivatization method was used to quantify the concentrations of ceftiofur and its active metabolites (expressed as desfuroylceftiofur acetamide) in plasma samples. A non-compartment& method was used to calculate the pharmacokinetics parameters. Result: The terminal half-life (t(1)(/2)(lambda z)) was calculated as 3.19 +/- 0.28 and 3.36 +/- 0.17 h following intravenous and intramuscular injections, respectively. After intravenous treatment, the total body clearance (CI) and volume of distribution at steady state (V-SS) were determined as 73.79 +/- 5.83 ml/h/kg and 318.65 +/- 30.06 ml/kg, respectively. After intramuscular injection, the peak concentration (C-max ; 22.55 +/- 0.89 mu g/ml) was observed at 1.67 +/- 0.26 h and the absorption half-life (t(1)(/2)(lambda z)) and absolute bioavailability (F) were calculated as 0.40 +/- 0.13 h and 93.03%+/- 7.07%, respectively. The current results demonstrated the rapid and complete absorption, however, poor distribution and rapid elimination of ceftiofur and its active metabolites in black-bone silky fowl.