title: Pharmacokinetics of ceftiofur crystalline-free acid following subcutaneous administration of a single dose to sheep.
abstract: OBJECTIVE
  To determine the pharmacokinetics of ceftiofur crystalline-free acid (CCFA) following SC administration of a single dose to sheep.
  
  
  METHODS
  9 healthy adult female Suffolk-crossbred sheep.
  
  
  METHODS
  Each sheep was administered 6.6 mg of CCFA/kg, SC, in the cervical region once. Serial blood samples were collected at predetermined intervals for 14 days. Serum concentration of ceftiofur free-acid equivalents (CFAE) was determined by high-performance liquid chromatography. Pharmacokinetic parameters were determined by compartmental and noncompartmental methods.
  
  
  RESULTS
  Pharmacokinetics for CCFA following SC administration in sheep was best described with a 1-compartment model. Mean ± SD area under the concentration-time curve from time 0 to infinity, peak serum concentration, and time to peak serum concentration were 206.6 ± 24.8 μ•h/mL, 2.4 ± 0.5 μg/mL, and 23.1 ± 10.1 h, respectively. Serum CFAE concentrations ≥ 1 μg/mL (the target serum CFAE concentration for treatment of disease caused by Mannheimia haemolytica and Pasteurella multocida) were maintained for 2.6 to 4.9 days. No significant adverse reactions to CCFA administration were observed.
  
  
  CONCLUSIONS
  Results indicated that adequate therapeutic serum concentrations of CFAE for treatment of disease caused by M haemolytica and P multocida were achieved in sheep following SC administration of a single dose (6.6 mg/kg) of CCFA. Thus, CCFA might be useful for the treatment of common respiratory tract pathogens in sheep.
authors.affiliation: William R. Pritchard Veterinary Medical Teaching Hospital, College of Agricultural and Environmental Sciences, University of California-Davis, Davis, CA 95616.
authors.forename: Sarai
authors.initials: S
authors.lastname: Rivera-Garcia
authors.forename: John A
authors.initials: JA
authors.lastname: Angelos
authors.forename: Joan D
authors.initials: JD
authors.lastname: Rowe
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Byrne
authors.forename: Scott E
authors.initials: SE
authors.lastname: Wetzlich
authors.forename: Dana B
authors.initials: DB
authors.lastname: Van Liew
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Tell
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D019540:Area Under Curve; D002511:Cephalosporins / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D003692:Delayed-Action Preparations; D005260:Female; D006207:Half-Life; D007279:Injections, Subcutaneous / Q000662:veterinary; D012756:Sheep / Q000097:blood / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D003692:Delayed-Action Preparations; C053503:ceftiofur