title: Pharmacokinetics of a single intramuscular injection of ceftiofur crystalline-free acid in American black ducks (Anas rubripes).
abstract: OBJECTIVE
  To determine the pharmacokinetic properties of 1 IM injection of ceftiofur crystalline-free acid (CCFA) in American black ducks (Anas rubripes).
  
  
  METHODS
  20 adult American black ducks (6 in a preliminary experiment and 14 in a primary experiment).
  
  
  METHODS
  Dose and route of administration of CCFA for the primary experiment were determined in a preliminary experiment. In the primary experiment, CCFA (10 mg/kg, IM) was administered to ducks. Ducks were allocated into 2 groups, and blood samples were obtained 0.25, 0.5, 1, 2, 4, 8, 12, 48, 96, 144, 192, and 240 hours or 0.25, 0.5, 1, 2, 4, 8, 24, 72, 120, 168, and 216 hours after administration of CCFA. Plasma concentrations of ceftiofur free acid equivalents (CFAEs) were determined by use of high-performance liquid chromatography. Data were evaluated by use of a naive pooled-data approach.
  
  
  RESULTS
  The area under the plasma concentration versus time curve from 0 hours to infinity was 783 h•μg/mL, maximum plasma concentration observed was 13.1 μg/mL, time to maximum plasma concentration observed was 24 hours, terminal phase half-life was 32.0 hours, time that concentrations of CFAEs were higher than the minimum inhibitory concentration (1.0 μg/mL) for many pathogens of birds was 123 hours, and time that concentrations of CFAEs were higher than the target plasma concentration (4.0 μg/mL) was 73.3 hours.
  
  
  CONCLUSIONS
  On the basis of the time that CFAE concentrations were higher than the target plasma concentration, a dosing interval of 3 days can be recommended for future multidose CCFA studies.
authors.affiliation: Department of Animal Health, Smithsonian National Zoological Park, 3001 Connecticut Ave NW, Washington, DC 20008, USA. hopek@si.edu
authors.forename: Katharine L
authors.initials: KL
authors.lastname: Hope
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Tell
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Byrne
authors.forename: Suzan
authors.initials: S
authors.lastname: Murray
authors.forename: Scott E
authors.initials: SE
authors.lastname: Wetzlich
authors.forename: Lisa H
authors.initials: LH
authors.lastname: Ware
authors.forename: Warren
authors.initials: W
authors.lastname: Lynch
authors.forename: Luis R
authors.initials: LR
authors.lastname: Padilla
authors.forename: Nancy C
authors.initials: NC
authors.lastname: Boedeker
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*; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D004372:Ducks / Q000097:blood / Q000378:metabolism*; D005260:Female; D006207:Half-Life; D007273:Injections, Intramuscular / Q000662:veterinary; D008297:Male
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; C063324:desfuroylceftiofur; C053503:ceftiofur