Pharmacokinetics of a single intramuscular injection of ceftiofur crystalline-free acid in American black ducks (Anas rubripes)

Objective—To determine the pharmacokinetic properties of 1 IM injection of ceftiofur crystalline-free acid (CCFA) in American black ducks (Anas rubripes). Animals—20 adult American black ducks (6 in a preliminary experiment and 14 in a primary experiment). Procedures—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/m...