PHARMACOKINETICS OF CEFTIOFUR SODIUM IN EXOTIC AND DOMESTIC AVIAN SPECIES

The pharmacokinetics of ceftiofur sodium were determined in domestic c hicks, turkey poults, adult cockatiels (Nymphicus hollandicus), and ad ult orange-winged Amazon parrots (Amazona amazonica) after subcutaneou s (chicks and turkey poults) and intramuscular (i.m.) dosing (cockatie ls and Amazon parrots). Turkey poult data were best fit to a single ex ponential model with disappearance half-lives (t(1/2)) of 8.6, 7.4 and 5.6 h after doses of 0.12, 0.24 and 0.48 mg ceftiofur free acid equiv alents (CFAE)/poult, respectively. Data from chicks were best fit to a biexponential model with primary and secondary half-lives of 2.2 and 7.5, 3.7 and 6.8, and 3.8 and 5.3 h after doses of 0.04, 0.08 and 0.16 mg CFAE/chick, respectively. Cockatiel and Amazon parrot data were be st fit to a biexponential model with primary and secondary half-lives of 0.28 and 2.5, and 0.93 and 7.9 h, respectively, after doses of 10 m g CFAE/kg body weight. The maximum concentration (C-max) and area unde r the concentration time curve (AUC) in chicks and poults were dose-pr oportional. The C-max for cockatiels was 5.2 mu g/mL and for Amazon pa rrots was 11 mu g/mL. Clearance in cockatiels and Amazon parrots were 11.3 and 3.8 mL/min/kg, respectively, and reflected the much greater A UC seen in Amazon parrots. Clearance values of ceftiofur were similar in chicks and Amazon parrots, slightly greater in turkey poults and gr eatest in cockatiels. These results indicate that pharmacokinetic diff erences must be considered when establishing dosage regimens for diffe rent avian species.