Pharmacokinetic Disposition of Itraconazole in Red-Tailed Hawks (Buteo jamaicensis)

Abstract

The pharmacokinetic disposition of itraconazole in plasma and tissues was evaluated in a multiple dose study using 11 nonreleasable red-tailed hawks (Buteo jamaicensis). An itraconazole solution was administered by gavage at a dosage of 5 mg/kg in 4 hawks and 10 mg/kg in 7 hawks once daily for 15 days. On days 1 and 14, blood samples were obtained at 1, 8, 16, and 24 hours after itraconazole administration. The hawks were killed on day 15, and samples of air sac, brain, kidney, liver, lung, and small intestine were retrieved. High-pressure liquid chromatography was used to measure the concentration of the parent drug, itraconazole, and its active metabolite, hydroxyitraconazole, in plasma and tissues of each hawk. Concentrations represent point-in-time values. Results suggest that hawks gavaged with itraconazole at 10 mg/kg once daily will reach steady state plasma concentrations of itraconazole and hydroxyitraconazole within 2 weeks. Although plasma concentrations were lower than those reported in parrots and pigeons, concentrations of both itraconazole and hydroxyitraconazole in organs other than the brain were comparable among species of birds.