Pharmacokinetics of zidovudine in cats

Objective—To characterize the pharmacokinetics of zidovudine (AZT) in cats. Animals—6 sexually intact 9-month-old barrier-reared domestic shorthair cats. Procedure—Cats were randomly alloted into 3 groups, and zidovudine (25 mg/kg) was administered IV, intragastrically (IG), and PO in a 3-way crossover study design with 2-week washout periods between experiments. Plasma samples were collected for 12 hours after drug administration, and zidovudine concentrations were determined by high-performance liquid chromatography. Maximum plasma concentrations (Cmax), time to reach Cmax (Tmax), and bioavailability were compared between IG and PO routes. Area under the curve (AUC) and terminal phase halflife (t½) among the 3 administration routes were also compared. Results—Plasma concentrations of zidovudine declined rapidly with t½ of 1.4 ± 0.19 hours, 1.4 ± 0.16 hours, and 1.5 ± 0.28 hours after IV, IG, and PO administration, respectively. Total body clearance and steady-state volume of distribution were 0.41 ± 0.1...