Pharmacokinetics of meloxicam following intramuscular, subcutaneous, and oral administration in white storks (Ciconia ciconia)

Abstract Background Meloxicam (MLX) is a preferential cyclooxygenase-2 inhibitor widely used in avian medicine as an anti-inflammatory agent. Despite marked interspecific variability in avian drug disposition, no pharmacokinetic data are available for MLX in the white stork ( Ciconia ciconia ). This study aimed to characterise and compare the plasma pharmacokinetics of MLX in this species. Methods Six clinically stable, non-releasable white storks (three of each sex) received a single 1 mg/kg dose of MLX by the IM, SC and PO routes in a randomised three-way crossover design with a 2-week washout period between treatments. Plasma MLX concentrations were quantified up to 24 h using HPLC and analysed using non-compartmental methods. Results Peak plasma concentrations (C max ) differed significantly among all three routes (IM 11.49 ± 2.34, SC 6.43 ± 1.62, PO 1.53 ± 0.89 µg/mL; p < 0.05) and were reached most rapidly after IM administration. Systemic exposure was comparable between the IM and SC routes (AUC 0–24h 80.7 ± 40.2 and 81.1 ± 22.7 µg·h/mL, respectively) and approximately 7-fold greater than after PO administration (11.9 ± 4.8 µg·h/mL; p < 0.05), corresponding to relative bioavailabilities versus IM of 100.4% for SC and 14.8% for PO. Terminal half-life progressively increased from IM (9.81 ± 2.30 h) through SC (15.13 ± 4.41 h) to PO (18.85 ± 2.16 h). Conclusion SC administration may represent a practical parenteral alternative to IM, whereas PO administration displayed low and variable bioavailability in white storks.