Pharmacokinetics of meloxicam in pigeons after single intravenous, oral, and intramuscular administration.

ABSTRACT

This study aimed to determine the pharmacokinetics of meloxicam in pigeons. Twenty-four 7-wk-old meat pigeons (Columba livia) were randomly divided into 3 groups (PO, IM, and IV) and given a single dose of 1 mg/kg body weight of meloxicam. Plasma samples were taken at predetermined times, which were then analyzed using a validated high-performance liquid chromatography (HPLC) method and subjected to noncompartmental analysis using Phoenix software. Results indicated that meloxicam was absorbed effectively and quickly after PO and IM dosing. Peak concentrations (0.83 ± 0.21 and 1.59 ± 0.49 µg/mL) were achieved at 2 and 0.26 h, respectively, with mean absorption times of 2.56 ± 1.50 and 1.47 ± 0.89 h. Bioavailability was high at 86.31 ± 43.45% and 81.57 ± 52.58%, respectively, and the area under the concentration-time curve (AUC0-∞) was 5.33 ± 2.68 and 5.03 ± 3.26 h·µg/mL. After IV administration, the elimination was faster with a total body clearance (CL) of 188.75 ± 83.23 mL/h/kg, an elimination half-life (t1/2λz) of 1.76 ± 0.56 h, and a volume of distribution at steady-state (VSS) of 427.50 ± 188.43 mL/kg. Considering the lack of a precise analgesic threshold of meloxicam in pigeons and the notable differences in its analgesic threshold among various animal species, formulating a dosing regimen in pigeons presented a significant challenge. Based on the previous analgesic threshold (3.5 µg/mL) in parrots, a higher dose (e.g., 2 mg/kg) or shorter dosing interval (e.g., every 6 h) is recommended for treating pain in pigeons. Nonetheless, further pharmacodynamic research is required to verify these recommendations.