Comparative pharmacokinetics of a single oral dose of meloxicam in the California sea lion (Zalophus californianus) and Pacific harbor seal (Phoca vitulina richardii)

Abstract Pharmacokinetics studies have investigated meloxicam, a non‐steroidal anti‐inflammatory drug, dosing strategies in a wide variety of non‐domestic animals; however, there is no prior study examining well‐founded dosing for pinnipeds. To develop dosing protocols, pharmacokinetic information is needed, with an examination of differences between pinniped species. Apparently, healthy California sea lions ( Zalophus californianus : CSL; n = 13) and Pacific harbor seals ( Phoca vitulina richardii : PHS; n = 17) that had completed rehabilitation were enrolled into a population‐based pharmacokinetic study. Each animal was administered a single oral dose of meloxicam at 0.1 mg/kg, and two blood samples were collected from each animal at varying intervals during a 96‐h study period. Plasma concentrations of meloxicam were determined by high‐pressure liquid chromatography. Data were analyzed with nonlinear mixed effects modeling (Phoenix® NLME™, Certara, St. Louis, MO 63105, USA). The results indicated that in PHS, peak plasma concentration (C max ) was 0.33 μg/mL with an elimination half‐life (K e t½) of 31.53 h. In CSL, C max was 0.17 μg/mL with K e t½ of 32.71 h. All animals enrolled completed the study without outward adverse clinical signs. The elimination half‐life was longer than previously recommended dosing intervals for pinnipeds; however, we cannot speculate in the optimum clinical dose from these results.