Pharmacokinetics of robenacoxib after a single intramuscular dose in smooth dogfish (Mustelus canis)

Abstract

OBJECTIVE To determine the pharmacokinetics of robenacoxib after a single intramuscular dose (4.0 mg/kg) in smooth dogfish (Mustelus canis). ANIMALS 8 healthy adult male smooth dogfish in human care within the same habitat. METHODS All sharks received a single intramuscular dose of robenacoxib (4.0 mg/kg) in the right caudolateral epaxial mus-culature. Blood samples were collected under manual restraint from the ventral tail vessel at 30 minutes, 1 hour, 2 hours, 4 hours, 8 hours, and 24 hours after drug administration. Plasma drug concentrations were determined by HPLC followed by noncompartmental pharmacokinetic analysis of the data. RESULTS A maximum plasma concentration of 1.24 µg/mL was reached at a mean time of 30 minutes following robenacoxib administration with a plasma elimination half-life of 3.79 hours. Plasma concentrations did not fall below the lower limit of quantification (0.1 µg/mL) at the time points sampled in this study. CLINICAL RELEVANCE Intramuscular administration of a single dose (4.0 mg/kg) of robenacoxib in smooth dogfish resulted in rapid absorption to a maximum concentration at approximately 30 minutes after administration and persisted above levels considered to be therapeutic in domestic species for at least 8 hours.