Plasma Concentrations of Ketoprofen and Meloxicam after Subcutaneous and Topical Administration in the Smoky Jungle Frog (Leptodactylus pentadactylus)

Abstract

Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used for analgesia in veterinary patients; however, evaluation of NSAID pharmacokinetics in amphibians is limited. A wide variety of pharmacotherapeutics have been administered topically to the skin of anurans with limited empirical evidence of absorption or efficacy. Systemic absorptions of two NSAIDs, meloxicam and ketoprofen, were evaluated after subcutaneous and topical cutaneous administration in smoky jungle frogs (Leptodactylus pentadactylus). Eighty-four, 8 month old, 38.0 g (26.1–56.6 g) (median [range]) frogs were randomly assigned to receive one of four treatments, with 21 animals in each group: 1 mg/kg racemic ketoprofen administered either subcutaneously (SK) or topically (TK) or 0.2 mg/kg meloxicam administered either subcutaneously or topically. Plasma concentrations of meloxicam and the R- and S-enantiomers of ketoprofen were quantified at 3, 8, and 24 h after administration. At each time point, seven frogs per group were anesthetized for blood collection and then euthanized. Plasma samples were pooled within each group for drug quantification. Both enantiomers of ketoprofen were detectable in groups SK and TK, and plasma concentrations decreased from 3 to 24 h. The drop in concentration was less predictable for TK than for SK. Plasma concentrations of meloxicam were nondetectable at most time points by both routes. Topical absorption of ketoprofen is possible in frogs, although therapeutic levels have not been determined for this species.