Pharmacokinetics of enrofloxacin following oral and subcutaneous administration in the common ringtail possum (Pseudocheirus peregrinus)

[Correction added on 23 March 2015, after first online publication: Terminal half-life values of enrofloxacin is corrected in the fourth sentence of the abstract] Clinically healthy common ringtail possums (n = 5) received single doses of 10 mg/kg enrofloxacin orally and then 2 weeks later subcutaneously. Serial plasma samples were collected over 24 h for each treatment phase, and enrofloxacin concentrations were determined using a validated HPLC assay. Pharmacokinetic parameters were determined by noncompartmental analysis. Following oral administration, plasma concentrations were of therapeutic relevance (Cmax median 5.45 μg/mL, range 2.98–6.9 μg/mL), with terminal-phase half-life (t½) shorter than in other species (median 3.09 h, range 1.79–5.30 h). In contrast, subcutaneous administration of enrofloxacin did not achieve effective plasma concentrations, with plasma concentrations too erratic to fit the noncompartmental model except in one animal. On the basis of the AUC:MIC, enrofloxacin administered at 10 mg/kg orally, but not subcutaneously, is likely to be effective against a range of bacterial species that have been reported in common ringtail possums.