Effect of oral administration of robenacoxib on experimentally-induced anterior uveitis in normal cats

Abstract

Objectives- To determine the effect of oral robenacoxib on experimentally-induced anterior uveitis, and to evaluate the ability of robenacoxib to cross an intact blood-aqueous barrier. Animals- Twelve healthy adult domestic shorthair cats. Procedures- Cats in the treatment group (n=6) received oral robenacoxib (1.51 ± 0.36 mg/kg ) once daily beginning 1 day before experimental induction of uveitis by anterior chamber paracentesis (ACP) and continuing 1 day after paracentesis. Anterior chamber paracentesis was performed using a 30 g needle attached to a 1 mL syringe, and 100 µL of aqueous humor were aspirated over 3-5 seconds. Anterior chamber fluorophotometry was performed in both eyes of each cat immediately before ACP (time 0), and at 6, 24, and 48 hours after ACP. An independent t-test was used to compare percent fluorescein increase in treatment versus control cats at each time point. Values of p<0.05 were considered significant. Concentrations of robenacoxib in aqueous humor were measured using liquid chromatography and mass spectrometry. Results- There was no statistically significant difference between the ACP and control eye at time 0 (p=0.322). When comparing the percent fluorescein increase between treatment and control groups, there was no statistically significant difference at any time point (p>0.05). Robenacoxib was present in small but detectable levels in 5/6 cats in the treatment group. Conclusions and clinical relevance- Administration of oral robenacoxib did not significantly lessen experimentally-induced anterior uveitis in normal cats, as assessed by fluorophotometry. Low concentrations of aqueous humor robenacoxib were detectable in the majority of cats receiving the drug.