Ocular tolerance in rabbits after intracameral administration of a fixed combination of tropicamide, phenylephrine, and lidocaine with and without rinsing

Abstract

To evaluate the safety and tolerability of a single intracameral administration of a combined mydriatic (tropicamide and phenylephrine) and anesthetic (lidocaine) formulation (Mydrane) with or without rinsing. Iris Pharma, La Gaude, France. Experimental study. Sixty pigmented rabbits received 100μL or 200μL of the combination product or a placebo (sodium chloride 0.9%) by intracameralinjection. For the combination product, separate groups were included with and without rinsing after administration. From day 1day to day 7, assessments included general clinical and ocular observations,pupil diameter measurements, corneal assessments, confocal microscopy, and electroretinography (ERG). Necropsy examinationswere performed at study completion at day8. Rapid mydriasis, stable24minutes after injection and returning to baseline levels by day 1, was induced in all groups that received the combination mydriatic and anesthetic drug. Rinsing had no effect. The combination product induced no adverse effects on the anterior or posterior segment of the eye (ie, no increased corneal thickness and endothelial cell loss, no abnormalities in ERG). Slitlamp examination showed slightly increased anterior chamber inflammation with rinsing in both the study group and placebo group. This observation was not confirmed by aqueous flare examination. No toxic effects of the products were found on histological evaluation. The combination mydriatic and anesthetic drug administered to pigmented rabbits as a single intracameral injection at volumes of 100μL and 200μL was well tolerated with no ocular adverse effects and no effect on the corneal endothelium.