Efficacy of low concentrations of ketorolac tromethamine in animal models of ocular inflammation.

Abstract

To determine if topical ophthalmic application of ketorolac tromethamine concentrations below 0.5% can block the biochemical and physiological processes associated with chemically induced ocular inflammation in rabbits. Ocular inflammation was induced in rabbits by intravenous (i.v.) injection of endotoxin (2.5 microg/kg) isolated from Salmonella typhimurium, or by a topical application of arachidonic acid (1.0%). The effect of ketorolac (at concentrations ranging from 0.001%-0.5%) on ocular inflammation was determined by measuring changes in the blood-aqueous barrier, using fluorophotometry (dextran-isothiocyanate-fluorescein; FITC-dextran 2%) and by measuring changes in aqueous humor protein concentrations. Changes in aqueous humor prostaglandin E(2) (PGE(2)) concentrations were also measured. Ketorolac 0.01%-0.5% produced substantial decreases in endotoxin-induced fluorescein leakage into the aqueous humor. The decrease produced by ketorolac 0.1% was comparable to that produced by ketorolac 0.5%. Ketorolac 0.1%-0.5% produced substantial decreases in endotoxin-induced increases in prostaglandin concentrations in the aqueous humor, and in arachidonic acid-induced protein leakage into the aqueous humor. Topical application of ketorolac concentrations as low as 0.01%-0.1% significantly reduce chemically induced ocular inflammation in rabbits.