Comparison of ketorolac tromethamine, diclofenac sodium, and loteprednol etabonate in an animal model of ocular inflammation.

PURPOSE

The aim of this study was to compare the anti-inflammatory activities of ketorolac tromethamine 0.4% and 0.1%; diclofenac sodium 0.1%; and loteprednol etabonate 0.5% suspension in an animal model of ocular inflammation.

METHODS

An ocular inflammatory response was induced in New Zealand White rabbits by the intravenous (i.v.) administration of 10 microg/kg lipopolysaccharide (LPS). In study animals, 1 eye was treated topically with 50 microL of study medication (n = 8 animals per drug) and the other eye was treated topically with a 50-microL vehicle (buffered saline). In control animals (n = 8), both eyes were treated with vehicle. All animals were treated twice: 2 h and 1 h before LPS challenge. The breakdown of the blood-aqueous barrier in the anterior chamber was measured by fluorophotometry (FITC-dextran 30 mg/kg, i.v. given immediately after LPS challenge). Aqueous prostaglandin E(2) (PGE(2)) levels were measured using an enzyme-linked immunosorbent assay (ELISA) immunoassay.

RESULTS

Ketorolac 0.4% resulted in a nearly complete inhibition of endotoxin-induced increases in FITC-dextran and PGE(2) synthesis (P < 0.001 vs. vehicle). Diclofenac 0.1% had much less of an effect on these parameters (P < 0.01 vs. ketorolac 0.4%). Loteprednol 0.5% was no more effective than vehicle at inhibiting increases in FITC-dextran.

CONCLUSIONS

Ketorolac has greater anti-inflammatory effects than diclofenac and loteprednol.