Anti-inflammatory effectiveness of topically administered corticosteroids in the cornea without epithelium

The present studies demonstrate that modification of the derivative of a given steriod base alters its anti-inflammatory potential as measured by suppression of leukocyte invasion of the cornea. A comparison of each drug's corneal bioavailability with its anti-inflammatory effectiveness shows the acetate derivative of prednisolone to be a more potent anti-inflammatory agent than the phosphate derivative. Similarly, the free alcohol derivative of dexamethasone proved to be more potent than the phosphate derivative. Increasing the concentration of prednisolone acetate from 0.125 per cent to 1.0 per cent results in a significant increase in its anti-inflammatory effectiveness in the cornea following topical administration. The same increase in prednisolone phosphate concentration does not produce a significant increase in its ability to suppress polymorphonuclear leukocyte infiltration of the cornea. When the epithelium of the inflamed cornea is intact, prednisolone acetate, 1.0 per cent ophthalmic suspension, is the most effective of the corticosteroid preparations studied. In the absence of an intact epithelium, prednisolone acetate, 1.0 per cent ophthalmic suspension, again produces the greatest mean reduction in polymorphonuclear leukocytic infiltration of the cornea although here one cannot demonstrate a statistically significant difference from the anti-inflammatory effect produced by prednisolone phosphate, 1.0 per cent ophthalmic solution, or dexamethasone alcohol, 0.1 per cent ophthalmic suspension. Overall, therefore, prednisolone acetate 1.0 per cent is the most effective of the topical agents studied for suppression of corneal inflammation.