Ethoxzolamide analogue gel. A topical carbonic anhydrase inhibitor

R. A. Lewis, R. D. Schoenwald, M. G. Eller, C. F. Barfknecht and C. D. Phelps

An analogue of ethoxzolamide, 6-hydroxyethoxzolamide, was synthesized to enhance corneal permeability yet retain carbonic anhydrase inhibitory activity for use in lowering intraocular pressure. In a 1% suspension, the analogue caused a small but statistically significant unilateral reduction of IOP when applied to one eye of normal rabbits. When formulated in a gel vehicle, 6-hydroxyethoxzolamide caused a more prolonged and larger reduction in IOP in normal and ocular hypertensive rabbits compared with its effect in suspension or with the parent compound.