Topical carbonic anhydrase inhibitors

Ethoxzolamide and several derivatives (1-6) were synthesized and evaluated for carbonic anhydrase inhibition (CAI), solubility, pKa, distribution, and corneal permeability. The 6-hydroxy (5) and, particularly, the 6-chloro (6) analogues have the best combination of properties for penetrating the site of action and reducing intraocular pressure. Both 5 and 6 exhibited topical effectiveness in the normal rabbit, with 6 showing greater potency.