Cyclodextrin complexes of sulfonamide carbonic anhydrase inhibitors as long-lasting topically acting antiglaucoma agents

Complexes of several 1,3,4‐thiadiazole‐2‐sulfonamide derivatives possessing strong carbonic anhydrase (CA) inhibitory properties with β‐cyclodextrin and hydroxypropyl‐β‐cyclodextrin were obtained and characterized. Although the investigated CA inhibitors possessed very powerful inhibitory properties against the two CA isozymes involved in aqueous humor production within the eye, i.e., CA II and CA IV, these compounds were topically ineffective as intraocular pressure (IOP) lowering agents in normotensive/hypertensive rabbits, due to their very low water solubility. On the contrary, the cyclodextrin–sulfonamide complexes proved to be effective and long‐lasting IOP lowering agents in the two animal models of glaucoma mentioned above.