Studies on Corneal Permeation and Oculo-Hypotensive Effect of Benazepril in Chronic and Acute Models of Glaucoma

The present study was carried out to investigate the effect of benazepril on corneal permeation in goat cornea and its effect on experimentally induced acute and chronic glaucoma in rabbits. Acute glaucoma was produced by i.v. infusion of 5% glucose (15 mL/kg) in rabbits, whereas chronic glaucoma was induced by injection of alpha-chymotrypsin into posterior chamber of rabbit eye. We studied the interaction of benazepril on isolated rat ileum pre-administered with acetylcholine, the enzyme cholinesterase biochemically and on ACE levels in aqueous humor after topical application. A significant increase in intra ocular pressure (IOP) in rabbits was observed which reached to the peak of 41 ± 0.85 after 90 min. Injection of alpha-chymotrypsin produced sustained elevation of Intraocular Pressure which lasted for almost 3 months. Benazepril produced significant fall in Intraocular Pressure in normotensive as well as glucose or alpha-chymotrypsin treated rabbit eyes. It was been observed that the benazepril produced significant potentiation of responses to acetylcholine in isolated rat ileum preparation and inhibition of cholinesterase enzyme. The corneal permeation of benazepril from 0.1% solution was maximum at 15 min after which there is a decline in rate of permeation was observed. The results observed in the present study indicate that the potential ocular hypotensive activity of benazepril which may be due to inhibition of ACE (Kininase-II) and cholinesterase.