Effects of aldose reductase inhibitor, CT-112, on sugar alcohol accumulation in corneal epithelium of galactose-fed rats.

A study was made of inhibitory effects of an aldose reductase inhibitor, CT-112 (5-(3-ethoxy-4-pentyloxyphenyl)-2,4-thiazolidinedione) ophthalmic solution, on the accumulation of sugar alcohol (dulcitol) in the corneal epithelium of rats fed on a 50% galactose diet. The effects were correlated with the concentrations of the drug solution. The rats were divided into 6 groups. One group was fed on a regular laboratory chow and was untreated. The other 5 groups were fed on a 50% galactose diet, and 0.1, 0.25, 0.5 or 1.0% CT-112 ophthalmic solution or its vehicle was instilled in both eyes 4 times a day in each of the 5 treated groups. After 2 weeks, the corneal epithelium was scraped off in all rats and its dulcitol content was determined by gas chromatography. CT-112 ophthalmic solution was found to inhibit the accumulation of dulcitol in a dose-dependent manner, except for the 1.0% solution which had an activity comparable to the 0.25% solution.