Toxicological evaluation of cyclosporine eyedrops

The short-term toxicological effects of two cyclosporine A eyedrop formulations are compared.

Formula A was based on Sandimmune (Novartis, Switzerland) infusion concentrate with a final ethanol concentration of 1% (w/w), and formula B on Sandimmune oral solution. Both formulations were diluted in sterile peanut oil (10 mg/ml). The left eyes of 12 rabbits were treated with the cyclosporine eyedrops over a two-week period. The right eyes served as controls. Slit-lamp and scanning electron microscopic examinations were performed, and the total protein concentration in aqueous humor was measured in treated and control eyes.

Both Sandimmune oral solution and infusion concentrate-derived eyedrops were found to be non-toxic to rabbit eyes and there were no significant differences between the two formulations. More definite conclusions as to the safety of these cyclosporine formulations cannot be made without long-term trials.