INFLUENCE OF TOPICAL CYCLOSPORINE-A AND DISSOLVENT ON CORNEAL EPITHELIUM PERMEABILITY OF FLUORESCEIN

The corneal stroma is the major barrier to penetration for the lipophi lic Cyclosporine A (CsA) molecule and prevents the use of the common o phthalmic solvents. At present, corn oil, castor oil and olive oil are the three most commonly used vehicles. The aim of this study was to d etermine the effect that topically applied CsA dissolved in different oils has on corneal epithelial permeability measured by fluorophotomet ry. Forty healthy volunteers, with absence of ocular or systemic disea se and not receiving topical or systemic drugs were enrolled. Measurem ents were taken before and 45 min after the instillation of 40 microli ters of a 2% aqueous solution of sodium fluorescein without preservati ves. Basal corneal permeability and the permeability 24 h after the in stillation of 2% CsA-olive oil, olive oil alone, 2% CsA-castor oil, ca stor oil alone, 2% CsA-corn oil and corn oil alone, were calculated. T o prepare the topical 2% CsA, a Sandimmun oral solution (Sandoz, Basel , Switzerland) was employed under sterile conditions. We found that ep ithelial permeability 24 h after the instillation of any CsA formulati ons or solvents increased more than 6.62 times (p < 0.001). No differe nces in corneal permeability values were found between any of the CsA formulations and the vehicles. We conclude that oils used to dissolve CsA are mainly responsible for the increased corneal epithelial permea bility. No differences were found in the effects of the tested solvent s on corneal epithelial permeability.