A NOVEL-APPROACH TO ASSESSING EYE IRRITATION POTENTIAL USING THE BOVINE CORNEAL OPACITY AND PERMEABILITY ASSAY

The bovine corneal opacity and permeability assay (BCOP) as originally described by Gautheron is now utilized by several laboratories to ass ess the eye irritation potential of individual chemicals, chemical ble nds, and consumer formulations. We have applied the principles establi shed by Gautheron to the equipment and data available in our laborator y to devise a variation of this assay. This variation differs in three ways: how we evaluate corneal opacity, how we apply opacity and perme ability measurements to predict irritation potential, and how we evalu ate solid materials. For opacity measurement, a UV-VIS spectrophotomet er is used to measure light absorbance. This contrasts with Gautheron' s use of an opacitometer to measure changes in voltage as an indicator of opacity. Permeability is measured in the same manner but we interp ret the results differently by applying them to a table of results rel ating to degrees of irritation potential. The corneal holding apparatu s has also been modified to allow direct application of solids, such a s laundry and dishwashing powders, onto corneal surface. To evaluate t hese changes, we assayed the Cosmetic, Toiletry and Fragrance Associat ion's (CTFA) phase III test materials, individual chemicals listed in the European Centre for Ectotoxicity and Toxicology of Chemicals' (ECE TOC) Eye Irritation Chemicals Reference Bank, surfactant raw materials , and Amway products with historical rabbit eye irritation data. High in vivo/in vitro correlations demonstrate the variations we have emplo yed to be as predictive as earlier work and demonstrate the wide adapt ability the BCOP provides to assess eye irritation potential.