Development of an in vitro ocular test system for the prediction of all three GHS categories.

In the present study we considered a new approach that allows the individual quantification of damages induced in the epithelium and stroma of an in vitro hemi-cornea model after chemical treatment. We aimed at a stand-alone test system for classification according to the classification of the globally harmonized system of classification and labelling of chemicals (GHS). We have modified a previously developed 3D hemi-cornea model by the insertion of a collagen membrane between epithelium and stroma. This membrane allows the separation and independent assessment of these compartments after topical exposure to potential eye irritants. The cell viability quantified by MTT assay was used as the toxicological endpoint. The prediction model based on the results obtained from 30 test chemicals uses a single exposure period and the combination of cut-off values in tissue viability from both epithelium and stroma. The in vitro-in vivo concordance of the test system is 77%. All of the GHS category 1, 80% of the GHS category 2 and 50% of the GHS not categorized chemicals are predicted correctly. In conclusion, the test system predicts and discriminates GHS category 1 and GHS category 2 chemicals, but is over-predictive for GHS not categorized materials.