Prediction of Ocular Irritancy of Full-Strength Cleaners and Strippers by Tissue Equivalent and Bovine Corneal Assays

Abstract

The Tissue Equivalent Assay (TEA) utilizing Skin² (model ZK 1200) and Bovine Corneal Opacity and Permeability assay (BCOP) were evaluated for their ability to predict the eye irritation potential of 20 full-strength industrial and household cleaning formulations. All products evaluated in this study had previously been tested for eye irritation in vivo using a modified (30 μ1) or the standard (100 μl) Draize assay protocol. Significant correlations with Draize data were observed when comparisons were made with MTT reduction in the TEA and with BCOP Total Score. No significant correlation with Draize Maximum Average Score (MAS) was observed when lactate dehydrogenase (LDH) or prostaglandin E2 (PGE2) release was used as endpoint in the TEA. Correlation of TEA (MTT) scores with BCOP total scores yielded an r value of 0.84. The results from this study suggest that strong formulations such as some floor strippers and metal cleaners may be distinguished from milder formulations such as some neutral floor cleaners using either the TEA or BCOP assay. The strong industrial cleaners evaluated were extremely cytotoxic: MTT t₅₀ values were < 1 min. BCOP total scores for these products also indicated severe irritancy. The complementarity noted between these assays supports their use in tandem as a basis for product labeling decisions.