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In vitro methods for GHS ocular irritation categorisation

The Draize rabbit eye test had long been the standard for assessment of eye irritation and corrosion potential. However, due to recent legislation, alternative non-animal methods are being developed and validated as a replacement to the Draize rabbit eye test where animal testing is banned (e.g., Cosmetics Regulation in EU), where animal testing should only be considered as a last resort (e.g. REACH regulation) or where justification is required for animal testing (e.g., new Lautenburg Chemical Safety Act). CON4EI (Consortium for in vitro Eye Irritation testing strategy) has been formed by the European Chemical Industry Council (Cefic) to evaluate eight different in vitro methods for distinguishing between UN GHS Category 1, Category 2 or No Category chemicals for ocular irritation.

Working as a member of CON4EI, Cyprotex evaluated the in vitro Short Time Exposure (STE) Assay for Serious Eye Damage. In this study, 80 compounds were tested using the STE assay under OECD 491 to determine their GHS Category. The STE assay is able to differentiate compounds as either Category 1 (severely irritating) or No Category (non-irritating) by measuring Statens Seruminstitut Rabbit Cornea (SIRC) cell viability using the MTT assay following exposure to two concentrations of each test chemical.

The results showed greater success identifying the No Category chemicals (72.5% accuracy) than the Category 1 chemicals (61.3% accuracy), indicating that the STE assay does have potential for successful GHS Categorisation, especially when employed in a bottom-up tiered testing strategy.

This research was presented at Eurotox 2016. Download the poster.