Validation of the SkinEthic HCE Time-to-Toxicity test method for eye hazard classification of chemicals according to UN GHS

This study describes the within-and between-laboratory reproducibility (WLR and BLR) of a Time-to-Toxicity (TTT) approach for chemicals based on the SkinEthicTM HCE tissue construct, capable to distinguish chemicals that do not require classification for serious eye damage/eye irritation (No Cat.) from chemicals that require classification for eye irritation (Cat. 2), and serious eye damage (Cat. 1). The WLR and BLR was assessed with three participating laboratories. Each laboratory tested 40 coded chemicals in three independent runs. The predictive capacity of the method was assessed on a larger set of 150 chemicals (70 liquids and 80 solids) by combining the results of this study with the results of the test method developer. The WLR for the 20 liquids ranged from 85% to 95% with a BLR of 90%. For the 20 solids, a WLR and BLR of 100% was obtained. The test method developer obtained a WLR of 80% and 95%, based on 50 liquids and 48 solids tested in three independent runs, respectively. Regarding the predictive capacity, the SkinEthicTM HCE TTT test method identified 80.8% Cat. 1, 69.2% Cat. 2, and 74.9% No Cat. correctly. An independent peer review panel concluded that based on all available data, the relevance and reliability of the SkinEthicTM HCE TTT has been demonstrated for discriminating the three UN GHS eye hazard categories.

Automated summary

This study examines the reproducibility of a TTT approach for chemicals utilizing the SkinEthicTM HCE tissue construct. The method is capable of accurately distinguishing between different classifications of chemicals. The results demonstrate high accuracy in both liquid and solid tests, and the predictive capacity of the method has been validated.