Defined approaches can be used to predict GHS and US EPA classifications of eye irritation potential of agrochemical formulations

A new study published in Cutaneous and Ocular Toxicology demonstrates that four defined approaches (DAs), comprising in vitro and ex vivo methods, can be used to predict eye irritation and corrosion categories for the Globally Harmonized System of Classification and Labelling (GHS) and the US Environmental Protection Agency (EPA) classification systems for pesticide formulations.

In the study, co-authored by the National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM), PETA Science Consortium International e.V., the Institute for In Vitro Sciences, and others, twenty-nine formulations were assessed in up to four DAs. The DAs were developed using the following test methods: bovine corneal opacity and permeability (BCOP; OECD TG 437) including histopathology, EpiOcular Eye Irritation Test (EO; OECD TG 492), SkinEthic time-to-toxicity for liquids (TTL; OECD TG 492B), and EyeIRR-IS. Across the 29 formulations, the predictions from each of the four DAs were overall as, or more, protective of human health than the Draize rabbit eye irritation test.

The paper, “Defined approaches to predict GHS and EPA classifications for ocular irritation potential of agrochemical formulations,” builds on the Science Consortium’s previous co-authored publications in Cutaneous and Ocular Toxicology on eye irritation testing for agrochemicals. One paper published in 2023 showed two defined approaches that are as or more fit for purpose, reliable, and relevant than the rabbit eye irritation test. The other paper, published in 2021, showed that tests that do not use live rabbits produce more consistent results, and are as or more reflective of human responses.

Overall, these three publications collectively demonstrate that (1) the four test methods used to develop the DAs are as or more reflective of human biology and more reliable than the Draize rabbit eye test, and (2) the four developed and refined DAs are more protective of human health than the Draize rabbit eye test when used to classify into EPA or GHS hazard categories. This information could be used by the EPA as the scientific support for allowing the use of these DAs to assess pesticides.