Agricultural chemicals consist of multiple product types including fertilizers, pesticides, and herbicides. As a result, these chemicals can cover a wide range in the irritation spectrum, from materials that are classified as mild irritants to those that are designated as corrosive. Classification is needed for registration through organizations such as the US EPA, REACH, or Brazil ANVISA.
Multiple in vitro assays have OECD test guidelines that can be used to provide GHS hazard classifications that may meet necessary testing requirements. Ocular and dermal irritation are some of the primary concerns for manufacturers of agricultural chemicals due to the intended uses of these chemicals. Assays such as the Skin Irritation Test (OECD TG 439) or the Skin Corrosion assay using the Reconstructed Human Epidermis (OECD TG 431), and the Corrositex® Assay (OECD TG 434) have been approved for assessing skin irritation or corrosion.
Additionally, the Eye Irritation Test using Reconstructed Human Cornea-Like Epithelium (OECD TG 492), and the Bovine Corneal Opacity and Permeability (BCOP) Assay (OECD TG 437) have been approved for assessing ocular irritation. Another endpoint that may be of concern is skin sensitization, which can be measured using the ARE-Nrf2 Luciferase Test Method (OECD TG 442D), the Direct Peptide Reactivity Assay (OECD TG 442C), and Human Cell Line Activation Test (draft OECD guideline). These assays cover three of the required testing areas for the US EPA “6-pack” for pesticide registration, and can also provide hazard determination for other regulatory agencies that have approved the use of in vitro assays.
In May of 2015, the US EPA’s Office of Pesticide Programs updated their “Alternative Testing Framework for the Classification of Eye Irritation Potential of EPA Pesticide Products”. While this testing program was initially intended for antimicrobial products making cleaning claims, the document states that other pesticides and classes of pesticides that do not fall within this category, can be submitted on a case-by-case basis. The program uses in vitro assays (EpiOcular, Cytosensor Microphysiometer, and the BCOP assays) in a tiered-testing approach to predict EPA hazard categories for ocular irritation.