ICCVAM Biennial Report 2018-2019

To provide an estimate of dermal absorption, the EPA Office of Pesticide Programs combines data from in vivo rat, in vitro rat, and in vitro human dermal absorption studies, commonly referred to as the “triple pack”, to calculate a chemical-specific dermal absorption factor. The dermal absorption factor estimates the percentage of the external dose that will cross the skin barrier and end up in the systemic circulation. To assess the feasibility of using data from in vitro studies alone to estimate this value, EPA and NICEATM, in conjunction with the Health Canada Pest Management Regulatory Agency and industry stakeholders, are conducting a retrospective analysis of triple pack reports for agrochemicals completed between 2005 and 2015. Data were extracted from study reports provided to NICEATM by EPA and agrochemical products companies ADAMA, BASF, Bayer, Corteva, FMC, Syngenta, and Valent. The aim of this analysis is to determine whether the rate of in vitro absorption is equal to or greater than the rate of in vivo absorption. Absorption values from in vitro rat studies are also being compared to in vitro human studies to determine the differences in permeability between rat skin and human skin. A stakeholder meeting was convened in May 2019 at EPA to discuss the preliminary findings from this review and to identify and discuss additional information needs for both U.S. and Canadian regulators to finalize the assessment. A paper detailing this work is planned for submission in 2020.