Chapter 3:Development of an Evaluation Support System for Estimating Repeated-Dose Toxicity of Chemicals Based on Chemical Structure

Repeated dose toxicity (RDT) testing is one of the important endpoints of Chemical Substances Control Law (CSCL). However, a reliable and satisfactory (Q)SAR or category approach method for evaluating the RDT of chemicals still remains undeveloped. In order to make an in silico evaluation of RDT for target chemicals from their chemical structure, a comprehensive collaboration of experts possessing a variety of knowledge on the analogue chemicals is necessary.The project, “Development of hazard assessment techniques using structure–activity relationship methods,” sponsored by New Energy and Industrial Technology Development Organization (NEDO) in Japan, aims to develop the “Hazard Evaluation Support System Integrated Platform (HESS)” for providing decision support information to experts to evaluate the RDT of chemicals by the category approach (project period: 2007–2011). This chapter contains an overview of HESS and describes the methodology for evaluating RDT by the category approach developed in this project.