Stereoisomers may exhibit different toxicological and/or environmental properties from one another and from the non‑stereoisomeric form; as a general principle, they should be treated as different chemical components in (eco)toxicological risk assessments. Plant protection product (PPP) active substances may contain stereoisomers as part of their intended composition or as impurities, or may generate transformation products or metabolites that exist in stereoisomeric form. EFSA has identified a need for advice for PPP applicants and evaluators considering how best to generate and assess data on stereoisomers, particularly where information on individual isomers is not available or difficult to obtain. As such, new draft guidance has been released in the context of the data requirements for active PPP substances given under Regulation (EU) 283/2013.

European Food Safety Authority (2019). Draft guidance of EFSA on risk assessments for active substances of plant protection products that have stereoisomers as components or impurities and for transformation products of active substances that may have stereoisomers. http://www.efsa.europa.eu/sites/default/files/consultation/consultation/Draft_Guidance_of_EFSA_on_isomers.rev_.5.pdf

 

The above items were taken from the June 2019 issue of Toxicology and Regulatory News which is sent automatically to members of bibra.

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