EUROPE – EFSA: Guidance on risk assessments for substances, impurities and transformation products that may have stereoisomers

EFSA has published a guidance on risk assessments for active substances of plant protection products that have stereoisomers as components or impurities. The document also proposes guidance to be used for active substances that, without containing any stereogenic element, may generate transformation products or metabolites  that do contain them. As a general principle, stereoisomers need to be treated as different chemical components for the risk assessment.

The draft version was proposed to public consultation in April – May 2019. A report presenting the  comments received and how they have been considered by EFSA has been made available.

In this guidance, Regulation (EU) 283/2013 on the data requirements for the plant protection active  substances is analysed, and recommendations are given on how to best address and assess the data requirements for active substances containing stereoisomers. Furthermore, the guidance gives recommendations on how to make the best  use of the available information to perform the risk assessment of these substances, particularly in situations when the information on individual isomers is not available or difficult to obtain, with the primary objective to reduce the need to repeat vertebrate animal testing.

One special situation is when active substances, that without containing any stereogenic element, may generate transformation products that do contain them. In these cases, it is appropriate to refer to metabolites containing stereoisomers. For these substances, the guidance should not be applied to the active substance but should be applied to assess metabolites that contain a stereogenic element.

 

To download: 

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

 

Outcome of the public consultation on the draft guidance on risk assessments for active substances of plant protection products that have stereoisomers as components or impurities and for transformation products of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

 

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