Chemical structure and properties criteria to be considered for the evaluation of new active substance (NAS) status of chemical substances - Scientific guideline

This document describes the chemical structure and properties criteria to be taken into account by the CHMP to qualify a chemical active substance as NAS. It provides guidance on the required elements to be submitted by applicants to substantiate their claims.

Keywords: New active substance (NAS), salts, complexes, isomers, mixtures of isomers, derivative, esters and ethers