1. PREAMBLE

This document is intended to provide guidance for registration applications on the content and qualification of impurities in new drug substances produced by chemical syntheses and not previously registered in a region or member state .It is not intended to apply to new drug substances used during the clinical research stage of development .Safety Aspects include specific guidance for qualifying those impurities that were not present , or were present at substantially lower levels , in batches of a new drug substance used in safety and clinical studies .