International Conference on Harmonisation; revised guidance on Q3A impurities in new drug substances; availability. Notice.

The Food and Drug Administration (FDA) is announcing the availability of a revised guidance entitled "Q3A(R) Impurities in New Drug Substances." The revised guidance, which updates a guidance on the same topic published in the Federal Register of January 4, 1996 (the 1996 guidance), was prepared under the auspices of the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH). The revised guidance clarifies the 1996 guidance, adds information, and provides consistency with more recently published ICH guidances. The revised guidance is intended to provide guidance to applicants for drug marketing registration on the content and qualification of impurities in new drug substances produced by chemical syntheses and not previously registered in a country, region, or member State.