Directives 2001/82/EC and 2001/83/EC, as amended, include obligations for manufacturing authorisation holders only to use active substances that have been manufactured in accordance with GMP. Provision is also made for inspections of active-substance manufacturers but only under certain specified circumstances.
IMPs are unaffected because the obligations of manufacturing authorisation holders in this case are laid down in Directive 2005/28/EC, which does not contain corresponding requirements for active substances. Furthermore, this is made clear in the introduction to part II of the GMP guideline.
Part II of the GMP guideline does include a short section on new active substances to be used as starting materials for IMPs and these remain as recommendations with no mandatory force. Nevertheless, active substances used in the manufacture of marketed products are already required to comply with GMP irrespective as to whether they may also used in the manufacture of IMPs.