What should buyers review for active ingredients and excipients?

Review exact identity, grade, pharmacopoeial or in-house standard, manufacturer and site, specification, analytical methods, storage and retest or expiry period. For actives, clarify regulatory support such as a master-file pathway where relevant. For excipients, confirm suitability for route, species and formula. Any change in source or grade may affect quality, stability, bioequivalence or the registered dossier, so the supply agreement should define approval and notification requirements.