Fate and Purge

Drug substances produced by chemical syntheses contain impurities (organic, inorganic, elemental, or residual solvents) which must be controlled in order to ensure the desired product quality. The various Regulatory Authorities require that impurities above a certain threshold be identified and tracked, and that all mutagenic and genotoxic impurities be reported at any level. Critical Quality Attributes (CQA) of the drug substance and all isolated intermediates need to be identified, justified, and included in the specifications. Generation and depletion of impurities which are formed during chemical syntheses or due to limited stability of intermediates should be investigated in a “fate and purge” study.