All drugs contain impurities that can arise from the drug substances (APIs) or inert materials (excipients). They are also introduced into the drug product during the formulation processes, packaging, and storage. Impurities have many unwanted effects, such as:
- Decreasing the therapeutic effect
- Lowering the product shelf-life
- Inducing toxicity
Identification, quantification, and control of impurities in API and the drug product are critical in drug development. Organic impurities are often free radicals from by-products, intermediates, or degradation products. Inorganic impurities include transition metals, reagents, and ligands.
