Drug Impurity Profiling: A Scientific Approach

There is an ever increasing interest in impurities present in APIs. Now days, not only purity profile but also impurity profile has become mandatory according to various regulatory authorities. In the pharmaceutical world, an impurity is considered as any other inorganic or organic material, or residual solvents other than the drug substances, or ingredients, arise out of synthesis or unwanted chemicals that remains with APIs. The impurity may be developed either during formulation, or upon aging of both APIs and formulated APIs in medicines. The presence of these unwanted chemicals, even in small amount, may influence the Identity, Strength, Safety, Purity, Quality and Efficacy of the pharmaceutical products. The different Pharmacopoeias, such as the British Pharmacopoeia (BP), United States Pharmacopeia (USP), and Indian Pharmacopoeia (IP) are slowly incorporating limits to allowable levels of impurities present in the APIs or formulations. As per ICH, Impurity profiling is a group of analytical activities, with aim of isolation, structure elucidation, identification and quantitative determination of organic and inorganic impurities and residual solvents in bulk drugs & pharmaceutical formulations. Impurity is any component of the drug substance or product that is not the chemical entity of it, or is any substance coexisting with the original drug, like starting materials or intermediates or that is formed, due to any side reactions. The ICH has published guidelines on impurities in new drug substances (ICH, Q3A), products (ICH, Q3B), and residual solvents (ICH, Q3C). Impurity profiling study has been in the limelight in the recent pharmaceutical scenario and its importance is increasing day-by-day.