Impurity Profiling: Theory and Practice

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. Impurity profiling includes identification, structure elucidation and quantitative determination of impurities and degradation products in bulk drug materials and pharmaceutical formulations. Impurity profiling has gained importance in modern pharmaceutical analysis due to the fact that unidentified, potentially toxic impurities are hazardous to health and in order to increase the safety of drug therapy, impurities should be identified and determined by selective methods. Terms such as residual solvents, byproduct, transformation products, degradation products, interaction products and related products are frequently used to define impurities. The control of impurities in Formulated products and Active Pharmaceutical ingredient’s were regulated by various regulatory authorities like ICH, USFDA, Canadian Drug and Health Agency are emphasizing on the purity requirements and the identification of impurities in Active Pharmaceutical Ingredient’s (API’s). Identification of impurities is done by variety of Chromatographic and Spectroscopic techniques, either alone or in combination with other techniques. There are different methods for detecting and characterizing impurities with TLC, HPLC, HPTLC, AAS etc. Impurity profiling study has been in the limelight in the recent pharmaceutical scenario and its importance is increasing day-by-day. The present review covers various aspects related to the analytical method development for impurity profiling of Active Pharmaceutical ingredient and pharmaceutical products.