Pharmaceuticals Impurities


Impurities is defined as an entity of drug substances or drug product that is not chemical entity defined as drug substances an excipients or other additives to drug product. In pharmaceutical world, an impurity is generally considered as other organic material beside the drug substances that is arises out of the synthesis most of the time, inorganic contaminants are not considered as an impurity unless they are toxic, such as heavy metal or arsenic. There are numerous sources of impurities and many different common terms are used for impurities such as by product, intermediate, transformation on product, related product, interaction product and degradation products.


Impurities in pharmaceuticals are the unwanted chemicals that remain with the active pharmaceutical ingredients (APIs), or develop during formulation, or upon aging of both API and formulated APIs to medicines.

The presence of these unwanted chemicals even in small amounts may influence the efficacy and safety of the pharmaceutical products.

According to ICH, an impurity in a drug substance is defined as-“any component of the new drug substance that is not the chemical entity defined as the new drug substance”. There is an ever increasing interest in impurities present in APIs recently, not only purity profile but also impurity profile has become essential as per various regulatory requirements. The presence of the unwanted chemicals, even in small amount, may influence the efficacy and safety of the pharmaceutical products.

“In the pharmaceutical world, an impurity is considered as any other organic material, besides the drug substance, or ingredients, arise out of synthesis or unwanted chemicals that remains with API’s”.