K. Vigneshwar Reddy's scientific contributions

Controlling and monitoring impurities in APIs and finished drug products is a crucial issue in drug development and manufacturing. Part I of this article, published in the February 2012 issue of Pharmaceutical Technology, discussed the various types of and sources of impurities with specific case studies (1). Part II, published in the March 2012 issue, examined chiral, polymorphic, and genotoxic impurities (2). In Part III, the authors examine various degradation routes of APIs, impurities arising from API–excipient interaction during formulation, metabolite impurities, various analytical methodologies to measure impurity levels, and ways to control impurities in pharmaceuticals.

The public and the pharmaceutical industry are placing greater attention on impurities in drug as evidenced by the attention given to pharmaceutical impurities in books, journal articles, and national and international guidelines (1–10). The health implications of impurities can be significant because of their potential teratogenic, mutagenic, or carcinogenic effects. Controlling and monitoring impurities in APIs and finished drug products, therefore, is a crucial issue in drug development and manufacturing. Part I of this article, which appeared in the February 2012 issue of Pharmaeceutical Technology, discussed the various types and sources of impurities with specific case studies (11). This article, Part II, discusses chiral, polymorphic, and genotoxic impurities (12, 13). Part III, to be published in the April 2012 issue of Pharmaceutical Technology, will examine various degradation routes of APIs, impurities arising from API–excipient interaction during formulation, metabolite impurities, various analytical methodologies to measure impurity levels, and measures to control impurities.

To ensure the quality of APIs and finished drug products, impurities must be monitored carefully during process development, optimization, and process changeover. The isolation, characterization, and control of impurities in pharmaceutical substances are being reviewed with greater attention based on national regulatory and international guidelines. In Part I of this article, the authors examine the different types and sources of impurities with specific examples.