Response to the Comments by Snodin on Our Article “Approaches to Assessment, Testing Decisions, and Analytical Determination of Genotoxic Impurities in Drug Substances” [Org. Process Res. Dev. Web publication November 13, 2008; DOI: 10.1021/op8002129; 2009, 13, 285−291.]

Abstract

2009, 13, 285-291.]Dear Editor:We would like to acknowledge David Snodin's Letter to the Editor in which he comments on our recent Org. Process Res. DeV. (OPRD) paper ("Approaches to assessment, testing decisions, and analytical determination of genotoxic impurities in drug substances"). Three specific topics relating to the need for specification limits, risk assessment and need for routine testing were discussed in the letter, and we find his comments to be consistent with our paper.As stated in the paper, avoidance of genotoxic impurities (GTIs) as reagents, starting materials, synthetic intermediates and byproducts in chemical processing is an initial consideration