TY - JOUR T1 - An Improved Impact Ratio for Identifying Critical Process Parameters in Pharmaceutical Manufacturing Processes JF - PDA Journal of Pharmaceutical Science and Technology JO - PDA J Pharm Sci Technol DO - 10.5731/pdajpst.2021.012662 SP - pdajpst.2021.012662 AU - Jens Lamerz AU - Oana Mihaela Danila AU - Andreas Schuster AU - Janine Burren AU - Christian Moessner AU - Wolfgang Göhring AU - Pankaj Rege AU - Helmut Stahr AU - Stefan Hildbrand AU - Daniel Coleman Y1 - 2022/01/01 UR - http://journal.pda.org/content/early/2022/07/15/pdajpst.2021.012662.abstract N2 - The identification of critical process parameters in biologics and small molecule process development is a key element of Quality by Design. The objectivity and consistency of procedures to identify critical process parameters can be improved with the use of impact ratios. Impact ratios quantify a process parameter′s practical effect on a critical quality attribute relative to the critical quality attribute′s acceptance limits. When the impact ratio is large, i.e., exceeds a predefined impact ratio threshold, the recommendation is to classify the process parameter as a critical process parameter. This paper introduces an improved and mathematically well-defined impact ratio. Benefits of this impact ratio are a consistent interpretation for many scenarios commonly encountered in practice, high suitability to automation and the possibility of standardizing on a single impact ratio definition for pharmaceutical manufacturing. ER -