PT  - JOURNAL ARTICLE
AU  - Lamerz, Jens
AU  - Danila, Oana Mihaela
AU  - Schuster, Andreas
AU  - Burren, Janine
AU  - Moessner, Christian
AU  - Göhring, Wolfgang
AU  - Rege, Pankaj
AU  - Stahr, Helmut
AU  - Hildbrand, Stefan
AU  - Coleman, Daniel
TI  - An Improved Impact Ratio for Identifying Critical Process Parameters in Pharmaceutical Manufacturing Processes
AID  - 10.5731/pdajpst.2021.012662
DP  - 2022 Jan 01
TA  - PDA Journal of Pharmaceutical Science and Technology
PG  - pdajpst.2021.012662
4099  - http://journal.pda.org/content/early/2022/07/15/pdajpst.2021.012662.short
4100  - http://journal.pda.org/content/early/2022/07/15/pdajpst.2021.012662.full
AB  - 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.