Evaluating concentration-dependent blood partitioning and establishing best practices for assessing whole blood stability

WRIB 2025 -- Establishing drug stability in whole blood is critical for ensuring accurate bioanalytical results for plasma assays due to the sample collection process. ICH M10 provides new guidance on assessing whole blood stability. During the whole blood stability assessment, drug distribution between red blood cells and plasma can be observed, which can be influenced by multiple factors (pH, physiochemical properties, protein binding, metabolism, etc.). Preferential distribution between red blood cells and plasma has important implications for PK modeling, and should be considered during bioanalytical method development.