Defining process design space for a hydrophobic interaction chromatography (HIC) purification step: Application of quality by design (QbD) principles

The concept of design space has been taking root under the quality by design paradigm as a foundation of in‐process control strategies for biopharmaceutical manufacturing processes. This paper outlines the development of a design space for a hydrophobic interaction chromatography (HIC) process step. The design space included the impact of raw material lot‐to‐lot variability and variations in the feed stream from cell culture. A failure modes and effects analysis was employed as the basis for the process characterization exercise. During mapping of the process design space, the multi‐dimensional combination of operational variables were studied to quantify the impact on process performance in terms of yield and product quality. Variability in resin hydrophobicity was found to have a significant influence on step yield and high‐molecular weight aggregate clearance through the HIC step. A robust operating window was identified for this process step that enabled a higher step yield while ensuring acceptable product quality. Biotechnol. Bioeng. 2010;107: 985-997.