(683d) Evaluation of Process Parameters Influencing Immobilized Metal Affinity Chromatography

The production of biopharmaceutical drugs requires high yielding and robust purification methods. Affinity chromatography is a preferred method to capture product from culture media due to its high selectivity. However, many protein therapeutics lack a suitable affinity capture modality and therefore require use of engineered tags for affinity purification. Immobilized metal ion affinity chromatography (IMAC) has been a popular choice for the purification of histidine-tagged molecules. One drawback of this technology is that process performance is often variable, making it difficult to predictably scale-up. This study contributes to the understanding of process parameters impacting performance and how to optimally control these parameters. Multivariate experiments were performed to investigate the binding of histidine-tagged proteins to commercial metal chelating resins. This study revealed that imidazole concentration, load capacity and metal binding ability of the resin influenced the protein binding capacity. This study also examined the impact of histidine tag structure on chromatographic performance. Adsorption isotherms were constructed to elucidate differences in equilibrium binding of multi-histidine tagged material. A mathematical model was then employed to describe the impact of changing process parameters on product quality. The findings of this study are useful to understanding factors impacting IMAC operation, including the relationship between process parameters, tag structure, process performance, and product quality.