Multi‐Stage Aqueous Two‐Phase Extraction for the Purification of Monoclonal Antibodies

Using monoclonal antibodies in a cell culture harvest as an example for complex biomolecules, a mini‐plant‐scale aqueous two‐phase purification process was studied. The results of this study indicate that antibodies can be concentrated and purified in a single extraction step employing a small phase ratio. Following the extraction step, a multi‐stage wash‐extraction for further purification was investigated. Starting at a test tube‐scale cross‐current wash, the process was advanced towards a continuous counter‐current mixer‐settler and column wash process. It was shown that a test tube cross‐current extraction operation can predict the multi‐stage purity reasonably well. The hydrodynamic process performance for the multi‐stage wash column was evaluated and related to the separation performance.