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Ewonde Ewonde R, Böttinger K, De Vos J, Lingg N, Jungbauer A, Pohl CA, Huber CG, Desmet G, Eeltink S. Selectivity and Resolving Power of Hydrophobic Interaction Chromatography Targeting the Separation of Monoclonal Antibody Variants. Anal Chem 2024; 96:1121-1128. [PMID: 38190620 PMCID: PMC10809212 DOI: 10.1021/acs.analchem.3c04011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 12/21/2023] [Accepted: 12/21/2023] [Indexed: 01/10/2024]
Abstract
This study presents a comprehensive investigation of the mechanistic understanding of retention and selectivity in hydrophobic interaction chromatography. It provides valuable insights into crucial method-development parameters involved in achieving chromatographic resolution for profiling molecular variants of trastuzumab. Retention characteristics have been assessed for three column chemistries, i.e., butyl, alkylamide, and long-stranded multialkylamide ligands, while distinguishing column hydrophobicity and surface area. Salt type and specifically chloride ions proved to be the key driver for improving chromatographic selectivity, and this was attributed to the spatial distribution of ions at the protein surface, which is ion-specific. The effect was notably more pronounced on the multialkylamide column, as proteins intercalated between the multiamide polymer strands, enabling steric effects. Column coupling proved to be an effective approach for maximizing resolution between molecular variants present in the trastuzumab reference sample and trastuzumab variants induced by forced oxidation. Liquid chromatography-mass spectrometry (LC-MS)/MS peptide mapping experiments after fraction collection indicate that the presence of chloride in the mobile phase enables the selectivity of site-specific deamidation (N30) situated at the heavy chain. Moreover, site-specific oxidation of peptides (M255, W420, and M431) was observed for peptides situated at the Fc region close to the CH2-CH3 interface, previously reported to activate unfolding of trastuzumab, increasing the accessible surface area and hence resulting in an increase in chromatographic retention.
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Affiliation(s)
- Raphael Ewonde Ewonde
- Department
of Chemical Engineering, Vrije Universiteit
Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - Katharina Böttinger
- Department
of Biosciences and Medical Biology, Bioanalytical Research Laboratories, University of Salzburg, Hellbrunner Strasse 34, 5020 Salzburg, Austria
| | - Jelle De Vos
- Department
of Chemical Engineering, Vrije Universiteit
Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - Nico Lingg
- Department
of Biotechnology, Institute of Bioprocess
Science and Engineering, University of Natural Resources and Life
Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Alois Jungbauer
- Department
of Biotechnology, Institute of Bioprocess
Science and Engineering, University of Natural Resources and Life
Sciences, Muthgasse 18, 1190 Vienna, Austria
| | | | - Christian G. Huber
- Department
of Biosciences and Medical Biology, Bioanalytical Research Laboratories, University of Salzburg, Hellbrunner Strasse 34, 5020 Salzburg, Austria
| | - Gert Desmet
- Department
of Chemical Engineering, Vrije Universiteit
Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - Sebastiaan Eeltink
- Department
of Chemical Engineering, Vrije Universiteit
Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
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