Mixed-mode Chromatography Selection Guide

HCIC is based on the pH-dependent behavior of ionizable, dual-mode ligands. Adsorption is based on mild hydrophobic interaction and is achieved without addition of lyotropic or other salts. Desorption is based on charge repulsion. It is performed by reducing pH.

MEP HyperCel™ Resin is a high capacity, high selectivity resin designed for the capture and purification of monoclonal and polyclonal antibodies. HCIC is based on the pH dependent behavior of ionizable, dual-mode ligands. MEP HyperCel resin carries an antibody-selective ligand, 4-Mercapto-Ethyl-Pyridine (4-MEP). Adsorption is based on mild hydrophobicinteraction and is achieved without addition of lyotropic or other salts. Desorption is based on charge repulsion. It is performed by reducing the pH.

HEA and PPA HyperCel Resins are novel industry scalable chromatography resins designed for protein capture and impurity removal in a biopharmaceutical environment. Operating on a "mixed-mode" mechanism, their chromatographic behavior is based on a combination of electrostatic and hydrophobic properties of the protein and ligands. HEA and PPA HyperCel resins provide unique and different selectivities not accessible with traditional ion exchange or HIC, that can be screened to facilitate process development. For example, the mixed-mode interaction mechanism can be exploited to achieve discrimination of proteins having similar or very close isoelectric points, a separation which cannot be performed by methods like an ion exchange.

Hydroxyapatite chromatography is considered to be a “pseudo-affinity” chromatography or “mixed-mode” ion exchange. It has proven to be an effective purification mechanism in a variety of processes, providing biomolecule selectivity complementary to more traditional ion exchange or hydrophobic interaction techniques. HA Ultrogel is easily scalable and is currently used in research scale to multi-liter column applications. HA Ultrogel Resin available from Pall is a hydroxyapatite agarose composite resin for the separation of biomolecules from research and development scale to manufacturing. HA Ultrogel is a cross-linked tridimensional composite based on spherical agarose beads with entrapped microcrystals of hydroxyapatite.

Plasma preparations may contain viruses that are effectively removed and inactivated by combining nanofiltration (for size exclusion removal of non-lipid enveloped viruses) and treatment with non-ionic solvents and detergents (effective for lipid-coated viruses). The elimination of solvent and detergent from biological fractions is necessary, and can be achieved by various methods including resin partitioning, size exclusion, affinity or batch extraction with vegetable oils combined to reverse phase on C18.

SDR HyperD Resin is a unique resin designed to eliminate solvent and detergent from biological fluids. SDR HyperD resin is made of silica-beads in which the pore volume is filled with a three-dimensional cross-linked hydrophobic polymer. The particle size distribution (40-100 µm), the small pore size of the silica beads, and the hydrophobic nature of the chemical groups make SDR HyperD resin an excellent tool for specific solvent detergent removal from biological liquids.