ABSTRACT
Recombinant proteins and monoclonal antibodies (mAb), although relatively complex, are becoming even more complex with the advent of mAb conjugates and antibody drug conjugates consisting of a mAb + conjugated small molecules. The basic principle of Ion exchange chromatography separation uses electrostatic interactions between charged variants and an oppositely charged stationary phase. The charged variants of the bio-molecule are bound, to the column, via electrostatic interactions which are facilitated by the mobile phase pH and ionic strength. The use of pH and ionic strength gradients also provides a good foundation for developing more appropriate mobile phases relative to the needs of the molecule. This strategy starts with a dilute buffer solution suitable for retaining the molecule, then gradually shifting the charge of the mobile phase, in the form of pH and or ionic strength increases, as necessary, to facilitate the separation.
