There are two thrusts to this research. First, fundamental studies to characterize the intrinsic kinetics and adsorption parameters of two key pharmaceutical, insulin and urokinase, in ion exchange, hydrophobic interaction, and affinity chromatography systems will be made. Measurements of the equilibrium isotherms and kinetic constants of the pure compounds will be made and the effects of pH and salt level on the affinities and kinetic constants will be investigated. An existing dynamic column simulation model will be extended to accommodate gradient systems. The model will be validated with pure component experimental data and then will be used to study how impurities and products compete for sorbent sites. As a second and supporting thrust the complex interplay between biomolecules and sorbent functional groups resulting from steric effects, hydration, as well as hydrophobic and electrostatic interactions will be studied. This research should provide a complete description of the configurations of a complex during binding, allow quantitative assessment of various intermolecular forces, and predict the reactive affinities for different molecules. In this way, the understanding of how molecular structure affects sorbent selectivity will be advanced. The research will also have a significant impact on the synthesis and identification of more selective sorbents for biochemical separations.
