University of Virginia Health System

The recent sequencing of the human genome promises to provide numerous new proteins as drug targets and therapeutic agents. We are tackling two obstacles to the efficient purification of these delicate molecules. Molecular Structure During Protein Purification and Formulation Proteins are exposed to conditions quite different from the natural environment for which they were designed during manufacturing, purification, formulation and use. For example, solvent conditions, exposure to interfaces, and complex phase behavior can all contribute to chemical and physical degradation of proteins in ways that are poorly understood. We are studying these changes in protein structure to determine the mechanisms of these degradation processes. Nuclear magnetic resonance, circular dichroism, isotope exchange, and mass spectrometry are being used to obtain molecular-level information about the type, magnitude, and kinetics of protein conformational changes. Currently we are focusing on structure changes induced during pharmaceutical formulation and exposure to purification environments. Nonideal Flow in Chromatography Fixed bed chromatography and adsorption are heavily used in the biotechnology industry to isolate labile biological macromolecules. Unfortunately, nonuniform column packing and flow instabilities can compromise chromatographic resolution and interfere with FDA regulatory procedures. To analyze these problems experimentally, we are using magnetic resonance imaging (MRI) to detect flow and transport inside operating chromatography columns. Recently we have initiated a collaborative experimental and modeling effort to study the genesis of column permeability heterogeneities.