Mechanistic Insights into Protein Stability, Aggregation, and Rheological Changes through Dynamic Light Scattering/Raman Spectroscopy and Microcapillary Viscometry

Samiul Amin1, Gregory Barnett2, E.Neil Lewis1, Wei Qi1,Christopher Roberts2

1Malvern Biosciences, Columbia, Maryland, USA

2Department of Chemical & Biomolecular Engineering, University of Delaware, Delaware, USA

Non-invasive and/or non-destructive determination of physicochemical properties of protein therapeutics, and their aggregates is critical for developing formulation conditions that enhance product efficacy, stability, and manufacturability. Moreover, to meet the analytical challenges in early stage development, where the amount of material is limited, tools that measure very small volumes and make in situ measurements are highly desirable. In this presentation, new analytical tools will be described that can work with small amounts of protein samples to measure relative protein molecular structure, size (including aggregation) and viscosity over a range of concentrations and formulation conditions. Rapid measurement of viscosity enhancement in aggregated protein systems is obtained through a novel microcapillary viscometry technique. Structural, thermodynamic and kinetic insights into the viscosity enhancement and underlying aggregation mechanisms are obtained through a combination of two well-established analytical techniques namely dynamic light scattering (DLS) and Raman spectroscopy. The presentation will detail the mechanistic insights for aggregation and viscosity enhancement that have been obtained for alpha-Chymotrypsinogen over a range of different pH conditions and concentrations. Further insights and cross- validation of the results through more traditional SEC-MALLS and CD measurements will also be presented.