Predicting the Stability of Monoclonal Antibodies at High Concentration Formulations

Abstract

Monoclonal antibodies (mAbs) used as therapeutics often require formulation at high concentrations to minimize administration volume. High concentration poses an increased risk of instability, primarily via complicated aggregation pathways. Identification of consistently reliable tools to predict longer term stability based on initial data remains a challenge in the biotechnology industry, especially in the context of protein aggregation. Aggregation is influenced by both colloidal and conformational stability. Colloidal stability can be evaluated by dynamic light scattering (DLS) and used to derive the diffusion coefficient based self-association constant (kD), which is representative of intermolecular attraction. Isothermal chemical denaturation (ICD), differential scanning calorimetry (DSC), and extrinsic and intrinsic fluorescence evaluate conformation and thermodynamic stability. The Gibbs Free Energy (ΔG), an indicator of the propensity for structural transition, is obtained through chemical denaturation. Thermal denaturation monitored via DSC and/or intrinsic and extrinsic fluorescence provides the temperature of onset (Tonset) and the midpoint (Tm) of molecular transitions. In this work, we evaluate the ability of these methods to predict the long-term aggregation for a series of monoclonal antibodies based on their intrinsic molecular properties.