(640h) Predicting the Stability of Biotherapeutics in Liquid and Solid Formulations

A key barrier in the manufacturing of new biotherapeutics is the formation of protein aggregates, which can lead to increased production costs, loss of the biological function, and immunogenic responses from patients. To detect the presence of aggregates and ensure protein stability upon storage, efficient pre-formulation screening methods are required. Many of these biotherapeutics are lyophilized (freeze-dried) to avoid or slow down the degradation of the product; however the stability for freeze-dried cakes is highly critical too as damaged freeze-dried products cannot be delivered to patients. Therefore, it is of great interest to investigate methods that are capable of predicting changes in mechanical and physical stability of fragile freeze dried cakes.

Self-Interaction Chromatography (SIC) has been shown to be an accurate and automated high-throughput technique to predict protein stability. In this study the efficiency of SIC as a screening tool in the biopharmaceutical industry, was investigated. Common formulation conditions were investigated using a therapeutic mAb and BSA. Additionally, the stabilising effects of NaCl, Tween 80®, L-arginine and trehalose were examined in the range of 0-250 mM, 0-0.1% v/v and 0-200 mM, respectively. The protein-protein interactions for each formulation condition were quantified by calculating the osmotic second virial coefficient (B₂₂), a fundamental physico-chemical property that describes protein-protein interactions in solution. These results were later compared with the Z-average sizes obtained with Dynamic Light Scattering (DLS). A number of these conditions were lyophilized afterwards to see if the conditions that had shown to provide the greatest stability for the proteins in solution also were suitable for use in solid formulation, as freeze-dried cakes.

SIC showed an increase in the stability of the mAb with the ionic strength and arginine concentration, but no major effect with the addition of polysorbate. BSA showed repulsive protein-protein interactions in all the range of concentrations analysed, as expected due to its high stability in solution, which could be increased with the addition of stabilisers, such as trehalose. Even in the freeze-dried cakes higher concentration of trehalose led to an increased Young’s modulus, and therefore higher mechanical stability.

Based on these results it could be seen that a protein-protein interaction technique such as SIC could be used as an early predictor for formulation behaviour both in liquid and solid states.