(595e) Linking Interfacial Shear & Dilatational Rheology to Long-Term Stability of Therapeutic Protein Formulations

Monoclonal Antibodies (mAbs) play an indispensable role in various disease treatments, including asthma, autoimmune diseases, and cancer.¹ The success of mAb therapeutics stems from their high specificity, potency, and ability to be engineered for various targets.² However, instabilities during manufacturing and in formulation and delivery limit their use. In particular, the aggregation propensity of mAb is a longstanding issue for biopharmaceutical development. The presence of aggregates in the final product could reduce therapeutic efficacy, trigger unwanted immune responses, and even cause life-threatening complications.³ Therefore, the ability to predict the aggregation propensity of these protein-based therapeutics during the early stage of formulation development is crucial and currently attracts much research from both industry and academia.

MAbs are surface-active species that adsorb to form viscoelastic gel-like layers at the air-water interface.⁴ The formation of the gel-like interface is relevant to the exposure of buried hydrophobic moieties through some degrees of conformational change.⁵ On the other hand, the aggregation mechanism of therapeutic proteins also involves the exposure of hydrophobic moieties when proteins undergo partial unfolding.³ We hypothesize that the interfacial properties of mAb interfacial layers are correlated to their intrinsic aggregation propensity. To test this hypothesis, the interfacial properties of four different mAbs with different bulk mAb aggregation propensity stability according to visible particle counts from a 3-year stability study are measured. MAb interfacial films are characterized by dynamic surface tension, interfacial shear rheology and dilatational rheology and X-ray and neutron reflectivity. The measured interfacial properties are compared to the bulk stability measurements to identify correlations between the interfacial rheological properties and the aggregation propensity of the therapeutic formulation. We find that the interfacial elastic modulus measured at 8 hours of adsorption correlates with the long-time solution stability within a particular class of mAb.

¹ L. Urquhart, et al., Nat Rev Drug Discov 2022.

² J.G. Elvin, et al., Int J Pharm 2013, 440, 83-98.

³ C.J. Roberts., Trends in Biotechnology 2014.

⁴ Y.S. Tein, et al., Langmuir 2020

⁵ A. D Kanthe, et al., Springer International Publishing, 2021; pp 9-49.