(580i) Quantifying the Competitive Adsorption between Monoclonal Antibodies and Surfactants at the Air/Water Interface Using X-Ray Reflectivity

The adsorption of therapeutic monoclonal antibodies (mAbs) at the air-water interface is central to the production and use of antibody-based pharmaceuticals. Air-water interfaces are generated during the production, processing and storage of therapeutic formulations by shaking in administering syringes and IV bags. The interfacial adsorption of the mAbs onto these air/water interfaces results in the conformational degradation of the antibody, where the loss of secondary and tertiary structure can result in diminished activity and promote immunogenicity, inhibiting the efficacy of the biologic. In order to solve this problem and enhance the physical stability of therapeutic monoclonal antibodies, the pharmaceutical industry uses a multicomponent formulation that includes surface active excipients whose role is to rapidly adsorb to the interface and prevent the adsorption of the antibody. The aim of this workis to explore the competitive adsorption process between surfactants and two monoclonal antibody (mAb) proteins. Pendant bubble tensiometer is used to characterize the equilibrium and dynamic surface tensions, and X-ray reflectivity (XR) is used to measure adsorbed amounts and their molecular configurations. Finally, a kinetic model is presented for the competitive adsorption process to predict the critical concentration of excipient necessary to prevent the adsorption of the mAbs.