Leveraging Asymmetric-Flow Field-Flow Fractionation for Characterization of Stable Nanoemulsion Adjuvants

Adjuvants are non-antigenic components of vaccines that are included in final drug products to enhance overall immunogenicity and durability. Oil-in-water stable nanoemulsions (SNEs) are a subtype of adjuvants used in commercial and investigational vaccine products. Traditionally, SNEs have been characterized using batched light scattering methods, which have low resolution for complex mixtures. To better characterize SNE population heterogeneity, separation methods coupled with light scattering detection can be used to inform process development. One limitation of traditional separation methods like size-exclusion chromatography is high shear causing nanodroplet degradation. Asymmetric-flow field-flow fractionation (AF4) is an alternative sized-based separation method that could be utilized to better characterize SNE samples with low sheer applied to the samples. In this presentation, method development using AF4 for SNE characterization is described. Several parameters are investigated, including elution profile, focusing area, and flow rate. Using the developed method, two products are characterized and method robustness is demonstrated.