Title : Overcoming biophysical characterization challenges of small antigens in dilute vaccine formulations
Abstract:
The large-scale manufacturing of vaccines is a complex series of steps that demands significant effort in process, formulation, and analytical development. One notable challenge in the vaccine manufacturing process is aggregation. Interfacial & shear stress, freeze/thaw and formulation components can all lead to aggregate formation. Aggregation can occur across different viral families, encompassing both enveloped and non-enveloped viruses, as well as segmented and non-segmented viruses, including DNA and RNA viruses [1]. Aggregation is an established phenomenon that can compromise the quality, safety, and efficacy of biotherapeutics. Aggregation can have a substantial effect on both the physical and chemical stability of vaccine formulations. Aggregation can have unknown outcomes on immunogenicity and needs to be carefully controlled and monitored in vaccine development. Regulatory considerations in vaccine development highlight the critical importance of quality control, especially in relation to the characterization of aggregates in vaccine products.
Regulatory agencies require a thorough understanding of aggregate formation, size distribution, and their potential impacts on safety and efficacy. Virus particles are inherently smaller than the size of the cells they infect. Several common viral pathogens are less than 100 nm in size, including adenovirus (90 nm), papillomavirus (55 nm), norovirus (40 nm) and poliovirus (30 nm)[2]. To maximize immunogenicity and safety, vaccine antigens would ideally have all the properties of the native pathogens except for the ability to cause disease[3]. Vaccine antigens are often designed to mimic key properties of the native pathogens, including size, shape, and surface properties[4]. However, based on current analytical technologies, analysis of particles less than 100 nm in size can be challenging even at moderate concentration levels.
There are numerous instruments available for the analysis of particles in parenteral formulations spanning the range of submicron to visible particulates. This work will focus on the analysis of small therapeutic antigens less than 80 nm in diameter and their submicron sized aggregates in both drug substance and drug product. A comparison of more established techniques, such as AUC, DLS and NTA will be made against the emerging technology of nano flow cytometry (Beckman Coulter Cytoflex Nano). Techniques will be evaluated for the ability to measure primary antigen particles and the formation of aggregates, including the ability to resolve multimeric populations.
