PAT solutions to monitor adsorption of Tetanus Toxoid with aluminum adjuvants
Manjit Haer, Kirsten A. Strahlendorf, Jessie Payne, Ryan Jung, Emily Xiao, Clémentine Mirabel, Nausheen Rahman, Przemek Kowal, Gabriel Gemmiti, James T. Cronin, Tyler Gable, Kevin Park-Lee, Katherine Drolet-Vives, Matthew T. Balmer, Marina Kirkitadze
Abstract
The focus of this study was to examine the small-scale adsorption process of Tetanus Toxoid (TT) as a model protein antigen to aluminum phosphate (AlPO4) and aluminum oxyhydroxide (AlOOH) adjuvants with real-time monitoring by in-line ReactIR™, ParticleTrack™ based on Focused Beam Reflectance Measurement (FBRM) and EasyViewer™ probes. The adsorption process of AlPO4 and AlOOH with TT using was monitored in the small-scale reactors. Conformational changes in TT were monitored using in-line infrared probe ReactIR, whereas particle formation associated with protein adsorption were measured by particle size, count, and imaging tools, such as ParticleTrack with FBRM and EasyViewer probes. ParticleTrack distribution results and kinetic measurements were also supported by observations made using EasyViewer. In addition to EasyMax, BioBLU reactor was also used for the adsorption experiments. ReactIR with ATR-Fiber probe was effectively able to monitor adsorption progress of TT to AlOOH and to AlPO4. ReactIR, EasyViewer, and ParticleTrack provided detailed mechanistic and kinetic information for reaction of TT with AlPO4 and AlOOH. These in-situ measurements revealed a possible multi-step process for TT to AlPO4 which may be an indication of antigen adsorption.