Christopher Mensch

We evaluated the effect of freeze-thawing on an aluminum adjuvant and an aluminum adjuvanted native outer membrane vesicle (nOMV) vaccine formulation. Specifically, we characterized the freeze/thaw-induced agglomeration through the use of static light scattering, micro-flow imaging, and cryo-electron microscopy analysis. Further, we evaluated the use of 0-9% v/v propylene glycol as an excipient which could be included in the formulation for the purpose of mitigating the agglomeration induced by freeze/thaw. The results indicate that using 7% v/v propylene glycol as a formulation excipient is effective at mitigating agglomeration of the nOMV vaccine formulation, otherwise induced by freeze-thawing.

TECHNICAL ABSTRACT: The purpose of this work was to investigate a potential mechanism for the inhibition of tungsten-mediated monoclonal antibody (mAb) biophysical modifications and sub-visible particle formation. A 1 mg/mL mAb formulated in 150 mM NaCl, 20 mM histidine, pH 6.0, was incubated with 1, 37, and 100 ppm of tungsten polyanions in the form of sodium tungstate both in the presence and absence of the anionic surfactant and chelating agent diethylene triamine pentaacetic acid (DTPA) or the cationic surfactant cetyl trimethyl ammonium bromide (CTAB) for 24 h at 25 °C. Assays including pH, UV-Vis spectroscopy, size exclusion chromatography, intrinsic tryptophan/tyrosine fluorescence, and micro-flow imaging were performed to assess the impact on short-term mAb stability and aggregation. We conclude that the use of micromolar concentrations of the formulation excipient and cationic surfactant CTAB equivalent to the anticipated tungsten concentration in solution effectively inhibits loss of protein concentration, fragmentation, changes in intrinsic fluorescence intensity, and the formation of sub-visible particles.