Saponin-lipid nanoparticles and their formulation intermediates: From molecular distribution to supramolecular structure

Saponins are a large family of glycoconjugates that share a triterpene structure. When formulated together with phospholipids and cholesterol, they self-assemble into a variety of unique structures depending on the composition. The Matrix-M™ adjuvant consists of two different populations of physically stable nanoparticles based on two different saponin fractions, and has been successfully applied in the clinic in e.g. vaccines against Covid, malaria and
veterinary vaccines. Their spherical cage-like structures and structural features have been previously characterised using lab-based methods and SAXS. However, little is understood about the molecular distribution within the saponin-lipid nanoparticles. We have recently successfully studied these particles using SANS. We now propose further characterization of the temperature related stability and the changes in morphology that the particles undergo during formulation. Knowledge of temperature effects and the self-assembly process will contribute to the scientific understanding of how these complex particles are formed which is essential information for product development.