title: Particle Formation and Aggregation of a Therapeutic Protein in Nanobubble Suspensions.
abstract: The generation of nanobubbles following reconstitution of lyophilized trehalose formulations has recently been reported. Here, we characterize particle formation and aggregation of recombinant human interleukin-1 receptor antagonist (rhIL-1ra) in reconstituted formulations of lyophilized trehalose. Particle characterization methods including resonant mass measurement and nanoparticle tracking analysis were used to count and size particles generated upon reconstitution of lyophilized trehalose formulations. In addition, accelerated degradation studies were conducted to monitor rhIL-1ra aggregation in solutions containing various concentrations of suspended nanobubbles. Reconstitution of lyophilized trehalose formulations with solutions containing rhIL-1ra reduced nanobubble concentrations and generated negatively buoyant particles attributed to aggregated rhIL-1ra. Furthermore, levels of rhIL-1ra aggregation following incubation in aqueous solution correlated with concentrations of suspended nanobubbles. The results of this study suggest that nanobubbles may be a contributor to protein aggregation and particle formation in reconstituted, lyophilized therapeutic protein formulations.
authors.affiliation: Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309.
authors.forename: Jared R
authors.initials: JR
authors.lastname: Snell
authors.affiliation: Department of Pharmaceutical Science, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhou
authors.affiliation: Department of Pharmaceutical Science, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045.
authors.forename: John F
authors.initials: JF
authors.lastname: Carpenter
authors.affiliation: Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309. Electronic address: Theodore.Randolph@colorado.edu.
authors.forename: Theodore W
authors.initials: TW
authors.lastname: Randolph
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism*; D053758:Nanoparticles / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism*; D010316:Particle Size; D066329:Protein Aggregates / Q000502:physiology*; D013535:Suspensions
chemical_list: D053590:Interleukin 1 Receptor Antagonist Protein; D066329:Protein Aggregates; D013535:Suspensions
keywords: nanobubbles; particle characterization; protein aggregation