Systematic screening of excipients to stabilize aerosolized lipid nanoparticles for enhanced mRNA delivery

Aerosolized lipid nanoparticles (LNPs) delivering mRNA are an attractive strategy for use in local, inhalable therapy to treat patients with lung diseases. However, a major barrier to delivering aerosolized mRNA LNPs is the shear forces encountered during aerosolization. These forces lead to significant morphology changes and subsequent decrease in efficacy of mRNA delivery. To best retain the physicochemical properties of mRNA LNPs during aerosolization, we took a formulation-based strategy to stabilize LNPs. We used a design-of-experiment (DOE) approach to comprehensively screen rationally chosen excipients at multiple concentrations. Excipients were carefully selected based on their use in clinically approved inhaled products or their ability to support lipid membrane properties. These excipients were added to the same mRNA LNP composition after formulation, were subsequently characterized, and used to transfect human lung cells at air-liquid interface. From this systematic screen, we identified that the addition of our lead candidate, poloxamer 188, best stabilizes LNP size throughout aerosolization and enhances mRNA expression after aerosolization. Additional morphological studies of the inclusion of poloxamer 188 in LNPs suggests that the excipient lowers aerosolization induced fusion or aggregation of particles without altering the internal structure. Our results indicate that poloxamer 188 can support aerosolized mRNA LNP delivery by maintaining LNP size and significantly enhancing therapeutic nucleic acid delivery to lung cells.