Ozde Oztekiner1, Benjamin Fiedler1, Christian Wells2, Pratik Gurnani1, Jenny Lam1
1University College London, School of Pharmacy, 29-39 Brunswick Square, London, WC1M 1AX, UK
2Croda, Cowick Hall, Snaith, Goole, East Yorkshire DN14 9AA
Summary
Inhaled mRNA-lipid nanoparticle (LNP) therapeutics hold transformative promise for treating pulmonary diseases by enabling targeted delivery and minimising systemic exposure. However, the stability of mRNA-LNPs during nebulisation remains a critical barrier, particularly due to the destabilising effects of aerosol shear forces and the immunogenicity associated with conventional PEG-lipids. This study systematically compares the performance of traditional PEG-lipids (DSPE-PEG, DMPE-PEG, DMG-PEG) and novel polymer-lipid alternatives (DMG-pSar, DMG-PX, DMG-PY, DMG-PZ) in stabilising mRNA-LNPs during and after nebulisation. LNPs were formulated with two clinically relevant ionisable lipids (ALC-0315 and SM102) and characterised for hydrodynamic diameter, polydispersity index (PDI), and in vitro transfection efficiency before and after nebulisation. Results demonstrate that DSPE-PEG provides the most robust stabilisation, maintaining small particle size, low PDI, and high transfection efficiency post-nebulisation. In contrast, increased hydrophilicity in alternatives such as DMPE-PEG, DMG-PEG, and especially DMG-pSar and DMG-PZ, leads to greater LNP destabilisation and reduced mRNA delivery. Notably, among the DMG polymer conjugates, DMG-PY (least hydrophilic) outperforms DMG-PX and DMG-PZ, highlighting the importance of balancing hydrophilicity and membrane anchoring. Lower molar percentages (1.5%) of all polymers consistently yield better outcomes. These findings provide critical guidance for the rational design of LNP surface chemistry, supporting the development of safer and more effective inhaled mRNA therapies by optimising stability and delivery efficiency for clinical translation.