(W1230-09-51) A Mucoadhesive Composition for Pulmonary Delivery of mRNA Lipid Nanoparticles

Purpose: Despite the recent successes of lipid nanoparticle (LNP)-mediated mRNA vaccines against SARS-CoV-2, inhalation-based gene therapy and mucosal immunization remain challenging for treating various lung diseases (e.g., inherited diseases, pulmonary hypertension, asthma, cystic fibrosis, cancers, etc.). Systemic therapeutic applications of currently available lipid- and nonlipid nanoparticulate platforms have been investigated mostly for liver diseases because of their favorable accumulation tendency into the liver, which restricts their access to other organs, including the lungs. Intranasal (IN) administration, aerosol inhalation, and intratracheal instillation of nucleic acid-encapsulated nanoparticles allow direct access to the pulmonary system, principally the lung epithelium. We demonstrate the preclinical success of the direct IN delivery of mRNA-encapsulated LNPs, which we premixed with our newly invented lung-targeting mucoadhesive solution.

Methods: We selected novel ionizable lipids from our library for use in LNPs. Firefly luciferase (Fluc) enzyme-encoded mRNA was encapsulated in LNPs using the NxGen^TM NanoAssemblr^™ technology platform. Characterization for hydrodynamic size, polydispersity index (PDI), loading, and encapsulation efficiency was performed before and after mixing with various IN mucoadhesive solution (INMS) compositions. We mixed the lead INMS compositions with the Fluc-mRNA-encapsulated LNPs at a 1:1 ratio and we assessed for in vivo luciferase expression in mouse lungs following a single IN administration of 0.1 mg/kg dose of Fluc-mRNA.

Results: The prepared and concentrated Fluc-mRNA-loaded LNPs were in the desired size range of 60 to 80 nm with a PDI value below 0.2 and with an encapsulation efficiency greater than 95% before mixing with the INMS. When we mixed with INMS at a 1:1 ratio, the average size and PDI of the LNPs increased to ~ 175 nm and ~ 0.3, respectively. In addition, the encapsulation efficiencies of the mixed formulations declined by not less than 80%. After lyophilization, the average size and PDI of the LNPs increased to ~ 700 nm and ~ 0.7, respectively, and encapsulation efficiencies were unchanged. Our preclinical investigations exhibited significant in vivo luciferase expression in the lungs of female BALB/c mice receiving intranasally administered Fluc-mRNA LNPs mixed with INMS at a 1:1 ratio. We observed no clinical symptoms or adverse effects. The lead INMS candidate is currently being used in preclinical investigations to explore its potential for mucosal immunization.

Conclusion: Our INMS platform can deliver nucleic acid-loaded nanoparticles into the lungs by retaining the critical quality attributes (CQA) of the drug product. Thus, the future development of non-systemic, nanoparticle-based delivery of nucleic acids for various lung diseases looks promising.