Eudragit® S 100 Coating of Lipid Nanoparticles for Oral Delivery of RNA

Lipid nanoparticle (LNP)-based delivery systems are promising tools for advancing RNA-based therapies. However, there are underlying challenges for the oral delivery of LNPs. In this study, we optimized an LNP formulation, which we encapsulated in a pH-sensitive Eudragit® S 100 (Eu) coating. LNPs were prepared using the DLin-MC3-DMA ionizable lipid, cholesterol, DMG-PEG, and DSPC at a molar ratio of 50:38.5:10:1.5. LNPs were coated with 1% Eu solution via nanoprecipitation using 0.25% acetic acid to get Eu-coated LNPs (Eu-LNPs). Particle characteristics of LNPs were determined by using dynamic light scattering (DLS). Ribogreen and agarose gel retardation assays were used to evaluate nucleic acid entrapment and stability. LNPs and Eu-LNPs were ~120 nm and 4.5 μm in size, respectively. Eu-LNPs decrease to an average size of ~191 ± 22.9 nm at a pH of 8. Phosphate buffer (PB)-treated and untreated Eu-LNPs and uncoated LNPs were transfected in HEK-293 cells. PB-treated Eu-LNPs showed significant transfection capability compared to their non-PB-treated counterparts. Eu-LNPs protected their nucleic acid payloads in the presence of a simulated gastric fluid (SGF) with pepsin and maintained transfection capacity following SGF or simulated intestinal fluid. Hence, Eu coating is a potentially promising approach for the oral administration of LNPs.