[P005] Poster

12:10 PM - 1:00 PM JST(3:10 AM - 4:00 AM UTC)

[P03-337] Lung-selective transdermal delivery of nucleic acid drugs using ionic liquids

○Kiyohiro Toyofuku¹, Rie Wakabayashi¹, Yoshirou Kawaguchi¹, Noriho Kamiya^1,2, Masahiro Goto^1,2 (1. Department of Applied Chemistry, School of Engineering, Kyushu University (Japan), 2. Center for Future Chemistry, Kyushu University (Japan))

Keywords:

Transdermal delivery,Organ-selective delivery,Nucleic acid drug,Ionic liquid,Protein corona

[Purpose]
Nucleic acid therapeutics inhibit protein synthesis by binding to target mRNA and blocking translation. Currently, administration is limited to invasive injections, and off-target distribution to non-target organs risks unintended gene silencing and adverse effects. To address these challenges, we developed an ionic liquid (IL) formulation for non-invasive, organ-selective transdermal delivery of nucleic acid therapeutics. Specifically, we prepared an solid-in-oil nanodispersion using a biocompatible IL (IL-S/O). We hypothesized that varying the IL composition within the IL-S/O formulation would alter the protein corona formed on nanoparticle surfaces after systemic absorption, thereby enabling control of in vivo biodistribution. We evaluated in vitro skin permeability, in vivo organ distribution, and gene knockdown across multiple organs for IL-S/O formulations of different compositions, using MALAT1 antisense oligonucleotide (ASO) as a model nucleic acid.

[Methods]
Three phosphatidylcholine derivatives (DMPC, DPPC, DOPC) were ethylated in chloroform to yield EDMPC, EDPPC, and EDOPC, respectively, and anion exchange was performed using three fatty acids: linoleic acid (Lin), oleic acid (Ole), and palmitic acid (Pal). IL-S/O was prepared by mixing an aqueous ASO solution with an IL ethanol solution, followed by freeze-drying and dispersion in isopropyl myristate. Skin permeability was assessed using Franz diffusion cells on mouse skin with FAM-ASO, and permeated ASO was quantified by microplate reader. For in vivo studies, IL-S/O formulations containing Cy5-ASO were applied transdermally to C57BL/6N mice. Organs (liver, kidney, spleen, heart, and lungs) were harvested 72 hours post-administration and analyzed by IVIS imaging. MALAT1 expression in the liver, kidneys, and lungs was quantified by RT-qPCR using Ppia as the housekeeping gene.

[Results and Discussion]
Skin permeability varied with the anionic fatty acid component of the IL, increasing in the order Pal < Ole < Lin. This trend is likely attributable to increased molecular bulk conferred by unsaturated bonds in the fatty acids. In vivo IVIS imaging revealed organ-selective ASO distribution depending on IL composition: [EDOPC][Ole]-S/O accumulated predominantly in the liver, whereas [EDMPC][Ole]-S/O and [EDPPC][Ole]-S/O showed preferential accumulation in the lungs. Consistent with these distribution profiles, RT-qPCR demonstrated significant MALAT1 knockdown in the lungs for the [EDMPC][Ole]-S/O and [EDPPC][Ole]-S/O transdermal administration groups. These findings indicate that IL composition modulates the protein corona, altering organ-selective biodistribution and enabling targeted antisense activity.

[Conclusion]
IL-S/O enhances the transdermal permeability of nucleic acid therapeutics and, through modification of IL composition, enables selective pulmonary accumulation following systemic circulation.