YSK05 is an ionizable amino lipid (apparent pK_a= ~6.5) that has been used in combination with other lipids in the formation of liposomes and lipid nanoparticles (LNPs).^1,2,3Administration of cyclic di-GMP in YSK05-containing liposomes increases serum levels of IFN-β, IFN-γ, IL-6, and TNF-α and activates natural killer (NK) cells in mice, as well as decreases lung metastasis in a B16/F10 murine melanoma model of metastasis.²Intravenous administration of factor VII siRNA in YSK05-containing LNPs reduces factor VII activity in isolated mouse plasma.³

1.Sato, Y., Hatakeyama, H., Sakurai, Y., et al.A pH-sensitive cationic lipid facilitates the delivery of liposomal siRNA and gene silencing activity in vitro and in vivoJ. Control. Release163(3)267-276(2012) 2.Nakamura, T., Miyabe, H., Hyodo, M., et al.Liposomes loaded with a STING pathway ligand, cyclic di-GMP, enhance cancer immunotherapy against metastatic melanomaJ. Control. Release216149-157(2015) 3.Sato, Y., Note, Y., Maeki, M., et al.Elucidation of the physicochemical properties and potency of siRNA-loaded small-sized lipid nanoparticles for siRNA deliveryJ. Control. Release22948-57(2016)