Transdermal Delivery of Small Interfering RNA with Elastic Cationic Liposomes in Mice

We developed elastic cationic liposomal vectors for transdermal siRNA delivery. These liposomes were prepared with 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) as a cationic lipid and sodium cholate (NaChol) or Tween 80 as an edge activator. When NaChol or Tween 80 was included at 5, 10, and 15% (w/w) into DOTAP liposomal formulations (C5-, C10-, and C15-liposomes and T5-, T10-, and T15-liposomes), C15- and T10-liposomes showed 2.4- and 2.7-fold-higher elasticities than DOTAP liposome, respectively. Although the sizes of all elastic liposomes prepared in this study were about 80–90 nm, the sizes of C5-, C10- and C15-liposome/siRNA complexes (lipoplexes) were about 1,700–1,800 nm, and those of T5-, T10-, and T15-lipoplexes were about 550–780 nm. Their elastic lipoplexes showed strong gene suppression by siRNA without cytotoxicity when transfected into human cervical carcinoma SiHa cells. Following skin application of the fluorescence-labeled lipoplexes in mice, among the elastic lipoplexes, C15- and T5-lipoplexes showed effective penetration of siRNA into skin, compared with DOTAP lipoplex and free siRNA solution. These data suggest that elastic cationic liposomes containing an appropriate amount of NaChol or Tween 80 as an edge activator could deliver siRNA transdermally.