Dotap/Udca vesicles: novel approach in oligonucleotide delivery

The relatively hydrophilic bile acid, ursodeoxycholic acid (UDCA), was used as additive to DOTAP cationic liposomes to evaluate the effect on the cellular uptake of an oligonucleotide. Nuclear magnetic resonance studies were applied to estimate the relative amount of incorporated UDCA into the lipidic bilayers. The interaction between the new formulations and 5’fluorescein conjugated 29-mer phosphorothioate oligonucleotide (PS-ODN) was studied using gel electrophoresis experiments. Besides, DOTAP or DOTAP/UDCA vesicles (MixVes; DOTAP/UDCA 1:0.25, 1:0.5, 1:1 and 1:2 molar ratio) were complexed with PS-ODN and tested after transfections the cellular uptake and the localization of the oligo in HaCaT cell line by the use of cytofluorimetric and confocal microscopic analysis. DOTAP lipid formulated in presence of defined amount of UDCA forms more stable, flexible and active MixVes. In particular, the MixVes at 1:0.25 and 1:0.5 molar ratio increase and modify the cellular uptake of PS-ODN if compared with DOTAP liposomes 3 h after the transfection studies. Besides, the in vitro data suggest that these new formulations are not toxic.