Effect of edge activators on the formation and transfection efficiency of ultradeformable liposomes.

Highly deformable hydrophilic lipid vesicles have been studied for transdermal delivery of therapeutically active small molecules and proteins. Here, we report the effects of edge activators on the formation of ultradeformable liposomes (UL) and transdermal gene delivery. Sodium cholate, sodium deoxycholate, and Tween 80 were tested as edge activators. Of the edge activators, sodium cholate and sodium deoxycholate resulted in the smaller sizes of UL and more positive zeta potentials than did Tween 80. Moreover, sodium deoxycholate-based UL showed the highest positive zeta potentials, which might lead to the firmer binding with negatively charged DNA. Following topical application onto mice, DNA complexed with UL containing either sodium cholate or sodium deoxycholate showed substantial transdermal absorption. In contrast, DNA complexed with Tween 80-based UL did not show in vivo transdermal absorption. These data suggest that UL might be of use as a transdermal delivery system of plasmid DNA, and that the choice of edge activators may play an important role in the transdermal delivery of plasmid DNA via UL.