A Fresh Look at the Potential of Cyclodextrins for Improving the Delivery of siRNA Encapsulated in Liposome Nanocarriers

[Image: see text] Liposomes are among the most effective vehicles to deliver siRNAs to cells, both in vitro and in vivo. However, despite numerous efforts to improve the potential of liposomes, siRNAs begin to leach out of liposomes as soon as they are formulated. This decreases the value of liposomes for drug delivery purposes significantly, masking their true potential. In this study, we examine the effect of β-cyclodextrins on the retention time and transfection efficiency of siRNAs formulated in a liposome. Cyclodextrins have been widely studied as solvating agents and drug delivery vectors mainly because these cyclic nontoxic glucose structures can bind several molecules of different physicochemical characteristics, through H-bonding or by forming inclusion complexes. These properties, although beneficial for most applications, have resulted in some contradictory results published in the literature, whereas cyclodextrins have been found to destabilize a liposome’s membrane. Here, we present a systematic study, which shows that β-cyclodextrin binds, possibly via hydrogen bonding, with siRNA and DOPC liposomes, resulting in increased siRNA serum stability and in vitro siRNA’s transfection efficiency when formulated together.