Cyclodextrins (CyDs) have recently been applied to gene transfer and oligonucleotide delivery [13] [14] [15] [16] . CyDs are 2 Journal of Drug Delivery cyclic (α-1,4)-linked oligosaccharides of α-D-glucopyranose containing a hydrophobic central cavity and hydrophilic outer surface, and they are known to be able to act as novel host molecules by chemical modification [17] . Davis and his colleagues reported that the ternary complex of a water-soluble β-CyD polymer with 6 A ,6 D -dideoxy-6 A ,-6 D -di-(2-aminoethanethio)-β-CyD and dimethylsuberimidate (βCDP6), galactosylated, or transferrin polyethylene glycol conjugates with adamantane, and pDNA possesses higher transfection efficiency in hepatoma or leukemia cells, respectively, through receptor-mediated endocytosis [18, 19] . Recently, we reported the potential use of PAMAM dendrimer functionalized with α-CyD (α-CDE) [20] and lactosylated α-CDE (Lac-α-CDE) as a hepatocyte specific gene delivery in vitro and in vivo [21] . Meanwhile, Lawrencia et al. reported that lipoplex transfection of pDNA with DOTAP (N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium methyl-sulfate) in the presence of cholesterol, which is solubilized by methyl-β-cyclodextrin (methyl-β-CyD), has significantly improved transfection efficiency in urothelial cells due to change in membrane fluidity by methyl-β-CyD [22] . In addition, we previously demonstrated that intravenous injection of the pegylated liposomes entrapping the doxorubicin (DOX) complex with γ-CyD in BALB/c mice bearing Colon-26 tumor cells showed DOX accumulation in tumor tissues and the potent antitumor effect, compared with those of DOX solution and pegylated liposomes entrapping DOX alone [23] . These lines of evidence suggest that transfection efficiency and pharmacokinetics of pDNA can be altered by the association of CyDs with AF-liposomes.