Biodistribution study of indium-111-labeled PEGylated niosomes as novel drug carriers for tumor-targeting

Abstract

Niosomes composed of non-ionic surfactants (NISs) are novel drug carriers that can deliver both hydrophilic and hydrophobic drugs similarly to liposomes, and have several advantages over liposomes, such as lower cost and higher availability owing to their relative abundance and variety. In this study, polyethylene glycol (PEG)-coated (PEGylated) Span 20 niosome was labeled with indium-111 using a remote-loading method, and its in vivo behavior was compared with that of the liposome. In addition, niosomes based on Span 20, 40, 60, and 80 were compared to evaluate the effects of differences in the lipophilic moiety of NIS. We succeeded in convenient labeling of PEGylated niosomes with high labeling efficiency (>95%) and purity (>95%). The stability of 111In-labeled niosomes in the serum was high enough to trace the in vivo behavior. Span 20 niosome exhibited significantly extended retention in the blood and high accumulation in the tumor at 48 h post-injection compared to the liposome. Niosomes composed of Span 80 with an unsaturated hydrocarbon chain showed decreased radioactivity in the blood and increased accumulation in the spleen compared with the other niosomes composed of Span 20, 40, and 60 with saturated hydrocarbon chain. Meanwhile, all studied niosomes were highly accumulated in the tumor. These results suggest that the PEGylated niosomes can be useful as tumor-targeting drug carriers.