Title: Radiolabeled niosomes as potential passive targeting nanocarriers

Alice Chuah Lay Hong

Monash University, Malaysia


Dr. Alice Chuah Lay Hong obtained her MPharm (Hons) degree from University of Strathclyde, UK. After completion of her pre-registration training in the hospital, she proceeded to pursue her PhD in the University of Nottingham. Dr. Chuah is currently a senior lecturer in the School of Pharmacy, Monash University Malaysia. Her research focusses on the development of various drug delivery systems to improve the delivery of natural compounds.


Nanocarriers have been widely studied as a promising approach in cancer therapy owing to their flexible physico-chemical characteristics. Despite the abundance of literature on nanocarrier formulations, there is still a lack of information regarding the fate of these nanocarriers in vivo. Radiolabeling of nanocarriers with radioisotopes such as Technetium-99m (99mTc) provides a good means to trace the nanocarriers in vivo, yielding information about nanocarriers distribution and accumulation in organs via scintrigraphic imaging.
           In this study, we investigated the distribution of radiolabeled niosomes in tumour-bearing mice xenograft. Niosomes were prepared via stirring method followed by sonication. The niosomes were characterized using Zetasizer and Transmission Electron Microscopy. The niosomes were radiolabeled by chelation of reduced 99mTc to DTPA found on the surface of the niosomes. The in vitro stability of 99mTc-labeled niosomes were evaluated in 0.9% saline and human serum for up to 8 h. Scintigraphic imaging was later carried out to evaluate the biodistribution of 99mTc-labeled niosomes in vivo.
           The average particle size of the niosomes was 108.8 ± 1.7 nm, with a polydispersity index (PDI) of 0.196 ± 0.023 and zeta potential of -61.8 ± 2.9 mV. The radiolabeling efficiency of 99mTc-labeled niosomes was 99.80 ± 1.51 %; proven to be stable in 0.9% saline and human serum for up to 8 h. Scintigraphic imaging showed a high uptake of 99mTc-labeled niosomes in the liver and spleen, due to opsonisation and recognition of the niosomes by the mononuclear phagocyte system. Little to no accumulation of 99mTc-labeled niosomes was found in the stomach and thyroid, indicating minimal leaching of the radiolabel and impurities in vivo.
           To our knowledge, this is the first reported study of 99mTc-labeled niosomes in vivo. We have successfully formulated 99mTc-labeled niosomes with appropriate labeling efficacy and stability. This will serve as a platform for future development of radiolabeled nanocarriers for nuclear imaging, to examine the distribution of these nanocarriers in vivo.

Audience take away:
• To formulate niosomes as nanocarriers for therapeutic agent
• To radiolabel niosomes for use in nuclear imaging
• To investigate the distribution and accumulation of nanocarriers in vivo using scintigraphic imaging.