The intracellular effects of non-ionic amphiphilic cyclodextrin nanoparticles in the delivery of anticancer drugs

The aim of this study was to develop nanoparticles made of the amphiphilic cyclodextrin heptakis (2-O-oligo(ethyleneoxide)-6-hexadecylthio-)-beta-CD (SC16OH) entrapping docetaxel (Doc) and establish their in vivo potential. Doc-loaded SC16OH nanoparticles were prepared by the emulsion-solvent evaporation technique and fully characterized for size, zeta potential, amount of entrapped drug, release rate and degradation rate. Spherical vesicular nanoparticles displaying a hydrodynamic radius of about 95 nm which did not change upon storage as an aqueous dispersion, a negative zeta potential and entrapment efficiency of Doc very close to 100\% were produced. DSC study highlighted the crystalline nature of SC16OH, unloaded and Doc-loaded SC16OH nanoparticles which resulted in their very slow dissolution during release stage and well-modulated release of entrapped Doc for about 8 weeks. Doc-loaded SC16OH nanoparticles were not hemolytic toward red blood cells as compared to a commercial Doc formulation (Taxotere) which shows a dose-dependent toxicity. After exposure of HEp-2 cells to equivalent doses of free Doc and Doc-loaded SC16OH nanoparticles, superior cell killing and cell damage were observed for nanoparticles. Finally, cell damage was attributed to aberrant mitosis which was found to be significantly higher for HEp-2 cells treated with Doc-loaded SC16OH nanoparticles as compared to free Doc likely due to the ability of nanoparticles to slowly release the drug allowing prolonged cell arrest in mitosis. Taken together, these results highlights a great potential of nanoparticles based on SC16OH in solid tumors therapy.