News & Views in ... Nanomedicine

This study deals with the preparation and investigation of a nanoscale delivery system for the anticancer drug doxorubicin (DOX) using its complexation with polyanionic carbohydrate dextran sulfate (DS).Dynamic light scattering, SEM, and zeta potential determination were used to characterize nanocomplexes.DOX-DS complexation was studied in the presence of ethanol as a hydrogen-bond disrupting agent, NaCl as an electrostatic shielding agent, and chitosan as a positively charged polymer.Thermodynamics of DOX-DS interaction was studied using isothermal titration calorimetry (ITC).A dialysis method was applied to investigate the release profile of DOX from DOX-DS nanocomplexes.Spherical and smooth-surfaced DOX-DS nanocomplexes (250-500 nm) with negative zeta potential were formed at a DS/DOX (w/w) ratio of 0.4-0.6, with over 90% drug encapsulation efficiency.DOX when complexed with DS showed lower fluorescence emission and 480 nm absorbance plus a 15 nm bathometric shift in its visible absorbance spectrum.Electrostatic hydrogen bonding and π-π stacking interactions are the main contributing interactions in DOX-DS complexation.Thermal analysis of DOX-DS complexation by ITC revealed that each DOX molecule binds with 3 DS glycosyl monomers.Drug release profile of nanocomplexes showed a fast DOX release followed by a slow sustained release, leading to release of 32% of entrapped DOX within 15 days.DOX-DS nanocomplexes may serve as a drug delivery system with efficient drug encapsulation and also may be taken into consideration in designing DOX controlled-release systems.