Polyethylene glycol-decorated doxorubicin/carboxymethyl chitosan/gold nanocomplex for reducing drug efflux in cancer cells and extending circulation in blood stream.

Polyethylene glycol (PEG)-decorated doxorubicin (Dox)/carboxymethyl chitosan (CMC)/gold nanoparticles (AuNPs) have been developed for cancer therapy. CMC was used as a reducing and stabilizing agent for the fabrication of AuNPs and Dox was loaded onto AuNPs as a chemotherapeutic agent. Dox-loaded CMC-stabilized AuNPs (Dox/CMC-AuNPs) with a mean diameter of 104.0 nm, zeta potential of -48.32 mV, and drug loading efficiency of 60.14% were prepared. PEG was attached to CMC-AuNPs for enhancing systemic drug exposure and prolonging the circulation in blood stream. Compared with Dox/CMC-AuNPs, Dox-loaded PEGylated CMC-AuNPs (Dox/CMC-AuNPs-PEG) showed a reduced hydrodynamic size (71.2 nm), less negative zeta potential (-12.83 mV), and an enhanced Dox loading efficiency (73.14%). Dox/CMC-AuNPs and Dox/CMC-AuNPs-PEG exhibited sustained and pH-dependent drug release profiles and exhibited antiproliferation effects against the A549 cells. In a bi-directional transport study of Caco-2 cell monolayers, AuNPs reduced the efflux ratio, which indicated that the P-glycoprotein-mediated multidrug resistance (MDR) was overcome. Dox/CMC-AuNPs-PEG resulted in reduced drug clearance (CL) and improved half-life (t1/2), compared with Dox/CMC-AuNPs, in rats after intravenous administration. These results suggest that Dox/CMC-AuNPs-PEG could be a promising nanotherapeutic approach to overcome MDR in cancer and prolong their circulation in the blood stream.