Stimuli-sensitive hollow spheres from chitosan-graft-β-cyclodextrin for controlled drug release

In this paper, sensitive polymeric hollow spheres self-assembled from chitosan-grafted-β-cyclodextrin (CS-g-CD) and sodium tripolyphosphate (TPP) were prepared for controlled release of doxorubicin (DOX). The assemblies were formed by electrostatic interactions between positively charged amino group in CS-g-CD and negatively charged phosphate in TPP. The hollow spheres with diameters about 100nm were confirmed by transmission electron microscopy (TEM) and laser particle analyzer. The microspheres with hollow cavity were beneficial to improve the drug loading capacity for DOX with entrapment efficiency above 60%. The cumulative release of DOX from CS-g-CD/TPP hollow microspheres increased with the decrease of pH and the increase of temperature or ionic strength. At 37 °C and pH 5.2, the maximum drug release was above 90% with a continuous release rate. In-vitro cytotoxicity tests indicate that drug loaded hollow spheres exhibited evidently inhibition against cancer cells. These sensitive polymeric hollow spheres are expected to be used in biomedical field as potential carrier.