Synthesis and characterisation of a pH-sensitive magnetic nanocomposite for controlled delivery of doxorubicin

We prepared a magnetic chitosan-cis-aconitic anhydride-doxorubicin nanocomposite, denoted by MCS-CAA-DOX. Chitosan (CS) was linked to magnetic nanoparticles (Fe3O4) to decrease cytotoxicity of the composite and provided a large number of reactive sites for coupling of drug molecules. DOX was attached to the magnetic chitosan (MCS) via a pH-sensitive linker, cis-aconitic anhydride, which hydrolyses in the acidic lysosomal environment to allow pH-responsive release of DOX. The prepared nanocomposites were within 15 nm and had good superparamagnetic properties. The loading rate of DOX was up to 83%. It was found that nearly 88% DOX was released within 60 h at pH 5.0, compared with only 29% at pH 7.4.