metal-chitosan complexes suffer from poor stability in physiologically relevant media leading to extensive uncontrolled release of loaded drugs, particularly for oral administration [15]. To overcome this problem, researchers synthetically modified chitosan to enhance the stability of its metal complexes. For example, chitosan was conjugated to succinic acid and hydroxamated succinic acid. The resulting semisynthetic polymers were employed in the formation of drug-loaded, iron (III)-crosslinked polymeric beads [4]. In another example, chitosan was modified by alkylation with mono-iodoacetic acid to generate
chitosan diacetate which was used later to generate Al3+, Zn2+, and Ca2+ crosslinked
matrices for controlled drug delivery [8]. Furthermore, in a recent report, chitosan was modified by attaching dithiocarbamate group to access metal-crosslinked drug-loaded
matrices based on complexation with Zn2+, Ca2+, Cu2+ and Mg2