3. Results and discussion
3.1. Synthesis and structural analysis of intermediates and
prodrugs
In this study, we used different amino acid as spacers to synthesize
a serial of Mel-OCM-chitosan conjugates and the synthesis
route of Mel-OCM-chitosan are illustrated in Fig. 1. The NH2 of
Mel were first protected with Fmoc-Osu. Then, the COOH was
activated and chemically coupled with the NH2 of different amino
acid linkers by carbodiimide chemistry. In the following step, Fmoc-
Mel and Fmoc-Mel-amino acid were grafted onto the NH2 of
OCM-chitosan under the catalysis of EDC·HCl and NHS. The removal
of the Fmoc moiety was achieved with piperidine treatment.