4. Conclusions
A serial of Mel-OCM-chitosan conjugates with different amino
acid spacers were synthesized and structures characterized by
FT-IR, 1H NMR. These Mel-OCM-chitosan conjugates showed satisfactory
water solubility comparing with free melphalan. In vitro
study showed that the conjugates are stable in plasma but rapidly
degraded in enzyme solution. The selection of amino acid spacers
had important influence on the solubility, drug content, and
drug release behavior of polymeric prodrugs. The conjugates with
Gly spacer was considered to be the best compound, as it had
good water solubility and the highest antitumor activity compared
with other conjugates. These results demonstrated that the polymeric
prodrugs designed in this paper can solve many problems
of melphalan and have the potential to be used as new polymeric
prodrugs.