Preparation and Antileukemic Activity of the Conjugate of Doxorubicin with Chitosan AX₂

ABSTRACT

Condensation of the antitumor antibiotic doxorubicin with oxidized chitosan in the presence of sodium borohydride provided a new conjugated antibiotic AC₂.A ring involving a N-atom from the 3¹-amino group of the doxorubicin—sugar moiety and the residue of the oxidized glucosamine ring of chitosan was formed during reductive alkilation. The resulting conjugate was studied spectroscopicaly. The resultant compound was characterized by IR- and UV-Vis spectra which support the conjugate structure. The quantity of the bound antibiotic was evaluated using the spectra of doxorubicin-chitosan conjugate in 20% acetic acid. The bound doxorubicin was evaluated as 397.1 residues or 24.6%. The antibacterial activity of the conjugate was studied against Bacillus subtilis ATCC6633. Compared to unmodified doxorubicin the activity of the conjugate was 88.1%. The antileukemic activity of the conjugate AC₂ of doxorubicin were studied against ascitic form of lymphocytic leukemia P388. A strong antileukemic activity of the conjugate AC₂ was found and the criterion “increase of life span” (T/C) reached 412.8% in comparition with 167.6% at doxorubicin (at dose 0.25 mg/kg).