Studies on Dextran Gadolinium Complex Containing Sulfadiazine Groups

Sulfadiazine-containing dextran ligand (SD-Dextran-DTPA) was synthesized by the incorporation of diethylenetriaminepentaacetic acid (DTPA) and sulfadiazine (SD) as a tumor-targeting group into dextran. This ligand was further reacted with gadolinium chloride to produce tumor-targeting macromolecule gadolinium complex (SD-Dextran-DTPA-Gd). Experimental data of H-1-NMR, IR, UV, average particle sizes and zeta potential evidenced the formation of the dextran ligand and gadolinium complex. In vitro properties including the relaxivity, cell uptake assay and magnetic resonance imaging were also evaluated. In the aqueous solutions, the average diameter of the dextran ligand SD-Dextran-DTPA and complex SD-Dextran-DTPA-Gd increased when the concentration of their solutions decreased. Compared with Gd-DTPA, this tumor-targeting dextran gadolinium complex SD-Dextran-DTPA-Gd possessed obviously higher relaxation effectiveness due to a slowly tumbling system and an increase in rotational correlation time. The cell uptake assay indicated that SD-Dextran-DTPA-Gd had a high affinity to the H460, MDA-MB-231 and T40D tumor cells and can be taken up selectively by these tumor cells. Magnetic resonance imaging (MRI) tests showed that SD-Dextran-DTPA-Gd possessed the relaxation effectiveness higher than that of Gd-DTPA and can enhance the contrast of MR images of the tumor cells. Moreover, the T-1 signal intensities of the MDA-MB-231 cell suspensions were obviously higher than those of the H460 and T40D cell suspensions. Therefore SD-Dextran-DTPA-Gd has shown the potential as a tumor-targeting contrast agent in MRI.