Gadolinium Complex of 1,4,7,10-Tetraazacyclododecane-1,4,7-trisacetic acid (DO3A) Conjugate of [(p-aniline benzothiazole)methyl]pyridine as a Tumor-Targeting MRI Contrast Agent

摘要

The synthesis of a DO3A conjugate of [(p-aniline benzothiazole)methyl]pyridine (L2H3) and its gadolinium complex of the type [Gd(L2)(H2O)] (GdL2) is described. The R1 relaxivity (= 4.50 mM−1sec−1) and kinetic inertness of GdL2 compares well with those of structurally analogous Dotarem® (R1 = 3.70 mM−1sec−1), a typical extracellular (ECF) MRI contrast agent (CA). Yet, by comparison with Dotarem®, GdL2 exhibits noncovalent interactions with human serum albumin (HSA) as evidenced by the ε* titration curve along with in vivo MR signal enhancement in both aorta and heart. Liver-specific nature of GdL2 is also observed as excretion is made through gallbladder. Most notably, GdL2 further demonstrates specificity toward the MDAMB- 231 breast cancer.