Manganese Complex of Ethylene­diamine­tetraacetic Acid (EDTA)–Benzothiazole Aniline (BTA) Conjugate as a Potential Liver-Targeting MRI Contrast Agent

A novel manganese­(II) complex based
on an ethylene­diamine­tetraacetic
acid (EDTA) coordination cage bearing a benzothiazole aniline (BTA)
moiety (Mn-EDTA-BTA) was designed and synthesized for use as a liver-specific
MRI contrast agent with high chelation stability. In addition to forming
a hydrophilic, stable complex with Mn2+, this new Mn chelate
was rapidly taken up by liver hepatocytes and excreted by the kidneys
and biliary system. The kinetic inertness and R1 relaxivity of the complex were much higher than those of
mangafodipir trisodium (MnDPDP), a clinically approved liver-specific
MRI contrast agent. The diagnostic utility of this new Mn complex
in MRI was demonstrated by high-sensitivity tumor detection in an
animal model of liver cancer.