Sc-HOPO: A Potential Construct for Use in Radioscandium-Based Radiopharmaceuticals

Area of Science:

• Nuclear chemistry
• Radiopharmaceutical science

Background:

• Scandium isotopes (Sc) like 43Sc, 44Sc, and 47Sc are promising for medical imaging and therapy.
• Development of stable chelators is crucial for effective radioscandium applications.

Purpose of the Study:

• To evaluate the octadentate chelator 3,4,3-(LI-1,2-HOPO) (HOPO) for radioscandium complexation.
• To characterize the stability and in vivo behavior of Sc-HOPO complexes.

Main Methods:

• Synthesis and characterization of the 1:1 Sc-HOPO complex.
• Assessment of complex stability under chemical and biological conditions.
• In vivo biodistribution and clearance studies in mice using 43Sc and 47Sc.

Main Results:

• HOPO forms a stable 1:1 complex with scandium.
• [47Sc]Sc-HOPO showed high stability over 7 days in vitro.
• [43,47Sc]Sc-HOPO exhibited rapid clearance and no demetalation in mice.

Conclusions:

• HOPO is an effective chelator for radioscandium isotopes.
• The Sc-HOPO complex is a strong candidate for developing novel radiopharmaceuticals for imaging and therapy.