Stable Chelation of Zr-89 and Ac-225 with Dual Size-Selective Macrocyclic py 2 -macrodipa for 225 Ac/ 89 Zr Paired Theranostics.

89 Zr and 225 Ac are promising radionuclides for PET imaging and targeted α-therapy, respectively, but require robust and versatile chelation strategies.

Herein, we report stable coordination using the 18-membered macrocyclic dual size-selective chelator py 2 -macrodipa with [ 89 Zr]Zr 4+ and [ 225 Ac]Ac 3+ ions.

The chelator demonstrated efficient radiolabeling with both 89 Zr and 225 Ac, exhibiting 89 Zr labeling efficiency comparable to the state-of-the-art chelator DFO at micromolar concentrations.