Getting a lead on Pb²⁺-amide chelators for ^203/212Pb radiopharmaceuticals

Abstract

Amide-based chelators DTPAm, EGTAm and ampam were synthesized to investigate which chelator most ideally coordinates [nat/203Pb]Pb2+ ions for potential radiopharmaceutical applications. 1H NMR spectroscopy was used to study each metal-ligand...

H2ampa─Versatile Chelator for [203Pb]Pb2+, [213Bi]Bi3+, and [225Ac]Ac3+

“…Furthermore, H e and H l shift to overlap with the methylene groups between the ether groups. This same acetamide shift was observed for [Pb­(ampam)] 2+ , which showed a similar 1 H NMR spectrum signal pattern and a 10-coordinate complex with a C 2 axis of symmetry in its crystal structure …”

Medicinal inorganic chemistry – challenges, opportunities and guidelines to develop the next generation of radioactive, photoactivated and active site inhibiting metal-based medicines

“…Specifically, lead-212 ( 212 Pb, t 1/2 = 10.6 h, b À = 100%, E max = 0.57 MeV) and lead-203 ( 203 Pb, t 1/2 = 51.9 h, g = 81%, E g = 279 keV, SPECT) represent a matched theranostic radioisotope pair for application in targeted radionuclide therapy and single-photon emission computed tomography (SPECT), respectively. 12 Originally, the DOTA ligand was used for radiolabeling with 212 Pb resulting in kinetically stable Pb-DOTA complexes. However, the release of Pb in vivo in the acidic tumor environment was observed and as the consequence a more efficient and stable chelate, 1,4,7,10-tetra-(2-carbamoyl-methyl)-cyclododecane (TCMC) has been introduced for Pb labeling, and more recently, a bicyclic cryptand-like system, Pb-CRYPT (Fig.…”

Highlight selection of radiochemistry and radiopharmacy developments by editorial board

“…In 2017, an expanded 18-membered macrocyclic MACROPA has been proved as an effective chelating agent for large ion 225 Ac with excellent stability (Thiele et al 2017), but its poor affinity and stability in binding smaller ions may hinder its use in TAT (Hu et al 2021). On the other hand, acyclic chelators based on a pyridinecarboxylate scaffold has shown its utility with an array of metals with medical applications, such as H4octapa (Jaraquemada-Peláez et al 2017;Platas-Iglesias et al 2004) and its amido-derivative of hybrid EGTA ligand, ampam (Ingham et al 2021).…”