%0 Journal Article
%A Blei, Magdalena K
%A Waurick, Lukas
%A Reissig, Falco
%A Kopka, Klaus
%A Stumpf, Thorsten
%A Drobot, Björn
%A Kretzschmar, Jerome
%A Mamat, Constantin
%T Equilibrium Thermodynamics of Macropa Complexes with Selected Metal Isotopes of Radiopharmaceutical Interest.
%J Inorganic chemistry
%V 62
%N 50
%@ 0020-1669
%C Washington, DC
%I American Chemical Society
%M DKFZ-2023-01876
%P 20699-20709
%D 2023
%Z 2023 Dec 18;62(50):20699-20709
%X To pursue the design of in vivo stable chelating systems for radiometals, a concise and straightforward method toolbox was developed combining NMR, isothermal titration calorimetry (ITC), and europium time-resolved laser-induced fluorescence spectroscopy (Eu-TRLFS). For this purpose, the macropa chelator was chosen, and Lu3+, La3+, Pb2+, Ra2+, and Ba2+ were chosen as radiopharmaceutically relevant metal ions. They differ in charge (2+ and 3+) and coordination properties (main group vs lanthanides). 1H NMR was used to determine four pKa values (±0.15; carboxylate functions, 2.40 and 3.13; amino functions, 6.80 and 7.73). Eu-TRLFS was used to validate the exclusive existence of the 1:1 Mn+/ligand complex in the chosen pH range at tracer level concentrations. ITC measurements were accomplished to determine the resulting stability constants of the desired complexes, with log K values ranging from 18.5 for the Pb-mcp complex to 7.3 for the Lu-mcp complex. Density-functional-theory-calculated structures nicely mirror the complexes' order of stabilities by bonding features. Radiolabeling with macropa using ligand concentrations from 10-3 to 10-6 M was accomplished by pointing out the complex formation and stability (212Pb > 133La > 131Ba ≈ 224Ra > 177Lu) by means of normal-phase thin-layer chromatography analyses.
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:37702665
%R 10.1021/acs.inorgchem.3c01983
%U https://inrepo02.dkfz.de/record/282757