Stabilities of the Fe(III), Ga(III) and In(III) chelates of N,N′,N″-triazacyclononanetriacetic acid

Characterisation of 67Ga3+ complexes of triaza macrocyclic ligands: biodistribution and clearance studies

“…We found no evidence of bone marrow accumulation, which is observed when the gallium(III)-transferrin complex is formed (25). The thermodynamic stability constant of Ga(NOTA) has been reported elsewhere (log K st ϭ 30.98 [6]) and is considerably higher than that determined for the complex of Ga 3ϩ with transferrin (log K st ϭ 20.3 [13]), which is the main competitor for Ga 3ϩ in serum (13,24,25). The thermodynamic stability constant for Ga(NOTP) 3Ϫ has not been determined, but our solution studies by 71 Ga NMR spectroscopy demonstrate that this complex remains intact in aqueous solution, in the pH range of 2-11 (M.I.M.…”

“…The resonance shifts were measured relative to tetrametylsilane (TMS) and the [Ga(H 2 O) 6 ] 3ϩ species present in 0.1 M Ga(NO 3 ) 3 in D 2 O, respectively. Assignments of the proton NMR spectra were based on literature data on similar systems and the results of two-dimensional homonuclear correlation spectra (COSY) (2).…”

Analytical characterization of NOTA-modified somatropins

“…Ga(III), while possessing a functional group which can be used for protein attachment. p-SCN-Bn-NOTA is a well-established hexadentate BFCA, forming an exceedingly stable complex with Ga(III) (log K = 30.98) [48]. The isothiocyanate function (R-NCS) allows formation of stable thiourea bonds at alkaline pH with free amines (Fig.…”

Development of 68Ga-labeled multivalent nitroimidazole derivatives for hypoxia imaging

“…For preparing 68 Ga-labeled radiopharmaceuticals, 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA, 1, Figure 5) is one of the most commonly used bifunctional chelating agents due to its commercial availability and its formation an extremely stable six-coordinate Ga complex with high thermodynamic stability [43]. The bifunctional chelating agents like 1,4,4,) [44] and 1,4,7,4,7, [45] , and thus, various peptides conjugated with NOTA derivatives have been developed.…”