Formation kinetics of an aluminium(III)–ethylenedinitrilotetraacetate–fluoride mixed ligand complex ‡

Nemes, Judit; Tóth, I.; Zékány, László

doi:10.1039/a802603c

Cited by 11 publications

(11 citation statements)

References 31 publications

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“…Based on the reported first- and second-order rate constants by Farkas et al, 87 half-lives ( t 1/2 ) of base hydrolysis can be calculated as 71.8 and 21.8 h in 0.1 and 1.0 M sodium hydroxide, respectively. The formation kinetics of the Al-(EDTA)F 2− ternary complex were studied by Nemes et al 96 using potentiometric and 19 F NMR methods. Various simultaneous reactions between Al(EDTA) − , Al(EDTA)-(OH) 2− and F − and HF were proposed.…”

Section: ■ Aluminum Coordination Chemistrymentioning

confidence: 99%

“…Two second-order rate constants, 20.7 ± 0.3 M −1 s −1 and 471 ± 93 M −1 s −1 for the reaction of F − and HF, respectively, with Al(EDTA) − were reported. 96 Due to the kinetic inertia of Al(NOTA), there was no reaction observed between the chelate and the fluoride, however, the formation of Al(NOTA)F − was complete in 15 min by heating Al 3+ , NOTA, F − in 1:1 ethanol:water mixture at 100 °C (as given above). It appears that kinetics of formation of Al(NOTA)F − ternary complex is fairly complicated in the Al 3+ -NOTA-F − -H + four-compartment system and requires more work to understand the chemistry.…”

Section: ■ Aluminum Coordination Chemistrymentioning

confidence: 99%

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¹⁸F-AlF Labeled Peptide and Protein Conjugates as Positron Emission Tomography Imaging Pharmaceuticals

Kumar

Ghosh

2018

Bioconjugate Chem.

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The clinical applications of positron emission tomography (PET) imaging pharmaceuticals have increased tremendously over the past several years since the approval of fluorine-fluorodeoxyglucose (F-FDG) by the Food and Drug Administration (FDA). Numerous F-labeled target-specific potential imaging pharmaceuticals, based on small and large molecules, have been evaluated in preclinical and clinical settings.F-labeling of organic moieties involves the introduction of the radioisotope by C-F bond formation via a nucleophilic or an electrophilic substitution reaction. However, biomolecules, such as peptides, proteins, and oligonucleotides, cannot be radiolabeled via a C-F bond formation as these reactions involve harsh conditions, including organic solvents, high temperature, and nonphysiological conditions. Several approaches, including F-labeled prosthetic groups, silicon, boron, and aluminum fluoride acceptor chemistry, and click chemistry have been developed, in the past, forF labeling of biomolecules. Linear and macrocyclic polyaminocarboxylates and their analogs and derivatives form thermodynamically stable and kinetically inert aluminum chelates. Hence, macrocyclic polyaminocarboxylates have been used for conjugation with biomolecules, such as folate, peptides, affibodies, and protein fragments, followed by F-AlF chelation, and evaluation of their targeting abilities in preclinical and clinical environments. The goal of this report is to provide an overview of theF radiochemistry and F-labeling methodologies for small molecules and target-specific biomolecules, a comprehensive review of coordination chemistry of Al, F-AlF labeling of peptide and protein conjugates, and evaluation ofF-labeled biomolecule conjugates as potential imaging pharmaceuticals.

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Section: ■ Aluminum Coordination Chemistrymentioning

confidence: 99%

Section: ■ Aluminum Coordination Chemistrymentioning

confidence: 99%

¹⁸F-AlF Labeled Peptide and Protein Conjugates as Positron Emission Tomography Imaging Pharmaceuticals

Kumar

Ghosh

2018

Bioconjugate Chem.

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“…It should be noted, that the behavior of [Al(EDTA)F] 2could easily be followed by fluoride selective electrode. [20] Fig . 8 shows the dependence of 19 F-NMR spectra in samples with equimolar Al(III), NOTA and fluoride on heating time, recorded 24 h afterwards.…”

Section: Kinetic Studymentioning

confidence: 99%

Equilibrium and dissociation kinetics of the [Al(NOTA)] complex (NOTA = 1,4,7-triazacyclononane-1,4,7-triacetate)

Farkas

Fodor

Kálmán

et al. 2015

Reac Kinet Mech Cat

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A detailed investigation of the equilibria and dissociation kinetics for the [Al(NOTA)] complex has been carried out. This complex and its derivatives are known as very good carriers for 18 F-isotope in positron emission tomography. The thermodynamic stability of [Al(NOTA)] has been studied by ''out of cell'' pH-potentiometric technique since the formation rate of the complex is very low in acidic medium. 1 H-and 27 Al-NMR spectra have been recorded to check the time course of equilibration and to validate the equilibrium model consisting of [Al(NOTA)] with lgK = 17.9(1) and [Al(HNOTA)] ? with lgK H = 1.9(3). A metastable mixed hydroxido complex [Al(NOTA)(OH)]with lgK Al(NOTA) OH = -12.2(1) was detected in alkaline solution by direct pH-potentiometry, which transforms slowly to [Al(OH) 4 ] -. The decomplexation reactions of [Al(NOTA)] have been investigated in both acidic and basic conditions. The rate of dissociation is extremely low in acidic medium, while in alkaline solution, it can be characterized by the rate law k obs = k 0 ? k 1 [OH -], where k 0 = (2.0 ± 0.1) 9 10 -6 s -1 and k 1 = (6.8 ± 0.5) 9 10 -6 M -1 s -1 . The formation of the ternary [Al(NOTA)(F)]complex via direct reaction of [Al(NOTA)] and Fcannot be detected by either fluoride selective electrode or by 19 F-NMR spectroscopy. However, by applying solvent mixture (1:1 ethanol:water) Electronic supplementary material The online version of this article (and heating, the ternary [Al(NOTA)(F)]complex was found to form quantitatively within 15 minutes.

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“…If the pH is too basic, metal tends to bond with a hydroxyl anion instead of fluoride and precipitates [43]. If the pH is too acidic, the favored fluorinated species would be hydrogen fluoride (HF) [52]. Therefore, a pH close to 4 would favor the formation of aluminum monofluoride while also being adapted to the complexation of this salt with a polyaminocarboxylate chelating agent [53].…”

Section: Introductionmentioning

confidence: 99%

A Comprehensive Review of Non-Covalent Radiofluorination Approaches Using Aluminum [18F]fluoride: Will [18F]AlF Replace 68Ga for Metal Chelate Labeling?

et al. 2019

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Due to its ideal physical properties, fluorine-18 turns out to be a key radionuclide for positron emission tomography (PET) imaging, for both preclinical and clinical applications. However, usual biomolecules radiofluorination procedures require the formation of covalent bonds with fluorinated prosthetic groups. This drawback makes radiofluorination impractical for routine radiolabeling, gallium-68 appearing to be much more convenient for the labeling of chelator-bearing PET probes. In response to this limitation, a recent expansion of the 18F chemical toolbox gave aluminum [18F]fluoride chemistry a real prominence since the late 2000s. This approach is based on the formation of an [18F][AlF]2+ cation, complexed with a 9-membered cyclic chelator such as NOTA, NODA or their analogs. Allowing a one-step radiofluorination in an aqueous medium, this technique combines fluorine-18 and non-covalent radiolabeling with the advantage of being very easy to implement. Since its first reports, [18F]AlF radiolabeling approach has been applied to a wide variety of potential PET imaging vectors, whether of peptidic, proteic, or small molecule structure. Most of these [18F]AlF-labeled tracers showed promising preclinical results and have reached the clinical evaluation stage for some of them. The aim of this report is to provide a comprehensive overview of [18F]AlF labeling applications through a description of the various [18F]AlF-labeled conjugates, from their radiosynthesis to their evaluation as PET imaging agents.

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Formation kinetics of an aluminium(III)–ethylenedinitrilotetraacetate–fluoride mixed ligand complex ‡

Cited by 11 publications

References 31 publications

¹⁸F-AlF Labeled Peptide and Protein Conjugates as Positron Emission Tomography Imaging Pharmaceuticals

¹⁸F-AlF Labeled Peptide and Protein Conjugates as Positron Emission Tomography Imaging Pharmaceuticals

Equilibrium and dissociation kinetics of the [Al(NOTA)] complex (NOTA = 1,4,7-triazacyclononane-1,4,7-triacetate)

A Comprehensive Review of Non-Covalent Radiofluorination Approaches Using Aluminum [18F]fluoride: Will [18F]AlF Replace 68Ga for Metal Chelate Labeling?

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Formation kinetics of an aluminium(III)–ethylenedinitrilotetraacetate–fluoride mixed ligand complex ‡

Cited by 11 publications

References 31 publications

18F-AlF Labeled Peptide and Protein Conjugates as Positron Emission Tomography Imaging Pharmaceuticals

18F-AlF Labeled Peptide and Protein Conjugates as Positron Emission Tomography Imaging Pharmaceuticals

Equilibrium and dissociation kinetics of the [Al(NOTA)] complex (NOTA = 1,4,7-triazacyclononane-1,4,7-triacetate)

A Comprehensive Review of Non-Covalent Radiofluorination Approaches Using Aluminum [18F]fluoride: Will [18F]AlF Replace 68Ga for Metal Chelate Labeling?

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¹⁸F-AlF Labeled Peptide and Protein Conjugates as Positron Emission Tomography Imaging Pharmaceuticals

¹⁸F-AlF Labeled Peptide and Protein Conjugates as Positron Emission Tomography Imaging Pharmaceuticals