The EDTA complexes of astatine

Milesz, S.; Jovchev, M.; Schumann, D.; Khalkin, V.A.; Milanov, M.

doi:10.1007/bf02164864

Cited by 11 publications

(8 citation statements)

References 5 publications

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“…1). We observed a dose value m^5.5 • 10"'^ cm^Vs"' at pH~10 in our experiments with EDTA [12]. In principle, one can assume that this effect is related to the destruction of the complex by reduction of At(0)"^ in weak alkaline solutions.…”

Section: Resultssupporting

confidence: 50%

“…Using the method of electrophoresis in free electrolyte solutions [10,11], we proved in our previous work that astatine forms complexes with EDTA [12], To obtain additional Information on this class of At(6)'^ Compounds, we carried out experiments with another complexone -nitrilotriacetic acid (NTA). Here we also used the electromigration technique which is very convenient to study the behaviour of carrier-free radionuclides.…”

Section: Introductionmentioning

confidence: 99%

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Nitrilotriacetate Complex of Univalent Astatine

Schumann¹,

Milesz²,

Jovchev³

et al. 1992

Radiochimica Acta

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Formation of the complex of the Univalent astatine cation with nitrilotriacetic acid (AtL)^^ and its stability constant (lgA^i = 8.97(4). 25 C, fi = 0.1) have been found experimentally for the first time. The complex is stable in Perchlorate solutions in presence of 5 • 10"' mol • 1"' of the oxidizer Na2S208 in the interval 4 < pH <8.5. The complex is supposed to be destroyed in weak alkaline solutions by reduction of astatine to astatide. The deprotonation constant of hypoastatic acid pA^dp = 5.23(9) was found to be lower than determined previously.The investigation was carried out by the method of ion electrophoresis in free electrolyte solutions.

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Section: Resultssupporting

confidence: 50%

Section: Introductionmentioning

confidence: 99%

Nitrilotriacetate Complex of Univalent Astatine

Schumann¹,

Milesz²,

Jovchev³

et al. 1992

Radiochimica Acta

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“…Several papers have shown the formation of complexes between AtO + and simple organic and inorganic ligands. , Some structural parameters were recently determined by (quasi) relativistic quantum calculations for the complexes AtOX and AtOX 2 – , with X = Cl, SCN, and Br . It has been shown by electromigration in noncomplexing medium (H/NaClO 4 ) that AtO + reacts with water above pH 1. ,− The mobility of the species decreases when the pH increases until it equals 0 above pH 6. Milanov and co-workers proposed the formation of a neutral hydrolyzed species AtO(OH) with an apparent hydrolysis constant of 10 –1.5 M –1 (at ionic strength μ = 0.4 M) and 10 –4.1 M –1 (at μ = 0.25 M). , A constant of 10 –5.23 M –1 (μ = 0.1 M) was also proposed by Schumann et al for the pH range of 1–10 using migration data in the presence of nitrilotriacetic acid and nitroacetate .…”

Section: Introductionmentioning

confidence: 99%

Investigation of Astatine(III) Hydrolyzed Species: Experiments and Relativistic Calculations

et al. 2013

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This work aims to resolve some controversies about astatine(III) hydroxide species present in oxidant aqueous solution. AtO(+) is the dominant species existing under oxidizing and acidic pH conditions. This is consistent with high-performance ion-exchange chromatography data showing the existence of one species holding one positive charge. A change in speciation occurs as the pH changes from 1 to 4, while remaining under oxidizing conditions. Dynamic experiments with ion-exchange resins evidence the existence of a neutral species witnessed by its elution in the void volume. Batch-experiments using a competition method show the exchange of one proton indicating the formation of the AtO(OH) species. The hydrolysis thermodynamic constant, extrapolated to zero ionic strength, was determined to be 10(-1.9). This value is supported by two-component relativistic quantum calculations and therefore allows disclosing unambiguously the structure of the formed species.

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“…Labeling strategies that attempt to exploit the metallic character of the astatine atom through the formation of complexes of 211 At with chelating agents such as diethylenetriamine pentaacetic acid (DTPA) [60] and calix[4]arenes [61] have been reported. Likewise, labeling of antibodies via DTPA complexation also has been described [62-64].…”

Section: Astatine-211mentioning

confidence: 99%

Astatine Radiopharmaceuticals: Prospects and Problems

Vaidyanathan¹,

Zalutsky²

2008

CRP

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For the treatment of minimum residual diseases such micrometastases and residual tumor margins that remain after debulking of the primary tumor, targeted radiotherapy using radiopharmaceuticals tagged with α-particle-emitting radionuclides is very attractive. In addition to the their short range in tissue, which helps minimize harmful effects on adjacent normal tissues, α-particles, being high LET radiation, have several radiobiological advantages. The heavy halogen, astatine-211 is one of the prominent α-particle-emitting radionuclides in practice. Being a halogen, it can often be incorporated into biomolecules of interest by adapting radioiodination chemistry. A wide spectrum of compounds from the simple [ 211 At]astatide ion to small organic molecules, peptides, and large proteins labeled with 211 At have been investigated with at least two reaching the stage of clinical evaluation. The chemistry, cytotoxic advantages, biodistribution studies, and microdosimetry/ pharmacokinetic modeling of some of these agents will be reviewed. In addition, potential problems such as the harmful effect of radiolysis on the synthesis, lack of sufficient in vivo stability of astatinated compounds, and possible adverse effects when they are systemically administered will be discussed.

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The EDTA complexes of astatine

Cited by 11 publications

References 5 publications

Nitrilotriacetate Complex of Univalent Astatine

Nitrilotriacetate Complex of Univalent Astatine

Investigation of Astatine(III) Hydrolyzed Species: Experiments and Relativistic Calculations

Astatine Radiopharmaceuticals: Prospects and Problems

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