Stability and in vivo behavior of Rh[16aneS<inf>4</inf>-diol]<sup>211</sup>At complex: A potential precursor for astatine radiopharmaceuticals


Journal Article

© 2014 Elsevier Inc. Introduction: The heavy halogen 211 At is of great interest for targeted radiotherapy because it decays by the emission of short-range, high-energy α-particles. However, many astatine compounds that have been synthesized are unstable in vivo, providing motivation for seeking other 211 At labeling strategies. One relatively unexplored approach is to utilize prosthetic groups based on astatinated rhodium (III) complex stabilized with a tetrathioether macrocyclic ligand - Rh[16aneS4-diol]211 At. The purpose of the current study was to evaluate the in vitro and in vivo stability of this complex in comparison to its iodine analog - Rh[16aneS4-diol]131 I. Methods: Rh[16aneS4-diol]211 At and Rh[16aneS4-diol]131 I complexes were synthesized and purified by HPLC. The stability of both complexes was evaluated in vitro by incubation in phosphate-buffered saline (PBS) and human serum at different temperatures. The in vivo behavior of the two radiohalogenated complexes was assessed by a paired-label biodistribution study in normal Balb/c mice. Results: Both complexes were synthesized in high yield and purity. Almost no degradation was observed for Rh[16aneS4-diol]131 I in PBS over a 72h incubation. The astatinated analog exhibited good stability in PBS over 14h. A slow decline in the percentage of intact complex was observed for both tracers in human serum. In the biodistribution study, retention of 211 At in most tissues was higher than that of 131 I at all time points, especially in spleen and lungs. Renal clearance of Rh[16aneS4-diol]211 At and Rh[16aneS4-diol]131 I predominated, with 84.1±2.3% and 94.6±0.9% of injected dose excreted via the urine at 4h. Conclusions: The Rh[16aneS4-diol]211 At complex might be useful for constructing prosthetic groups for the astatination of biomolecules and further studies are planned to evaluate this possibility.

Full Text

Duke Authors

Cited Authors

  • Pruszyński, M; Łyczko, M; Bilewicz, A; Zalutsky, MR

Published Date

  • January 1, 2015

Published In

Volume / Issue

  • 42 / 5

Start / End Page

  • 439 - 445

Electronic International Standard Serial Number (EISSN)

  • 1872-9614

International Standard Serial Number (ISSN)

  • 0969-8051

Digital Object Identifier (DOI)

  • 10.1016/j.nucmedbio.2014.12.011

Citation Source

  • Scopus