Logo image
Isomeric Trimethylene and Ethylene Pendant-armed Cross-bridged Tetraazamacrocycles and in Vitro/in Vivo Comparisions of their Copper(II) Complexes
Journal article   Open access   Peer reviewed

Isomeric Trimethylene and Ethylene Pendant-armed Cross-bridged Tetraazamacrocycles and in Vitro/in Vivo Comparisions of their Copper(II) Complexes

Antoinette Y. Odendaal, Ashley L. Fiamengo, Riccardo Ferdani, Thaddeus J. Wadas, Daniel C. Hill, Yijie Peng, Katie J. Heroux, James A. Golen, Arnold L. Rheingold, Carolyn J. Anderson, …
Inorganic chemistry, Vol.50(7), pp.3078-3086
04/04/2011
DOI: 10.1021/ic200014w
PMCID: PMC3065210
PMID: 21381676
url
https://doi.org/10.1021/ic200014wView
Published (Version of record) Open Access

Abstract

Ethylene cross-bridged tetraamine macrocycles are useful chelators in coordination, catalytic, medicinal, and radiopharmaceutical chemistry. Springborg and co-workers developed trimethylene cross-bridged analogues, although their pendant-armed derivatives received little attention. We report here the synthesis of a bis-carboxymethyl pendant-armed cyclen with a trirnethylene cross-bridge (C3B-DO2A) and its isomeric ethylene-cross-bridged homocyclen ligand (CB-TR2A) as well as their copper(II) complexes. The in vitro and in vivo properties of these complexes are compared with respect to their potential application as Cu-64-radiopharmaceuticals in positron emission tomography (PET imaging). The inertness of Cu-C3B-DO2A to decomplexation is remarkable, exceeding that of Cu-CB-TE2A. Electrochemical reduction of Cu-CB-TR2A is quasi-reversible, whereas that of Cu-C3B-DO2A is irreversible. The reaction conditions for preparing Cu-64-C3B-DO2A (microwaving at high temperature) are relatively harsh compared to Cu-64-CB-TR2A (basic ethanol). The in vivo behavior of the Cu-64 complexes was evaluated in normal rats. Rapid and continual clearance of Cu-64-CB-TR2A through the blood, liver, and kidneys suggests relatively good in vivo stability, albeit inferior to Cu-64-CB-TE2A. Although Cu-64-C3B-DO2A clears continually, the initial uptake is high and only about half is excreted within 22 h, suggesting poor stability and transchelation of Cu to proteins in the blood and/or liver. These data suggest that in vitro inertness of a chelator complex may not always be a good indicator of in vivo stability.
Chemistry Chemistry, Inorganic & Nuclear Physical Sciences Science & Technology

Details

Metrics

Logo image