Affordable Access

Access to the full text

Bone-seeking TRAP conjugates: surprising observations and their implications on the development of gallium-68-labeled bisphosphonates

Authors
  • Notni, Johannes1
  • Plutnar, Jan2
  • Wester, Hans-Jürgen1
  • 1 Technische Universität München, Pharmaceutical Radiochemistry, Walther-Meissner-Str. 3, Garching, 85748, Germany , Garching (Germany)
  • 2 Charles University in Prague, Department of Inorganic Chemistry, Faculty of Science, Hlavova 2030, Prague, Czech Republic, 2 12843 , Prague
Type
Published Article
Journal
EJNMMI Research
Publisher
Springer (Biomed Central Ltd.)
Publication Date
Mar 30, 2012
Volume
2
Issue
1
Identifiers
DOI: 10.1186/2191-219X-2-13
Source
Springer Nature
Keywords
License
Green

Abstract

BackgroundBisphosphonates possess strong affinity to bone. 99mTc bisphosphonate complexes are widely used for bone scintigraphy. For positron emission tomography (PET) bone imaging, Ga-68-based PET tracers based on bisphosphonates are highly desirable.FindingsTwo trimeric bisphosphonate conjugates of the triazacyclononane-phosphinate (TRAP) chelator were synthesized, labeled with Ga-68, and used for microPET imaging of bone in male Lewis rats. Both Ga-68 tracers show bone uptake and, thus, are suitable for PET bone imaging. Surprisingly, Ga-71 nuclear magnetic resonance data prove that Ga(III) is not located in the chelating cavity of TRAP and must therefore be bound by the conjugated bisphosphonate units.ConclusionThe intrinsic Ga-68 chelating properties of TRAP are not needed for Ga-68 PET bone imaging with TRAP-bisphosphonate conjugates. Here, TRAP serves only as a trimeric scaffold. For preparation of Ga-68-based bone seekers for PET, it appears sufficient to equip branched scaffolds with multiple bisphosphonate units, which serve both Ga-68-binding and bone-targeting purposes.

Report this publication

Statistics

Seen <100 times