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Am J Nucl Med Mol Imaging 2013;3(1):44-56

Original Article
One-step and one-pot-two-step radiosynthesis of
cyclo-RGD-18F-aryltrifluoroborate conjugates for
functional imaging

Ying Li, Jinxia Guo, Shiqing Tang, Lixin Lang, Xiaoyuan Chen, David M Perrin

Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, B.C., V6T-1Z1, Canada; Laboratory of Molecular
Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of
Health (NIH), 31 Center Drive, Suite 1C14, Bethesda, MD 20892-2281, USA

Received August 23, 2012; Accepted September 22, 2012; Epub January 5, 2013; Published January 15, 2013

Abstract: Arylboronates capture aqueous 18F-fluoride in one step to afford a highly polar 18F-labeled aryltrifluoroborateanion
(18F-ArBF3-) that clears rapidly in vivo. To date however, there is little data to show that a ligand labeled with a prosthetic 18F-ArBF3-
will provide functional images. RGD, a high-affinity ligand for integrins that are present on the cell surface of numerous tumors, has
been labeled in many formats with many different radionuclides, and as such represents a well-established ligand that can be used
to evaluate new labeling methods. Herein we have labeled RGD with a prosthetic 18F-ArBF3- via two approaches for the first time: 1)
a RGD-boronate bioconjugate is directly labeled in one step and 2) an alkyne-modified arylborimidine is first converted to the
corresponding 18F-ArBF3- which is then conjugated to an RGD-azide via Cu+-mediated [2+3] dipolar cycloaddition in one pot over
two steps. RGD-18F-ArBF3- bionconjugates were produced in reasonable radiochemical yields using low amounts of 18F-fluoride
anion (10-50 mCi). Despite relatively low specific activities, good tumor images are revealed in each case. (ajnmmi1208007).

Keywords: One-step 18F-labeling, click labeling, RGD, PET imaging

Address all correspondence to:
Dr. David M Perrin
Chemistry Department
UBC, 2036 Main Mall
Vancouver, B.C., V6T-1Z1, Canada.
Phone: 604 822 0567
E-mail: dperrin@chem.ubc.ca