Methods for 18F-labeling of RGD peptides: comparison of aminooxy [18F]fluorobenzaldehyde condensation with 'click labeling' using 2-[18F]fluoroethylazide, and S-alkylation with [18F]fluoropropanethiol

Amino Acids. 2009 Oct;37(4):717-24. doi: 10.1007/s00726-008-0200-0. Epub 2008 Nov 15.

Abstract

Three strategies for chemoselective labeling of RGD peptides with (18)F have been compared. Aminooxy [(18)F]fluorobenzaldehyde conjugation provided 40 +/- 12% decay-corrected radiochemical yield using a fully automated method. An one-pot protocol for 'click labeling' of the RGD scaffold with 2-[(18)F]fluoroethylazide afforded 47 +/- 8% decay-corrected radiochemical yield. Attempted conjugation with 3-[(18)F]fluoropropanethiol led to extensive decomposition and was therefore found unsuitable for labeling of the RGD peptide investigated. The results suggest that 'click labeling' of RGD peptides provides an attractive alternative to aminooxy aldehyde condensation, however, 2-[(18)F]-fluoroethylazide may be too small to allow separation of large (18)F-labeled RGD peptides from their precursors.

Publication types

  • Comparative Study

MeSH terms

  • Azides / chemistry*
  • Fluorine Radioisotopes / chemistry*
  • Isotope Labeling / methods*
  • Oligopeptides / chemical synthesis
  • Oligopeptides / chemistry*

Substances

  • 2-fluoroethylazide
  • Azides
  • Fluorine Radioisotopes
  • Oligopeptides
  • arginyl-glycyl-aspartic acid