Fluoride-18 radiolabeling of peptides bearing an aminooxy functional group to a prosthetic ligand via an oxime bond.
We have developed a novel F-18 prosthetic ligand named fluoro-PEG-benzaldehyde (FPBA) 1. [(18)F]-FPBA 1 is formed in situ from its radiolabeled precursor [(18)F]6. Compound 6 is efficiently synthesized in four steps starting from commercially available 6-bromo-3-pyridine carbaldehyde 2. [(18)F]-FPBA was evaluated as a prosthetic ligand to radiolabel three cyclic peptides bearing an aminooxy functional group at the N-terminus position. Acetal [(18)F]6 is purified by either solid-phase extraction (SPE) or reverse-phase HPLC with the overall radiochemical yields (RCY) and radiochemical purity (RCP) in very close agreement. The SPE purification process has the advantage of shorter reaction times (71-87 min for entire reaction sequence), while the use of the reverse-phase HPLC purification process allows the use of up to fifty times less of the expensive synthetic peptides (~ 50 nmol) in the oxime coupling reaction. We have demonstrated an efficient methodology in the production of [(18)F]-FPBA 1 and demonstrated its use as a prosthetic ligand for the labeling of peptides possessing an aminooxy functional group.
Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
Patrick
P
Carberry
Alan P
AP
Carpenter
Hank F
HF
Kung
D000588:Amines / Q000737:chemistry*; D001547:Benzaldehydes / Q000138:chemical synthesis / Q000737:chemistry*; D005462:Fluorine Radioisotopes / Q000737:chemistry*; D008024:Ligands; D015394:Molecular Structure; D010091:Oximes / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*
D000588:Amines; D001547:Benzaldehydes; D005462:Fluorine Radioisotopes; D008024:Ligands; D010091:Oximes; D010455:Peptides