The efficiency of 18F labelling of a prostate specific membrane antigen ligand via strain-promoted azide-alkyne reaction: reaction speed versus hydrophilicity

Here we report the F-18 labeling of a prostate specific membrane antigen (PSMA) ligand via a strain promoted oxa-dibenzocyclooctyne (ODIBO)- or bicyclo[6.1.0]nonyne (BCN)-azide reaction. Although ODIBO reacts with azide 20 fold faster than BCN, in vivo PET imaging suggests that F-18-BCN-azide-PSMA demonstrated much higher tumor uptake and a much higher tumor to background contrast.