One pot radiofluorination of a new potential PSMA ligand [AI~(18)F]NOTA-DUPA-Pep

摘要

Up to now, many radioiabeled ligands targeting prostate-specific membrane antigen (PSMA) have been synthesized. To carry out radiofluorinations, there have been several approaches mainly involving two steps of radiosynthesis. However, in case of labelings with high activities, one radiosynthetic step ('one pot synthesis') is highly desirable. As an alternative, radiofluorinations of peptides coupled to the NOTA complex via AI~(18)F appear to be very promising, both in terms of feasible labelling procedure and stability in vivo. Therefore, in the present study, we synthesized a new PSMA-ligand, that is, NOTA-DUPA-Pep, labeled with AI~(18)F and examined the reaction kinetics in dependence on temperature, time, concentration of precursor, and AICI3 solution. Highest radiochemical yields of 83 +- 1.1% were obtained at 105degC after 15min of reaction time. At the end of synthesis, [Al~(18)F]NOTA-DUPA-Pep was prepared with a radiochemical purity of >98% with an overall yield of 79 +-0.7% (n = 3) (decay uncorrected) within 55 min.