Direct radiolabeling of the somatostatin analogs RC-160 and octreotide with (sup 99m)Tc and (sup 188)Re: Initial results with stannous reductions

摘要

Reductive insertion of (sup 99m)Tc and rhenium between cysteine residues of cyclic peptides is a possible technique for the direct labeling of somatostatin analogues. Such a labeling technique could also be applicable to labeling with (sup 188)Re and consequently is of general interest in regard to cyclic peptides and specific interest in regard to potential clinical applications of somatostatin analogues. In this study, the somatostatin analogues octreotide and RC-160 were evaluated after direct labeling with (sup 99m)Tc and (sup 188)Re. The peptide analogues were prepared as cold kits, and labeled on demand as needed. Both peptides were found to be easily and reproducibly radiolabeled with both radionuclides with labeling efficiencies greater than 95% as determined by TLC.