Preparation of 188Re-RC-160 somatostatin analog: a peptide for local/regional radiotherapy

Conditions are described for the preparation of 188Re-RC-160, a radiolabeled synthetic peptide derived from an analogue of somatostatin, using a lyophilized labeling kit containing RC-160 (200 μg) and stannous tartrate to which is added carrier-free 188Re (β, Emax, 2,12 MeV; γ, 155 KeV, 10%, T1/2 = 16.7 h). The 3its have been radiolabeled with > 2960 Mbq (80 mCi) with a high labeling efficiency and no need for subsequent purification. Radiolabeling results in one major peak when analyzed by reverse-phase (RP) HPLC. Presumptive radiolysis was detected at 2.5 h post-labeling; however, a convenient method is described for stabilizing the kits against radiolysis by the post-labeling addition of ascorbic acid.