Radiolabelling of DOTA-TATE with ~177Lu. Preliminary Studies with a View to Somatostatin Receptor Radionuclide Therapy

摘要

This study describes the radiolabelling method of DOTA-TATE with ~177Lu as well as the in vitro experiments for quantification of the biological properties. The radiolabelling was performed taking into account the usual biological and radioactively therapeutic doses. Radiochemical purities higher than 95% were obtained for the following parameters: ~177Lu to DOTA-TATE molar ratio: 3.8; pH: 4.5 in acetate buffer; incubation time: 30min; temperature: 80°C; HABA (3hydroxi-4aminobenzoic acid) as stabilizer. The competition binding assay of natLu-DOTA-TATE/~125I-Tyr3-Octreotide and the saturation binding assay of ~177Lu-DOTA-TATE using rat brain cortex membrane as somatostatin receptor model were done. The obtained results, analyzed using Prism 2 software, allow determination of IC_(50) (4.74 nM) and K_d (142.8 pM). These pharmacological parameters values illustrate the excellent capacity of ~177Lu-DOTA-TATE to bind to somatostatin receptors as well as the formed bounds stability.