Radiosynthesis and Preliminary Evaluation of ~131I-DOTA-TATE as a Potential Tracer for Somatostatin Receptors Visualization

摘要

The purposes of this work were to study, select and optimize the radiosynthesis parameters of ~131I-DOTA-TATE and to determine its specific biological properties.The electrophilic radioiodination of DOTA-TATE, using chloramines-T (Cl-T), leads to good radiochemical purities (RCP>95.2%). The optimal reaction parameters are: DOTA-TATE to ~131I molar ratio: 1.7; DOTA-TATE to Cl-T molar ratio: 0.09; pH 7.4, buffer: 0.01M PBS; stabilizer: HABA. The ~131I-DOTA-TATE was stable up to 7 days, at 4-8 °C.The competition binding assay and the saturation binding assay of ~131I-DOTA-TATE were performed using rat brain cortex membrane as biological somatostatin receptor model. The pharmacological parameters values, IC_(50) = 1.28 nM and K_d = 157.6 pM, recommend this radiopeptide as potential agent for somatostatin receptors visualization.