Preparation of [In-111]-labeled-DTPA-bombesin conjugates at high specific activity and stability: Evaluation of labeling parameters and potential stabilizers

The aim of the present work was to obtain stabilized high specific activity (HSA) 111In-labeled bombesin conjugates for preclinical evaluations. Parameters influencing the kinetics of labeling were investigated and the effect of stabilizers on HSA radiopeptides stability at room temperature were systematically categorized applying chromatography techniques. A SA of 174 GBq/μmol was achieved with high radiochemical purity, but the labeled compounds exhibited low stability. The addition of stabilizers avoided their radiolysis and significantly increased their stability.

► We aimed to obtain stabilized high specific activity (SA) 111In-labeled bombesin conjugates. ► The effect of stabilizers on high SA radiopeptides stability were investigated. ► A maximum specific activity of 174 GBq/μmol was achieved. ► The studied stabilizers significantly increased the stability of high SA radiopeptides. ► These stabilized bombesin conjugates will be applied in preclinical studies.