Labeling bombesin-like peptide with 99mTc via hydrazinonicotinamide: description of optimized radiolabeling conditions

• Published in: Journal of radioanalytical and nuclear chemistry Vol. 284; no. 3; pp. 539 - 545
• Main Authors: Yurt Lambrecht, F., Durkan, K., Bayrak, E.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.06.2010
• Subjects: Chemistry; Chemistry and Materials Science; Conjugates; Diagnostic Radiology; Hadrons; Heavy Ions; Inorganic Chemistry; Nuclear Chemistry; Nuclear Physics; Physical Chemistry; Co-ligand; Litorin; HYNIC-BNN-like peptide; Gastrin-releasing peptide; Tc
• ISSN: 0236-5731; 1588-2780
• DOI: 10.1007/s10967-010-0530-8

Bombesin (BNN)-like peptides have very high binding affinity for the gastrin-releasing peptide (GRP) receptor. The goal of the current study was to optimize the labeling conditions of a new 99m Tc-radiolabeled BNN-like peptide based on the bifunctional chelating ligand HYNIC using different co-ligands (EDDA and tricine). The radiolabeling conditions (pH, amount of co-ligand, amount of stannous chloride, temperature and reaction time) for newly-formed 99m Tc-tricine-HYNIC-Q-Litorin and 99m Tc-EDDA-HYNIC-Q-Litorin were optimized and evaluated by RHPLC and RTLC. Radiochemical yields for 99m Tc-tricine-HYNIC-Q-Litorin and 99m Tc-EDDA-HYNIC-Q-Litorin were 98.0 ± 1.7 and 97.5 ± 2.5%, respectively. When EDDA was used as co-ligand, the labeling of 99m Tc-EDDA-HYNIC-Q-Litorin was optimal in the following reaction mixture: HYNIC-peptide: EDDA: 10 μg/5 mg, pH 3, SnCl 2 concentration: 12 μg/0.1 mL, reaction temperature: 100 °C, reaction time: 15 min. Besides, the optimum conditions were HYNIC-peptide:tricine: 10 μg/50 mg, pH 5, SnCl 2 concentration: 12 μg/0.1 mL, reaction temperature: 100 °C, reaction time: 15 min for preparing 99m Tc-tricine-HYNIC-Q-Litorin. The manufactured 99m Tc-HYNIC-Q-Litorin conjugates may offer new possibilities for imaging cancer cells expressing bombesin receptors.