Synthesis, characterization, and in vitro and in vivo (68)Ga radiolabeling of thiosemicarbazone Schiff base derived from dialdehyde dextran as a promising blood pool imaging agent

Abstract

To be used as a carrier of (68)Ga radioisotope for possible blood pool imaging studies, dialdehyde dextran thiosemicarbazone (DADTSC) Schiff base polymer with different thiosemicarbazone contents (TSCC)=0.93, 2.43, and 3.4mmol/g were synthesized and characterized by FT-IR, GPC, and CHNS. Although they were successfully radiolabeled at room temperature, stable radio-complexes were prepared at 60 degrees C. Effect of thiosemicarbazone content on the dissolution rate, cytotoxicity, coagulation and hemolysis activities, and radiolabeling efficiency of Schiff bases as well as on the in-vitro radio-complexes stability was investigated. DADTSC1 (TSCC=0.93mmol/g) showed a less cytotoxicity (cell viability, CV50=490mug/ml), a better solubility, suitable coagulation and hemolytic activities, and a sufficient radiolabeling efficiency (Radiochemical purity (RCP)>95) and formed a stable (RCP>90) radio-complex, which be chosen for in-vivo biodistribution study in healthy rats through tissue sampling and counting for radioactivity. Like blood pool imaging agents, (68)Ga-DADTSC1 presented a retention profile in blood circulation, though more studies, including imaging in larger mammals, are required.