Synthesis and biological evaluation of 90Y-labeled porphyrin-DOTA conjugate for targeted tumor therapy

Development of tumor-avid substances has received considerable attention in current cancer diagnostic and therapeutic protocols. Among the various substances exhibiting tumor specificity, hematoporphyrin and its derivatives have been extensively investigated with the aim to identifying potential agents for targeted tumor diagnosis and therapy. Working in this direction, a water soluble unsymmetrical porphyrin, namely 5-(4-(3-amino)-n-propyloxyphenyl)-10,15,20-tris-(4 carboxymethyleneoxyphenyl)porphyrin was synthesized and subsequently coupled with a bi-functional chelating agent (BFCA), namely p-isothiocyanato-benzyl-1,4,7,10 -tetraazacyclododecane- 1,4,7,10-tetraacetic acid (p-NCS-benzyl-DOTA), for its radiolabeling with 90Y. 90Y was chosen as a therapeutic radionuclide owing to its suitable nuclear decay characteristics (Eβmax= 2.28 MeV, T1/2= 64h) and easy availability in high radionuclidic purity from a 90Sr-90Y generator. The emission of high energy β- particle makes it a suitable candidate for therapy in large-sized tumors