Preparation and biodistribution of [ 125I]Melphalan: A potential radioligand for diagnostic and therapeutic applications

摘要

This paper addresses the development of a new radiopharmaceutical for cancer imaging and therapy. The optimization of the labeling conditions of thymidine analogue, melphalan, with 125I is described. High radiochemical yield 96.8% was obtained by reacting 0.2mg melphalan with 125I in the presence of choloramin-T as oxidizing agent in 0.5M phosphate buffer, pH 7, at 70°C for 15 min. Preliminary in vivo study was done in non-tumor bearing mice. The results revealed that this new tracer, 125I-melphalan, has a high affinity to be localized in the tumor site for a long period, which indicates the specificity of this tracer to the tumor cells. The labeled compound was cleared quickly from most of the body organs. These findings suggest that 125I-melphalan allows imaging and treatment of cancer. 125I-melphalan meets most of the requirements necessary to be used as a successful diagnostic and therapeutic agent: it is a low-molecular-weight molecule that diffuses readily in the tissues, and dose not induce an antibody response.