SYNTHESIS, RADIOLABELING, AND PRELIMINARY EVALUATION IN MICE OF SOME (N-DIETHYLAMINOETHYL)-4-IODOBENZAMIDE DERIVATIVES AS MELANOMA IMAGING AGENTS

N-(2-Diethylaminoethyl)-4-iodobenzamide (BZA) is a radiopharmaceutical recently developed in our laboratory for the scintigraphic detection of melanoma and metastases. Optimal time for imaging was between 18-24 h p.i. of [I-123] BZA. With a view to selecting compounds able to pro vide quality images shortly after the injection, synthesis of an initi al series of BZA derivatives and their evaluation in B16 melanoma bear ing mice have been carried out. The [I-125] radiolabeled products were obtained by a simple isotopic exchange procedure with high radiochemi cal yields (85-95%). After i.v. administration of the compounds we obs erved a good tumoral targeting ability. Tumoral activity peaked at 2.6 to 7.70% injected dose per g within 1 h post-injection. One of the be nzamides with a blood clearance faster than that of BZA-0.06 vs. 0.2% I D/g-6 h p.i. gave the same tumor to blood and to organ ratios as BZA at 12-18 h p.i. Based on these preclinical data we hope to obtain goo d tumoral images 6 h p.i. in scintigraphic studies in man.