Synthesis, radiolabeling, and biodistribution of putative metabolites of iodoazomycin arabinoside

Scintigraphic evaluation of patients with advanced oncological disease show ed uptake of radioactivity in the brain following administration of the hyp oxic imaging agent I-123-iodoazomycin arabinoside (I-123-IAZA). Three propo sed metabolites of IAZA-methyl 5-deoxy-5-iodo-D-arabinofuranoside, methyl 2 ,3-di-O-acetyl-5-deoxy-5-iodo-or-D-arab and 1-(5-deoxy-5-iodo-alpha-D-arabi nofuranosyl)-2-aminoimidazole (IAIA)-were synthesized, radiolabeled with I- 125, and investigated in normal and tumor bearing murine models for their c ontribution to this unusual phenomenon. The three compounds were readily ra diolabeled by melt or solvent exchange procedures. Biodistribution data ind icated rapid blood clearance, rapid excretion, and little tissue accumulati on in the brain. IAIA showed significant tumor to blood ratios at 4 h (4.3: 1) and liver to blood ratios at 24 h (30:1). NUCL MED BIOL 27;1:61-68, 2000 . (C) 2000 Elsevier Science Inc. All rights reserved.