EVALUATION OF [I-125] 7-ALPHA-O-IODOALLYL DIPRENOPHINE AS A NEW POTENTIAL SPECT OPIOID RECEPTOR IMAGING AGENT

A new iodinated diprenorphine analog, [I-125]7 alpha-O-iodoallyl dipre norphine ([I-125]7 alpha-O-IA-DPN), was prepared by iododestannylation and characterized. As an opioid antagonist, this agent showed very hi gh affinity (K-i = 0.4 +/- 0.2 nM) and 63% of specific binding by in v itro and in vivo binding studies, Inhibition curves indicated that thi s tracer labeled with the same affinities to three opioid receptors (m u = delta = kappa). The findings demonstrate that this proposed compou nd appears to be a potential radioprobe for future study of opioid rec eptors by in vivo SPECT. (C) 1997 Elsevier Science Inc.