Potential tissue-imaging agents: 23-(trimethyl [117mSn]stannyl)-24-nor-5 alpha-cholan-3 beta-ol

Tin-117m-labeled 23-(trimethylstannyl)-24-nor-5 alpha-cholan-3 beta-ol (2) has been prepared by reaction of trimethyl [117mSn]tin lithium with 3 beta-acetoxy-23-bromo-24-nor-5 alpha-cholane (1). Tin-117m (2) shows pronounced adrenal uptake (2.5% injected dose) in female rats 1 day after injection. Furthermore, the adrenal to liver (9.1:1) and adrenal to blood (33.7:1) ratios are high after this period. The absorbed radiation dose values from [117mSn]2 to human organs have also been estimated by using rat tissue distribution and excretion data. [117mSn]2 is the first reported tissue-specific organic radiopharmaceutical labeled with this nuclide and may have potential as an adrenal imaging agent.