Radiosynthesis, in vitro cellular uptake and in vivo biodistribution of 3′-O-(3-benzenesulfonylfuroxan-4-yl)-5-[125I]iodo-2′-deoxyuridine, a nucleoside-based nitric oxide donor

[125I]1 undergoes only minimal deoiodination under both in vitro and in vivo conditions. Under conditions of the in vitro NO release assay, 1 reacts to produce a single, major, unstable adduct that decomposes upon workup. Protein binding of [125I]1 could not be assessed because of similar chemical reaction with albumin. Incorporation of radioactivity into the cellular nucleic acid fraction was low, and in vivo distribution of [125I]1 was consistent with nonspecific reactivity towards tissue nucleophiles. The chemical reactivity of [125I]1 mitigates against its use as a NO donor and as a tracer for this class of compounds.