Kit formulation for the preparation of radiolabeled iododeoxyuridine by demetallation.

Abstract

The fastest and most reliable preparation of radiolabeled 5-iodo-2'- deoxyuridine (*IUdR) is accomplished by iododemetallation. We describe a kit formulation for the preparation of *IUdR by demercuration whereby [123I/125I/131I]IUdR is synthesized virtually instantaneously following the incubation of an aqueous solution of the chloromercuric precursor with Na123I/125I/131I in the presence of lodogen. We also report the conditions for the radiosynthesis of IUdR by destannylation of the tributylstannyl precursor using hydrogen peroxide as the oxidant. In each case, the total procedure is completed in 5 min. HPLC indicates the total transformation of iodide into IUdR with no detectable UV-absorbing by-products. The metal content of the sample is low. The product, therefore, does not require purification. *IUdR can be prepared instantly, by either demercuration of ClHgUdR or destannylation of Bu3SnUdR. The use of a mercuric precursor favors a kit formulation since the metallic derivative is stable when kept in aqueous solution, aliquoted in vials coated with the oxidant, for up to 3 mo.