New preparation of (I-123) iodolisuride from the 2-tri-n-butylstannalisuride derivative

A simplified and efficient method is described for the preparation of [I-12 3]2-iodolisuride. The radioiodination of 3-(9,10-didehydro-6methyl-8a-ergol inyl)-1,1-diethylurea (lisuride) is based on tributyltin to I-123 exchange in oxidative conditions. After optimization of the reaction parameters [I-1 23]2-iodolisuride was obtained without high performance liquid chromatograp hy purification with radiochemical yields >90% and a radiochemical purity h igher than 95%. The specific activity of the product was more than 500 MBq/ nmol. In vivo binding studies on striatal membranes and ex vivo autoradiogr aphy in rats showed that [I-123] or [I-125]2-iodolisuride prepared using th is method, have the same radiopharmacological characteristics as radioiodin ated iodolisuride prepared using the Iodgen(R) method.