Preparation of cyclic 67Cu-diethylene-triamine-penta-acetic anhydride as a bifunction potential Beta-emitter chelator for radioimmunotherapy

The study presented herewith describes the radiochemical synthesis of a cyclic 67Cu-DTPA anhydride labelled compound using carrier free copper ( 67Cu ) formerly prepared by irradiation of natural zinc-67 metal as a target material, which was irradiated in ETRR-2 research reactor (Egypt) followed by separation of the carrier free copper-67 as copper chloride using Dowex 1x8 Cl? ion form. Complexation of 67Cu with cyclic DTPA anhydride was achieved by the addition of 0.2 ml 67CuCl2 (3.7-18.5MBq) in 0.1M HCl to 30 mg cyclic DTPA anhydride in 1ml of dry dimethyl sulfoxide (DMSO) and 0.2ml of 67CuCl2 containing tracer amount of sodium acetate followed by 30 min incubation time at 100oC and pH of 6.5. The labelling yield of cyclic 67Cu-DTPA anhydride was found to be more than 97% currently determined by chromatographic analysis. Biodistribution results demonstrated the efficient clearance of the compound through blood, liver and kidney of mice. Cyclic 67Cu-DTPA anhydride may be useful as a bifunctional chelator (BFC) in diagnostic and radiotherapeutic studies using nuclear medicine instrumentations