The gallium–deferoxamine complex: stability with different deferoxamine concentrations and incubation conditions

Previous studies report that deferoxamine (DFO) binds metallic ions such as Fe3+, In3+ and Ga3+ with very high affinity. This property of DFO has been utilized to label DFO-coupled compounds with radiometals such as 67Ga and 111In. We have studied the effect of low DFO concentrations and of different incubation conditions on the stability of the 67Ga–DFO complex. In our experience high (>5 μM) DFO concentration appears to be critical in obtaining high radiochemical purity of such complexes.