Receptor-mediated targeting of 67Ga-deferoxamine-folate to folate-receptor-positive human KB tumor xenografts.

The radiochemical synthesis and stability of 67Ga-deferoxamine-folate ([67Ga]Ga-DF-Folate) were examined as a function of DF-Folate concentration. Optimal labeling occurred at DF-Folate concentrations > or =2.5 microg/mL. To define the possible biological significance of variations in product formulation, the biodistribution of [67Ga]Ga-DF-Folate was examined as a function of administered deferoxamine-folate dose in an athymic mouse KB tumor model. The folate-receptor-positive KB tumors were found to concentrate the 67Ga radiolabel in a dose-dependent fashion, consistent with saturable involvement of the folate receptor in mediating tumor accumulation of the radiopharmaceutical.