Preparation and Biodistribution of ¹³¹I Labeled 3-Amino-1-Hydroxypropylidene-1,1-Bisphosphonate

3-amino-1-hydroxypropylidene-1,1-bisphosphonate (ABP) was synthesized and labeled with ¹³¹I using N-succinimidyl-5-(tri-butylstannyl)-3-pyridinecarboxylate(SPC) as a bi-functional linker. ¹³¹I could be coupled to ABP via a ¹³¹I-SIPC intermediate with a labeling yield of more than 64%, and a radiochemical purity of more than 99% after HPLC purification. After72 h at room temperature, the radiochemical purity was still more than 98.8%, implying that the ¹³¹I-SIPC-ABP is stable in vitro. Biodistribution experiments in mice show that ¹³¹I-SIPC-ABP has high affinity to bone and high stability in vivoas well as in vitro.