Synthesis of novel bisphosphonate polyamine conjugates and their affinity to hydroxyapatite

Bisphosphonates are negatively charged molecules, widely used as bone drugs since they have high affinity to bone surface. Polyamines are small organic bases that are positively charged under the physiological conditions and they participate in the regulation of important cellular functions. In this study, we report a general synthesis strategy for bisphosphonate-polyamine conjugates starting from ethenylidene bisphosphonates and N-Boc protected polyamines. Four novel conjugates were prepared and characterized with spectroscopic methods. The affinity of these novel compounds to hydroxyapatite was also determined by using Tc-99m procedure.