diphosphonate /difos′fonāt/ , any of a group of related phosphorus-containing compounds that are structurally similar to pyrophosphate but have enhanced stability to enzymatic and chemical hydrolysis and have affinity for sites of osteoid mineralization. They are used as sodium salts to inhibit bone resorption and are complexed with technetium Tc 99m for bone imaging. The group includes alendronate, etidronate, and pamidronate. Also called bisphosphonate.
