New amino bisphosphonate compound for skeletal imaging: Comparison study with methylenediphosphonic acid (MDP) and (1-hydroxyethane-1,1-diyl) diphosphonic acid (HEDP)

Technetium-99m radiopharmaceuticals play an important role in wide range of applications in nuclear medicine. Bone imaging agents are among the fi rst developed 99mTc-radiopharmaceuticals and the most widely used radiopharmaceuticals in diagnostic nuclear medicine [1]. Bisphosphonates (BPs) are synthetic organic compounds characterized by a P-C-P backbone structure. They are chemically stable analogues of the endogenous metabolites, inorganic pyrophosphates. The biological effects of BPs on calcium metabolism were originally ascribed to their physicochemical effects to impede the dissolution of hydroxyapatite crystals [2–4]. Because of their inhibitory effect on the bone resorption, various types of BPs are used in bone scanning, and provide an effective way of diagnosis of primary bone cancer, metastatic bone disease, Paget’s disease, osteoporosis, bone trauma, etc. Several 99mTc-labeled BPs have been synthesized, such as methylenediphosphonic acid (MDP) [2], (1-hydroxyethane-1,1-diyl)diphosphonic acid (HEDP) and hydroxyl methylene diphosphonate (HMDP), (Fig. 1), and used in nuclear medicine for both diagnosis and treatment purposes [5–14]. To continue the previous efforts to fi nd better bone-imaging agents, we report in this manuscript the synthesis of a new bisphosphonate compound, AEDP, and investigate its radiolabeling abilities with 99mTc. Subsequently, we have performed preliminary in vivo studies in rats and compared the results with those obtained using two reference New amino bisphosphonate compound for skeletal imaging: Comparison study with methylenediphosphonic acid (MDP) and (1-hydroxyethane-1,1-diyl) diphosphonic acid (HEDP) Thaer Assaad