Skeletal localization of samarium-153 chelates: potential therapeutic bone agents.
A series of stable complexes of 153Sm has been produced using multidentate acetate and phosphonate ligands. Biodistribution studies in unanesthetized rats showed varying degrees of bone and soft-tissue uptake for these complexes. Of the complexes studied, [153Sm] ethylenediaminetetramethylenephosphonate (EDTMP) showed the best combination of high bone uptake, low nonosseous uptake, and rapid blood clearance which warranted its further investigation in rabbits. Rabbit studies confirmed the [153Sm]EDTMP results obtained in rats. Blood clearance in rabbits was found to be more rapid than [99mTc] methylene diphosphonate (MDP). Scintigraphic images were virtually indistinguishable from [99mTc]MDP images. Lesion/normal bone ratios were determined from digitized images obtained using a drill hole model and found to be approximately 17:1. Based on these excellent biodistribution characteristics, [153Sm] EDTMP could be therapeutically useful in treating metastatic bone cancer.
D000818:Animals; D001842:Bone and Bones / Q000378:metabolism*; D002614:Chelating Agents / Q000138:chemical synthesis / Q000378:metabolism* / Q000627:therapeutic use; D008297:Male; D011817:Rabbits; D011868:Radioisotopes / Q000627:therapeutic use; D051381:Rats; D011919:Rats, Inbred Strains; D012493:Samarium / Q000627:therapeutic use; D014018:Tissue Distribution
D002614:Chelating Agents; D011868:Radioisotopes; D012493:Samarium