The interactions of99mTc phosphorus radiopharmaceuticals and human serum proteins

Dialysis and precipitation methods have been used to study the binding affinity of selected technetium-99m phosphorus radiopharmaceuticals to human serum proteins. The binding affinities of three different99mTc bone imaging agents were found to be inversely related to their respective clearance rates from blood in vivo. The binding order showed99mTcPPi>99mTcHEDP>99mTcMDP. The99mTc phosphorus radiopharmaceuticals were bound primarily to alpha globulins. The results suggest that the binding of99mTc phosphorus radiopharmaceuticals to human serum proteins in blood is largely determined by their affinities to the alpha globulins.