Technetium-99m labeled renal function and imaging agents: III. Synthesis of 99mTc-MAG3 and biodistribution of by-products.

99mTc-MAG3, a new 99mTc radiopharmaceutical with biological properties similar to o-iodohippuric acid (OIH), is expected to find wide clinical application for renal function studies. Therefore it is important to make a kit formulation available which provides reproducibly the desired product in high radiochemical yields. Some differences between the biokinetic data of kit prepared 99mTc-MAG3 and HPLC-purified 99mTc-MAG3 were reported by different authors. The subject of this paper is the isolation of the by-products which are formed with our own kits, the evaluation of their biological behaviour and the comparison with the main product 99mTc-MAG3 in rats. The results suggest that the radiochemical purity of 99mTc-MAG3-preparations should be not less than 95%.