Abstract
In this study, 99mTc complexes with 2,2,4,9,9-pentamethyl-4,7- diaza-1,10-decanedithiol (PDD) and 2,2,9,9-Tetramethyl-4,7-diaza-1,10- decanedithiol (TDD) mixed and dissolved in lipiodol were administrated in hepatoma-bearing rats by intrahepatic arterial injection. Biodistribution in the rats as well as hepatoma uptake of 99mTc-PDD and 99mTc-TDD in lipiodol have been explored. The synthesis of the chelating agent—PDD and TDD proceeded with 5 and 4 steps﹔optimal conditions either for PDD or for TDD were established. PDD and TDD were identified by NMR, IR and EA. Labeling PDD and TDD with 99mTc were carried out by mixing 99mTcO4-/saline with the ligand solution of PDD or TDD, saturated stannous tartrate solution, and a specific pH buffer. The solution mixture was shaken for 20 min for accomplishing the 99mTc complexation . The labeling efficiency, lipophilicity and stability of 99mTc-PDD and 99mTc-TDD were determined by electrophoresis, solvent extraction and thin layer chromatography. For the results, 99mTc-PDD and 99mTc-TDD was characterized to be of high labeling yield (~85% and ~82%), neutrality, high lipophilicity, and high stability. The complexes were mixed with lipiodol at the ratio of two to one (V/V), and then washed by saline. The lipiodol layer was separated as the 99mTc-complex solutions in lipiodol, 99mTc-PDD-lipiodol and 99mTc-TDD-lipiodol.Twenty four male rats bearing with hepatoma were injected with approximately 0.2 mCi of either 99mTc-PDD-lipiodol or 99mTc-TDD-lipiodol via the hepatic artery. The same number of male rats bearing with hepatoma were injected with approximately 0.3 mCi of either 99mTc-PDD or 99mTc-TDD via the tail veins. The rats were separately sacrificed at 10 min, 1h, 3h and 24h postinjection. Various organs or tissues were dissected, weighed, and counted. Percent injected dose per gram of organ or tissue ( ％ID/g organ or tissue) was calculated from the radioactivitions measured. Uptake by hepatoma of either 99mTc-PDD or 99mTc-TDD was significant and about two-fold higher than the normal liver tissue. The uptake in the lung reached maximally high at 1h postinjection but then decreased rapidly either for 99mTc-PDD-Lipiodol or 99mTc-TDD-Lipiodol, which was initially injected via the hepatic artery.