Preparation and Biolocalization of Technetium-99m Complexes with N2O2 Schiff-Base Compounds

Received 9/25/2003; revised 12/5/2003; accepted 12/9/2003. For correspondence or reprints contact: Wen-Tao Huang, Ph.D., Department of Radiological Technology, Yuanpei University of Science and Technology, 306 Yuanpei Street, Hsinchu 300, Taiwan, ROC. Tel: (886)3-5381183 ext. 8312, Fax: (886)3-5385353, E-mail: [email protected] A series of tetradentate N2O2 Schiff-base compounds were synthesized by condensing one equivalence of 1,3-diaminopropane derivatives along with four groups of two equivalences of salicylaldehyde derivatives. Chemical characteristics of these compounds were analyzed by using proton nuclear magnetic resonance (H-NMR) and Fourier transform infrared spectroscopy (FTIR). These Schiff-base compounds were labeled with tracer-level 99mTcO4 to proceed with complexing in forming Tc-complex. The complexing yields and lipophilicities were evaluated by solvent extraction technique. The complexing yields ranged from 76.9% to 97.5% for the eight Tc-complexes in pH 8~9 buffer. The complexes studied varied in lipophilicity from log P = 1.10 to log P = 2.68, where P was the octanol/water partition coefficient. Biodistributions of the eight Tccomplexes in Wistar rats were similar. Biodistribution tests demonstrated that the metabolic pathway of Tccomplexes on Wistar rats was via hepatobiliary duct; however, low clearance of activities is through kidneys.