[99mTc]polyamine analogs as potential tumor imaging agent

Polyamines are essential for the growth and survival of all cells with biosynthesis and transportation of polyamines being very active in tumors. With the aim of developing a new tumor imaging agent, three artificial synthetic polyamine analogs, diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA), were labeled with 99mTc. The 99mTc-labeled complexes were characterized by TLC and studied for stability. 99mTc-DETA, 99mTc-TETA, and 99mTc-TEPA were formed in high yields and found to be stable. 99mTc-DETA, 99mTc-TETA, and 99mTc-TEPA revealed high tumor uptakes of 0.65, 0.58, and 0.59% ID/g at 4 h pi, respectively, in HepA tumor-bearing mice. The ratios of the tumor to the contralataral muscle (T/CM) were 13.68, 5.99, and 9.81, respectively. SPECT images revealed clear visualization of tumors. Excretion routes were mainly through urine and feces. The tumor-to-muscle count density ratios of 99mTc-DETA, 99mTc-TETA, and 99mTc-TEPA were 2.47, 2.45, and 2.91, respectively. [99mTc]-labeled polyamine analogs are promising agents for tumor imaging and warrant further evaluation. Drug Dev Res 69:520–525, 2008. © 2008 Wiley-Liss, Inc.