Syntheses of 2-Nitroimidazole Derivatives Conjugated with 1,4,7-Triazacyclononane-N,N′-Diacetic Acid Labeled with F-18 Using an Aluminum Complex Method for Hypoxia Imaging
journal contributionposted on 21.02.2016, 14:39 by Lathika Hoigebazar, Jae Min Jeong, Ji-Youn Lee, Dinesh Shetty, Bo Yeun Yang, Yun-Sang Lee, Dong Soo Lee, June-Key Chung, Myung Chul Lee
Hypoxia imaging is important for diagnosis of ischemic diseases, and thus various 18F-labeled radiopharmaceuticals have been developed. However, 18F-labeling requires multistep procedures including azeotropic distillation, which is complicated and difficult to automate. Recently, 18F-labeling method using Al–F complex in aqueous solution was devised that offered a straightforward 18F-labeling procedure. We synthesized nitroimidazole derivatives conjugated with 1,4,7-triazacyclononane-1,4-diacetic acid (NODA) that can be labeled with 18F using Al–F complex and examined their radiochemistries, in vitro and in vivo biological properties, and animal PET imaging characteristics. We found that the synthesized derivatives have excellent 18F-labeling efficiencies, high stabilities, specific uptakes in cultured hypoxic tumor cells, and high tumor to nontumor ratios in xenografted mice. Furthermore, the derivatives were labeled with 18F in a straightforward manner within 15 min at high labeling efficiencies and radiochemical purities. In conclusion, 18F-labeled NODA–nitroimidazole conjugates were developed and proved to be promising hypoxia PET agents.