Synthesis and evaluation of ¹⁸F-labeled carbonic anhydrase IX inhibitors for imaging with positron emission tomography

Abstract

Two carbonic anhydrase IX (CA IX) inhibitors were radiolabeled with ¹⁸F, and evaluated for imaging CA IX expression. Despite good affinity for CA IX and excellent plasma stability, uptake of both tracers in CA IX-expressing HT-29 tumor xenografts in mice was low. ¹⁸F-FEC accumulated predominately in the liver and nasal cavity, whereas a significant amount of ¹⁸F-U-104 was retained in blood. Due to minimal uptake in HT-29 tumors compared to other organs/tissues, these two tracers are not suitable for use for CA IX-targeted imaging.

• Benzenesulfonamide
• coumarin
• cytochrome P450

Acknowledgements

We are thankful to Jean-Pierre Appiah and Milan Vuckovic for operating the cyclotron and providing ¹⁸F-fluoride for radiolabeling experiments.