Continuous-Flow Synthesis Of N-Succinimidyl 4-[F-18]Fluorobenzoate Using A Single Microfluidic Chip

In the field of positron emission tomography ( PET) radiochemistry, compact microreactors provide reliable and reproducible synthesis methods that reduce the use of expensive precursors for radiolabeling and make effective use of the limited space in a hot cell. To develop more compact microreactors for radiosynthesis of F-18-labeled compounds required for the multistep procedure, we attempted radiosynthesis of N-succinimidyl 4-[F-18]fluorobenzoate ([F-18]SFB) via a three-step procedure using a microreactor. We examined individual steps for [F-18]SFB using a batch reactor and microreactor and developed a new continuous-flow synthetic method with a single microfluidic chip to achieve rapid and efficient radiosynthesis of [F-18]SFB. In the synthesis of [F-18]SFB using this continuous-flow method, the three-step reaction was successfully completed within 6.5 min and the radiochemical yield was 64 +/- 2% (n = 5). In addition, it was shown that the quality of [F-18]SFB synthesized on this method was equal to that synthesized by conventional methods using a batch reactor in the radiolabeling of bovine serum albumin with [F-18]SFB.