Fully Automated Cassette-Based Production of [18F]Albumin Using the Trasis AllinOne Module

Fluorine-18 labeling of peptides and proteins is typically performed by an indirect labeling method. In this labeling approach, a labeled prosthetic group is prepared first and then conjugated to the proteins and peptides of interest. 6-[¹⁸F]fluoronicotinic acid-2,3,5,6-tetrafluorophenyl ester is a useful prosthetic group for indirect labeling. We have recently developed an efficient radiolabeling method, “fluorination on Sep-Pak,” that enables the preparation of this prosthetic group with high radiochemical yield and purity in under 10 min. A variety of biomolecules have been radiolabeled using this prosthetic group. The radiolabeling procedure was either manual or semiautomated. However, a fully automated synthesis method is essential for successful clinical translation. Therefore, we developed a fully automated reproducible radiolabeling method to prepare fluorine-18–labeled albumin using the Trasis AllinOne module. The procedure was completed in 50 min. The overall radiochemical yield was 25%–36% (decay-corrected, n = 6) using 1 mg of albumin with a radiochemical purity > 98%.