Automated preparation of 2-[¹⁸ F]fluoropropionate labeled peptides using a flexible, multi-stage synthesis platform...

Radiolabelled peptides are vital tools used in positron emission tomography imaging for the diagnosis of disease, drug discovery, and biomedical research. Peptides are typically labeled through conjugation to a radiolabelled prosthetic group, which usually necessitates complex, multi-step procedures, especially for fluorine-18 labeled peptides. Herein, we describe the automated synthesis and formulation of 2-[¹⁸ F]fluoropropionate labeled RGD-peptides through use of the iPHASE Flexlab as an effective dual-stage radiochemical synthesis module. The fully automated preparation of the monomeric RGD-peptides, [¹⁸ F]FP-GalactoRGD and [¹⁸ F]FP-c(RGDy(SO₃ )K), was accomplished in under 90 minutes with n.d.c. radiochemical yields ca. 7% from fluoride. Similarly, the automated preparation of the dimeric RGD-peptides, [¹⁸ F]F-PRGD₂ and [¹⁸ F]FP-E(RGDy(SO₃ )K)₂ , was accomplished in under 105 minutes with n.d.c. yields ca. 4% from fluoride.