2'-[18F]Fluorofolic acid

2'-[18F]Fluorofolic acid is a radiopharmaceutical designed for Positron Emission Tomography (PET) imaging. It is a fluorine-18 labeled analog of folic acid, a vital B vitamin involved in methylation and DNA synthesis. This agent selectively targets cells that overexpress the high-affinity folate receptor, a characteristic found in various human epithelial tumor cells, including those of ovarian, endometrial, breast, colorectal, renal, and lung carcinomas, as well as in activated macrophages. The uptake of 2'-[18F]Fluorofolic acid can be significantly reduced by pretreatment with unlabeled folic acid, indicating receptor-mediated uptake. It is synthesized through a two-step process involving nucleophilic radiofluorination and subsequent acid hydrolysis, achieving a radiochemical purity typically greater than 95%.