[11C]SP203

[11C]SP203 is a carbon-11 labeled radiopharmaceutical developed as a positron emission tomography (PET) radioligand for the high-affinity and selective imaging of metabotropic glutamate receptor 5 (mGluR5) in the brain. It is the short-lived carbon-11 analog (t1/2 ≈ 20.4 min) of the fluorine-18 labeled ligand [18F]SP203, designed to facilitate multiple scanning sessions in the same subject within a single day. Chemically, it is a thiazole derivative where the carbon-11 label is typically incorporated into the nitrile group. The ligand binds with high specificity to mGluR5, a G-protein coupled receptor implicated in various neurological and psychiatric conditions, including Fragile X syndrome, depression, and Parkinson's disease. While preclinical studies in rhesus monkeys showed high brain uptake followed by rapid metabolism in blood, studies in humans have supported its utility as a tool for quantifying mGluR5 density and occupancy in the central nervous system.

Other names

Carbon-11 SP203Carbon11 SP203Carbon 11 SP203[11C]-SP203