Application of LC-MS to the analysis of new radiopharmaceuticals.

Liquid chromatography in combination with mass spectrometry (LC-MS) is key to the identification of metabolites in new molecular imaging probes. These metabolites can be generated using hepatocytes from various species in vitro. Metabolites produced from 4-fluoro-N-[2-[4-(2-methoxylphenyl)piperazino]ethyl]-N-(2-pyridyl)cyclohexane carboxamide (FCWAY) using rat and human hepatocytes are different, whereas metabolites from (3-(3-fluoropropylthio)-1,2,5-thiadiazol-4-yl)-tetrahydro-l-methyl-pyridine (FP-TZTP) using rat and human hepatocytes were similar. The combination of LC-MS and hepatocytes are an indispensable tool in the development of new molecular imaging probes.