Quantification of the radio-metabolites of the serotonin-1A receptor radioligand [carbonyl-11C]WAY-100635 in human plasma: An HPLC-assay which enables measurement of two patients in parallel

[Carbonyl-11C]WAY-100635 is a potent and effective antagonist for the 5-HT1A receptor subtype. We aimed to assess the status of [carbonyl-11C]WAY-100635 and its main radio-metabolites, [carbonyl-11C]desmethyl-WAY-100635 and [carbonyl-11C]cyclohexanecarboxylic acid, on the basis of an improved radio-HPLC method. Common methods were characterized by preparative HPLC columns with long runtimes and/or high flow rates. Considering the short half-life of C-11, we developed a more rapid and solvent saving HPLC assay, allowing a fast, efficient and reliable quantification of these major metabolites.

► We developed a HPLC assay which allows the measurement of two patients in parallel.
► It allows a fast and efficient quantification of WAY-100635 and its metabolites.
► Better counting statistics with late samples for modeling the input function is achieved.
► The fastest assay so far is about 40% slower in comparison to the presented method.