A new analytical workflow could eliminate the need for radioactive labeling in drug metabolism studies – long considered the gold standard – by instead tracking fluorine atoms using inductively coupled plasma mass spectrometry (ICP-MS). The approach enables sensitive, quantitative metabolite profiling much earlier in drug development, without exposing patients or researchers to radioactivity.
The method combines optimized capillary LC with tandem ICP-MS to detect fluorine via barium fluoride (BaF⁺) formation, achieving detection limits below 1 ng on-column. Because ICP-MS measures elemental signals rather than molecular structure, it provides a uniform, quantitative response across parent drugs and metabolites – without requiring radiolabeled compounds or authentic standards. The workflow was validated against traditional ¹⁴C radioactivity detection, showing comparable performance in both in vitro and in vivo samples.
Fluorine is a particularly attractive target, given its presence in up to half of drugs in development and its minimal background in biological matrices. By avoiding radiolabel synthesis and enabling earlier-stage studies – including first-in-human and steady-state analyses – the technique could streamline ADME workflows and expand study design flexibility. Beyond drug metabolism, the authors suggest the method may also find applications in areas such as environmental analysis of fluorinated compounds.
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