MetIDfyR, an Open-Source R Package to Decipher Small-Molecule Drugs Metabolism Through High Resolution Mass Spectrometry

After administration to humans or animals, small-molecule drugs most frequently undergo several biochemical transformations by the endogenous enzymatic machinery, called phase I and phase II metabolism. These molecular processes allow organisms to eliminate xenobiotics through modification of their chemical properties and generate metabolites. With recent advances in analytical chemistry, LC-HRMS/MS has become an essential tool for metabolite discovery and detection. Even if most common drug transformations have already been extensively described, manual search of drug metabolites in LC-HRMS/MS datasets is still a common practice in toxicology laboratories, disabling efficient metabolite discovery. Furthermore, the availability of free open-source software for metabolite discovery is still limited.

In this article, we present MetIDfyR, an open-source and cross-platform R package for in-silico drug phase I/II biotransformations prediction and mass-spectrometric data mining. MetIDfyR has proven efficacy for advanced metabolite identification in semi-complex and complex mixtures in in-vitro or in-vivo drug studies and is freely available at