Analytical Procedures for Metabolites: Metabolite Profiling and the Isolation and Identification of Metabolites

Metabolism studies may be subdivided into two parts, metabolite profiling and metabolite isolation and identification. The principal analytical procedures for these studies are chromatography and spectroscopy. The investigation of the metabolic fate of a drug or pesticide is greatly facilitated by the use of radiolabeled compounds, most commonly containing ¹⁴C or tritium, but it is also possible to obtain some information using nonradiolabeled substances. Where radioactive isotopes are used a careful choice of the site of labeling is essential to ensure that it is not lost from the molecule during subsequent metabolism (especially if tritium is used). This aspect is discussed more fully elsewhere in this volume.