Chromatographic‐mass spectrometric analysis of the urinary metabolite profile of chlorphenesin observed after dermal application of chlorphenesin‐containing sunscreen

4-CPA is a common metabolite of meclofenoxate, chlorphenesin, and chlorphenesin carbamate. Monitoring the diagnostic urinary metabolites of chlorphenesin provides conclusive supporting evidence of whether chlorphenesin or the prohibited nootropic meclofenoxate was administered.