Determination of PDE-5 inhibitors and appetite suppressants in adulterated dietary supplements using LC/PDA and LC/MS

Abstract

There have been a number of reports of dietary supplements contaminated with illegal adulterants that threaten consumers’ health because of their adverse pharmacological effects. In the present study, a convenient and economic method was developed to detect illegal pharmaceutics, such as PDE-5 inhibitor and appetite suppressants, using liquid chromatography (LC)/photodiode array (PDA) for screening and LC/mass spectrometry (MS) for successive confirmation. Target peaks were identified by comparison of their chromatographic retention times and PDA spectra with those of synthetic standards and finally confirmed by LC/MS. As a result, tadalafil, a PDE-5 inhibitor, and N-desmethylsibutramine, a derivative of sibutramine, were detected in various dietary supplements at concentrations of 13.5–21.9 mg and 3.0 mg per single dose, respectively. The present study will contribute to the development of an analytical method enabling rapid screening of a variety of health foods, and the result suggests that consumers should be aware of serious health risks related to these illegal compounds.