title: Analysis of illicit dietary supplements sold in the Italian market: identification of a sildenafil thioderivative as adulterant using UPLC-TOF/MS and GC/MS.
abstract: Identification of pharmaceutical active ingredients sildenafil and tadalafil and the characterization of a dimethylated thio-derivative of sildenafil, called thioaildenafil or thiodimethylsildenafil, in illicit dietary supplements were described. A multi-residual ultra-performance liquid chromatography-time of flight mass spectrometry (UPLC-TOF/MS) method was developed to screen for the presence of the phosphodiesterase-5 (PDE-5) inhibitors sildenafil, tadalafil, and vardenafil and their analogues thioaildenafil and thiohomosildenafil in powders and pharmaceutical dosage forms. The study was developed in connection with an operation supervised by the Italian Medicines Agency (A.I.F.A.), aimed to monitor dietary supplements in the Italian market. In two of the eleven specimens under investigation, high-resolution mass spectrometry (HR-MS) allowed the identification of the PDE-5 inhibitors sildenafil and tadalafil, while another specimen proved to contain a unapproved dimethylated thioderivative of sildenafil, thioaildenafil or thiodimethylsildenafil, identified for the first time in Italy as adulterant in food supplements.
authors.affiliation: Carabinieri, Department of Scientific Investigation, via Parco Ducale 3, 43126 Parma, Italy. Electronic address: fabio.damiano@carabinieri.it.
authors.forename: Fabio
authors.initials: F
authors.lastname: Damiano
authors.affiliation: University of Parma, Department of Pharmacy, Parco Area delle Scienze, 27/A, 43124 Parma, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Silva
authors.affiliation: Carabinieri, Department of Scientific Investigation, via Parco Ducale 3, 43126 Parma, Italy.
authors.forename: Adolfo
authors.initials: A
authors.lastname: Gregori
authors.affiliation: University of Parma, Department of Pharmacy, Parco Area delle Scienze, 27/A, 43124 Parma, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Vacondio
authors.affiliation: University of Parma, Department of Pharmacy, Parco Area delle Scienze, 27/A, 43124 Parma, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Mor
authors.affiliation: University of Torino, Department of Analytical Chemistry, via Pietro Giuria 5, 11025 Torino, Italy.
authors.forename: Mattia
authors.initials: M
authors.lastname: Menozzi
authors.affiliation: Italian Medicines Agency, Counterfeit Prevention Unit, via del Tritone 181, 00187 Rome, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Di Giorgio
keywords: Dietary supplement; PDE-5 inhibitors; Sildenafil; Tadalafil; Thioaildenafil; Thiohomosildenafil; Vardenafil