title: Identification of a new tadalafil analogue in commercial dietary supplements: isopropylnortadalafil.
abstract: A new tadalafil analogue was found in a commercial dietary supplement for enhancing sexual performance. The compound was detected by a high-performance liquid chromatography-diode array detector (HPLC-DAD). The analogue was isolated using semi-preparative HPLC, and its accurate mass was established by two LC-high-resolution-mass spectrometers (LC-HRMS). The structure was determined by nuclear magnetic resonance (NMR) spectroscopy. The accurate mass of the compound corresponded to a molecular formula of C24H23N3O4. The compound was identified as a structural analogue of tadalafil in which the N-methyl group of tadalafil was replaced with an N-isopropyl group. We have named the new analogue isopropylnortadalafil and it is first reported herein.
authors.affiliation: a Advanced Analysis Team, Toxicological Evaluation and Research Department , National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety , Cheongju-si , Chungcheongbuk-do , South Korea.
authors.forename: Han Na
authors.initials: HN
authors.lastname: Park
authors.affiliation: a Advanced Analysis Team, Toxicological Evaluation and Research Department , National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety , Cheongju-si , Chungcheongbuk-do , South Korea.
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Lee
authors.affiliation: a Advanced Analysis Team, Toxicological Evaluation and Research Department , National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety , Cheongju-si , Chungcheongbuk-do , South Korea.
authors.forename: Sung-Kwan
authors.initials: SK
authors.lastname: Park
authors.affiliation: b College of Pharmacy , Kangwon National University , Chuncheon , Gangwon-do , South Korea.
authors.forename: Jongkook
authors.initials: J
authors.lastname: Lee
authors.affiliation: a Advanced Analysis Team, Toxicological Evaluation and Research Department , National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety , Cheongju-si , Chungcheongbuk-do , South Korea.
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Baek
mesh_terms: D002851:Chromatography, High Pressure Liquid; D019587:Dietary Supplements / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008968:Molecular Conformation; D000068581:Tadalafil / Q000031:analogs & derivatives* / Q000032:analysis* / Q000737:chemistry
chemical_list: C000614943:isopropylnortadalafil; D000068581:Tadalafil
keywords: LC-HRMS; NMR; PDE-5 inhibitor; adulterated dietary supplement; isopropylnortadalafil; tadalafil analogue