title: Identification and structural elucidation of three new tadalafil analogues found in a dietary supplement.
abstract: Compounds elucidated as new tadalafil analogues were found to be adulterated in a dietary supplement and detected during routine analysis by HPLC with photodiode array detection. The UV spectra of these compounds were found to be almost identical to that of tadalafil. The unknown compounds were isolated by preparative HPLC and elucidated by quadrupole-time-of-flight MS and NMR spectroscopy. Two compounds were identified as cyclopentyltadalafil and trans-cyclopentyltadalafil, from the substitution of the tadalafil N-methyl group with a cyclopentyl group. Another analogue was a dimeric form of tadalafil with an N-cyclopentyl group. This represents the first report of the elucidation of compounds used as adulterants in a dietary supplement.
authors: 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 363-700, Republic of Korea.
authors: Ji Hyun
authors: JH
authors: Lee
authors: College of Pharmacy, Kangwon National University, Chuncheon, Kangwon-do 200-701, Republic of Korea.
authors: Suresh
authors: S
authors: Mandava
authors: 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 363-700, Republic of Korea. Electronic address: stepany9838@korea.kr.
authors: Sun Young
authors: SY
authors: Baek
authors: College of Pharmacy, Chungbuk National University, Chungdae-Ro, Seowon-Ku, Cheongju 362-763, Republic of Korea. Electronic address: ymleefn@chungbuk.ac.kr.
authors: Yong-Moon
authors: YM
authors: Lee
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D019587:Dietary Supplements / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D013058:Mass Spectrometry / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D000068581:Tadalafil / Q000031:analogs & derivatives* / Q000737:chemistry*
chemical_list: D000068581:Tadalafil
keywords: Cyclopentyltadalafil; LC-TOF/MS; NMR; Tadalafil analogues