title: Development of a comprehensive spectral library of sildenafil and related active analogues using LC-QTOF-MS and its application for screening counterfeit pharmaceuticals.
abstract: The abuse or misuse of forged erectile-dysfunction drugs, containing phosphodiesterase type 5 inhibitors (e.g. sildenafil), is a serious issue globally. Therefore, the detection of sildenafil and related active analogues in counterfeit pharmaceuticals or the differentiation between counterfeit and authentic drugs has been performed with a variety of analytical techniques. Recently, a liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS)-based in-house library, consisting of accurate mass ion fragmentation information and retention times, was effectively applied to screen a large number of compounds in field of forensic toxicology. However, a comprehensive LC-QTOF-MS spectral library of sildenafil and related active analogues has not yet been reported. In the present study, a spectral library of 40 compounds of sildenafil and related analogues was developed with accurate mass spectra and retention times using LC-QTOF-MS, and applied to screen nine marketed counterfeit products. The in-house library successfully identified sildenafil, dimethylsildenafil, hydroxyhomosildenafil, demethylhongdenafil, pseudovardenafil and vardenafil in the samples. Our LC-QTOF-MS-based spectral library search is considered a powerful approach for identifying sildenafil and related active analogues in counterfeit pharmaceuticals.
authors.affiliation: College of Pharmacy, Keimyung University, 1095 Dalgubeoldaero, Dalseo-gu, Daegu 704-701, Republic of Korea.
authors.forename: Sooyeun
authors.initials: S
authors.lastname: Lee
authors.affiliation: College of Pharmacy, Keimyung University, 1095 Dalgubeoldaero, Dalseo-gu, Daegu 704-701, Republic of Korea.
authors.forename: Dajeong
authors.initials: D
authors.lastname: Ji
authors.affiliation: National Forensic Service, 10, Ipchun-ro, Wonju 220-170, Gangwon-do, Republic of Korea.
authors.forename: Meejung
authors.initials: M
authors.lastname: Park
authors.affiliation: School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746, Gyeonggi-do, Republic of Korea. Electronic address: khchung@skku.edu.
authors.forename: Kyu Hyuck
authors.initials: KH
authors.lastname: Chung
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D058110:Counterfeit Drugs / Q000737:chemistry*; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D058986:Phosphodiesterase 5 Inhibitors / Q000737:chemistry*; D000068677:Sildenafil Citrate / Q000737:chemistry*
chemical_list: D058110:Counterfeit Drugs; D058986:Phosphodiesterase 5 Inhibitors; D000068677:Sildenafil Citrate
keywords: Counterfeit drugs; LC–QTOF–MS; Sildenafil; Spectral library