| Reference | [1]. Hong Kong Med J. 2007 Oct;13(5):359-63.<br />
Analogues of erectile dysfunction drugs: an under-recognised threat.<br />
Poon WT(1), Lam YH, Lai CK, Chan AY, Mak TW.<br />
Author information: (1)Hospital Authority Toxicology Reference Laboratory, Princess Margaret Hospital, Laichikok, Hong Kong.<br />
OBJECTIVES: To investigate the problem of drug analogue adulteration in male erectile dysfunction health products. DESIGN: Survey of over-the-counter male erectile dysfunction health products available in convenience stores and pharmacies in Hong Kong. SETTING: Tertiary referral centre for clinical toxicology analysis in Hong Kong. MAIN OUTCOME MEASURES: The pattern and extent of adulteration of male erectile dysfunction health products with sildenafil, tadalafil, and vardenafil as well as their structurally modified analogues. RESULTS: Of 26 products studied, one (4%) was found to contain undeclared sildenafil, while 14 (54%) contained drug analogues of different kinds. The latter included acetildenafil, hydroxyacetildenafil, hydroxyhomosildenafil, and piperidenafil. The first three were analogues of sildenafil and the last was an analogue of vardenafil. One young patient presented with ataxia after taking an acetildenafil-containing product. CONCLUSIONS: The positive rate of concealed drug analogues in male erectile dysfunction health products is alarmingly high. Such analogues are difficult to detect by ordinary laboratory methods, and might be used in an attempt to evade regulatory inspection. Without going through the stringent drug testing process, the adverse effects of these chemicals remain largely unknown and unpredictable. Effective surveillance system and control measures are needed urgently. The medical profession and the public should be alerted to this under-recognised threat.<br />
PMID: 17914141 [Indexed for MEDLINE]<br />
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[2]. J AOAC Int. 2015 Sep-Oct;98(5):1226-33. doi: 10.5740/jaoacint.14-285.<br />
Simultaneous Detection of Three Phosphodiesterase Type 5 Inhibitors and Eight of Their Analogs in Lifestyle Products and Screening for Adulterants by High-Performance Thin-Layer Chromatography.<br />
Do TT, Theocharis G, Reich E.<br />
Comment in J Urol. 2016 Aug;196(2):514-5.<br />
An HPTLC method is proposed to permit effective screening for the presence of three phosphodiesterase type 5 inhibitors (PDE5-Is; sildenafil, vardenafil, and tadalafil) and eight of their analogs (hydroxyacetildenafil, homosildenafil, thiohomosildenafil, acetildenafil, acetaminotadalafil, propoxyphenyl hydroxyhomosildenafil, hydroxyhomosildenafil, and hydroxythiohomosildenafil) in finished products, including tablets, capsules, chocolate, instant coffee, syrup, and chewing gum. For all the finished products, the same simple sample preparation may be applied: ultrasound-assisted extraction in 10 mL methanol for 30 min followed by centrifugation. The Rf values of individual HPTLC bands afford preliminary identification of potential PDE5-Is. Scanning densitometry capabilities enable comparison of the unknown UV spectra with those of known standard compounds and allow further structural insight. Mass spectrometric analysis of the material derived from individual zones supplies an additional degree of confidence. Significantly, the proposed screening technique allows focus on the already known PDE5 Is and provides a platform for isolation and chemical categorization of the newly-synthesized analogs. Furthermore, the scope could be expanded to other therapeutic categories (e.g., analgesics, antidiabetics, and anorexiants) that are occasionally coadulterated along with the PDE5-Is. The method was successfully applied to screening of 45 commercial lifestyle products. Of those, 31 products tested positive for at least one illegal component (sildenafil, tadalafil, propoxyphenyl hydroxyhomosildenafil, or dimethylsildenafil).<br />
DOI: 10.5740/jaoacint.14-285 PMID: 26525240 [Indexed for MEDLINE]<br />
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[3]. Rapid Commun Mass Spectrom. 2006;20(15):2317-27. doi: 10.1002/rcm.2594.<br />
Accurate mass measurement using Fourier transform ion cyclotron resonance mass spectrometry for structure elucidation of designer drug analogs of tadalafil, vardenafil and sildenafil in herbal and pharmaceutical matrices.<br />
Gratz SR(1), Gamble BM, Flurer RA.<br />
Author information: (1)Food and Drug Administration, Forensic Chemistry Center, Cincinnati, OH 45237, USA. [email protected]<br />
Phosphodiesterase type 5 (PDE-5) inhibitors are a class of drugs used primarily in the treatment of erectile dysfunction. The Food and Drug Administration (FDA) approved PDE-5 inhibitors include sildenafil citrate, vardenafil hydrochloride and tadalafil. In this study, accurate mass measurements were made by electrospray ionization (ESI) using Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) to elucidate the structures of sildenafil, tadalafil and vardenafil analogs that were found in products marketed as dietary supplements. Initial detection of these analogs was accomplished through routine screening of suspect samples by liquid chromatography/electrospray ionization multi-stage mass spectrometry (LC/ESI-MS(n)) on a low-resolution ion trap instrument. The chromatographic behavior and mass spectrometric fragmentation patterns observed were often similar to those observed for FDA approved PDE-5 inhibitors. The mass accuracy and resolving power associated with FTICRMS allows for the determination of elemental compositions. Elucidation of the product ion structures for the analogs was accomplished through the use of accurate mass measurements with the aid of Mass Frontier software (version 4.0). Using FTICRMS, accurate masses with measurement errors averaging <0.4 ppm were achieved, allowing assignment of one possible elemental formula to each fragment ion. The mass measurement errors associated with [M + H](+) for the analogs aminotadalafil, piperidino vardenafil, hydroxyacetildenafil and piperidino acetildenafil were 0.1, 0.0, 0.1 and 0.5 ppm, respectively. Based on the accuracy of the measurements, structural assignments could be made with a high degree of confidence.<br />
DOI: 10.1002/rcm.2594 PMID: 16817245 [Indexed for MEDLINE]<br />
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[4]. Food Addit Contam. 2006 Sep;23(9):870-5. doi: 10.1080/02652030600803856.<br />
Structural identification of a new acetildenafil analogue from pre-mixed bulk powder intended as a dietary supplement.<br />
Hou P(1), Zou P, Low MY, Chan E, Koh HL.<br />
Author information: (1)Department of Pharmacy, Faculty of Science, National University of Singapore, Science Drive 4, Singapore 117543.<br />
An analogue of acetildenafil was detected in an extract of pre-mixed bulk powder. To our knowledge, the powder was destined to be encapsulated and sold as a dietary supplement. The structure was identified by NMR, HR-ESI-MS, ESI-MSn and FTIR analyses. Owing to the inclusion of a hydroxyl group in acetildenafil, the detected compound was called 'hydroxyacetildenafil'. With increasing use of dietary supplements marketed for penile erectile dysfunction, the detection of analogues of sexual performance enhancers is important and timely.<br />
DOI: 10.1080/02652030600803856 PMID: 16901855 [Indexed for MEDLINE]
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