This article is a U.S. Government work and is in the public domain in the U.S.A.
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†
Article first published online: 3 JUL 2006
This article is a U.S. Government work and is in the public domain in the U.S.A. Published in 2006 by John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry
Volume 20, Issue 15, pages 2317–2327, 15 August 2006
How to Cite
Gratz, S. R., Gamble, B. M. and Flurer, R. A. (2006), 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. Rapid Commun. Mass Spectrom., 20: 2317–2327. doi: 10.1002/rcm.2594
- Issue published online: 3 JUL 2006
- Article first published online: 3 JUL 2006
- Manuscript Accepted: 2 JUN 2006
- Manuscript Revised: 1 JUN 2006
- Manuscript Received: 1 MAY 2006
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-MSn) 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. Published in 2006 by John Wiley & Sons, Ltd.