Structural characterization of sulfoaildenafil, an analog of sildenafil.
Phosphodiesterase type 5 (PDE-5) inhibitors represent a class of drugs used primarily in the treatment of erectile dysfunction. Currently, three PDE-5 inhibitors have been approved by the U.S. Food and Drug Administration (FDA) for use in the United States: sildenafil citrate, tadalafil, and vardenafil hydrochloride trihydrate. A bulk material, labeled as an ingredient for a dietary supplement, was analyzed for the presence of PDE-5 inhibitors. The compound that was detected displayed structural similarities to sildenafil, and was characterized further using LC-MS(n), FTICRMS, X-ray crystallography and NMR. The compound was given the name sulfoaildenafil. When compared to sildenafil, sulfoaildenafil contains a sulfur atom substitution for the oxygen atom in the pyrazolopyrimidine portion of the molecule, and a 3,5-dimethyl substitution on the piperazine ring, rather than the 4-methyl moiety. The X-ray crystallographic data indicate that the material in this sample is comprised of two polymorphs, which may affect the chemical and/or biological properties of any product formulated with this compound.
U.S. Food and Drug Administration, Forensic Chemistry Center, 6751 Steger Drive, Cincinnati, OH 45237, USA.
Samuel R
SR
Gratz
Matthias
M
Zeller
Daryl W
DW
Mincey
Cheryl L
CL
Flurer
D002853:Chromatography, Liquid; D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008958:Models, Molecular; D015394:Molecular Structure; D010726:Phosphodiesterase Inhibitors / Q000737:chemistry*; D010879:Piperazines / Q000737:chemistry*; D011687:Purines / Q000737:chemistry; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000737:chemistry*
D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; C543174:sulfoaildenafil; D000068677:Sildenafil Citrate