Isolation and Identification of a Vardenafil Analogue in a Dietary Supplement
Kuo-Chih Lai1, Yi-Chu Liu1, Mu-Chang Tseng1, Yun-Lian Lin2 and Jer-Huei Lin1*
1. Bureau of Food and Drug Analysis, Department of Health, Executive Yuan, 161-2, Kunyang St., Nangang, Taipei 115, Taiwan, R.O.C.
2. Natiearch Institute of Chinese Medicine, 155-1, Sec. 2, Linong St., Beitou, Taipei 112, Taiwan, R.O.C.
(Received: August 31, 2006; Accepted: March 13, 2007)
(Received: August 31, 2006; Accepted: March 13, 2007)
A vardenafil analogue was found to be added illegally into a dietary supplement marketed for erectile dysfunction. Its structure was determined as 2-(2-ethoxyphenyl)-5-methyl-7-propyl-imidazo[5,1-f][1,2,4]triazin-4(3H)-one. The sample was extracted with ethanol and isolated by column chromatography. The structure was identified with a series of 1-D and 2-D NMR techniques and LC/MS/MS. Having compared with structure of vardenafil, the data showed that the ethylpiperazinyl and sulfonyl of vardenafil were removed from the phenyl group. Since its structure was similar to that of vardenafil, side effects of vardenafil might associate with this analogue. This vardenafil analogue has been included in the inspection list of illegal adulterants in Taiwan.
Key words: vardenafil analogue, LC/MS/MS, NMR