一種暗示具壯陽效果之食品，檢出非法摻加威而剛類緣物（sildenafilanalogue）成分，其結構經鑑定為5-{2-ethoxy-5-[2-(4-ethylpiperazine-1-yl)-acetyl] phenyl}-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one。該食品檢體先以甲醇萃取，經酸鹼平衡重覆分離純化處理後，再由一維與二維核磁共振儀（1H-nMR, 13C-nMR, COsy, dePt, HMQC,HMBC）、紅外線吸收光譜儀（IR），高解析度質譜分析儀（HRMs）及高效液相串聯式質譜儀（lC/Ms/Ms）等儀器鑑定其結構。此結構為威而剛類緣物，係首次在台灣發現之非法外添加成分。為保障民眾健康，已將此成分列為非法摻加西藥例行檢查項目之一。

A new sildenafil analogue was found to be added illegally to a dietary supplement marketed for erectile dysfunction. The structure was determined as 5-{2-ethoxy-5-[2-(4-ethylpiperazine-1-yl)-acetyl]phenyl}-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one. The sample was extracted with methanol and purified with a liquid-liquid partition method. The structure was identified with a series of 1-D and 2-D NMR techniques, infrared spectrum, high-resolution mass and LC/MS/MS. Having compared the structure with sildenafil, the results showed the methylpiperazine was switched with an ethylpiperazine and the sulfonyl group with an acetyl group. This new sildenafil analogue was isolated and identified for the first time in Taiwan. Since the structure was similar to that of sildenafil, side effects of sildenafil might associate with this new analogue. Therefore, it has been included in the inspection list of illegal health-related substances in Taiwan.