Structure Confirmation of Illegal Additive N-benzyltadalafil in Chinese Patent Medicine

OBJECTIVE To identify a new tadalafil analogue in Chinese patent medicine.METHODS HPLC-DAD preliminary screening and preparative liquid chromatography were used to separate and purify the illegal additives in Chinese patent medicine. The precise molecular weight and structural fragments were determined by high resolution mass spectrometry. The structure of the additive was determined by combining carbon and hydrogen spectroscopy.RESULTS The additive was N-benzyl tadalafil.CONCLUSION The chemical structure of N-benzyl tadalafil has been reported, but it has been detected for the first time as an illegal additive of Chinese patent medicine.