Fadanafil

Main objectives: 1. To investigate the distribution of [14C]-fadanafil in plasma and whole blood and the pharmacokinetics of total radioactivity in plasma after a single oral administration of [14C]-fadanafil to healthy subjects; 2. To quantitatively analyze the total radioactivity in excreta after oral administration of [14C]-fadanafil to healthy subjects, and obtain the data of recovery rate and main excretion pathway in human body; 3. To determine the radioactive metabolite spectrum in plasma, urine and feces of healthy subjects after oral administration of [14C]-fadanafil and identify the main metabolites, and provide data on the main metabolic pathways of fadanafil in human body. Secondary objectives: 1. To quantitatively analyze the concentration of fadanafil parent drug and metabolites in plasma using the validated liquid chromatography-mass spectrometry (LC-MS/MS) technology, and obtain the pharmacokinetic parameters of fadanafil and metabolites in plasma; 2. To observe the safety of a single oral administration of [14C]-fadanafil to healthy subjects.