Identification of a novel sildenafil analogue in an adulterated herbal supplement

► iErect is a new dietary supplement “100% natural” sold over the Internet. ► It contains thiosildenafil and a new analog named depiperazinothiosildenafil. ► LC–MS n, accurate mass, NMR and IR were used to characterize the new analog. ► A capsule contains ≈220 and ≈30 mg of thiosildenafil and depiperazinothiosildenafil. iErect, a new dietary supplement marketed as “100% natural” and sold over the Internet, was analyzed. It contains thiosildenafil, a sildenafil analogue already reported as an adulterant in herbal formulations, and a new compound whose structure was elucidated after isolation using NMR, MS and IR. It was named depiperazinothiosildenafil as it results from the hydrolytic cleavage of the S–N bond of the sulfonamide group of thiosildenafil. A capsule of iErect contains a very high amount (≈220 mg) of thiosildenafil and ≈30 mg of depiperazinothiosildenafil, which places consumers at risk for potentially serious side-effects.