Identification of a novel vardenafil analogue, 19-O-propyl hydroxy vardenafil, as a dietary supplement adulterant

J Pharm Biomed Anal. 2024 Nov 4:253:116563. doi: 10.1016/j.jpba.2024.116563. Online ahead of print.

Abstract

A novel vardenafil analogue was discovered during adulterant screening of a dietary supplement. After extraction and purification, this analogue was identified using liquid chromatography-high resolution mass spectrometry (LC-HRMS) and nuclear magnetic resonance (NMR) analyses. The molecular formula determined using LC-HRMS was C24H34N6O5S. Fragmentation data suggested that this unknown compound may have two modifications to vardenafil. NMR analysis confirmed the presence of a hydroxyl group on the piperazine moiety and a propyl group attached to the phenoxy group. Consequently, this compound was named 19-O-propyl hydroxy vardenafil.

Keywords: 19-O-propyl hydroxy vardenafil; HRMS; NMR; PDE-5 inhibitor; Vardenafil analogue.