Synthesis and Spectral Characterization of Related Substances of Vardenafil, an Erectile Dysfunction Drug

Abstract

Vardenafil hydrochloride trihydrate (Levitra) is used to treat erectile dysfunction (ED) and is an inhibitor of phosphodiesterase type 5 (PDE-5) enzyme. It maintains higher levels of cyclic guanosine monophosphate (cGMP), relaxes smooth muscles, promotes penile blood flow, and enhances erectile function. During the bulk drug synthesis of vardenafil hydrochloride trihydrate, six related substances (impurities), vardenafil dimer, vardenafil N-oxide, vardenafil glycene, vardenafil oxopiperazine, vardenafil oxoacetic acid, and phenyl vardenafil were identified, and these are reported herein for the first time. The present work describes the synthesis and characterization of these impurities.

GRAPHICAL ABSTRACT

Keywords:

• Erectile dysfunction drug
• related substances
• spectral characterization
• synthesis
• vardenafil

ACKNOWLEDGMENTS

The authors are grateful to their colleagues in the Analytical Research Department of IPDO, Discovery Research, and the management of Dr. Reddy's Laboratories Ltd., for providing necessary support.