Vilazodone -d 8 hydrochloride is deuterated labeled Vilazodone. Vilazodone (EMD 68843; SB 659746A) is a potent, selective and orally active serotonin reuptake inhibitor (SSRI) and partial 5-HT 1 A receptor agonist. Vilazodone exhibits antidepressant efficacy in vivo can be used for the research of major depressive disorder (MDD) and affective disorders.