Escitalopram ((S) -Citalopram) oxalate, the S-enantiomer of racemic Citalopram, is a selective serotonin reuptake inhibitor (SSRI) with a Ki of 0.89 nM. Escitalopram oxalate has ∼30 fold higher binding affinity than its R (-) -enantiomer and shows selectivity over both dopamine transporter (DAT) and norepinephrine transporter (NET) . Escitalopram oxalate is an antidepressant for the research of major depression[1][2].