Desvenlafaxine (brand name: Pristiq, Desfax), also known as O-desmethylvenlafaxine, is an antidepressant of the serotonin-norepinephrine reuptake inhibitor (SNRI) class developed and marketed by Wyeth (now part of Pfizer). Desvenlafaxine is a synthetic form of the major active metabolite of venlafaxine (sold under the brand names Effexor and Efexor). It is being targeted as the first non-hormonal based treatment for menopause. Desvenlafaxine is a synthetic phenethylamine bicyclic derivative with antidepressant activity. Desvenlafaxine is a selective reuptake inhibitor of serotonin and norepinephrine due to its high binding affinities to the pre-synaptic serotonin and norepinephrine transporters. By blocking both transporters, this agent prolongs neurotransmitter activities of both serotonin and norepinephrine, thereby alleviating depressive state. (Source: https://en.wikipedia.org/wiki/Desvenlafaxine).

Providing storage is as stated on the product vial and the vial is kept tightly sealed, the product can be stored for up to 24 months.
Wherever possible, you should prepare and use solutions on the same day. However, if you need to make up stock solutions in advance, we recommend that you store the solution as aliquots in tightly sealed vials at -20°C. Generally, these will be useable for up to one month. Before use, and prior to opening the vial we recommend that you allow your product to equilibrate to room temperature for at least 1 hour.