Basics
Milnacipran is an active substance that is used to treat depression. It belongs to the group of serotonin-norepinephrine reuptake inhibitors (SNRIs). Milnacipran is usually available as milnacipran hydrochloride, is a white crystalline powder and is readily soluble in water. The active substance is a racemic 1:1 mixture consisting of the 1R,2S isomer and the 1S,2R isomer. A racemate is an active substance that consists of 2 molecules that occur in a 1:1 ratio and behave like image and mirror image. One speaks of the R-(dextrorotatory) enantiomer and S-(levorotatory) enantiomer. Enantiomers do NOT differ in their physical properties such as melting or boiling point. However, they can behave in opposite ways in terms of their effects. For example, (S)-carvone smells like caraway and (R)-carvone smells like mint. The amino acid (S)-valine tastes bitter, while (R)-valine tastes sweet. For these reasons, both enantiomers are always tested in today's approval procedures for new active ingredients. Sometimes one enantiomer can be converted into the other in the body.