Ketamine is characterized by a few rings: an aryl ring, a cyclohexyl ring, and an amine ring (Determine 1). The cyclohexane ring is frequently intact because it is needed for antagonism of the NMDA receptor. ACHs are chiral; the asymmetric carbon from the C2 position has two optical isomers. Ketamine is marketed to be a racemate (i.Disclaimer: The