O3 Molecular Weight:
Eszopiclone, marketed by Sepracor under the brand-name Lunesta, is a nonbenzodiazepine hypnotic agent (viz., a sedative) used as a treatment for insomnia. Eszopiclone is the active stereoisomer of zopiclone, and belongs to the class of drugs known as cyclopyrrones.
Its main selling point is that it is approved by the U.S. Food and Drug Administration for long-term use, unlike almost all other hypnotic sedatives, which are approved only for the relief of short-term (6-8 weeks) insomnia. From: DrugBank