Crystalline form III of agomelatine, or N-[2-(7-methoxy-1-naphthyl)ethyl]acetamide is new. The compound is confirmed by powder X-ray diffraction pattern as given in the specification. An independent claim is included for preparation of the crystalline form III of agomelatine, or N-[2-(7-methoxy-1-naphthyl)ethyl]acetamide involves: heating agomelatine at 110[deg]C until fully melted, and then slowly cooled until recrystallization occurs. ACTIVITY : Hypnotic； Tranquilizer； Antidepressant； Gastrointestinal-Gen； CNS-Gen； Cardiovascular-Gen.； Neuroleptic； Muscular-Gen.； Immunomodulator； Eating-Disorder-Gen.； Anorectic； Anticonvulsant； Antidiabetic； Antiparkinsonian； Nootropic； Neuroprotective； Dermatological； Antimigraine； Cerebroprotective； Endocrine-Gen.； Cytostatic； Analgesic； Contraceptive. MECHANISM OF ACTION : Melatoninergic system receptor agonist； 5-HT(hydroxytryptamine)-2C receptor antagonist. No biological data given.
