Methadone hydrochloride

What is Methadone hydrochloride?

Methadone hydrochloride definition and meaning on Dictionary terms:
noun Biochemistry.
an amino acid, CH3SCH2CH2CH(NH2)COOH, found in casein, wool, and other proteins or prepared synthetically: used as a supplement to a special diet in the prevention and treatment of certain liver diseases. Abbreviation: Met; Symbol: M