Esmethadone (; developmental code name REL-1017), also known as dextromethadone, is the (''S'')-
enantiomer
In chemistry, an enantiomer (Help:IPA/English, /ɪˈnænti.əmər, ɛ-, -oʊ-/ Help:Pronunciation respelling key, ''ih-NAN-tee-ə-mər''), also known as an optical isomer, antipode, or optical antipode, is one of a pair of molecular entities whi ...
of
methadone
Methadone, sold under the brand names Dolophine and Methadose among others, is a synthetic opioid used medically to treat chronic pain and opioid use disorder. Prescribed for daily use, the medicine relieves cravings and opioid withdrawal sym ...
antagonist
An antagonist is a character in a story who is presented as the main enemy or rival of the protagonist and is often depicted as a villain. Unlike levomethadone, it has low
affinity
Affinity may refer to:
Commerce, finance and law
* Affinity (law), kinship by marriage
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* Affinity Credit Union, a Saskatchewan-based credit union
* Affinity Equity Pa ...
for
opioid receptor
Opioid receptors are a group of inhibitory G protein-coupled receptors with opioids as ligands. The endogenous opioids are dynorphins, enkephalins, endorphins, endomorphins and nociceptin. The opioid receptors are ~40% identical to somatostati ...
s and lacks significant respiratory depressant action and abuse liability. Esmethadone is under development for the treatment of
major depressive disorder
Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive depression (mood), low mood, low self-esteem, and anhedonia, loss of interest or pleasure in normally ...
clinical trial
Clinical trials are prospective biomedical or behavioral research studies on human subject research, human participants designed to answer specific questions about biomedical or behavioral interventions, including new treatments (such as novel v ...
s for this indication.
There is an asymmetric synthesis available to prepare both esmethadone (S-(+)-methadone) and levomethadone (R-(−)-methadone).