• Molecular NameMethadone
  • Synonym(+/-)-Methadone; (+/-)-Methadone hydrochloride; dl-Methadone; DL-Methadone hydrochloride; Methadon; Methadone HCL; Methadone hydrochloride; Phenadone hydrochloride
  • Weight309.453
  • Drugbank_IDDB00333
  • ACS_NO76-99-3
  • Show 3D model
  • LogP (experiment)3.93
  • LogP (predicted, AB/LogP v2.0)4.23
  • pka8.94
  • LogD (pH=7, predicted)2.54
  • Solubility (experiment)0.0485 mg/ml
  • LogS (predicted, ACD/Labs)(ph=7)-1.76
  • LogSw (predicted, AB/LogsW2.0)0.05
  • Sw (mg/ml) (predicted, ACD/Labs)0.07
  • No.of HBond Donors0
  • No.of HBond Acceptors2
  • No.of Rotatable Bonds7
  • TPSA20.31
  • StatusFDA approved
  • AdministrationOral, intravenous, insufflation, sublingual, rectal
  • PharmacologyA synthetic opioid, used medically as an analgesic, antitussive and a maintenance anti-addictive for use in patients on opioids.
  • Absorption_value80.0
  • Absorption (description)Methadone is well absorbed from the gastrointestinal tract and can be detected in plasma within 30 minutes after oral ingestion; it reaches peak concentrations at about 4 hours.
  • Caco_2N/A
  • Bioavailability92.0
  • Protein binding89.0
  • Volume of distribution (VD)3.6 L/kg
  • Blood/Plasma Partitioning ratio (D_blood)N/A
  • MetabollsmMethadone undergoes extensive biotransformation in the liver. The major metabolites, the results of N-demethylation and cyclization to form pyrrolidines and pyrroline, are excreted in the urine and the bile along with small amounts of unchanged drug.
  • Half life27 h
  • ExcretionUrine, Test by specific gravity and bilirubin
  • Urinary Excretion24
  • Clerance1.7 ml/min/kg
  • ToxicityN/A
  • LD50 (rat)N/A
  • LD50 (mouse)N/A