title: Therapeutic modulation of cannabinoid lipid signaling: metabolic profiling of a novel antinociceptive cannabinoid-2 receptor agonist.
abstract: OBJECTIVE
  AM-1241, a novel, racemic cannabinoid-2 receptor (CB2) ligand, is the primary experimental agonist used to characterize the role of CB2-mediated lipid signaling in health and disease, including substance abuse disorders. In vivo pharmacological effects have been used as indirect proxies for AM-1241 biotransformation processes that could modulate CB2 activity. We report the initial pre-clinical characterization of AM-1241 biotransformation and in vivo distribution.
  
  
  METHODS
  AM-1241 metabolism was characterized in a variety of predictive in vitro systems (Caco-2 cells; mouse, rat and human microsomes) and in the mouse in vivo. Liquid chromatography and mass spectrometry techniques were used to quantify AM-1241 tissue distribution and metabolic conversion.
  
  
  RESULTS
  AM-1241 bound extensively to plasma protein/albumin. A pharmacological AM-1241 dose (25mg/kg, i.v.) was administered to mice for direct determination of its plasma half-life (37 min), following which AM-1241 was quantified in brain, spleen, liver, and kidney. After p.o. administration, AM-1241 was detected in plasma, spleen, and kidney; its oral bioavailability was ~21%. From Caco-2 permeability studies and microsomal-based hepatic clearance estimates, in vivo AM-1241 absorption was moderate. Hepatic microsomal metabolism of AM-1241 in vitro generated hydroxylation and demethylation metabolites. Species-dependent differences were discovered in AM-1241's predicted hepatic clearance. Our data demonstrate that AM-1241 has the following characteristics: a) short plasma half-life; b) limited oral bioavailability; c) extensive plasma/albumin binding; d) metabolic substrate for hepatic hydroxylation and demethylation; e) moderate hepatic clearance.
  
  
  CONCLUSIONS
  These results should help inform the design, optimization, and pre-clinical profiling of CB2 ligands as pharmacological tools and medicines.
authors: Center for Drug Discovery, Northeastern University, Boston, MA, USA. j.wood@neu.edu
authors: Jodianne T
authors: JT
authors: Wood
authors: Dustin M
authors: DM
authors: Smith
authors: David R
authors: DR
authors: Janero
authors: Alexander M
authors: AM
authors: Zvonok
authors: Alexandros
authors: A
authors: Makriyannis
mesh_terms: D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D001711:Biotransformation; D001798:Blood Proteins / Q000378:metabolism; D018938:Caco-2 Cells; D002186:Cannabinoids / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D063388:Endocannabinoids / Q000502:physiology*; D006801:Humans; D007202:Indicators and Reagents; D007274:Injections, Intraperitoneal; D007279:Injections, Subcutaneous; D008055:Lipids / Q000502:physiology*; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D011485:Protein Binding; D043885:Receptor, Cannabinoid, CB2 / Q000819:agonists*; D015398:Signal Transduction / Q000187:drug effects; D013057:Spectrum Analysis; D014018:Tissue Distribution
chemical_list: C439263:AM 1241; D000700:Analgesics; D001798:Blood Proteins; D002186:Cannabinoids; D063388:Endocannabinoids; D007202:Indicators and Reagents; D008055:Lipids; D043885:Receptor, Cannabinoid, CB2