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Research tools

URB597Also known as KDS-4103

The reference FAAH inhibitor. The standard pharmacological tool for studying endogenous AEA in vivo.

Unscheduled
Level of detail

C₂₀H₂₂N₂O₃

CAS 546141-08-6

Family
ECS pharmacological toolEnzyme inhibitor
Origin
Pharmaceutical research (Piomelli)
First described
2003
Molar mass
338.40 g/mol

Updated on

In plain terms

URB597 is a laboratory compound that stops an enzyme (FAAH) from destroying anandamide, a cannabinoid made by the body. It is used to study this system in animals. It has never been marketed.

Receptors and activity

Target network

FAAHInhibitorIC50 = 5 nM · ratbrain membranes; 3 nM on human liver microsomes
  • Blocks or inhibits

The lower the cited value, the closer the target sits to URB597: one ring per factor of 100. A target with no measured value stays on the edge.

Where these targets live

Where each target has been found in humans, according to the cited studies. The map shows the target, not an effect of URB597.

Brain, side view
Body, front view
Blood

FAAHFAAH found in 7 regions of the body

  1. CortexpresentCortical pyramidal neurons1
  2. Basal gangliapresentStriatal neurons1
  3. HypothalamuspresentPresent in hypothalamic nuclei1
  4. CerebellumpresentPurkinje cells and cerebellar layers1
  5. BrainstempresentInferior olivary nuclei1
  6. Adipose tissuepresentExpressed in mature adipocytes2
  7. BonepresentPresent on osteoclasts3

Map sources

  1. Romero J et al. Fatty acid amide hydrolase localization in the human central nervous system: an immunohistochemical study. Brain Res Mol Brain Res, 2002 (new tab)
  2. Engeli S et al. Activation of the peripheral endocannabinoid system in human obesity. Diabetes, 2005 (new tab)
  3. Rossi F et al. The endovanilloid/endocannabinoid system in human osteoclasts: possible involvement in bone formation and resorption. Bone, 2009 (new tab)

Cited values

  1. FAAHInhibitorIC50 = 5 nM · rat72 out of 100

    Piomelli et al., CNS Drug Rev 2006 (new tab) · brain membranes; 3 nM on human liver microsomes

Bar length follows the measured value (Ki, Kd, EC50 or IC50), on one scale shared by every entry, from 100 µM to 0.1 nM. A target with no cited value has no bar.

Measured effects

Not characterised. No placebo-controlled human trial has measured the effects of URB597, so no level is shown.

Levels computed from placebo-controlled human trials: difference from placebo on 100, at the dose and route stated. Read the method

Pharmacology

URB597 (KDS-4103) is a covalent inhibitor of FAAH, the enzyme that breaks down anandamide. It belongs to the O-arylcarbamate series developed by Piomelli's group (Kathuria et al., Nat Med 2003, PMID 12461523); in the structure-activity study by Mor et al. (J Med Chem 2004, PMID 15456244) it is the most potent derivative of the series, with an IC50 of 4.6 nM. In vitro it inhibits FAAH with an IC50 of 5 nM on rat brain membranes and 3 nM on human liver microsomes, with no significant interaction with cannabinoid receptors (Piomelli et al. 2006, PMID 16834756). In rats it raised brain anandamide and produced anxiolytic-like effects, blocked by a CB1 antagonist (Kathuria 2003), then antidepressant-like effects in a chronic mild stress model (Bortolato et al., Biol Psychiatry 2007, PMID 17511970). The crystal structure of the FAAH-URB597 complex was solved at 2.3 Å (Mileni et al., J Mol Biol 2010, PMID 20493882). It is a preclinical research tool and is not marketed.

Key sources.

Origin

Research tool

A covalent inhibitor of FAAH; a synthetic molecule of the O-arylcarbamate series (a biphenyl carbamic ester).

Classification

Family, origin and source verification

Family

ECS pharmacological tool › Enzyme inhibitor

Verification

Classification, sources and binding values checked on 20 October 2026; text read against its sources and Wikipedia.

Wikipedia (English)

EX-597 (new tab)

Article paired by the molecule's structure (InChIKey), revision read on 19 October 2026. Read as a second opinion, never cited as a source.

References

  1. Kathuria et al., Nat Med 2003: series of FAAH inhibitors, anxiolytic-like effects in the rat (new tab)PMID 12461523
  2. Mor et al., J Med Chem 2004: URB597, IC50 4.6 nM (new tab)PMID 15456244
  3. Piomelli et al., CNS Drug Rev 2006: pharmacological profile of KDS-4103 (URB597) (new tab)PMID 16834756
  4. Bortolato et al., Biol Psychiatry 2007: antidepressant-like effect in the rat (new tab)PMID 17511970
  5. Mileni et al., J Mol Biol 2010: crystal structure of the FAAH-URB597 complex (new tab)PMID 20493882

Identifiers

Names

Common name
URB597 (KDS-4103)
IUPAC name
[3-(3-carbamoylphenyl)phenyl] N-cyclohexylcarbamate
Other names
KDS-4103 · URB-597 · Cyclohexylcarbamic acid 3'-carbamoylbiphenyl-3-yl ester

Identifiers

Formula
C₂₀H₂₂N₂O₃
CAS
546141-08-6
PubChem CID
1383884(new tab)
InChIKey
ROFVXGGUISEHAM-UHFFFAOYSA-N
SMILES
C1CCC(CC1)NC(=O)OC2=CC=CC(=C2)C3=CC(=CC=C3)C(=O)N

Machine-readable entry (JSON)

LLM ingestion format: a structured superset of the entry (identifiers, binding, versioned legal status). Full corpus.