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5-Chloro-2-hydroxybenzoxazole, 5-Chloro-2(3H)-benzoxazolone
Empirical Formula (Hill Notation):
CAS Number:
Molecular Weight:
EC Number:
MDL number:
PubChem Substance ID:

Quality Level


≥98% (TLC)




white to off-white


191-192 °C (lit.)


DMSO: 50 mg/mL, clear


Johnson & Johnson

storage temp.

room temp

SMILES string




InChI key


Gene Information

human ... KCNN4(3783)

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Chlorzoxazone may be used:
  • as a calcium-activated potassium (KCa) channel activator in patch-clamp electrophysiology to test its effect on dendritic hyperexcitability
  • as a substrate for cytochrome P450 2E1 (CYP2E1) enzyme in cultured human hepatocytes
  • as a benzimidazolone compound to test its effect on epithelial sodium (Na+) transport


25, 100 g in poly bottle

Biochem/physiol Actions

Chlorzoxazone inhibits the multisynaptic reflex arcs primarily in the spinal cord and brain subcortical areas. It is an activator of calcium activated potassium channels and may contribute to the aortic artery relaxation in mice. Chlorzoxazone also activates the calcium-activated potassium (KCa) channel and small conductance calcium-activated potassium channels (SK). It is metabolized by cytochrome P450 2E1 (CYP2E1) and serves as a probe for monitoring this enzyme function.
Chlorzoxazone is a skeletal muscle relaxant.

Features and Benefits

This compound was developed by Johnson & Johnson. To browse the list of other pharma-developed compounds and Approved Drugs/Drug Candidates, click here.
This compound is featured on the Potassium Channels page of the Handbook of Receptor Classification and Signal Transduction. To browse other handbook pages, click here.
This compound is a featured product for ADME Tox research. Click here to discover more featured ADME Tox products. Learn more about bioactive small molecules for other areas of research at


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Hazard Statements

Hazard Classifications

Acute Tox. 4 Oral - Eye Irrit. 2 - Skin Irrit. 2 - STOT SE 3

Target Organs

Respiratory system

Storage Class Code

11 - Combustible Solids



Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

Certificate of Analysis

Enter Lot Number to search for Certificate of Analysis (COA).

Certificate of Origin

Enter Lot Number to search for Certificate of Origin (COO).

Karina Alviña et al.
The Journal of neuroscience : the official journal of the Society for Neuroscience, 30(21), 7258-7268 (2010-05-28)
Episodic ataxia type 2 (EA2) is a hereditary cerebellar ataxia associated with mutations in the P/Q-type voltage-gated calcium (Ca(2+)) channels. Therapeutic approaches for treatment of EA2 are very limited. Presently, the potassium (K(+)) channel blocker 4-aminopyridine (4-AP) constitutes the most
Yong-Long Han et al.
Journal of ethnopharmacology, 139(1), 104-109 (2011-11-15)
Herba Erigerontis injection (HEI), one of the most popular herbal prescription in China, is made from the aqueous extracts of Erigeron breviscapus whole plant. Now HEI is widely used for the treatment of cardiovascular diseases and cerebrovascular diseases such as
Karina Alviña et al.
The Journal of neuroscience : the official journal of the Society for Neuroscience, 30(21), 7249-7257 (2010-05-28)
Episodic ataxia type-2 (EA2) is an inherited movement disorder caused by mutations in the gene encoding the Ca(v)2.1alpha1 subunit of the P/Q-type voltage-gated calcium channel that result in an overall reduction in the P/Q-type calcium current. A consequence of these
Cyrus Ghobadi et al.
Clinical pharmacokinetics, 50(12), 809-822 (2011-11-18)
The maintenance dose of a drug is dependent on drug clearance, and thus any biochemical and physiological changes in obesity that affect parameters such as cardiac output, renal function, expression of drug-metabolizing enzymes and protein binding may result in altered
F Woodward Hopf et al.
Biological psychiatry, 69(7), 618-624 (2011-01-05)
Alcoholism imposes a tremendous social and economic burden. There are relatively few pharmacological treatments for alcoholism, with only moderate efficacy, and there is considerable interest in identifying additional therapeutic options. Alcohol exposure alters SK-type potassium channel (SK) function in limbic

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