Basic information Skeletal muscle relaxants Pharmacokinetics Indications Chlorzoxazone synthesis Medicine interactions Side effects Uses Category Toxicity grading Acute toxicity Flammability and hazard properties Storage characteristics Extinguishing agent Safety Related Supplier
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Basic information Skeletal muscle relaxants Pharmacokinetics Indications Chlorzoxazone synthesis Medicine interactions Side effects Uses Category Toxicity grading Acute toxicity Flammability and hazard properties Storage characteristics Extinguishing agent Safety Related Supplier
Chlorzoxazone Basic information
Chlorzoxazone Chemical Properties
  • Melting point:191-192 °C(lit.)
  • Density 1.3771 (rough estimate)
  • refractive index 1.5557 (estimate)
  • storage temp. -20°C Freezer
  • solubility DMSO: soluble50mg/mL, clear
  • form Powder
  • pkapKa 8.3 (Uncertain)
  • color white to off-white
  • Water Solubility 0.1 g/100 mL
  • Merck 14,2194
  • CAS DataBase Reference95-25-0(CAS DataBase Reference)
  • NIST Chemistry ReferenceChlorzoxazone(95-25-0)
  • EPA Substance Registry SystemChlorzoxazone (95-25-0)
Safety Information
  • Hazard Codes Xn,T,Xi
  • Risk Statements 22-36/37/38-20/21/22
  • Safety Statements 26-36-24/25-37/39
  • WGK Germany 3
  • RTECS DM5250000
  • Hazard Note Toxic/Irritant
  • TSCA Yes
  • HazardClass IRRITANT
  • HS Code 29349990
  • ToxicityLD50 in mice (mg/kg): 3650 orally, 380 i.p. (suspensions); 440 orally, 183 i.p. (solns of Na salt) (Hofrichter)
Chlorzoxazone Usage And Synthesis
  • Skeletal muscle relaxantsChlorzoxazone is an orally active central skeletal muscle relaxant with its chemical structure being completely different with all the other muscle relaxants. It, mainly through acting on the central cerebral cortex and the spinal cord, inhibits the multi-synaptic reflection related to muscle spasms and produces muscle relaxation, further relieves the spasm caused pain and increase the flexibility of the muscles involved. Acetaminophen belongs to non-steroidal anti-inflammatory drugs and may mainly exert the analgesic and antipyretic effects through the inhibition of prostaglandin synthesis. Muscle relaxation studies through mouse traction test have demonstrated that the compound Chlorzoxazone showed a dose-dependent muscle relaxant effect with excellent protective effect on the strychnine-induced seizures in mice. The existence of paracetamol in the compound chlorzoxazone tablets can further enhance the effect of chlorzoxazone. Hot plate analgesic tests have showed the compound chlorzoxazone has a significant analgesic effect in a dose-dependent manner. It also has antagonism effect on the painful writhing of mice caused by antimony potassium tartrate in a good dose-response relationship. Test results have showed that acetaminophen and chlorzoxazone analgesic synergy.
    This information is edited by Xiongfeng Dai from Chemicalbook.
  • PharmacokineticsThis product can be completely absorbed by the digestive tract with the plasma concentration reaching peak at 1.5-2 hours. It is distributed in muscle, kidney, liver, brain and fat. After 6 hours, the drug concentration decreases significantly. Almost all of the goods can subject to in vivo catabolism with the elimination half-life being about 1 hour.
    This information is edited by Xiongfeng Dai from Chemicalbook.
  • IndicationsChlorzoxazone is suitable for the treatment of various kinds of acute and chronic soft tissue (muscles, ligaments and fascia) sprain, contusion, muscle pain after exercise, pain caused by muscle strain and the muscle spasms caused by the central nervous system lesions as well as chronic fasciitis.
  • Chlorzoxazone synthesisTake 2, 5-dichloro-nitrobenzene as raw material; go through hydrolysis, reduction reaction to give 2-amino-4-chloro-phenol, followed by cyclization reaction in hydrochloric acid to obtain the finished product of Chlorzoxazone with the total yield being 84%.

  • Medicine interactionsWhen this product is used in combination with central inhibitory drugs such as phenothiazines and barbituric acid derivative and monoamine oxidase inhibition drugs, we should reduce the usage amount of this product.
  • Side effectsThere may be occasionally mild drowsiness, dizziness, nausea, heart palpitations, weakness, abdominal pain and other reactions. This drug should be discontinued in case of allergic reactions. These adverse reactions are generally mild and may go away automatically or alleviated after stopping using this drug.
  • UsesIt can be used as pharmaceutical intermediates.
    It can be used as central muscle relaxants, for being applied to a variety of soft tissue pain caused by chronic sprain, contusion and muscle strain as well as muscle spasms and pain caused by the central nervous system and so on.
  • CategoryToxic substances.
  • Toxicity gradingHighly toxic.
  • Acute toxicityOral-rat LD50: 763 mg/kg; Oral-Mouse LD50: 440 mg/kg.
  • Flammability and hazard propertiesThermal decomposition can release nitrogen oxides and chlorides smoke.
  • Storage characteristicsTreasury: ventilated, low temperature and dry; store it separately from food raw materials.
  • Extinguishing agentWater, carbon dioxide, foam, powder.
  • Chemical PropertiesWhite to Off-White Solid
  • OriginatorParaflex ,McNeil, US ,1958
  • UsesChlorzoxazone is a benzoxazolone derivative that causes skeletal muscle relaxation and blocks spasticity in clinical studies. Chlorzoxazone enhances small and intermediate conductance calcium-activated potassium channels (EC50s = 87 and 98 μM for KCa2.2 and KCa3.1, respectively). The cytochrome P450 isoform CYP2E1 converts chlorzoxazone to 6-hydroxy chlorzoxazone . The urinary excretion of this 6-hydroxy metabolite is often used as a probe of CYP2E1 activity in studies of hepatotoxicity.
  • UsesMuscle relaxant (skeletal)
  • UsesFor the relief of discomfort associated with acute painful musculoskeletal conditions.
  • DefinitionChEBI: A member of the class of 1,3-benzoxazoles that is 1,3-benzoxazol-2-ol in which the hydrogen atom at position 5 is substituted by chlorine. A centrally acting muscle relaxant with sedative properties, it is used for the symptomatic treatment of painful mus le spasm.
  • Manufacturing ProcessA solution of 16.9 g (0.1 mol) of 2-amino-5-chlorobenzoxazole in 200 ml of 1 N HCl is refluxed until precipitation is complete. The resulting solid is collected
    by filtration, dissolved in 200 ml of 1 N NaOH and the solution extracted with 50 ml of ether. Acidification of the alkaline solution gives a precipitate which is purified by crystallization from acetone to give 2-hydroxy-5-chlorobenzoxazole melting at 191° to 191.5°C.
  • brand nameParaflex (Ortho-McNeil).
  • Therapeutic FunctionMuscle relaxant
Chlorzoxazone Preparation Products And Raw materials
Chlorzoxazone(95-25-0)Related Product Information
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