Chlorzoxazone , ≥98% , 95-25-0

Synonym(s):
5-Chloro-2(3H)-benzoxazolone;5-Chloro-2-hydroxybenzoxazole;Chlorzoxazone;CLZ

CAS NO.：95-25-0

Empirical Formula: C7H4ClNO2

Molecular Weight: 169.57

MDL number: MFCD00005717

EINECS: 202-403-9

PRODUCT Properties

• Melting point: 191-192 °C (lit.)
• Density: 1.3771 (rough estimate)
• refractive index: 1.5557 (estimate)
• storage temp.: room temp
• solubility: DMSO: soluble50mg/mL, clear
• pka: pKa 8.3 (Uncertain)
• form: Powder
• color: white to off-white
• Water Solubility: 0.1 g/100 mL
• Merck: 14,2194
• LogP: 1.816 (est)

Description and Uses

Chlorzoxazone is a muscle relaxant. It acts by blocking nerve impulses or pain sensations that are sent to brain. Typically, it is used together with rest and physical therapy to treat skeletal muscle conditions such as pain or injury. Chlorzoxazone, 5-chloro-2-benzoxazolione, is synthesized by a heterocyclization reaction of 2-amino-4-chlorophenol with phosgene. Skeletal muscle relaxants have conventionally been classified into one group; however, they are actually a heterogeneous group of medications commonly used to treat two different types of underlying conditions – spasticity from upper motor neuron syndromes and muscular pain or spasms from peripheral musculoskeletal conditions. Medications classified as skeletal muscle relaxants are baclofen, carisoprodol, chlorzoxazone, cyclobenzaprine, dantrolene, metaxalone, methocarbamol, orphenadrine, and tizanidine. These drugs may impair mental and/or physical abilities required for driving vehicles. As a class, skeletal muscle relaxants have central nervous system (CNS)-related side effects: drowsiness, dizziness, decreased alertness, blurred vision, and ataxia. Their use has been associated with a twofold increase in the risk for motor vehicle crashes. Muscle relaxants are included in the ‘Beers List’ of potentially inappropriate medications in older adults. Most muscle relaxants are poorly tolerated by elderly patients because they cause anticholinergic adverse effects, sedation, and weakness. Although extremely uncommon, this compound may yield to idiosyncratic and unpredictable type of liver toxicity. The concomitant use of alcohol or other CNS depressants may have an additive effect. Individuals on chlorzoxazone containing drugs should be monitored for abnormal liver enzymes (e.g., aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase, bilirubin, etc.).

For the relief of discomfort associated with acute painful musculoskeletal conditions.

Safety

• Symbol(GHS): GHS07
• Signal word: Warning
• Hazard statements: H302-H315-H319-H335
• Precautionary statements: P261-P264-P270-P301+P312-P302+P352-P305+P351+P338
• 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
• Toxicity: LD50 in mice (mg/kg): 3650 orally, 380 i.p. (suspensions); 440 orally, 183 i.p. (solns of Na salt) (Hofrichter)