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Antispasmodic drugs Mechanisms of action Production process Pharmacokinetics Indications Precautions Side effects Dosage and usage Chemical Properties Uses Production method Category Toxicity grading Acute toxicity Flammability and hazardous characteristics Storage Characteristics Extinguishing agent
Baclofen structure
Chemical Name:
Molecular Formula:
Formula Weight:
MOL File:

Baclofen Properties

Melting point:
Boiling point:
364.3±32.0 °C(Predicted)
1.2069 (rough estimate)
refractive index 
1.5500 (estimate)
storage temp. 
1 M HCl: 50 mg/mL
pKa 3.87±0.1(H2O) (Uncertain)
white to very faintly yellow
Water Solubility 
Soluble in dilute NaOH or dilute HCl. Soluble in water at approximately 4mg/ml at pH 7.6
CAS DataBase Reference
1134-47-0(CAS DataBase Reference)
NCI Dictionary of Cancer Terms
baclofen; Lioresal
NCI Drug Dictionary
ATC code
NIST Chemistry Reference
EPA Substance Registry System
.beta.-(Aminomethyl)-4-chlorobenzenepropanoic acid (1134-47-0)
  • Risk and Safety Statements
Signal word  Danger
Hazard statements  H335-H360-H315-H317-H319-H334-H301
Precautionary statements  P261-P264-P270-P272-P280-P284-P301+P310+P330-P302+P352+P333+P313+P363-P304+P340+P342+P311-P305+P351+P338+P337+P313-P405-P501-P201-P301+P310a-P305+P351+P338-P501a
Hazard Codes  T,Xn
Risk Statements  61-25-36/37/38-42/43-20/21/22
Safety Statements  53-22-36/37/39-45-52-36-26
RIDADR  UN 2811 6.1/PG 3
WGK Germany  3
RTECS  MW5084200
HazardClass  6.1(b)
PackingGroup  III
HS Code  2922492050
Toxicity LD50 in male mice, rats (mg/kg): 45, 78 i.v.; 103, 115 s.c.; 200, 145 orally (Tadokoro)

Baclofen price More Price(49)

Manufacturer Product number Product description CAS number Packaging Price Updated Buy
Sigma-Aldrich B0200000 Baclofen European Pharmacopoeia (EP) Reference Standard 1134-47-0 $190 2021-12-16 Buy
Sigma-Aldrich B5399 (±)-Baclofen ≥98% (TLC), solid 1134-47-0 5g $312 2021-12-16 Buy
Sigma-Aldrich 1048200 Baclofen United States Pharmacopeia (USP) Reference Standard 1134-47-0 350mg $366 2021-12-16 Buy
TCI Chemical B3343 Baclofen >98.0%(T) 1134-47-0 5g $72 2021-12-16 Buy
TCI Chemical B3343 Baclofen >98.0%(T) 1134-47-0 25g $245 2021-12-16 Buy

Baclofen Chemical Properties,Uses,Production

Antispasmodic drugs

Baclofen is a γ-aminobutyric acid derivative. It is an antispasmodics class drugs acting on the central nervous system, the brain and spinal cord as a skeletal muscle relaxants and sedatives. It take antispasmodic effect by stimulating receptors to inhibit the release of excitatory amino acids such as glutamic acid, aspartic acid and thereby inhibiting the transfer of single and multi-synaptic reflex in central nervous system, brain and spinal cord. Clinically it has already been used as racemic agent for treating Muscle spasticity since mid-1960s. Recent studies have also found that this product can significantly reduce the symptoms of gastroesophageal reflux and alleviating related symptoms. It can also alleviate the dystonia of children and treat the urination dysfunction caused by central spinal cord injury. In addition, the intrathecal injection therapy of the product in clinical application can further improve the clinical efficacy, and make it possible to adjust drugs dosage which stabilizes the treatment effect. For the past 10 years, the clinical application of central muscle relaxant baclofen has made significant progress, particularly in accumulating a lot of experiences in the neurological rehabilitation treatment of reducing muscular tension and pain alleviation treatment.
Structure of Baclofen
Figure 1 Structure of Baclofen

Mechanisms of action

The content of γ-aminobutyric acid (GABA) is very high in the human central nervous system, brain and spinal cord. Its level is 1000 times higher than monoamine such as catecholamines, to higher norepinephrine, and dopamine. It is presented at the highest inside the substantia nigra and globus pallidus. There are about 20% to 40% of the synapses using GABA as neurotransmitter inside the brain. GABA is the major inhibitory neurotransmitter of the central nervous system, brain and spinal cord. However, it is not able to penetrate the blood-brain barrier. GABA can be converted into baclofen by connecting carbon atom to the p-chlorophenyl. In this case, it changes from hydrophilic substance to lipophilic substances, which can then go through the blood-brain barrier. The main effect of this product are stimulating the GABA receptors, inhibiting the release of excitatory amino acids such as aspartic acid, glutamic acid, also cause the efflux of K +, Ca 2+ , which results in hyper-polarization, reducing the transfer single and multi-synaptic reflex, maintaining the normal function of middle-neuronal activity in order to reduce the activity of motor neurons, thereby alleviating skeletal muscle spasticity caused by damage to the pyramidal tract, reducing muscle tension, and promoting sports functional recovery.
The above information is edited by the Chemicalbook of Dai Xiongfeng.

Production process

Chlorobenzaldehyde and ethyl acetoacetate are condensed into chlorobenzene methylene-bis-ethyl acetoacetate. Heat and hydrolyze to obtain chlorophenyl glutaric acid. Use acetic anhydride for dehydration and cyclization to obtain chlorophenyl glutaric anhydride. And then perform amination reaction by concentrated aqueous ammonia to generate chlorophenyl glutaric acid imide. The open the ring, degrade to obtain the final product.


After oral administration, concentration in plasma reaches a peak in about 1.9h. There is large fluctuation in plasma concentration with the maximum concentration/minimum concentration × 100%: 188-439%. The total clearance rate is about 175mL.min-1, and the apparent renal clearance crisp is the same as that of muscle. The plasma protein binding rate is 35%. The excretion rate of kidney prototype drug is 65%, which is consistent with healthy results. Because renal excretion is the major route of elimination, patients with renal impairment should pay attention to adjust the dose.


This product is an antispasmodic drug. It inhibits the transmission in spinal cord of mono-synapse multiple synapse. The mechanism is inhibiting the release of excitatory amino acid glutamate and aspartate through stimulating GABA receptor. Thus reduce the increased limbs muscle tension caused by spinal cord lesions, multiple sclerosis, and spinal cord injury. It can be used for treatment of muscle spasms caused by brain and spinal cord diseases or injuries.


1. Among the overdose behavior, the depression of central nervous system is the most prominent. Severe poisoning manifestations include seizures, coma, respiratory depression and muscle hypotonia associated with loss of reflexes of the limbs, and also hypotension and low blood pressure sometimes. Strategies for emergence treatment of acute poisoning include respiratory support, gastric lavage, and diuretic. However, there is no special antidote reported. There are some reports that seizures and myoclonic seizures appeared in some patients appear during the recovery period. Epileptic seizure can be treated by diazepam or clonazepam, although these drugs can cause extension of the duration of unconsciousness. Patients of cardiovascular disease should be carefully observed for 1 week to monitor delayed tachycardia and hypertension.
2. Patients who are allergic to the drug, suffering Parkinson's disease, spasms, and the women who are in the first three months of pregnancy are not allowed for using.
3. Patients of hypertension, peptic ulcer disease, cerebrovascular disease and respiratory, issue liver and kidney dysfunction, who have a history of seizures or convulsions, accompanied by mental disorders, schizophrenia or confusion, pregnant and lactating women, drivers or operator of machine should use with caution.
4. Epileptic patients should be controlled of the attack of epilepsy when applying this drug. Also they should do EEG monitoring.
5. Gradually reduce the dosage before the withdrawal, to prevent rebound phenomenon.

Side effects

The main side effects mainly happen at the beginning of treatment when the dose increases too fast, when overdose happens and for elderly patients. It is mainly mild transient symptoms, Patients with historical mental illness and elderly patients with cerebral vascular disease may suffer from an even more severe adverse reaction. During the beginning of treatment, there are often some side effects such as daytime sedation, drowsiness and nausea.

Dosage and usage

Oral: adult, Initial amount of 5mg per time, tid, then every increase taking this amount every 3d until it reaches the appropriate dose 30~75mg/d. Take this in 3 times. The dose should not exceed 80 mg/d except in special cases. Gradually reduce the dosage before withdrawal; For children, the initial amount should be 0.3mg/(kg.d), and the maintenance dose should be 0.75~2mg/(kg.d). For children under 10 years-old, the maximum dose should be 2.5mg /(kg.d). The recommended daily amount for maintenance therapy: 1 to 2 years-old, 10~20mg, 2~10 years-old: 30~60mg (maximum 70mg), take it with meal or with milk.

Chemical Properties

White powder. Melting point: 206-208 °C. Dissolve using hot water, the aqueous solution was neutral, almost insoluble in alcohol, ether, acetone and other organic solvents, easily soluble in acidic, alkaline aqueous solution. The melting point of Chlorobenzene aminobutyric acid hydrochloride: 179-181 °C.


1. The product is a relaxant and antispasmodic agent acting on the skeletal muscle of spinal cord. Suitable for treating multiple-sclerosis bones spasms, spinal infection, degenerated muscle spasms; spinal cord trauma, and neoplastic muscle spasms.
2. It is currently the most effective muscle relaxants with least side effects.

Production method

Chlorobenzaldehyde and ethyl acetoacetate is condensed into chlorobenzene methylene-bis-ethyl acetoacetate. Add heating water for hydrolysis to obtain chlorophenyl glutaric acid. Dehydrate and cyclize to obtain chlorophenyl glutaric anhydride using acetic anhydride. Then perform amination reaction with concentrated aqueous ammonia to generate chlorophenyl glutaric acid imide. The open the ring, degrade to obtain the final product. Detailed procedures as follow: Add 42.25g β-(p-chlorophenyl) glutaric acid imide with stir to 200 mL aqueous solution containing 8.32g of sodium hydroxide. The mixture was heated at 50 °C for 10min, cool to 10-15 °C. Titrate for 200 mL aqueous solution of 40.9g of sodium hydroxide. After 20min, add 38.8g bromine, stir at 20-25 °C for 8h. Use concentrated hydrochloric acid to adjust the pH of the reaction solution to 7, and then precipitate out the fine crystals of i.e. [beta] (p-chlorophenyl) amino-gamma-acid. Re-crystallize in water with m.p. 206-208 °C.


toxic substances

Toxicity grading

highly toxic

Acute toxicity

Oral-rat LD50; 145 mg/kg; Oral-Mouse LD50: 200 mg/kg.

Flammability and hazardous characteristics

Combustible, Burning yields toxic chloride fumes and nitrogen oxides; Patients takes with side effects: low blood pressure, pulse rate decreases, muscle weakness.

Storage Characteristics

ventilation, low-temperature and dry; and Separate from food raw materials for storage.

Extinguishing agent

Dry powder, foam, sand, carbon dioxide, water spray.

Chemical Properties

Off-White Solid


Lioresal,Ciba Geigy,Switz.,1971


Specific GABA-B receptor agonist. Muscle relaxant (skeletal)


Baclofen may be used as a pharmaceutical secondary reference standard for the determination of the analyte in plasma samples by liquid chromatography tandem mass spectrometry and tablet formulations by UV spectroscopy, respectively.


ChEBI: A monocarboxylic acid that is butanoic acid substituted by an amino group at position 4 and a 4-chlorophenyl group at position 3. It acts as a central nervous system depressant, GABA agonist and muscle relaxant.

Manufacturing Process

42.45 g of β-(p-chlorophenyl)glutaric acid imide are stirred into a solution of 8.32 g of sodium hydroxide in 200 ml of water. The mixture is heated for 10 minutes at 50°C, and the solution thus formed is cooled to 10° to 15°C. At this temperature there are then added dropwise a solution of 40.9 g of sodium hydroxide in 200 ml of water and then, in the course of 20 minutes, 38.8 g of bromine. When all has been dropped in, the batch is stirred for 8 hours at 20° to 25°C. The reaction solution is then cautiously adjusted with concentrated hydrochloric acid to pH 7, whereupon finely crystalline γ-amino- β-(p-chlorophenyl)butyric acid settles out. To purify it, it is recrystallized from water. Melting point is 206°to 208°C.

brand name

Kemstro (Schwarz Pharma); Lioresal (Medtronic); Lioresal (Novartis).

Therapeutic Function

Muscle relaxant

Biological Functions

Baclofen (Lioresal) is the parachlorophenol analogue of the naturally occurring neurotransmitter γ-aminobutyric acid (GABA).

General Description

Odorless or practically odorless white to off-white crystalline powder.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

Baclofen is an amine. Amines are chemical bases. They neutralize acids to form salts plus water. These acid-base reactions are exothermic. The amount of heat that is evolved per mole of amine in a neutralization is largely independent of the strength of the amine as a base. Amines may be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. Flammable gaseous hydrogen is generated by amines in combination with strong reducing agents, such as hydrides.

Health Hazard

SYMPTOMS: Symptoms of exposure to Baclofen via ingestion may include drowsiness, insomnia, dizziness, weakness, mental confusion, nausea, constipation, anorexia, urinary retention, impotence, nystagmus, diplopia and incoordination. Ingestion may lead to cholinergic effects and lassitude. It may also lead to ataxia. Other symptoms due to ingestion may include impaired renal function, fatigue, headache, hypotension, urinary frequency, rash, pruritis, ankle edema, excessive perspiration, weight gain, nasal congestion, and rarely, euphoria, excitement, depression, hallucinations, paresthesia, muscle pain, tinnitus, slurred speech, tremor, rigidity, dystonia, blurred vision, strabismus, miosis, mydriasis, dysarthia, epileptic seizure, dyspnea, palpitation, chest pain, syncope, dryness of the mouth, taste disorder, abdominal pain, vomiting, diarrhea, blood in the stools, enuresis, dysuria, inability to ejaculate, nocturia and hematuria. Overexposure through ingestion may result in seizures, and coma with respiratory depression. Aspiration pneumonia is a frequent complication of coma with respiratory depression. Other symptoms due to overdosage may include vomiting, muscular hypotonia, drowsiness, and accommodation disorders. Cyanosis has been reported. Chronic ingestion may result in drowsiness, depression, weakness, anxiety, ataxia, headaches, blurred vision, gastric upset and pruritic skin rashes characterized by urticaria or erythematous macular eruptions. Sudden withdrawal after chronic ingestion may cause auditory and visual hallucinations, anxiety and tachycardia. Seizures may also occur after sudden withdrawal. Abuse may lead to drug dependence.

Fire Hazard

Flash point data for Baclofen are not available. Baclofen is probably combustible.

Biological Activity

Selective GABA B receptor agonist. Skeletal muscle relaxant.

Mechanism of action

Baclofen appears to affect the neuromuscular axis by acting directly on sensory afferents, γ-motor neurons, and collateral neurons in the spinal cord to inhibit both monosynaptic and polysynaptic reflexes. The principal effect is to reduce the release of excitatory neurotransmitters by activation of presynaptic GABAB receptors. This seems to involve a G protein and second-messenger link that either increases K+ conductance or decreases Ca++ conductance.

Clinical Use

Baclofen is an agent of choice for treating spinal spasticity and spasticity associated with multiple sclerosis. It is not useful for treating spasticity of supraspinal origin. Doses should be increased gradually to a maximum of 100 to 150 mg per day, divided into four doses.

Side effects

Side effects are not a major problem, and they can be minimized by graduated dosage increases.They include lassitude, slight nausea, and mental disturbances (in including confusion, euphoria, and depression). The drowsiness is less pronounced than that produced by diazepam—an important therapeutic advantage. Hypotension has been noted, particularly following overdose. Elderly patients and patients with multiple sclerosis may require lower doses and may display increased sensitivity to the central side effects. Baclofen may increase the frequency of seizures in epileptics.

Safety Profile

Poison by ingestion,subcutaneous and intravenous routes. Human systemiceffects by ingestion: blood pressure lowering, coma,muscle weakness, pulse rate decrease, respiratorydepression. When heated to decomposition it emits toxicfumes of Cl-

Chemical Synthesis

Baclofen, 4-amino-3-(4-chlorophenyl)butyric acid (15.3.5), is synthesized in two ways. According to the first, 4-chlorobenzaldehyde is condensed with two moles of acetoacetic ester, giving the product (15.3.1), which initially undergoes alkaline hydrolysis and decarboxylation forming 3-(4-chlorphenyl)glutaric acid (15.3.2). Dehydration of this gives 3-(4-chlorophenyl)glutaric acid anhydride (15.3.3), and further treatment with ammonia gives the corresponding glutarimide (15.3.4). Reacting this with an alkaline solution of a halogen (Hofmann rearrangement) gives baclofen (15.3.6).

Veterinary Drugs and Treatments

Baclofen may be useful to decrease urethral resistance in dogs to treat urinary retention. It is not recommended for cats.


Baclofen is rapidly and effectively absorbed after oral administration. It is lipophilic and able to penetrate the blood-brain barrier.Approximately 35% of the drug is excreted unchanged in the urine and feces.

Baclofen Preparation Products And Raw materials

Raw materials

Preparation Products

Baclofen Suppliers

Global( 377)Suppliers
Supplier Tel Fax Email Country ProdList Advantage
Joyochem Co.,Ltd
+8613290333633 +86-0531-82687558
0531-82687996; China 28 58
Guangzhou TongYi biochemistry technology Co.,LTD
+8613073028829 China 3000 58
Guangzhou Biocar Biotechnology Co.,Ltd.
027-86589876 China 402 58
Henan Tianfu Chemical Co.,Ltd.
0371-55170693 China 22607 55
Shanghai Yingrui Biopharma Co., Ltd.
+86-21-34979012 CHINA 739 60
Hefei TNJ Chemical Industry Co.,Ltd.
86-0551-65418697 China 3000 55
career henan chemical co
+86-0371-55982848 China 29953 58
Wuhan Boyuan Import & Export Co., LTD
0311-89850048 China 298 58
+86 18953170293
+86 0531-67809011 CHINA 2940 58
Hebei Jimi Trading Co., Ltd.
+86 319 5273535 CHINA 292 58

View Lastest Price from Baclofen manufacturers

Image Release date Product Price Min. Order Purity Supply Ability Manufacturer
2022-01-24 Baclofen
US $9.90-9.90 / g/Bag 10g/Bag 99.99%HPLC.USP42——Powder、Oil、Pills、Capsules、Tablets,Customized packaging 100KG/Month Wuhan Biocar Pharmacy Co., Ltd.
2022-01-24 Baclofen
2022-01-21 Baclofen
US $122.00 / g 100g 99.9% 1000kg/month Shanxi Lianxu New Material Co., LTD

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