Methimazole

Iupac Name：3-methyl-1H-imidazole-2-thione

CAS No.：60-56-0

Molecular Weight：114.16900

Introduction: Methimazole is an antithyroid medication used in the therapy of hyperthyroidism and Graves disease. It works by making it harder for the body to make thyroid hormone.It is also known as thiamazole, is a thioamide and a thyroid hormone antagonist which acts by inhibiting the incorporation of iodine into tyrosyl residues of thyroglobulin and, thus, lowering thyroid hormone levels.It resembles propylthiouracil both in chemical structure and activity.Methimazole is primarily used for the treatment of hyperthyroidism, by inhibiting the peroxidase system, hindering thyroxine (T4) and tri-triiodothyronine (T3) synthesis, animal experiments show that it can inhibit B lymphocytes synthesizing antibodies, and reduce levels of thyroid stimulating antibodies in blood circulating it can make suppressing T cell function return to normal, it is applicable to hyperthyroidism caused by a variety of factors . Like other various drugs (propylthiouracil), it also has some adverse reactions while it is taken, Including hematologic adverse reactions, primarily neutropenia, hematopoietic dysfunction or disorder, thrombocytopenia, reduction of prothrombin or factor VII ; long-term medication can also cause liver damage,such as cholestatic jaundice and toxic hepatitis ; other skin reactions such as hair loss, itching, rash, dermatitis, lupus erythematosus, as well as some other rare adverse reactions. Also methimazole allows prothrombin time to prolong , and increases serum alkaline phosphatase, aspartate aminotransferase (AST) and alanine aminotransferase (ALT)and causes blood bilirubin and blood lactate dehydrogenase increasing. Therefore, patients in the medication should regularly take blood tests, liver function tests and peripheral blood leukocytes. View more+

Request For Quotation

1. Names and Identifiers

1.1 Name: Methimazole
1.2 Synonyms: 1-Methyl-1,3-dihydro-2H-imidazole-2-thione 1-methyl-1H-imidazole-2(3H)-thione 1-methyl-1H-imidazole-2-thiol 1-Methyl-2-mercapto-1H-imidazole 1-methyl-2-mercapto-imidazole 1-Methyl-4-imidazoline-2-thione 1-methylimidazole-2-thione 2H-Imidazole-2-thione, 1,3-dihydro-1-methyl- 2-Mercapto-1-methyl-1H-imidazole 2-Mercapto-1-methylimidazole 2-mercapto-1-methyl-imidazole 3-methyl-imidazole-2-thione Basolan EINECS 200-482-4 Favistan Frentirox mercaptomethylimidazole Mercazole Merkastan METAZOLE Metazolo Methiamazole Methimazol methyl-2-mercaptoimidazole Metizol MFCD00179321 N-METHYLIMIDAZOLETHIOL Tapazole Tapuzole thiamazole Thimazol thioimidazole Thymidazole

1.3 CAS No.: 60-56-0

1.4 CID: 1349907

1.5 EINECS(EC#): 200-482-4

1.6 Molecular Formula: C4H6N2S (isomer)

1.7 Inchi: InChI=1S/C4H6N2S/c1-6-3-2-5-4(6)7/h2-3H,1H3,(H,5,7)

1.8 InChkey: PMRYVIKBURPHAH-UHFFFAOYSA-N

1.9 Canonical Smiles: CN1C=CNC1=S

1.10 Isomers Smiles: CN1C=CNC1=S

2. Properties

3.1 Density: 1.28 g/cm3

3.1 Melting point: 144-147°C(lit.)

3.1 Boiling point: 280 °C

3.1 Refractive index: 1.5000 (estimate)

3.1 Flash Point: 280°C

3.1 Precise Quality: 114.02500

3.1 PSA: 56.62000

3.1 logP: 0.70880

3.1 Solubility: 200g/l

3.2 Appearance: White Solid

3.3 Color/Form: LEAFLETS FROM ALCOHOL
WHITE TO PALE BUFF, CRYSTALLINE SUBSTANCE; STARCH-LIKE IN APPEARANCE & TO TOUCH

3.4 pKa: 12.37±0.50(Predicted)

3.5 Water Solubility: soluble

3.6 Spectral Properties: MAX ABSORPTION (CHLOROFORM): 267 NM (LOG E= 4.23)
IR: 2:1062C (Aldrich Library of Infrared Spectra, Aldrich Chemical Co, Milwaukee, WI)
UV: 3-18 (Organic Electronic Spectral Data, Phillips et al, John Wiley & Sons, New York)
NMR: 8:30A (Aldrich Library of Mass Spectra, Aldrich Chemical Co, Milwaukee, WI)
UV max (0.1 N sulfuric acid): 211, 251.5 nm (E 593, 1528, 1%, 1cm).

3.7 StorageTemp: Refrigerator

3. Use and Manufacturing

4.1 General Description: Methimazole, 1-methylimidazole-2-thiol (Tapazole), occurs as a white to off-white, crystallinepowder with a characteristic odor and is freely soluble inwater. A 2% aqueous solution has a pH of 6.7 to 6.9. It shouldbe packaged in well-closed, light-resistant containers.

4.2 Produe Method: React amino acetal with methyl isothiocyanate to genarate this product. The product can also be produced from thiocyanate and N-substituted amino acetal.

4.3 Purification Methods: Crystallise it from EtOH. UV: at 251nm (H2O), 260nm (EtOH) and 267nm (CHCl3). [Lawson max & Morley J Chem Soc 1103 1956, Beilstein 24 H 17, 24 III/IV 61.] Methimazole Preparation Products And Raw materials Raw materials

4.4 Safety Profile: Poison by subcutaneous route. Moderately toxic by ingestion and intraperitoneal routes. Human teratogenic effects. An experimental teratogen. Experimental reproductive effects. Questionable carcinogen with experimental neoplastigenic data. Human mutation data reported. An antithyroid drug. When heated to decomposition it emits very toxic fumes of NOx and SOx. See also MERCAPTANS.

4.5 Storage: Ambient temperatures.

4.6 Usage: Carbimazole intermediates.anti-thyroid drugs.

4. Safety and Handling

5.1 Symbol: GHS07, GHS08

5.1 Hazard Codes: Xn

5.1 Signal Word: Warning

5.1 Risk Statements: R43; R62; R63

5.1 Safety Statements: S26-S27-S36-S45-S36/37

5.1 Exposure Standards and Regulations: Manufacturers, packers, and distributors of drug and drug products for human use are responsible for complying with the labeling, certification, and usage requirements as prescribed by the Federal Food, Drug, and Cosmetic Act, as amended (secs 201-902, 52 Stat. 1040 et seq., as amended; 21 U.S.C. 321-392).

5.2 Octanol/Water Partition Coefficient: log Kow = -0.34

5.3 Hazard Declaration: H317-H361

5.3 DisposalMethods: SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

5.4 RIDADR: NONH for all modes of transport

5.4 Caution Statement: P280

5.4 Formulations/Preparations: ...METHIMAZOLE, USP (1-METHYL-2-MERCAPTOIMIDAZOLE; TAPAZOLE), MARKETED IN 5- & 10-MG TABLETS.

5.5 WGK Germany: 3

5.5 RTECS: NI8615000

5.5 Protective Equipment and Clothing: Rashes may follow high doses of methimazole (120 mg daily). Both major (agranulocytosis, hepatotoxicity) and minor (arthralgias, skin rash, gastric intolerance) adverse effects are not dose related.

5.6 Report: Reported in EPA TSCA Inventory.

5.7 Skin, Eye, and Respiratory Irritations: Rashes may follow high doses of methimazole (120 mg daily). Both major (agranulocytosis, hepatotoxicity) and minor (arthralgias, skin rash, gastric intolerance) adverse effects are not dose related.

5.8 Safety: Hazard Codes:?Xn
Risk Statements: 43-62-63
43: May cause sensitization by skin contact
62: Possible risk of impaired fertility
63: Possible risk of harm to the unborn child
Safety Statements: 26-27-45-36/37
26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice
27: Take off immediately all contaminated clothing
45: In case of accident or if you feel unwell, seek medical advice immediately (show label where possible)
36/37: Wear suitable protective clothing and gloves
WGK Germany: 3
RTECS: NI8615000
HS Code: 29332990
Poison by subcutaneous route. Moderately toxic by ingestion and intraperitoneal routes. Human teratogenic effects. An experimental teratogen. Experimental reproductive effects. Questionable carcinogen with experimental neoplastigenic data. Human mutation data reported. An antithyroid drug. When heated to decomposition it emits very toxic fumes of NO_x and SO_x. See also MERCAPTANS.

5.9 Specification: General Information: As in any fire, wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear.
Extinguishing Media: Use water spray, dry chemical, carbon dioxide, or chemical foam.?
Handling: Avoid breathing dust, vapor, mist, or gas. Avoid contact with skin and eyes. Avoid ingestion and inhalation. Use only in a chemical fume hood.
Storage: Store in a cool, dry place. Store in a tightly closed container.

5.10 Toxicity

Organism	Test Type	Route	Reported Dose (Normalized Dose)	Effect	Source
mouse	LD50	intraperitoneal	500mg/kg (500mg/kg)	?	National Technical Information Service. Vol. AD277-689,
mouse	LD50	oral	860mg/kg (860mg/kg)	PERIPHERAL NERVE AND SENSATION: SPASTIC PARALYSIS WITH OR WITHOUT SENSORY CHANGE BEHAVIORAL: SOMNOLENCE (GENERAL DEPRESSED ACTIVITY) BEHAVIORAL: TREMOR	Arzneimittel-Forschung. Drug Research. Vol. 4, Pg. 20, 1954.
mouse	LD50	subcutaneous	345mg/kg (345mg/kg)	PERIPHERAL NERVE AND SENSATION: SPASTIC PARALYSIS WITH OR WITHOUT SENSORY CHANGE BEHAVIORAL: SOMNOLENCE (GENERAL DEPRESSED ACTIVITY) BEHAVIORAL: TREMOR	Arzneimittel-Forschung. Drug Research. Vol. 4, Pg. 20, 1954.
rat	LD50	oral	2250mg/kg (2250mg/kg)	PERIPHERAL NERVE AND SENSATION: SPASTIC PARALYSIS WITH OR WITHOUT SENSORY CHANGE BEHAVIORAL: SOMNOLENCE (GENERAL DEPRESSED ACTIVITY) BEHAVIORAL: TREMOR	Arzneimittel-Forschung. Drug Research. Vol. 4, Pg. 20, 1954.
rat	LD50	subcutaneous	1050mg/kg (1050mg/kg)	?	Farmaco, Edizione Scientifica. Vol. 14, Pg. 54, 1959.
women	TDLo	oral	13mg/kg/33D-I (13mg/kg)	SENSE ORGANS AND SPECIAL SENSES: OTHER: EAR BEHAVIORAL: EXCITEMENT GASTROINTESTINAL: OTHER CHANGES	Clinical Endocrinology Vol. 51, Pg. 667, 1999.
women	TDLo	oral	492mg/kg/88W- (492mg/kg)	ENDOCRINE: CHANGE IN GONADOTROPINS BLOOD: AGRANULOCYTOSIS	Netherlands Journal of Medicine. Vol. 43, Pg. 71, 1993.

View all

5. MSDS

2.Hazard identification

2.1 Classification of the substance or mixture

Skin sensitization, Category 1

Reproductive toxicity, Category 2

2.2 GHS label elements, including precautionary statements

Pictogram(s)
Signal word	Warning
Hazard statement(s)	H317 May cause an allergic skin reaction H361 Suspected of damaging fertility or the unborn child
Precautionary statement(s)
Prevention	P261 Avoid breathing dust/fume/gas/mist/vapours/spray. P272 Contaminated work clothing should not be allowed out of the workplace. P280 Wear protective gloves/protective clothing/eye protection/face protection. P201 Obtain special instructions before use. P202 Do not handle until all safety precautions have been read and understood.
Response	P302+P352 IF ON SKIN: Wash with plenty of water/... P333+P313 If skin irritation or rash occurs: Get medical advice/attention. P321 Specific treatment (see ... on this label). P362+P364 Take off contaminated clothing and wash it before reuse. P308+P313 IF exposed or concerned: Get medical advice/ attention.
Storage	P405 Store locked up.
Disposal	P501 Dispose of contents/container to ...