Methylchloroisothiazolinone

Methylchloroisothiazolinone

Names
IUPAC name 5-Chloro-2-methyl-1,2-thiazol-3(2H)-one
Other names 5-Chloro-2-methylisothiazol-3(2H)-one 5-Chloro-2-methyl-4-isothiazolin-3-one Chloromethylisothiazolinone Chloromethylisothiazolone Methylchloroisothiazolinone Methylchloroisothiazolone CMI CMIT MCI MCIT
Identifiers
CAS Number	26172-55-4 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:53621 Y
ChemSpider	30800 Y
ECHA InfoCard	100.043.167
PubChem	33344
UNII	DEL7T5QRPN Y
InChI InChI=1S/C4H4ClNOS/c1-6-4(7)2-3(5)8-6/h2H,1H3 Y Key: DHNRXBZYEKSXIM-UHFFFAOYSA-N Y InChI=1/C4H4ClNOS/c1-6-4(7)2-3(5)8-6/h2H,1H3 Key: DHNRXBZYEKSXIM-UHFFFAOYAV
SMILES ClC=1SN(C(=O)C=1)C
Properties
Chemical formula	C4H4ClNOS
Molar mass	149.59 g·mol−1
Appearance	Colorless liquid
Density	1.02 g/cm³
Solubility in water	Miscible
Hazards
R-phrases	R23/24/25 R34 R43 R50/53
S-phrases	(S2) S26 S28 S36/37/39 S45 S60 S61
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Methylchloroisothiazolinone (5-chloro-2-methyl-4-isothiazolin-3-one), also referred to as MCI, is a preservative with antibacterial and antifungal effects within the group of isothiazolinones. It is effective against gram-positive and gram-negative bacteria, yeast, and fungi.

Methylchloroisothiazolinone is found in many water-based personal care products and cosmetics.^[1] Methylchloroisothiazolinone was first used in cosmetics in the 1970s. It is also used in glue production, detergents, paints, fuels, and other industrial processes. Methylchloroisothiazolinone is known by the registered tradename Kathon CG when used in combination with methylisothiazolinone.^[2]

Methylchloroisothiazolinone may be used in combination with other preservatives including ethylparaben, benzalkonium chloride, or 2-bromo-2-nitropropane-1,3-diol.

Safety

In pure form or in high concentrations, methylchloroisothiazolinone is a skin and membrane irritant and causes chemical burns. In the United States, accepted concentrations are 15 ppm in rinse-offs and 8 ppm in other cosmetics. In Canada, the accepted concentrations are 15 ppm and 7.5 ppm respectively.^[3] The Canadian levels are also reflected in a paper published in the International Journal of Toxicology.^[4]

The International Agency for Research on Cancer (IARC), does not currently list methylchloroisothiazolinone as a known, probable, or possible human carcinogen,^[5] nor have in vivo tests found evidence of carcinogenic activity.

Allergic contact dermatitis

Methylchloroisothiazolinone is an allergen and can cause severe skin reactions in some people.^[6] Since 2013 the use of the product particularly in cosmetics has received increased media coverage in the UK. In 2013 GP doctors asked cosmetics companies to remove it from products.^[7] Some cosmetics with the MI in have been investigated by the BBC Watchdog programme.^[8] The first publication of the preservative as a contact allergen was in 1988.^[9] A common indication of an allergic reaction is eczema-like symptoms including redness and itching, and upon longer exposure also burning sensations and blisters on the part of the skin that is exposed to the allergen. Cases of photoaggravated allergic contact dermatitis, i.e. worsening of skin lesions after sun exposure, have also been reported.^[6] Continued exposure can lead to high sensitization which will be triggered each time the individual comes in contact with the allergen due to the memory T-cells that will remain in the local skin area.

References

Pirmez R, Fernandes ALC, Melo MGM. Photoaggravated contact dermatitis to Kathon CG (methylchloroisothiazolinone/methylisothiazolinone): a novel pattern of involvement in a growing epidemic? Br J Dermatol. 2015 Jun 30. doi: 10.1111/bjd.13986. [Epub ahead of print] http://onlinelibrary.wiley.com/doi/10.1111/bjd.13986/abstract

External links

• Record in the Household Products Database of NLM
• methylchloroisothiazolinone at the National Library of Medicine