|Jmol-3D images||Image 1|
|Molar mass||149.60 g mol−1|
|Density||1.02 g/cm³, liquid|
|Solubility in water||miscible with|
|R-phrases||R23/24/25 R34 R43 R50/53|
|S-phrases||(S2) S26 S28 S36/37/39 S45 S60 S61|
| (what is: / ?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Methylchloroisothiazolinone (5-chloro-2-methyl-4-isothiazolin-3-one) 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. 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.
In pure form or in high concentrations, methylchloroisothiazolinone is a skin and membrane irritant and causes chemical burns. It was largely removed from most cosmetic products except for those with only short duration skin contact such as rinse-offs. Its inclusion in certain forms makes it more acceptable to sensitive users, so it can be found in cosmetic creams and lotions which require skin contact. In the United States, accepted concentrations are 15 ppm in rinse-offs and 8 ppm in other cosmetics.
The International Agency for Research on Cancer (IARC), does not currently list methylchloroisothiazolinone as a known, probable, or possible human carcinogen, nor have in vivo tests found evidence of carcinogenic activity. Methylchloroisothiazolinone is an allergen for 2-3% of individuals. A common indication of an allergic reaction is eczematous (rashy) symptoms such as redness and itching on surfaces exposed to the allergen. These symptoms will disappear several weeks after exposure is ceased. Common points of exposure in household items are shampoos, hair conditioners, soaps, pre-moistened toilet/bath wipes and sunscreen.
- Reinhard et al.: "Preservation of products with MCI/MI in Switzerland". Contact Dermatitis. 2001 Nov;45(5):257-64. PMID 11722483
- Knudsen BB, Menne T: "Kathon CG--a new contact sensitizing preservative". Ugeskr Laeger. 1990 Mar 5;152(10):656-7. PMID 2321281
- "International Agency for Research on Cancer". IARC (updated November 2007). Retrieved 7 January 2008.
- Zoller L, Bergman R, Weltfriend S. (2006). "Preservatives sensitivity in Israel: a 10-year overview (1995-2004)". Contact Dermatitis 55 (4): 227–9. doi:10.1111/j.1600-0536.2006.00902.x. PMID 16958921.
- Zug KA, Warshaw EM, Fowler JF Jr, Maibach HI, Belsito DL, Pratt MD, Sasseville D, Storrs FJ, Taylor JS, Mathias CG, Deleo VA, Rietschel RL, Marks J. Dermatitis. Patch-test results of the North American Contact Dermatitis Group 2005-2006. 2009 May-Jun;20(3):149-60.