Methylisothiazolinone

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Methylisothiazolinone
Methylisothiazolinone
General
Systematic name 2-methylisothiazol-3(2H)-one
Other names MIT
Molecular formula C4H5NOS
SMILES CN1SC=CC1=O
Molar mass 115.1 g/mol
Appearance  ?
CAS number [2682-20-4]
Properties
Density and phase  ? g/cm³, ?
Solubility in water  ? g/100 ml (?°C)
Melting point  ?°C (? K)
Boiling point  ?°C (? K)
Acidity (pKa)  ?
Basicity (pKb)  ?
Viscosity  ? cP at ?°C
Structure
Molecular shape  ?
Coordination
geometry		  ?
Crystal structure  ?
Dipole moment  ? D
Hazards
MSDS External MSDS
Main hazards  ?
NFPA 704
Flash point  ?°C
R/S statement R: ?
S: ?
RTECS number  ?
Related compounds
Related compounds  ?
Except where noted otherwise, data are given for
materials in their standard state (at 25 °C, 100 kPa)
Infobox disclaimer and references

Methylisothiazolinone or MIT, sometimes erroneously called methylisothiazoline, is a powerful biocide and preservative.

Contents

[edit] Applications

Methylisothiazolinone is an antimicrobial used to control slime-forming bacteria, fungi, and algae in cooling water systems, fuel storage tanks, pulp and paper mill water systems, oil extraction systems, and other industrial settings. It is frequently used in personal care products such as shampoos and other hair care products, as well as certain paint formulations. There, it is often used in combination with either chloromethylisothiazolinone (known as Kathon CG when paired with methylisothiazolinone) or benzisothiazolinone (an added antiseptic). It is also used to control the growth of mold, mildew, and sapstain on wood products.

[edit] Functional group

MIT needs to be soluble in water to perform its uses, and so MIT’s carbon molecules bond with water molecules, making MIT soluble—but several components are responsible for this. The ketone function stabilizes the other chemical elements in MIT when bonded with water so that the active bacteria-killing factors do not degrade quickly, but last longer. Ketones stabilize the relationship between MIT and water because a ketone, a carbonyl group, is a polar compound (of equally sharing electrons) that is hydrogen-bond accepting, not hydrogen-bond giving. And when MIT needs to be soluble, the carbon’s geminal diol dehydrates MIT’s carbons and converts it to a slightly reduced version of MIT and water. And as water’s hydrogen molecule bonds with MIT’s oxygen molecule (whose bond with its carbon has been degraded into a carbonyl group by the diol process), a hydroxyl (-OH) group forms, creating an alcohol function, which helps with the detoxification and breaking down of bacteria.

[edit] Human health

Some studies have shown MIT to be allergenic and cytotoxic, and this has led to some concern over its use.[1][2] In early December, 2004, a news broadcast from WNYT in Albany, NY reported that methylisothiazolinone had been linked to nerve cell death in scientific studies. In 2002, there was an in vitro study of the neurotoxicity of MIT in the department of Neurobiology at the University of Pittsburgh.[3] In that study, it was showed that a short exposure (10 min) relatively high concentrations of MIT (30-100 micromolar) were lethal to mature neurons in tissue culture, but not to other brain cells, such as astrocytes (support cells). The lethal actions of MIT were due to its ability to liberate the metal zinc from intracellular metal-binding sites. The liberated zinc, in turn, triggered a cell death cascade in neurons that was characterized by the sequential activation extracellular signal-regulated kinase (ERK) and NADPH oxidase. This activity led to production of reactive oxygen species (free radicals), DNA damage and the overactivation of the DNA repair enzyme poly(ADP-ribose)polymerase, or PARP. Overactivation of PARP has been linked by many investigators to cell death due to it's consumption of reduced equivalents and depletion of cellular energy sources (ATP).

[edit] Physiopathological effects of MIT on developing neurons

The physiopathological effects of MIT and it's closely related analog, chloromethylisothiazolinone or CMIT, reside in affecting the ability of young or developing neurons to grow processes (axons and dendrites) in tissue culture. The specific protein that is affected by MIT is called focal adhesion kinase, or FAK. Normal FAK function is required for the growth of axons and dendrites. But FAK has to be modified by a process called phospohorylation to perform its function, so phosphates are added to FAK’s amino acid chain (a process called tyrosine phosphorylation). MIT inhibits the tyrosine phosphorylation of FAK by another kinase called Src, preventing the growth of axons and dendrites, at least in culture. These findings were recently published in the Journal of Pharmacology and Experimental Therapeutics.[4] The toxic actions of MIT on developing neurons occurs at much lower concentrations than those inducing lethal injury (1-3 micromolar).

[edit] External links

[edit] References

  1. ^ A. Schnuch, J. Geier, W. Utur, P. J. Frosch: "Patch testing with preservatives, antimicrobials and industrial biocides. Results from a multicentre study", British Journal of Dermatology, 137(3), 467-476 (1998).
  2. ^ A. C. De Groot, A. Herxheimer: "Isothiazolinone Preservative: Cause Of A Continuing Epidemic Of Cosmetic Dermatitis", The Lancet, Volume 333, Issue 8633, Pages 314-316 (1989).
  3. ^ Shen Du, BethAnn McLaughlin, Sumon Pal, Elias Aizenman (2002): In Vitro Neurotoxicity of Methylisothiazolinone, a Commonly Used Industrial and Household Biocide, Proceeds via a Zinc and Extracellular Signal-Regulated Kinase Mitogen-Activated Protein Kinase-Dependent Pathway Journal of Neuroscience 22:7408-7416; 2002.
  4. ^ K. He, J. Huang, C. F. Lagenaur, E. Aizenman: "Methylisothiazolinone, a neurotoxic biocide, disrupts the association of Src family tyrosine kinases with focal adhesion kinase in developing cortical neurons", J. Pharmacol. Exp. Therap. 317:1320-1329; 2006
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