April 2014

# Organic molecules of everyday life.12. Triclosan

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Jenn Coggan, Nano-biomaterials senior laboratory instructor, University of Waterloo, Waterloo ON

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This series of articles considers some common organic molecules that we encounter in our everyday lives. Described will be some general chemical information about the organic molecule, how it is useful to us and other interesting facts.

## Triclosan

Chemical name: 5-chloro-2-(2,4-dichlorophenoxy)phenol

CAS registry number: 3380-34-5

Formula: C12H7Cl3O2

Structure:

This organic compound is a white powdery solid with a slight aromatic/phenolic odour. It is a chlorinated aromatic compound that contains both ether and phenol functional groups. Phenols have been shown to have antibacterial properties.1 Triclosan is only slightly soluble in water, but soluble in ethanol, methanol, diethyl ether and strongly basic solutions such as a 1 M sodium hydroxide solution.

You may hear a lot about triclosan in the news due to the controversy about its use as an antimicrobial agent. Triclosan’s ability to block a key bacterial enzyme is what makes it so effective, and since humans lack that enzyme, it does not affect us.2 Triclosan has been used since 1972 and was created as a surgical scrub for hospitals. Since then it has shown up in many of our everyday products such as soaps, toothpaste, body washes, cosmetics, antiperspirants/deodorants, cleansers and hand sanitizers — all being touted as anti-bacterial. It is now even found in household products such as garbage bags, toys, linens, mattresses, toilet fixtures, clothing, furniture fabric and paints — all advertised as anti-bacterial.

So why all the controversy? It is due to the fact that there is no evidence that triclosan in personal care products provides an extra benefit to health beyond its anti-gingivitis effect in toothpaste,3 according to the United States Food and Drug Administration (FDA).4 It has never been shown that triclosan in antibacterial soaps and body washes provides any benefit over washing with regular soap and water, although manufacturers have highly disputed this.

In addition triclosan could potentially be doing more harm than good. Scientists have raised concerns about triclosan for decades. The concern is based on recent studies about the possible health impacts of triclosan. Studies have increasingly linked triclosan to a range of adverse health and environmental effects including skin irritation, endocrine disruption5 and antibiotic resistance,6 to the contamination of water and negative impacts on fragile aquatic ecosystems.7 Triclosan bioaccumulates in our ecosystem; in other words, it doesn't easily degrade and can build up in the environment after it has been rinsed down the shower drain. It is so prevalent that a survey by the Centers for Disease Control found the chemical present in the urine of 75 percent of Americans over the age
of 5.8

In May of 2013, the FDA announced that it was reviewing antibacterial soaps and body washes since it does not have evidence that triclosan provides any benefit over washing with regular soap and water.9 It proposed a new rule that requires manufacturers of antibacterial hand soaps, body washes and other consumer goods to prove that their products are both safe for long-term use and more effective than regular bar soap in order to remain on the market. The agency will give manufacturers until June 2014 to respond to the planned regulation, following which the FDA will finalize the rule and decide whether the products are generally recognized as safe and effective by September 2016. The Canadian Medical Association has also called for a ban on antibacterial consumer products, such as those containing triclosan.10

If you want to know whether or not a product contains triclosan, take a look at the ingredient list or drug label. Antibacterial soaps, body washes and toothpastes are considered over-the-counter drugs and, as such, triclosan will be listed as an active ingredient. If a cosmetic contains triclosan, it will be included in the ingredient list on the product label.

It seems to make sense that if washing with plain old soap and water are effective at cleaning our hands and antibacterial, then why use products with a chemical that could have adverse effects and may or may not be beneficial? And this, coming from a chemist.

## References (all websites accessed February 2014)

1. L. Jurd, A.D. King, K. Mihara, W.L. Stanley. Applied Microbiology, 1971, 21(3), pages 507-510.
2. C.W. Levy, A. Roujeinikova, S. Sedelinikova, Nature, 1999, 398, pages 383-4.
3. S. Peter, D.G. Nayak, P. Philip, N.S. Bijlani, International Dental Journal, 2004, 54, pages 299-303.
4. http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm205999.htm
5. M.O. James, W. Li, D.P. Summerlot, L. Rowland-Faux, C.E. Wood. Environment International, 2010, 36, pages 942-9.
6. L.M. McMurry, M. Oethinger, S.B. Levy. Nature, 1998, 394,
   pages 531-2.
7. H. Singer, S. Muller, C. Tixier, L. Pillonel. Environmental Science and Technology, 2002, 36, pages 4998-5004.
8. http://www.cdc.gov/biomonitoring/pdf/Triclosan_FactSheet.pdf
9. http://www.fda.gov/forconsumers/consumerupdates/ucm378393.htm
10. https://www.canada.ca/en/news.html

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