Methyldibromo glutaronitrile (inci)

Metyldibromo glutaronitrile, also known as dibromdizyanobutane, is a preservative with a broad spectrum of action against bacteria, yeasts and moulds. Metyldibromo glutaronitrile is banned in the EU on the advice of the relevant Scientific Committee in products intended to remain on skin and hair (leave on cosmetics). Products containing Metyldibromo glutaronitrile may no longer be placed on the market after 24 March 2005. However, it is still contained in rinse-off care products such as soaps, shower gels or shampoo in concentrations of up to 0.1%.

Not in medicinal products: The use of the substance is prohibited in authorised medicinal products as it is considered to be insufficiently researched. Thus, its use is also prohibited in pharmaceutical formulations.

Only for rinse-off products: Metyldibromo glutaronitrile is still contained in rinse-off care products such as soaps, shower gels or shampoo in the EU in a concentration of 0.05% to 0.1%.

Epicutaneous testing is performed in 1% test concentrations in petroleum jelly.

About 30 years ago the first cases of contact allergies were described by Euxyl K 400. Allergic reactions to this mixture were observed in 2.1% of the patients tested.

In a large Danish study on 766 patients (Zachariae C et al. 2005) with eczematous changes, an average sensitization rate to Metyldibromo glutaronitrile of 4.9% was found. In numerous cases, moist toilet paper has also been reported to trigger contact allergic reactions to Metyldibromo glutaronitrile. Increasingly, cases of occupational hand eczema caused by industrial hand cleansers and skin protection creams are becoming known (Johansen JD et al. 2005).

Investigations for the MDGN show that even 0.015 % concentrations in leave-on products can have a sensitizing effect and trigger contact allergies, and even in rinse-off products, even a 0.1 % concentration can be sufficient to trigger a contact allergic reaction on repeated contact.

However, for "rinse-off" products, such as soaps, shampoo or facial cleansing products, the risk of triggering contact dermatitis on MDGN is estimated to be low. Only occupational contact dermatitis in hairdressers was observed in this context. Shampoos containing 0.02 % MDGN can be considered safe even in sensitized persons (Heratizadeh A et al. 2010).

Metyldibromo glutaronitriles in fixed combinations with phenoxyethanol (dibromodicyanobutane/phenoxyethanol): Metyldibromo glutaronitrile (dibromdicyanobutane) is often used in combination with phenoxyethanol (trade name Euxyl K 400) for the preservation of cosmetics, personal care products, skin cleansing products, body care products, skin care milk, face and hand creams, in shower and washing emulsions, in shampoos, massage products, in refreshing tissues (also in moist toilet paper) and ultrasonic gel, but also in the industrial sector (technical emulsions such as cutting oil emulsions, drilling solutions, cooling liquids).

Increase in the sensitisation rate: The reason for the restrictive attitude of the European Commission was a significant increase in the sensitisation rate, which went hand in hand with the greater spread of methyl dibromoglutaronitrile. In ulcer-cruris patients, 9.5% (for methyl dibromo glutaronitrile-phenoxyethanol combination) showed by far the highest rate for all preservatives.

1. Heratizadeh A et al (2010) Quantitative repeated open application testing with a rinse-off product in methyldibromo glutaronitrile-sensitive patients: results of the IVDK. Contact dermatitis 62: 330-337.
2. Jensen CD et al(2005) Methyldibromo glutaronitrile contact allergy: effect of single versus repeated daily exposure. Contact Dermatitis 52:88-92.
3. Johansen JD et al(2005) Contact allergy to methyldibromo glutaronitrile--data from a 'front line' network. Contact dermatitis 52:138-141.
4. Young HS et al(2004) Post-coital contact dermatitis from methyldibromo glutaronitrile. Contact dermatitis 50:48.
5. Zachariae C et al.,(2003) Allergic contact dermatitis from methyldibromo glutaronitrile--clinical cases from 2003. contact dermatitis 52:6-8.
6. Zachariae C et al (2005) Methyldibromoglutaronitrile: clinical experience and exposure-based risk assessment. Contact Dermatitis 48:150-154.