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Description of key information

There are no experimental data available for DTDMAC. Read-across was performed to the structural closely related quaternary ammonium compound dioctadecyldimethylammonium chlorid/ dihydrogenated tallowalkyldimethylammonium chloride (DHTDMAC, CAS No. 61789-80-8). To use read-across is not only justified by structural similarities but also due to comparable physico-chemical properties. There are two valid in vivo skin irritation guideline studies available for assessment purposes. Whereas high concentrated, pure quaternary ammonium compounds revealed only slight skin irritating effects, technical grade material in isopropanol exhibited strong irritating effects up to skin corrosivity. For assessment purposes the data with dioctadecyldimethylammonium chlorid indicating skin corrosive effects are taken for the assessment of DTDMAC. Serious eye effects were shown for DODMAC/DHTDMAC.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (corrosive)

Eye irritation

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (irritating)

Additional information

No experimental data is available for DTDMAC on skin irritation / corrosion. However, a read-across approach based on SAR (structure-activity-relationship) considerations is used as predictive tool to evaluate the irritative potential of DTDMAC. Two valid guideline studies on structural closely related quaternary ammonium compounds are available for assessment purposes of this endpoint. Read-across is scientifically justified because of the structural similarities and the comparable physical-chemical properties of dialkyldimethylammonium chlorides. Clustering quaternary ammonium compounds for assessment purposes was also considered appropriate by the U.S. EPA for registration purposes under FIFRA because of similar toxicological profiles of dialkyldimethylammonium chlorides. Based hereupon, read-across from experimental data on skin irritation / corrosion coming from DODMAC (CAS-No. 107 -64 -2)/ DHTDMAC (CAS No. 61789 -80 -8) should allow reliable estimates of the respective properties of DTDMAC. The experimental results of these studies indicate that technical grade quaternary ammonium salts when applied in isopropanol exhibit strong skin irritative / skin corrosive properties whereas highly concentrated long-chain solid material is only slightly irritating to skin. This well known effect seems to be mainly triggered by the solvent isopropanol which is thought to increase the accessibility of the test material to the skin. Whereas pure DODMAC (97% with 3% water) was only slightly irritating to skin, technical grade DHTDMAC (77% with 11.3% isopropanol and 11.7% water) was severely irritating up to corrosive to skin following a 4 hour exposure period. Taking into account that technical grade DTDMAC has a comparable composition comprising approximately 70% active, 20% isopropanol and 10% water, similar skin corrosive properties have to be assumed.

With regard to eye irritation no experimental study was performed for DTDMAC based on animal welfare reasons. Due to the skin corrosive effects of DTDMAC, testing of eye irritation potential is not justified but severe eye irritating effects have to be anticipated. This is confirmed by data from the structural analogue DODMAC/DHTDMAC which have demonstrated the risk of serious eye effects in a respective guideline study.


Effects on skin irritation/corrosion: corrosive

Effects on eye irritation: highly irritating

Justification for classification or non-classification

Based on the results of studies performed on the structural analogue DHTDMAC and in accordance with the criteria laid down in Regulation 1272/2008/EC (CLP) and directive 67/548/EEC (DSD), the substance is classified Corrosive Category 1B and Corrosive R34 respectively.

Considering that the substance is classified as corrosive to skin, the undiluted substance must be considered as being able to cause serious eye effects.Therefore, the undiluted substance is classified Eye Category 1 and Xi, R41 according to the EU regulation 1272/2008/EC (CLP) and directive 67/548/EEC (DSD) respectively.

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