Quaternary ammonium compounds, bis(C16-18 and C18-unsatd. alkyl)dimethyl, chlorides

Endpoint summary

Description of key information

Short description of key information on bioaccumulation potential result: Data from analogous quaternary ammonium compounds with close structural similarities and comparable physico-chemical characteristics to DTDMAC can be used for read-across concerning toxicokinetic parameters like absorption and excretion. Based hereupon low absorption rates after oral or dermal exposure to DTDMAC are to be expected. For risk characterization absorption rates of 5% and 1% are used for the oral and dermal route of exposure, respectively. A bioaccumulative potential can also be excluded on the basis of all available data. Short description of key information on absorption rate: Data from analogous quaternary ammonium compounds with close structural similarities and comparable physico-chemical characteristics to DTDMAC can be used for read-across concerning toxicokinetic parameters like absorption and excretion. Based hereupon low absorption rates after oral or dermal exposure to DTDMAC are to be expected. For risk characterization absorption rates of 5% and 1% are used for the oral and dermal route of exposure, respectively. A bioaccumulative potential can also be excluded on the basis of all available data.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Absorption rate - dermal (%):

1

Additional information

Data on toxicokinetics for N-C16-C18(even numbered), C18 unsaturated-alkyl-N,N-dimethyl-C16-C18(even numbered), C18 unsaturated-alkyl-1-aminium chloride (common name: Quaternary ammonium compounds, dimethylditallow alkyl chlorides) are not available.

However, experimental data on toxicokinetic aspects exist for some dialkylquaternaries like N-decyl-N,N-dimethyldecan-1 -aminium chloride (EC name: Didecyldimethylammonium chloride, DDAC) and for 1 -Octadecanaminium,N,N-dimethyl-N-octadecyl chloride (Dioctadecyldimethylammonium chloride, DODMAC) which allow basic considerations concerning toxicokinetic parameter like absorption following the oral and the dermal route of exposure.

Studies with Didecyldimethylammonium chloride have shown low dermal and oral absorption. These findings are supported by data with DODMAC/DTDMAC, demonstrating very low dermal absorption. Due to comparable physico-chemical characteristics a similar low absorption rate following oral and dermal exposure can be assumed also for DTDMAC. Like Didecyldimethylammonium chloride and DODMAC, DTDMAC is insoluble in water and exists as quaternary ammonium salts in an ionic state which reduces the absorption potential compared to uncharged molecules which, however, are absorbed. Due to the apolar alkyl chain and its adherence to negatively charged surfaces, dialkylquaternaries like DTDMAC in general do not easily pass biological membranes. Also after oral exposure absorption is expected to be low. Based on the close structural analogy and supported by comparable physico-chemical characteristics, the findings of low absorption potential following oral and dermal exposures for Didecyldimethylammonium chloride and DODMAC can be extrapolated by read-across also to DTDMAC. With regard to potential inhalative exposure, due to the low vapour pressure of the dialkylquaternaries the potential for generating vapour and thus inhaling them is minimal. Although very unlikely if aerosols or particulates are inhaled, the pulmonary physiology and clearance dynamics would largely favour the oral absorption than the inhalation. Based on physico-chemical properties, a low inhalative bioavailability can be anticipated. The available toxicokinetic studies on structurally similar quarternary ammonium compounds like didecyldimethylammonium chloride and on DODMAC indicates an oral absorption rate of approximately 5% and a dermal absorption rate of around 1.0%. These experimental findings are supported by the physico-chemical properties like water solubility, log Pow, and the molecular weight of quaternary ammonium compounds under consideration. Thus, these absorption rates will be further considered in the assessment of DTDMAC since it is expected that ditallowdimethylammonium chloride follow a similar toxicokinetic profile based on its structural similarity.

Discussion on bioaccumulation potential result:

Experimental data on toxicokinetics of DTDMAC is not available. However, relevant information concerning toxicokinetic aspects exist for closely related quaternary ammonium compounds which allow basic considerations concerning toxicokinetic parameter like absorption and excretion. Read-across is justified by the structural similarities and supported by comparable physico-chemical properties of the quaternary ammonium compounds under consideration. From the available data of the structural analogous compounds Didecyldimethylammonium chloride and from DODMA/DHTDMACC it can be concluded that the absorption potential following oral or dermal exposure to DTDMAC is low. A bioaccumulative potential is not deducible.

Discussion on absorption rate:

Experimental data on toxicokinetics of DTDMAC is not available. However, results concerning toxicokinetic aspects exist for structural closely related quaternary ammonium compounds which allow basic considerations concerning toxicokinetic parameter like absorption and excretion. Studies with Didecyldimethylammonium chloride and with DODMAC revealed only very low oral or dermal absorption following respective exposures. Based on the structural similarities comparable low absorption rates are anticipated also for DTDMAC. For risk characterization absorption rates of 5% and 1% are used for the oral and dermal route of exposure, respectively. This view is supported by the physico-chemical properties of DTDMAC being insoluble in water and existing as a quaternary ammonium salt in an ionic state which reduces the penetration potential through biological membranes while uncharged molecules are absorbed. Furthermore, DTDMAC has a molecular weight of about 565 g/mol and usually only substances with lower molecular weight are absorbed.