Dimethyldioctylammonium chloride

Endpoint summary

Description of key information

The molecular weight of C8DAQ is 306, it is water soluble and has a Log P of 0.1 (not lipophilic). Although the molecular weight and physico-chemical properties of C8DAQ indicate that it is likely to be absorbed via the oral and dermal routes of exposure, the presence of the quaternized nitrogen makes the substance highly ionic and therefore it is unlikely to be absorbed by the gastrointestinal tract or the dermal route. There is no toxicokinetic data on C8DAQ itself, however toxicokinetic data is available for the analogous substance DDAC, which shows that the majority (>90%) of orally administered substance is excreted (very likely unabsorbed) via the faeces. Therefore, based on data on urine excretion and tissue retention coupled with recovery of radioactivity obtained in the available toxicokinetic study, it is expected that DDAC oral absorption is limited to ≈10%. DDAC metabolism is expected to be carried out by intestinal flora giving rise to hydroxylation products in the alkyl chain. Excretion of DDAC is expected to be the major route of excretion followed by a relatively small amount being excreted in the urine. Given the similarity in the chemical structures it is likely that C8DAQ would portray a similar toxicokinetic profile. Acute and repeated dose (oral) exposure to DDAC resulted in treatment-related adverse effects in a number of tissues. This indicates that there may be some systemic exposure via the oral route of exposure with organ distribution for DDAC. Both C8DAQ and DDAC are corrosive and therefore any systemic effects observed could be a result of the substance entering the systemic circulation following damage to skin. The physical chemical properties of the substance indicate that it has the potential to distribute to organs, which is further demonstrated by the occurrence of effects in tissues following dermal exposure to C8DAQ.The substance is not considered to be lipophilic based on the Log P of 0.1 and therefore not expected to distribute to fatty tissues. Although the presence of the quaternized nitrogen makes the substance highly ionic and therefore unlikely to be absorbed by the dermal route, the occurrence of adverse effects on the heart, kidneys, stomach and lungs following dermal application of C8DAQ in rabbits shows that there is some absorption occurring via this route. Moreover, the structurally similar substance, DDAC, has been shown to penetrate the skin (<0.5%) in in vitro studies. Exposure via the inhalation route to C8DAQ is unlikely given that the substance has a very low vapour pressure. However, in the absence of further information any absorption via this route should be assumed to be 100%. There is no evidence regarding the metabolism, metabolite fate or excretion of C8DAQ. Excretion via the kidneys is considered unlikely based on the excretion profile of DDAC, which is excreted predominantly via the faces most likely because it is not absorbed in the gastrointestinal tract. The low Log P indicates that bioaccumulation is unlikely.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential