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Description of key information

No data is available on the toxicokinetics, metabolism and distribution of the specific substance C16-22-(even numbered)alkylamines (CAS no 68037-92-3). The information in this chapter has therefore been derived based on the physicochemical properties of the substance. Exposure to the substance is unlikely by inhalation due to the low vapour pressure and its physical form.  Ingestion is not a likely route of exposure and the corrosive effects would limit accidental oral exposure.  The corrosive properties of the substance will limit the potential for repeated or prolonged skin exposure so dermal absorption should be limited. 

Key value for chemical safety assessment

Additional information

No data is available on the toxicokinetics, metabolism and distribution of the specific substance C16-22-(even numbered)alkylamines (CAS no 68037-92-3). The information in this chapter has therefore been derived based on the physicochemical properties of the substance.

Ingestion of C16-22-(even numbered)alkylamines (CAS no 68037-92-3) is not a likely route of exposure and the corrosive effects would limit accidental oral exposure. Still a worst case approach is taken and the default 100% is used in the risk assessment.

Exposure to C16-22-(even numbered)alkylamines (CAS no 68037-92-3) via inhalation is unlikely due to the low vapour pressure of the substance and its physical form. C16-22-(even numbered)alkylamines (CAS no 68037-92-3) is practically insoluble in water, has a low vapour pressure and the calculated log Kow values is 5.4. Taken together, based on physico-chemical properties, a low inhalative bioavailability can be anticipated. Based on this, the factor of 2 which ECHA guidance recommends for route to route extrapolation (oral to inhalation) is not considered relevant.  However, as a result of the observed effects after oral exposure, as a worst-case, a value of 100 % absorption by inhalation is taken.

Due to the corrosive nature of C16-22-(even numbered)alkylamines (CAS no 68037-92-3), the required risk management measures to handle it should minimize the potential for contact with the skin. In case of dermal exposure, based on the basicity and corrosive properties of the substance, dermal absorption as a consequence of facilitated penetration through damaged skin can be anticipated. For non-corrosion formulations containing the test substance, the high octanol-water partition coefficient of Log Kow 5.3 would reduce its potential for being absorbed through the skin. The substance displays a cationic surfactant structure which leads to high adsorptive properties to negatively charged surfaces, such as cellular membranes. The apolar tail will easily dissolve in the membranes, whereas the polar head of the substance causes disruption and leakage of the membranes leading to cell damage or lysis of the cell content. As a consequence, the whole molecule will not easily pass membrane structures. Cytotoxicity at the local site of contact through disruption of cell membrane is considered to be the most prominent mechanism of action for toxic effects. As a worst case assumption,100 % dermal absorption is used for assessment purposes.

Once absorbed there is no specific information on the metabolism, distribution and excretion of C16-22-(even numbered)alkylamines (CAS no 68037-92-3). It is likely that once the substance enters the body due to its lypophilic nature, it would be transported via the lymphatic system to the nearest draining lymph node rather than in the blood. It is likely that the macrophages will then ingest the material in the lymph nodes in order to metabolise the substance. This is also supported by the findings from the repeated dose studies available, where accumulation of histiocites /foam cells in the mesenteric lymph nodes are the effects seen at the lowest dose after exposure.  

Publications on the metabolism of structurally related long chain fatty acids shows that these substances are metabolized in peroxisomes by β-oxidation to form medium length acyl moieties which might indicate a relevant metabolism pathway also for the C16-22-(even numbered)alkylamines (CAS no 68037-92-3. For the long chain fatty acids, adaptation of the metabolism is seen in rats, which is explained mainly by increased capacity of the peroxisomal oxidation β-oxidation enzyme system. C16-22-(even numbered)alkylamines (CAS no 68037-92-3) is therefore considered to be metabolized by available pathways in the organisms.