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Physical & Chemical properties

Partition coefficient

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Description of key information

logPow = 2.5

Key value for chemical safety assessment

Log Kow (Log Pow):
2.5
at the temperature of:
23 °C

Additional information

A study (BASF SE, 16 -12882 -6) was conducted in accordance with OECD TG 107 to determine the partition coefficient using shake flask method. Pow was determined to be 295.8 (+/- 65.3) and logPow = 2.5. The pH value of the aqueous buffer phases was 7.1. The Partition coefficient was determined at 23 °C.

 

In addition to the experimentally determined partition coefficient QSAR calculations were performed for the test item. The test item is an UVCB substance consisting of the salt of LAS and DEA. Based on its structure LAS constituents are expected to be more lipohpilic than DEA and thus mainly contributing to a higher logPow value. Therefore, QSAR calculations were performed for the uncharged LAS molecule with an alkylchain length of C10 as well as C13. LogPow was calculated to be 3.8 and 5.8 for the shorter and the longer alkylchain molecule, respectively. Both values are greater than the experimentally determined logPow of 2.5. This is due to the fact that LAS is present as anion within the test substance. Charged molecules are less soluble in the lipophilic phase than the neutral molecule. Therefore, the logPow value of 2.5 is considered to be the most reliable value and is set as key value for the test item.

 

In Article 13 of Regulation (EC) No 1907/2006, it is laid down that information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI (of the same Regulation) are met. Furthermore according to Article 25 of the same Regulation testing on vertebrate animals shall be undertaken only as a last resort.

 

According to Annex XI of Regulation (EC) No 1907/2006 (Q)SAR results can be used if (1) the scientific validity of the (Q)SAR model has been established, (2) the substance falls within the applicability domain of the (Q)SAR model, (3) the results are adequate for the purpose of classification and labeling and/or risk assessment and (4) adequate and reliable documentation of the applied method is provided.

 

For the assessment of LAS DEA (Q)SAR results were used to support findings of an experimental study on partition coefficient. The criteria listed in Annex XI of Regulation (EC) No 1907/2006 are considered to be adequately fulfilled and therefore the endpoint(s) sufficiently covered and suitable for risk assessment.