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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

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Physical & Chemical properties

Partition coefficient

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Administrative data

Link to relevant study record(s)

Reference
Endpoint:
partition coefficient
Type of information:
calculation (if not (Q)SAR)
Remarks:
Migrated phrase: estimated by calculation
Adequacy of study:
key study
Study period:
2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Since Docusate Sodium is a surfactant, the typical experimental procedures cannot be applied. The calculations presented here are outlined in the EU method A.8 (2008).The determinations of the water and octanol solubilities were Klimisch 1 studies.
Reason / purpose for cross-reference:
reference to same study
Qualifier:
according to guideline
Guideline:
EU Method A.8 (Partition Coefficient)
Version / remarks:
calculation according to Annex 1
Deviations:
no
GLP compliance:
no
Type of method:
other: calculation
Partition coefficient type:
octanol-water
Analytical method:
other: The concentrations in water and n-octanol were determined using the XRF (X-ray fluorescence) method.
Type:
log Pow
Partition coefficient:
1.998
Temp.:
20 °C
pH:
5

Based on the n-octanol and water solubility of Docusate Sodium, its log Pow is 1.998.

Conclusions:
log Pow= 1.998
Executive summary:

According to EU method A.8 (2008) the shake flask and HPLC methods are "not applicable to surface active materials (for which a calculated value or an estimate based on the individual n-octanol and water solubilities should be provided)".

The saturation concentrations in water and n-octanol were determined in seperate experiments. The endpoint study records are included in this dossier.

The value of the partition coefficient was calculated using the solubilities of the test substance in the pure solvents (EU method A.8 (2008), appendix 1, page 75):

Pestimate = saturation c(n − octanol) / saturation c(water) with c=concentration

The water solubility of Docusate Sodium at 20 °C is 8.17 ± 0.16 g/l..

The solubility of Docusate Sodium in n-octanol at 20 °C is 841 ± 14 g/l..

(The endpoint study records for the water solubility and the n-octanol solubility can be found in the respective sections of this dossier.)

The log Pow at 20°C is therefore: 1.998.

This value is considered to be relevant and reliable for the risk assessment.

Description of key information

log Pow: 1.998

Key value for chemical safety assessment

Log Kow (Log Pow):
1.998
at the temperature of:
20 °C

Additional information

According to EU method A.8 (2008) the shake flask and HPLC methods are "not applicable to surface active materials (for which a calculated value or an estimate based on the individual n-octanol and water solubilities should be provided)".

Docusate sodium is a surfactant. Therefore, the value of the partition coefficient was calculated using the solubilities of the test substance in the pure solvents as proposed in EU method A.8 (2008) Appendix 1. Docusate Sodium is soluble in water (8.17 g/L) and n-octanol (814 g/L). Based on this information, the log Pow is 1.998. This value is considered to be reliable and relevant.

For the risk assessment a log Pow of 1.998 will be used.