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partition coefficient
Type of information:
Adequacy of study:
key study
Study period:
28 Sep 2015
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Structurally, Procrylat contains moieties that have fragment cofficients and structure corrections which are utilized by the software (KOWWIN) to calculate the log Kow. Thus, it is within the model applicability domain and is reliable.
Justification for type of information:
QSAR prediction: migrated from IUCLID 5.6

Data source

Reference Type:
other: QSAR prediction reporting format
Report date:

Materials and methods

Test guideline
according to guideline
other: REACH guidance on QSARs, R.6, May/July 2008
Principles of method if other than guideline:
KOWWIN v1.68 as implemented through EPI Suite v4.11
GLP compliance:
Type of method:
other: QSAR
Partition coefficient type:

Test material

Constituent 1
Reference substance name:

Results and discussion

Partition coefficient
log Pow
Partition coefficient:

Any other information on results incl. tables

Validity of Model (OECD 5 principles):

1) Defined endpoint: Partition coefficient

2) Unambiguous algorithm: The predicted value of the log Kow is calculated through the following equation: log Kow =∑f(j)n(j) + c(j)n(j) + 0.229 where f(j) is the coefficient for each atom/fragment), c(j) is the coefficient for each correction factor, and n(i) is the number of times the atom/fragment (and correction factor) occurs in the test species.

3) Applicability domain: The test substance has a molecular weight and predicted log Kow within the range of the software training set. The number of each type of fragment defined within the test substance structure structure is less than the maximum number of that fragment occurring in a single structure within the software's training set. The training set contains a wide variety of aromatic compounds, acrylate esters and aliphatic alcohols which are structurally related to the test substance. The test substance is therefore within the applicability domain of this QSAR model.

4) Statistical characterization: Statistical variation of 11 pairs of experimental and predicted log Kows for 11 representative analogous substances indicate that there is a 0.989 correlation coefficient (r-squared), a standard deviation of 0.162 and an absolute mean error of 0.141. The estimated and experimental data for structural analogs in the training set are in good agreement and Procrylat is within the applicability domain of the model.

5) Mechanistic interpretation: In aquatic systems chemicals may partition to lipid rich tissue of aquatic organisms. Octanol is considered a reasonable analog for the lipid-rich tissues of aquatic organisms. The octanol water partition coefficient is representative of a chemicals tendency to partition to the lipid-rich tissues or remain in the aqueous phase. The log Kow is a basis by which to assess a chemicals potential for bioconcentration (via lipid-rich tissue partitioning).

Please see attached QMRF and QPRF for justification of model and applicability.

Applicant's summary and conclusion

Procrylat has an estimated log Kow of 7.61 using KOWWIN v1.68 as implemented through EPI Suite v4.11.
Executive summary:

The partition coefficient n-octanol/water of Procrylat was determined using the KOWWIN v1.68 QSAR as implemented through EPI Suite v4.11. Water solubility of Procrylat is too low to allow accurate measurement of partition coefficient by either shake-flask or HPLC method. The software is an accepted, valid model for estimation of partition coefficient. The structure is within the parametric domain of the model (molecular weight, maximum number of structural fragments per structure, predicted log Kow). The use of this QSAR to predict log Kow for this substance was determined to be applicable and reliable based on representation of analogous substances within the training set and performance statistics (0.989 correlation coefficient (r-squared), a standard deviation of 0.162 and an absolute mean error of 0.141) derived from a comparison of experimental and estimated log Kow values for 11 representative analogous substances. This study is classified as an acceptable QSAR and satisfies the requirements for partition coefficient study. It is pertinent to the fate of Procrylat and may be used for risk analysis, classification and labelling, and PBT analysis.

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