Isotridecyl 3,5,5-trimethylhexanoate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

11 April 2017 - 12 July 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

ntroduction
Due to the fact that a definite water solubility value could not be determined; the practical methods for assessment of partition coefficient, as laid down in OECD 107 and 123, could not therefore be performed.
The absence of any chromophores meant that the UV signal was too poor for the HPLC simulation method described in OECD 117 to be performed.
Due to the low water solubility it was decided, in consultation with the Sponsor, that calculated values for the partition coefficient would be reported.
1. SOFTWARE
EPISUITE

2. MODEL (incl. version number)

KOWWIN v1.68 (september 2010)

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL

CAS NUMBER: 56231-35-5
SMILES: O=C(CC(CC(C)(C)C)C)OCCCCCCCC(C)C
NAME: Hexanoic acid, 3,5,5-trimethyl-, isodecyl ester

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- Defined endpoint: Log Kow at 25 °C

- Unambiguous algorithm:
Two separate regression analyses were performed.  The first regression related log P to atom/fragments of compounds that do not require correction factors (i.e., compounds estimated adequately by fragments alone).  The general regression equation has the following form:

 log P  = Σ(fini ) +  b     (Equation 1)

where Σ(fini )  is the summation of fi (the coefficient for each atom/fragment) times ni (the number of times the atom/fragment occurs in the structure) and b  is the linear equation constant.  This initial regression used 1120 compounds of the 2447 compounds in the total training dataset.

The correction factors were then derived from a multiple linear regression that correlated differences between the experimental (expl) log P and the log P estimated by Equation 1 above with the correction factor descriptors.  This regression did not utilize an additional equation constant.  The equation for the second regression is:

 lop P (expl)  -  log P (eq 1)  = Σ(cjnj )       (Equation 1)

where Σ(cjnj )  is the summation of cj (the coefficient for each correction factor) times nj  (the number of times the correction factor occurs (or is applied) in the molecule).

Regression Results

Results of the two successive multiple regressions (first for atom/fragments and second for correction factors) yield the following general equation for estimating log P of any organic compound:

 log P  = Σ(fini ) + Σ(cjnj ) + 0.229     (Equation 3)

(num = 2447,   r2 = 0.982,  std dev = 0.217,  mean error = 0.159)

Appendix D lists KOWWIN atom/fragment and correction factor descriptors with corresponding coefficient values. Appendix D also includes the number of compounds in the training and validation datasets containing each descriptor and the maximum number of instances that each descriptor occurs in any single compound.

The statistical accuracy of KOWWIN is described in section 6.2. KOWWIN Estimation Accuracy.
- Defined domain of applicability:
See "Accuracy & Domain.pdf" appended below.


5. APPLICABILITY DOMAIN
See "Accuracy & Domain.pdf" appended below.

6. ADEQUACY OF THE RESULT
The QSAR model was used as the water solubility of the test substance fell below the limit of quantification in an experimental test. The result is of the order of magnitude indicated in the experimental test. The model has been fully validated by a reputable government agency. The result is therefore considered adequatly reliable for use as the basis of the classification and labelling and PBT/vPvB assessment.

Qualifier:

no guideline required

Principles of method if other than guideline:

The QSAR model was used as the water solubility of the test substance fell below the limit of quantification in an experimental test. The model has been fully validated by a reputable government agency. The result is therefore considered adequatly reliable for use as the basis of the classification and labelling and PBT/vPvB assessment.

GLP compliance:

yes (incl. QA statement)

Type of method:

calculation method (fragments)

Partition coefficient type:

octanol-water

Key result

Type:

log Pow

Partition coefficient:

9.446

Temp.:

25 °C

Remarks on result:

other: QSAR: pH not determined

Conclusions:

The QSAR model KOWWIN v1.68 calculated the partition coefficient of the test material to be Log Pow 9.45 at 25 °C.

Executive summary:

In this validated QSAR (KOWWIN) study, conducted with GLP certification, the partition coefficient of the test material was determined to be Log Pow 9.45 at 25 °C.

Key value for chemical safety assessment

Log Kow (Log Pow):

9.45

at the temperature of:

25 °C