Registration Dossier

Administrative data

Endpoint:
vapour pressure
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2018
Reliability:
2 (reliable with restrictions)
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:
SOFTWARE
iSafeRat® HA-QSAR toolbox v1.1

MODEL NAME
Model iSafeRat® High-Accuracy-Quantitative Structure-Activity Relationship (HA-QSAR) to predict vapour pressure

MODEL VERSION
iSafeRat® vapour pressure HA-QSAR v1.3

SMILES USED AS INPUT FOR THE MODEL
C(C(C(C(C=O)O)O)O)O

SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
The evaluation of the effects was based on regression lines from validated data on vapour pressure for individual chemical structures. (e.g. a specific group for alkanes; a further group for alkenes, for tertiary alcohols etc.) and then validated using external test sets for each group. The R^2 values for these algorithms were extremely high (>0.98) and Root Mean Standard Error (RMSE) values are low enough (<0.22) which provide statistical verification of the prediction accuracy. Further statistical evidence of high prediction accuracy are provided in the QPRF and QMRF.
- Vapour pressure of the substance is determined using boiling point as the descriptor. The local model used is depending on the capability of the substance to participate in intermolecular interactions, such as hydrogen bonding.
- Defined domain of applicability: The limits of the applicability domain are defined by the mean distance values calculated for training samples from their 5 closest training neighbours. The test samples within the proximity of the training space are expected to fall within the applicability domain of the model whereas the ones outside the domain will be expected to be located a distance greater than the mean distance measure of their nearest training neighbours.

APPLICABILITY DOMAIN
- Descriptor domain: Test item falls outside the applicability domain of the iSafeRat® HA-QSAR module for vapour pressure. As described in the relevant QMRF report, the applicability domain was based on k-Nearest Neighbours approach taking into account 5 closest training neighbours (k=5). Therefore, the prediction is considered as an extrapolation.
- Structural and mechanistic domains: All chemical group within the molecular structure are represented within the datasets used by the model.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report Date:
2018

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 104 (Vapour Pressure Curve)
Deviations:
no
Principles of method if other than guideline:
The purpose of the in silico study was to determine the vapour pressure of the test item. The determination was performed using a regression method in which validated boiling point values are plotted against the log of vapour pressure values, where the pressure is in Pascals. The comparison was made with other members of the same chemical group. The results are considered to be as accurate as those from a good quality OECD guideline 104 study.
Type of method:
other: QSAR modelization

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
Dry powder, white to slightly yellow
Specific details on test material used for the study:
SMILES: C(C(C(C(C=O)O)O)O)O

Results and discussion

Vapour pressure
Key result
Temp.:
ca. 25 °C
Vapour pressure:
ca. 0.005 Pa
Remarks on result:
other: QSAR predicted value

Applicant's summary and conclusion

Conclusions:
The vapour pressure of the test item was calculated as 5.38 x 10^(-3) Pa at 25 °C.
Executive summary:

The vapour pressure test was performed by QSPR model adapted specifically from OECD test Guideline 104 (Vapour Pressure Curve).