Essential oil of Platycladus orientalis (L.) Franco obtained from branches and leaves by steam distillation followed by vacuum distillation

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

October 15th, 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:

iSafeRat® High-Accuracy-Quantitative Structure-Activity Relationship (HA-QSAR) based on a holistic approach for predicting physicochemical and ecotoxicological endpoints: Water solubility

1. SOFTWARE
iSafeRat® toolbox – in Silico Algorithms For Environmental Risk And Toxicity version 2.4

2. MODEL (incl. version number)
iSafeRat® holistic HA-QSAR v1.8

3. IDENTIFIERS USED AS INPUT FOR THE MODEL
logKOW of the constituents predicted using the iSafeRat® Log KOW module with the molecular structure (SMILES code) as the input (see attached QPRF).

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF

5. APPLICABILITY DOMAIN
See attached QPRF

6. ADEQUACY OF THE RESULT
See attached QPRF

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

yes

Remarks:

QSAR model

Principles of method if other than guideline:

A calculation method prediction was performed to assess the water solubility of the consituents of test item. This calculation method predicts the endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following the Guideline for Testing of Chemicals No. 105, "Water Solubility" adapted for testing as a mixture using the WAF method. The criterion predicted was the solubility in pure water in mg.L-1 at 25°C.

The water solubility of each constituent was determined using an algorithm based on Quantitative Structure-Property Relationship (QSPR) models which have been validated as QSAR models to be compliant with the OECD recommandations for QSAR modeling (OECD, 2004). The determination was performed using regression method in which validated log KOW values are plotted against the log of subcooled liquid water solubility from studies of high quality. These have been carried out using one of the methods recommended in the OECD 105 guideline or an adaptation of these. Further to this the water solubility of the WAF is determined by using a calculation method based on equilibrium thermodynamic principles.

GLP compliance:

no

Type of method:

other: QSAR

Key result

Water solubility:

>= 0.109 - <= 300 mg/L

Temp.:

25 °C

Remarks on result:

other: min - max of 19 constituents

Details on results:

None

None

Conclusions:

The water solubility of 19 constituents of the test item is predicted as follows (mg test item/L):
Constituents, Water solubility (mg test item.L-1) at 25°C
1 1.56
2 25.2
3 90.1
4 103
5 1.06
6 300
7 0.216
8 0.318
9 0.175
10 0.282
11 0.245
12 0.152
13 0.196
14 0.318
15 0.164
16 0.589
17 12.9
18 0.133
19 0.109

Executive summary:

A calculation method prediction was performed to assess the water solubility of the test item. This calculation method predicts the endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following Guideline for Testing of Chemicals No. 105, "Water Solubility" adapted for testing as a mixture using the WAF method. The criterion predicted was the solubility in pure water in mg.L-1 at 25°C.

The water solubility determination of the individual constituents of the mixture was performed using regression method in which validated log Kow values are plotted against the log of sub-cooled liquid water solubility from studies of high quality. These have been carried out using one of the methods recommended in the OECD 105 guideline or an adaptation of these. Further to this the water solubility of the WAF is determined by using a series of calculation steps using phase equilibrium thermodynamics.

Finally the water solubility of 19 components (covering more than 90% of the composition of the substance) has been determined to be between 0.109 and 300 mg/L each at 25°C.

Description of key information

The water solubility of 19 components (covering more than 90% of the composition of the substance) has been determined to be between 0.109 and 300 mg/L each at 25°C

(estimations based on valid QSAR estimations).

Additional information

No study was conducted on the oil itself.

The test item is a natural complex substance (NCS). It is a mixture of several constituents, but 19 of them represent more than 90% of that mixture.

Water solubility of the 19 constituents of the test item were calculated using valid QSAR estimations.

Finally, apparent water solubility of each of these 19 constituents was reported below:

Constituents	water solubility (mg test item.L^-1) at 25°C
1	1.56
2	25.2
3	90.1
4	103
5	1.06
6	300
7	0.216
8	0.318
9	0.175
10	0.282
11	0.245
12	0.152
13	0.196
14	0.318
15	0.164
16	0.589
17	12.9
18	0.133
19	0.109

As the substance is a UVCB with constituents of different solubility, the global solubility of the substance will depend on the composition and the loading rate (with varying ratio of constituents in the dissolved phase). Therefore we reported the water solubility of the 19 components of the substance in the range between 0.109 and 300 mg/L each at 25°C and no single key value was retained (nor calculated weighted WS nor worst-case).