Essential oil of Cinnamomum camphora (Lauraceae) obtained from leaves by steam 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:

November 6th, 2017

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® HA-QSAR toolbox v2.3

2. MODEL (incl. version number)
iSafeRat® holistic HA-QSAR v1.7

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:

The water solubility was determined using a calculation method for the substances generally classified as MOA 1 substances (non-polar narcotics) and ethers, esters, ketones, aldehydes, alcohols, acids and phenols. This algorithm is 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 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.

GLP compliance:

no

Type of method:

other: QSAR model

Key result

Water solubility:

1 982 mg/L

Temp.:

25 °C

Remarks on result:

other: Constituent 1

Remarks:

peer reviewed literature data

Key result

Water solubility:

1.4 mg/L

Temp.:

25 °C

Remarks on result:

other: Constituent 2

Key result

Water solubility:

521 mg/L

Temp.:

25 °C

Remarks on result:

other: Constituent 3

Key result

Water solubility:

0.195 mg/L

Temp.:

25 °C

Remarks on result:

other: Constituent 4

Key result

Water solubility:

0.341 mg/L

Temp.:

25 °C

Remarks on result:

other: Constituent 5

Key result

Water solubility:

231 mg/L

Temp.:

25 °C

Remarks on result:

other: Constituent 6

Key result

Water solubility:

0.088 mg/L

Temp.:

25 °C

Remarks on result:

other: Constituent 7

Key result

Water solubility:

0.148 mg/L

Temp.:

25 °C

Remarks on result:

other: Constituent 8

Key result

Water solubility:

0 mg/L

Temp.:

25 °C

Remarks on result:

other: Constituent 9

Key result

Water solubility:

0.071 mg/L

Temp.:

25 °C

Remarks on result:

other: Constituent 10

Key result

Water solubility:

0.058 mg/L

Temp.:

25 °C

Remarks on result:

other: Constituent 11

Conclusions:

The apparent water solubility of 11 major constituents of the substance at 25°C is calculated as follows (based on valid QSAR estimations or peer reviewed literature data):
Constituent 1   : 1982 mg/L at 25°C
Constituent 2   : 1.40 mg/L at 25°C
Constituent 3   : 521 mg/L at 25°C
Constituent 4   : 0.195 mg/L at 25°C
Constituent 5   : 0.341 mg/L at 25°C
Constituent 6   : 231 mg/L at 25°C
Constituent 7   : 0.0879 mg/L at 25°C
Constituent 8   : 0.148 mg/L at 25°C
Constituent 9   : 0.000473 mg/L at 25°C
Constituent 10 : 0.0708 mg/L at 25°C
Constituent 11 : 0.0584 mg/L at 25°C

Executive summary:

A calculation method prediction was performed to assess the apparent water solubility of the constituents of the substance. 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 11 components (covering more than 90% of the composition of the substance) has been determined to be between 0.000473 and 1982 mg/L each at 25°C.

Description of key information

The apparent water solubilities of the constituents of the substance at ambient temperature (11 components covering more than 90% of the composition) were determined to be between 0.000473 and 1982 mg/L each at 25°C (estimations based on valid QSAR estimations or peer reviewed literature data).

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 11 of them represent more than 90% of that mixture.

Water solubility of the 11 constituents of the test item were calculated using valid QSAR estimations or peer reviewed literature data taking into account the interactions between the constituents of the mixture.

Finally, apparent water solubility of each of these 11 constituents was reported below:

Constituent 1   :  1982 mg/L at 25°C

Constituent 2   :  1.40 mg/L at 25°C

Constituent 3   :  521 mg/L at 25°C

Constituent 4   :  0.195 mg/L at 25°C

Constituent 5   :  0.341 mg/L at 25°C

Constituent 6   :  231 mg/L at 25°C

Constituent 7   :  0.0879 mg/L at 25°C

Constituent 8   :  0.148 mg/L at 25°C

Constituent 9   :  0.000473 mg/L at 25°C

Constituent 10 :  0.0708 mg/L at 25°C

Constituent 11 :  0.0584 mg/L at 25°C

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 11 components of the substance in the range between 0.000473 and 1982 mg/L each at 25°C and no single key value was retained (nor calculated weighted WS nor worst-case)