Pyrrolo[3,4-c]pyrrole-1,4-dione, 3,6-bis(4-chlorophenyl)-2,5-dihydro-

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: other guideline: General Test Method for Measuring the Solubility of Organic Pigments (so-called “ETAD-method”)

Principles of method if other than guideline:

As determination of the octanol-water partition coefficient with standard methods is technically not feasible for the registered substance, the ETAD-method is applied. This method has been developed to assess the persistence and bioaccumulation properties of pigments (see also Appendix R.11-1 Annex 3 of the Guidance on information requirements and chemical safety assessment, Chapter R.11: PBT Assessment.
As a part of this method the water and octanol solubility of a pigment - after a thorough washing process - are determined separately.
Then the ratio of the two solubilities is used as the octanol-water partition coefficient.

GLP compliance:

no

Type of method:

other: UV/Vis

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material:
A31506
- Expiration date of the lot/batch:
-
- Purity test date:
-

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: Yes
- Preliminary purification step (if any): stirring in various solvents and filtration
- Final dilution of a dissolved solid, stock liquid or gel: -
- Final preparation of a solid: dry vacuuming at 160°C for 8 hours

Key result

Water solubility:

ca. 0 mg/L

Remarks on result:

other: No temperature is specified, but ambient conditions can be assumed. No pH indicated.

Details on results:

- The maximum absorption peak wavelength of PR 254 is 513 nm in water and n-octanol.
- Solubility of the PR 254 in water:
Peak height in the water-saturated solution: 0.00002
The water solubility of the PR 254 : Cwater= 0.4 ppb (= 0.0004 mg/L solvent)
- Solubility of the PR 254 in n-octanol:
Peak height in the n-octanol-saturated solution: 0.0097
The n-octanol solubility of the PR 254 : Cn-octanol = 103 ppb (= 0.103 mg/L solvent)

- Log Kow = Log (Cn-octanol / Cwater)

Conclusions:

The water solubility of the substance has been determined to be approx. 0.0004 mg/L. Therefore, it is concluded that it is insoluble in water.

Executive summary:

The substance's water solubility was determined in the context of determining the octanol-water partition coefficient using the estimation method (solubility ratio). In particular, the so-called the 'ETAD-method', which is specifically suitable for pigments and that uses UV/VIS to determine concentrations in solutions, has been applied. It has been developed to assess the persistence and bioaccumulation properties of pigments (see also Guidance on Information Requirements and Chemical Safety Assessment Chapter R.11: PBT/vPvB assessment (Version 3.0)). As a part of this method the water and octanol solubility of a pigment - after a thorough washing process - are determined separately. Using this approach, the water solubility was determined as approx. 0.0004 mg/L.

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Cinilex DPP Red SR2P S01103
- Expiration date of the lot/batch: -
- Purity test date: -

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature, in the dark

Water solubility:

< 0.6 mg/L

Temp.:

30 °C

pH:

>= 5.9 - <= 6

Conclusions:

The water solubility of the test material has been determined to be less than 0.6 mg/L at 20.0°C.

Executive summary:

The water solubility of the test material has been determined to be less than 0.6 mg/L at 20.0°C.

Reference 3

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The read-across is performed between two forms of the same substance. The identities of the two forms are describe below.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
The source form is 3,6-bis(4-chlorophenyl)-2,5-dihydropyrrolo[3,4-c]pyrrol-1,4-dione (EC-no. 401-540-3), referred to here as PR254. PR254 is an organic mono-constituent substance with a typical purity of > 99.5% (w/w). It does not contain any impurity relevant for classification or labelling of the substance.
The target form is the nanoform of the source substance, referred to here as PR254 nanoform. As the source form, it has a typical purity of > 99.5% (w/w) and it does not contain any impurity relevant for classification or labelling of the substance. The PR254 nanoform is spheroidal with a pure polyhedral shape and is not surface-treated.

3. ANALOGUE APPROACH JUSTIFICATION
The two analogue forms have the same structure. Under ambient atmosphere, the specific surface energy of particles increases with decreasing particle size. Therefore, particle aggregate to reach an energy minimum. The driving forces are hydrogen bonds and van der Waals forces (π-π interaction). Substantial energy is required to disperse the PR254 nanoform aggregates to particles that fall under the nanoform definition.
PR254 was been tested extensively addressing information requirements of Annexes VII to IX without identifying any biological target. PR254 nanoform could potentially have biological targets due to the different particle size distribution, which would require processes capable of dispersing the aggregates, e.g. in aqueous milieu. However, both forms have been tested according to OECD Test Guideline 318, demonstrating that PR254 nanoform cannot be dispersed under the condition of the study, i.e. immediately after sonification re-forms aggregates. Also, PR254 aggregates to a large extent, but can be more easily dispersed than the nanoform. The experiments demonstrated that exposure in aqueous milieu will be primarily to aggregates, regardless of the PR254 form.
Therefore, it is concluded that both forms will behave identically in studies, in which they are applied under atmospheric conditions and/or in aqueous milieus, so that for the PR254 nano-form no specific biological targets need to be considered.

Physico-chemical properties
Most physico-chemical properties (PCP) are inherent properties of a substance, which are not affected by the substance form. In addition, many PCP are determined starting the experimental procedure under ambient conditions, at which both forms have a similar particle size distribution. Therefore, the water solubility will also be similar and the read-across from the source to the target form is scientifically justified.

4. DATA MATRIX
The data matrix is included as Annex 1 in the assessment report ‘PR254 bulk nano analogue approach 210111’ attached here below under ‘Attached justification’.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: other guideline: General Test Method for Measuring the Solubility of Organic Pigments (so-called “ETAD-method”)

Principles of method if other than guideline:

As determination of the octanol-water partition coefficient with standard methods is technically not feasible for the registered substance, the ETAD-method is applied. This method has been developed to assess the persistence and bioaccumulation properties of pigments (see also Appendix R.11-1 Annex 3 of the Guidance on information requirements and chemical safety assessment, Chapter R.11: PBT Assessment.
As a part of this method the water and octanol solubility of a pigment - after a thorough washing process - are determined separately.
Then the ratio of the two solubilities is used as the octanol-water partition coefficient.

GLP compliance:

no

Type of method:

other: UV/Vis

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material:
A31506
- Expiration date of the lot/batch:
-
- Purity test date:
-

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: Yes
- Preliminary purification step (if any): stirring in various solvents and filtration
- Final dilution of a dissolved solid, stock liquid or gel: -
- Final preparation of a solid: dry vacuuming at 160°C for 8 hours

Key result

Water solubility:

ca. 0 mg/L

Remarks on result:

other: No temperature is specified, but ambient conditions can be assumed. No pH indicated.

Details on results:

- The maximum absorption peak wavelength of PR 254 is 513 nm in water and n-octanol.
- Solubility of the PR 254 in water:
Peak height in the water-saturated solution: 0.00002
The water solubility of the PR 254 : Cwater= 0.4 ppb (= 0.0004 mg/L solvent)
- Solubility of the PR 254 in n-octanol:
Peak height in the n-octanol-saturated solution: 0.0097
The n-octanol solubility of the PR 254 : Cn-octanol = 103 ppb (= 0.103 mg/L solvent)

- Log Kow = Log (Cn-octanol / Cwater)

Conclusions:

The water solubility of the substance has been determined to be approx. 0.0004 mg/L. Therefore, it is concluded that it is insoluble in water.

Executive summary:

The substance's water solubility was determined in the context of determining the octanol-water partition coefficient using the estimation method (solubility ratio). In particular, the so-called the 'ETAD-method', which is specifically suitable for pigments and that uses UV/VIS to determine concentrations in solutions, has been applied. It has been developed to assess the persistence and bioaccumulation properties of pigments (see also Guidance on Information Requirements and Chemical Safety Assessment Chapter R.11: PBT/vPvB assessment (Version 3.0)). As a part of this method the water and octanol solubility of a pigment - after a thorough washing process - are determined separately. Using this approach, the water solubility was determined as approx. 0.0004 mg/L.

Description of key information

The water solubility of the substance was determined to be 0.0004 mg/L. Therefore, it is considered insoluble in water.

Key value for chemical safety assessment

Water solubility:

0 mg/L

at the temperature of:

20 °C

Additional information

The substance's water solubility was determined in the context of determining the octanol-water partition coefficient using the estimation method (solubility ratio). Using this approach, the water solubility was determined as approx. 0.0004 mg/L.

This is supported by a reliable study according to EU test method A.6. In this study the water solubility of the substance is determined to be < 0.6 mg/L.