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Physical & Chemical properties

Water solubility

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Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
23-03-2018 to 29-03-2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study performed under GLP. All relevant validity criteria were met.
Qualifier:
according to guideline
Guideline:
OECD Guideline 105 (Water Solubility)
Version / remarks:
Determination of the water solubility of the test item employing the flask method with slow stirring approach.The decision of the slow stirring method was made due to the test item properties. The test guideline was consistent with OECD Guideline 105 (water solubility) modified according to Letinski et. al. (2002) and OECD TG 123 (2006).
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method A.6 (Water Solubility)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
inspected: June 2016 ; signature: January 2017
Type of method:
flask method
Water solubility:
8.5 mg/L
Conc. based on:
test mat.
Incubation duration:
>= 94.83 - <= 123.63 h
Temp.:
20 °C
pH:
5.8
Remarks on result:
other: Mean of 94 h to 123 h incubation measurements ; duplicate vessels (n = 2) : deviation between replicate means was: 0.1%

Preliminary test

The determined solubility in double distilled water was 9.0 mg/L. For the application dose for the definitive study, 0.1 % (v/v) was used to facilitate the application procedure.

 

Definitive test:

The solubility of the test item in double distilled water was determined employing the flask method slow stirring approach at 20 ± 0.5 °C. The water solubility was respectively at pH 5.8: 8.5 mg/L.

 

Table 1.0. Water Solubility Results

Incubation time1)
[h]

Calculated Concentration2)
[mg/L]

 

Replicate 1

Replicate 2

 

94.83

8.55

8.24

96.86

8.74

8.86

99.03

8.23

8.46

119.60

8.14

8.43

121.60

8.59

8.17

123.63

8.80

8.82

Overall

Mean

8.51

8.50

8.50

Deviation [%]

8.1

8.5

0.1

1) = Time after application

2) = Exact weight of the external standard taken into account

 

Temperatures were kept constant within ± 0.5 °C. The determined solubilities for each preincubation time did not differ by more than 15 %. The analytical method (GC MS, external standard) for the determination of the test item was validated and tested with satisfactory results in regard to linearity, accuracy, precision and specificity.

Conclusions:
Interpretation of results: slightly soluble (0.1-100 mg/L)
The test substance water solubility was determined to be 8.5 mg/L of solution at pH 5.8 and 20.0 °C.
Executive summary:

The water solubility of the substance was determined according to the flask method: OECD Method 105 and EU Method A.6 under GLP. Determinations were conducted with preincubation at 20 ± 0.5 °C and a slow stirring rate without vortex, prior to sampling. Equilibration was shown to have occurred during the study. The analytical method (GC MS, external standard) for the determination of the test item was validated and tested with satisfactory results in regard to linearity, accuracy, precision and specificity. The mean water solubility of the substance was determined to be 8.5 mg/L of solution at pH 5.8 and 20.0 °C.

Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
17-07-2020 to 31-07-2020
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study performed under GLP. All relevant validity criteria were met.
Qualifier:
according to guideline
Guideline:
EU Method A.6 (Water Solubility)
Version / remarks:
Determination of the water solubility of the test item employing the flask method with slow stirring approach.The decision of the slow stirring method was made due to the test item properties. The test guideline was consistent with OECD Guideline 105 (water solubility) modified according to Letinski et. al. (2002) and OECD TG 123 (2006).
Deviations:
no
Qualifier:
according to guideline
Guideline:
OECD Guideline 105 (Water Solubility)
Deviations:
no
GLP compliance:
yes
Type of method:
flask method
Water solubility:
8.95 mg/L
Conc. based on:
test mat.
Temp.:
20 °C
pH:
> 6 - < 6.7
Remarks on result:
other: The water solubility is the average of three separate vessels : determinations at 20.0 ± 0.5°C ; pH range was average : 6.0 to 6.7 in the three vessels with a mean pH = 6.25

Definitive test:

The peak area relating to the standard and sample solutions were determined in three separate vessels. The corresponding water solubilities are provided in table 1.0.

 

Table 1. Replicate test item concentrations and solution pH at respective time-points

 

Vessel 1

Vessel 2

Vessel 3

Mean (n=3)

Time Shaken at

20.0 ± 0.5 °C (hours)

Concentration (g/L)

Solution pH

Concentration (g/L)

Solution pH

Concentration (g/L)

Solution pH

Concentration (g/L)

Solution pH

72.5

8.56

7.00

8.86

6.40

8.63

6.40

 

 

74.25

8.91

6.70

8.76

6.60

8.76

6.50

 

 

76.25

8.26

6.80

8.38

6.10

8.55

6.10

 

 

78.25

8.80

6.40

9.63

5.80

8.31

5.80

 

 

96.25

8.92

7.10

8.43

5.70

8.80

6.10

 

 

98.25

8.10

6.00

8.50

5.50

8.71

6.70

 

 

100.25

8.75

6.90

9.33

6.90

8.47

6.10

 

 

102.25

9.10

7.10

9.06

6.80

9.11

5.80

 

 

120.25

9.25

6.90

9.88

6.00

7.58

6.20

 

 

122.25

9.62

6.60

8.80

6.60

9.70

6.30

 

 

124.25

9.33

6.30

9.80

5.50

10.00

5.60

 

 

147.25

9.53

7.10

(*)

(*)

9.7.0

5.60

 

 

149.25

8.75

6.20

9.42

5.50

9.22

5.50

 

 

151.25

9.27

6.80

8.97

5.70

8.81

5.50

 

 

168.5

9.44

7.00

8.95

5.60

9.19

5.50

 

 

170.25

9.01

7.20

9.38

5.60

(*)

(*)

 

 

172.25

7.72

7.00

8.02

6.20

8.86

6.30

 

 

242.5

9.88

6.60

8.94

5.70

8.15

6.00

 

 

245.25

(*)

(*)

(*)

(*)

9.15

5.50

 

 

mean

8.96

6.76

9.01

6.01

8.87

5.97

8.95

6.25

 

 

 

 

 

 

 

 

 

Where:
(*) = excluded as statistical outlier (Thompson-Tau Outlier Test)

 

Result: mean Water Solubility (n=3) = 8.95 mg/L at 20.0 ± 0.5 °C with a mean pH of ca. 6.25

 

The observed pH range of 6.0 to 6.7 during conduct of the test

 

Analytical method validation:

The linearity of the detector response with respect to concentration was assessed over the nominal concentration range of 1.0 to 12.5 mg/L. This was satisfactory with a correlation coefficient of 0.9994 being obtained.

 

For each vessel, all of the selected individual water solubility results were within ± 15% of the mean; thus, satisfying the criteria specified in the guidelines.

Conclusions:
Interpretation of results: slightly soluble (0.1-100 mg/L)
The test item water solubility was determined to be 8.95 mg/L at 20.0 ± 0.5°C and mean pH ca. 6.25
Executive summary:

The water solubility of the test item was determined according to EU Method A.6 and OECD Method 105, flask method with the slow-stirring adaptation (Letinksi et al 2002) in accordance with GLP. A volume of high purity water (1800 mL) was added to each of three glass closed vessels and these were allowed to equilibrate at the test temperature of 20.0 ± 0.5 °C for at least 1 hour. An aliquot of test item (1.8 mL) was then carefully added to the surface of the water in each vessel. The resulting systems were then slowly stirred using a magnetic stirring bar at such a rate that no or negligible visible vortex was observed at the surface of the water. The systems were protected from light. Test samples were taken from both test vessels at the bottom of the test vessel at a rate of three samples per day, approximately 2 hours apart, starting from approximately 72 hours contact time onwards, in order to establish the time required to achieve saturation equilibrium. At each time point, the stirring were halted for approximately 15 minutes, to allow the system to settle. The vessels were then visually assessed to ensure that the solutions were free from suspended excess test item. The solutions were also examined using a laser pointer, to ensure the absence of colloidal dispersed test item. An aliquot of sample solution was then decanted to initially flush the vessel tap of solution potentially not at saturation equilibrium. The required volume for analysis was then sampled and analysed without any further pre-treatment (i.e. without centrifugation or filtration) using a previously validated HPLC-UV/visible spectroscopic detection method. Saturation (and/or equilibration) was considered to have been established when at least six subsequent test item concentrations were within ± 15% of their mean value. Statistical outlier measurements at defined timepoints were excluded where applicable. For each vessel, all of the selected individual water solubility results were within ± 15% of the mean. All relevant validity criteria were considered to be met. Under the conditions of this study, the mean water solubility of the test item was determined to be 8.95 mg/L at 20.0 ± 0.5 °C with a mean pH of ca. 6.25.

Description of key information

Water Solubility: 8.95 mg/L at pH 6.25 and 20.0 ± 0.5 °C, EU Method A.6, 2020

Supporting information:

Water Solubility: 8.5 mg/L at pH 5.8 and 20 °C, OECD TG 105, 2018

Key value for chemical safety assessment

Water solubility:
8.95 mg/L
at the temperature of:
20 °C

Additional information

Key study : EU Method A.6, 2018 : The water solubility of the substance was determined according to the flask method: OECD Method 105 and EU Method A.6 under GLP. Determinations were conducted with preincubation at 20 ± 0.5 °C and a slow stirring rate without vortex, prior to sampling. Equilibration was shown to have occurred during the study. The analytical method (GC MS, external standard) for the determination of the test item was validated and tested with satisfactory results in regard to linearity, accuracy, precision and specificity. The mean water solubility of the substance was determined to be 8.5 mg/L of solution at pH 5.8 and 20.0 °C.

Key study: EU Method A.6, 2020 : The water solubility of the test item was determined according to EU Method A.6 and OECD Method 105, flask method with the slow-stirring adaptation (Letinksi et al 2002) in accordance with GLP. A volume of high purity water (1800 mL) was added to each of three glass closed vessels and these were allowed to equilibrate at the test temperature of 20.0 ± 0.5 °C for at least 1 hour. An aliquot of test item (1.8 mL) was then carefully added to the surface of the water in each vessel. The resulting systems were then slowly stirred using a magnetic stirring bar at such a rate that no or negligible visible vortex was observed at the surface of the water. The systems were protected from light. Test samples were taken from both test vessels at the bottom of the test vessel at a rate of three samples per day, approximately 2 hours apart, starting from approximately 72 hours contact time onwards, in order to establish the time required to achieve saturation equilibrium. At each time point, the stirring were halted for approximately 15 minutes, to allow the system to settle. The vessels were then visually assessed to ensure that the solutions were free from suspended excess test item. The solutions were also examined using a laser pointer, to ensure the absence of colloidal dispersed test item. An aliquot of sample solution was then decanted to initially flush the vessel tap of solution potentially not at saturation equilibrium. The required volume for analysis was then sampled and analysed without any further pre-treatment (i.e. without centrifugation or filtration) using a previously validated HPLC-UV/visible spectroscopic detection method. Saturation (and/or equilibration) was considered to have been established when at least six subsequent test item concentrations were within ± 15% of their mean value. Statistical outlier measurements at defined timepoints were excluded where applicable. For each vessel, all of the selected individual water solubility results were within ± 15% of the mean. All relevant validity criteria were considered to be met. Under the conditions of this study, the mean water solubility of the test item was determined to be 8.95 mg/L at 20.0 ± 0.5 °C with a mean pH of ca. 6.25.