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Physical & Chemical properties

Water solubility

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Reference
Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
04-06-2001 to 10-08-2001
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study performed under GLP. All relevant validity criteria were met with acceptable deviations.
Reason / purpose:
reference to other study
Qualifier:
according to
Guideline:
EU Method A.6 (Water Solubility)
Deviations:
yes
Remarks:
The result at 24 hour incubation and 24 hour equilibration was selected as the key result. This was deemed appopriate given the properties of the test item and considering the relevance of the guideline.
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 105 (Water Solubility)
Deviations:
yes
Remarks:
see above
GLP compliance:
yes (incl. certificate)
Remarks:
inspected: February 2000; signature: April 2000
Type of method:
flask method
Water solubility:
5.29 mg/L
Conc. based on:
test mat.
Temp.:
20 °C
pH:
5.4
Remarks on result:
other: The water solubility is the determination at incubation 24 hours (at 30°C) ; determination following 24 hours equilibration at 20.0 ± 0.5°C

Preliminary test:

The preliminary estimate of water solubility was 2.98 mg/L.

 

Definitive test:

The peak area relating to the standard and sample solutions were determined.

Table 1.0: Test item concentrations

Sample Number

Time shaken at 30°C (hours)

Time equilibrated at 20°C (hours)

Concentration (mg/L)

pH measured

1

24

24

5.29

5.4

2

48

24

4.03

5.1

3

72

24

3.56

5.9

120 

24 

2.19

5.1

Selected: Water Solubility concentration: 5.29 mg/L at 20.0 ± 0.5°C

 

Applicant assessment: It was noted that there was a decrease in analysed concentration with increasing shaking time. Information from an available EU Method C.7 (abiotic degradation: hydrolysis as a function of pH) study indicated that the test item was capable of hydrolysis (pH 4: t1/2 < 1 day and pH 7: t1/2: 5.86 days at 25°C). Therefore it was appropriate to select the shorted incubation and equilibration time (in duplicate). This indicates the maximum water solubility under the conditions of the study of the test item. Further details are available in the full study report.

Conclusions:
Interpretation of results: slightly soluble (0.1-100 mg/L)
The test item water solubility was determined to be 5.29 mg/L at 20.0 ± 0.5°C and ca. pH 5.4
Executive summary:

The water solubility of the test item was determined according to EU Method A.6, flask method in accordance with GLP. Determinations with preincubation at 30 ± 0.5 °C with shaking for 24, 48, 72 and 120 hours and then equilibration at 20 °C for 24 hours were conducted with subsequent analysis by Gas Chromatography (GC) using the test item as an external standard. The concentration measured at 24 hour incubation time and 24 stirring time, was selected as the water solubility concentration on the basis of observed declines in concentrations at 48 through 120 hours. This was attributed to hydrolytic instability. The temperature was kept constant to within ± 0.5 °C. Under the conditions of this study, the mean water solubility of the test item was determined to be 5.29 mg/L at 20 ± 0.5 °C and at approximately pH 5.4. Applicant assessment: It was noted that there was a decrease in analysed concentration with increasing shaking time. Information from an available EU Method C.7 (abiotic degradation: hydrolysis as a function of pH) study indicated that the test item was capable of hydrolysis (pH 4: t1/2 < 1 day and pH 7: t1/2: 5.86 days at 25°C). Therefore it was appropriate to select the shorted incubation and equilibration time (in duplicate). This indicates the maximum water solubility under the conditions of the study of the test item.

Description of key information

Water Solubility: 5.29 mg/L at 20.0 ± 0.5°C and ca. pH 5.4, flask method – EU Method A.6, 2002

Key value for chemical safety assessment

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

Additional information

Key study : EU Method A.6, 2002 : The water solubility of the test item was determined according to EU Method A.6, flask method in accordance with GLP. Determinations with preincubation at 30 ± 0.5 °C with shaking for 24, 48, 72 and 120 hours and then equilibration at 20 °C for 24 hours were conducted with subsequent analysis by Gas Chromatography (GC) using the test item as an external standard. The concentration measured at 24 hour incubation time and 24 stirring time, was selected as the water solubility concentration on the basis of observed declines in concentrations at 48 through 120 hours. This was attributed to hydrolytic instability. The temperature was kept constant to within ± 0.5 °C. Under the conditions of this study, the mean water solubility of the test item was determined to be 5.29 mg/L at 20 ± 0.5 °C and at approximately pH 5.4. Applicant assessment: It was noted that there was a decrease in analysed concentration with increasing shaking time. Information from an available EU Method C.7 (abiotic degradation: hydrolysis as a function of pH) study indicated that the test item was capable of hydrolysis (pH 4: t1/2 < 1 day and pH 7: t1/2: 5.86 days at 25°C). Therefore it was appropriate to select the shorted incubation and equilibration time (in duplicate). This indicates the maximum water solubility under the conditions of the study of the test item.