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Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12-20 November, 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was conducted according to an internationally recognised method, and under GLP. The substance is adequately identified. Therefore full validation applies.

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

11 March 2011

Type of method:

column elution method

Specific details on test material used for the study:

- Physical state: white crystalline powder.
- Storage condition: Room temperature protected from direct sun light.

Key result

Water solubility:

5.4 mg/L

Conc. based on:

test mat.

Temp.:

20 °C

pH:

>= 7.4 - <= 7.5

Estimated value

QSAR determination gave 2.85 mg/L at 25 °C as the estimated value (Source: WaterNT v. 1.01, EPI Suite, EPA).

 

Measured value

Experiment no. 1- 25 mL/h flow rate

A 1.5 g sand portion was coated with 500 µL of the test item stock solution. A sample of 0.6148 g portion of the coated sand was introduced in the micro-column. Analytical assessments of the coated sand showed that the micro-column was thus charged with approximately 36 mg of test item.

About 0.04 mg of the test item was controlled to be voided in the rinsed volume (15 mL).

A total of five successive samples were submitted to the analysis which corresponded to the elution over a 4-hour period. The hydrosolubility was measured as mean from the five measured concentrations.

Mean concentration in water = 5.0 mg/L with a standard deviation of 0.3 mg/L.

pH of the resulting solution was measured as 7.4.

 

Table 1: Samples collected from the micro-column at 25 mL/h flow rate

  

Sample n°	Dilution rate	Area	Measured mg/L^(1)	mg/L in water^(2)
1	1	624.95	12.60	5.04
2	1	566.81	11.45	4.58
3	1	653.26	13.17	5.27
4	1	634.23	12.79	5.12
5	1	632.98	12.76	5.11

 

(1) As measured in the chloroform phase resulting from a 2/5 concentration of the aqueous phase

(2) Recovery was considered as total

 

Experiment no. 2 - 13 mL/h flow rate

The whole procedure was reproduced without disturbing the coated sand: the micro-column was emptied and the volume of water was renewed. The system was allowed to stand for the night, and then the flow was set at 12.5 mL/h for 2 hours before the first sample was collected.

A total of five successive samples were submitted to the analysis which corresponded to the elution over a 8-hour period. All of them were used for the calculation of the hydrosolubility.

 

Table 2: Samples collected from the micro-column at 13 mL/h flow rate

 

Sample n°	Dilution rate	Area	Measured mg/L^(1)	mg/L in water^(2)
1	1	700.53	14.11	5.64
2	1	743.00	14.95	5.98
3	1	580.73	13.71	5.48
4	1	712.27	14.34	5.74
5	1	705.98	14.21	5.69

 

(1) As measured in the chloroform phase resulting from a 2/5 concentration of the aqueous phase

(2) Recovery was considered as total

 

Mean concentration in water = 5.7 mg/L with a standard deviation of 0.2 mg/L.

pH of the resulting solution was measured as 7.5.

The second value did not differ by more than 30 % to the first one.

Mean hydrosolubility = 5.4 mg/L.

Executive summary:

The water solubility of the test item was measured under GLP according EU A6 guideline, column elution method.

 

Two experiments were performed with a different flow rate, at 20.0 ± 0.5 °C.

The average of five successive samples was found as:

Test at 25 mL/h: 5.0 ± 0.3 mg/L; Test at 13 mL/h: 5.7 ± 0.2 mg/L. Individual results per flow and mean flow series results did not differ by more than 30%, so the overall mean solubility was retained.

 

The water solubility of the test item has been determined to be 5.4 mg/L at 20.0 ± 0.5 °C, pH 7.4-7.5.

Description of key information

Slightly soluble. pH of saturated solution: 7.4 -7.5.

Key value for chemical safety assessment

Water solubility:

5.4 mg/L

at the temperature of:

20 °C

Additional information

A fully reliable experimental study, conducted according to a recognized EC method and under GLP, is available. It is considered as a key study, and the result is retained as key data.