Iotroxic acid

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018-01-25 to 2018-05-18

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

GLP compliance:

no

Type of method:

flask method

Key result

Water solubility:

304 mg/L

Temp.:

20 °C

pH:

3.3

Preliminary test

In a stepwise procedure, increasing volumes of demineralized water were added at room temperature to a defined amount of the test item. After each addition of an amount of water the mixture was treated with ultrasound for 10 minutes and visually checked for any undissolved particles. Table 1 summarizes results of the preliminary test.

Table 1: Results of the preliminary test

Amount of test item / mg	Added volume of demineralized water / ml	Total volume of demineralized water / ml	Appearance of mixture
100.4	0.1	0.1	Slurry-like dispersion
	0.4	0.5	Strongly turbid solution with precipitate
	0.5	1.0	Strongly turbid solution with precipitate
	1.0	2.0	Strongly turbid solution with precipitate
	8.0	10.0	Turbid solution

Three additional preliminary tests were carried out with specified amounts of the test item and 100 ml, 500 ml and 1000 ml demineralized water, respectively. After each addition of an amount of water, the mixture was stirred for at least 24 hours, and visually checked for any undissolved particles. The results of those tests are shown in Table 2.

Table 2: Results of the preliminary test

Amount of test item / mg	Total volume of demineralized water / ml	Appearance of mixture
12.8	100	Solution with little particles
8.5	500	Solution with little particles
9.0	1000	Solution with little particles

The preliminary test showed that the water solubility of the test item was < 10 mg/l. According to the preliminary test the water solubility was first determined by the column elution method in the main test. The water solubility determined by the column elution method was > 10 mg/l. Therefore, the study was repeated with the flask method.

Flask method

After the equilibration time precipitate was observed in the flasks of the experiments excluding the ones in the blank experiment. The water solubility was calculated from the measured and unrounded concentration values and not from the rounded values given in Table 3.

Table 3: Results of the water solubility experiments with the test item

Experiment	24 h experiment	48 h experiment	72 h experiment	Blank experiment (72 h)
Amount of test item / g	5.01	5.00	5.02	-
Amount of demineralized water / ml	50	50	50	50
Stirring time at 30 °C / h	24	48	72	72
pH at ambient temperature	3.3	3.3	3.3	5.7
Dilution factor	40	40	40	40
Measured concentration / mg/l	6.99 / 7.01	7.93 / 7.95	7.82 / 7.85	- / -
Mean concentration / mg/l	7.00	7.94	7.84	-
Water solubility / mg/l	280	318	314	-

Conclusions:

The water solubility of the test item was 304 mg/l (± 21 mg/l) and the saturated solutions had a pH of 3.3.

Executive summary:

The water solubility of the test item was determined according to EC method A.6. and OECD test guideline 105 using the flask method and HPLC as analytical method. The water solubility of the test item was found to be 304 mg/l (± 21 mg/l) and the saturated solutions had a pH of 3.3.

Description of key information

The water solubility of the test item was determined according to EC method A.6. and OECD test guideline 105 using the flask method and HPLC as analytical method. The water solubility of the test item was found to be 304 mg/l (± 21 mg/l) and the saturated solutions had a pH of 3.3.

Key value for chemical safety assessment

Water solubility:

304 mg/L

at the temperature of:

20 °C