Fatty acids, tallow, compds. with triethanolamine

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 November 2015 to 6 September 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

yes

Remarks:

Due to the low solubility, the slow stir method from OECD Test Guideline 123 was adopted.

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Key result

Water solubility:

< 1 other: µg/mL

Conc. based on:

test mat. (dissolved fraction)

Loading of aqueous phase:

5 g/L

Incubation duration:

6 d

Temp.:

20 °C

pH:

7.53 - 8.38

Details on results:

The test material appeared to have reacted with the water as there was an oily top layer with a suspension of white particulates hanging from it, and small particles in motion in the supernatant. When the stirring was stopped these particulates quickly rose to the surface. When the sample was shaken after standing for about an hour it was clear to the naked eye.
The unfiltered samples gave a solubility of about 3.3 to 27.2 µg/mL and the filtered samples gave a solubility of about 0.03 to 1.0 µg/mL. There was a large variation in the results for both filtered (% RSD 110.91) and unfiltered (% RSD 70.91) both between vessels and time points. The mean pH of the unfiltered samples was 7.96.
Turbidity measurements on subsequent samples from all three vessels gave a wide range of turbidity across the vessels, with the filtered samples (0.215 to 0.803 NTU) being a lot lower than that of the unfiltered (3.47 to 12.0 NTU). Both filtered and unfiltered samples were clear to the naked eye. The results were also stable, suspended particulate’s would give very variable results; this might suggest a micro dispersion.
This evidence suggests that an actual value for the water solubility of the test material cannot be measured, but based on the results from the filtered samples it was < 1 µg/mL.

Table 1. Water Solubility Results

Date	Vessel	Concentration (µg/mL)		pH (unfiltered)
		Filtered	Unfiltered
Test 1	1	<LOD	8.8611*	7.67
	2	<LOD	8.9378*	8.38
	3	<LOD	9.1781*	8.24
Test 2	1	1.0436*	6.1351	8.15
	2	0.2157	4.3919	8.08
	3	0.0317	3.2605	7.81
Test 3	1	0.2530	13.1153	7.88
	2	0.1595	5.5225	8.07
	3	0.0433	4.1461	8.02
Test 4	1	0.4314*	27.2267*	7.90
	2	0.1719	11.4899*	7.53
	3	0.0534	6.8425	7.78
Mean		0.2671	9.092	7.96
SD		0.2962	6.453
% RSD		110.91	70.97

*These results were above the calibration line and therefore are considered indicative, but due to the nature of the TA included in the mean.

Conclusions:

Under the conditions of the study, the water solubility of the test material was determined to be < 1 µg/mL.

Executive summary:

The water solubilty of the test material was invesigated in a GLP study conducted in accordance to the standardised guideline OECD 105. Preliminary investigations suggested that the water solubility was very low and that the most appropriate method for the determination of water solubility was the adoption of the slow stir method detailed in OECD Test Guideline 123.

For the main test, three slow stir vessels were charged with double-distilled water (900 mL) and a stirrer bar added. An aliquot of test material (about 5 g) was carefully added to the surface of the water of each flask, so as not to induce mixing. The flasks were stoppered and placed on stirrer plates in an incubator controlled at 20 ± 0.5 °C. The stirring rate was adjusted to 200 rpm. Samples of the aqueous portion were taken from the drain tap at 7 day intervals until a constant level of test material in the water was established. The dead volume in the tap (about 5 mL) was run to waste and then an aliquot of about 15 mL taken. This aliquot was allowed to stand for 6 days at 20 ± 0.5 °C, before analysis. An aliquot of the sample was syringe filtered through a 0.45 µm PTFE filter and diluted with THF to be within the calibration line for the method.

The test material appeared to have reacted with the water as there was an oily top layer with a suspension of white particulates hanging from it, and small particles in motion in the supernatant. When the stirring was stopped these particulates quickly rose to the surface. When the sample was shaken after standing for about an hour it was clear to the naked eye.

The unfiltered samples gave a solubility of about 3.3 to 27.2 µg/mL and the filtered samples gave a solubility of about 0.03 to 1.0 µg/mL. There was a large variation in the results for both filtered (% RSD 110.91) and unfiltered (% RSD 70.91) both between vessels and time points. The mean pH of the unfiltered samples was 7.96.

Turbidity measurements on subsequent samples from all three vessels gave a wide range of turbidity across the vessels, with the filtered samples (0.215 to 0.803 NTU) being a lot lower than that of the unfiltered (3.47 to 12.0 NTU). Both filtered and unfiltered samples were clear to the naked eye. The results were also stable, suspended particulate’s would give very variable results; this might suggest a micro dispersion. This evidence suggests that an actual value for the water solubility of the test material cannot be measured, but based on the results from the filtered samples it was < 1 µg/mL.

Under the conditions of the study, the water solubility of the test material was determined to be < 1 µg/mL.

Description of key information

Under the conditions of the study, the water solubility of the test material was determined to be < 1 µg/mL.

Key value for chemical safety assessment

Water solubility:

0.001 µg/L

at the temperature of:

20 °C

Additional information

The water solubilty of the test material was invesigated in a GLP study conducted in accordance to the standardised guideline OECD 105. Preliminary investigations suggested that the water solubility was very low and that the most appropriate method for the determination of water solubility was the adoption of the slow stir method detailed in OECD Test Guideline 123. The study was assigned a reliability score of 1 in accordance with the criteria for assessing data quality set forth by Klimisch et al. (1997).

For the main test, three slow stir vessels were charged with double-distilled water (900 mL) and a stirrer bar added. An aliquot of test material (about 5 g) was carefully added to the surface of the water of each flask, so as not to induce mixing. The flasks were stoppered and placed on stirrer plates in an incubator controlled at 20 ± 0.5 °C. The stirring rate was adjusted to 200 rpm. Samples of the aqueous portion were taken from the drain tap at 7 day intervals until a constant level of test material in the water was established. The dead volume in the tap (about 5 mL) was run to waste and then an aliquot of about 15 mL taken. This aliquot was allowed to stand for 6 days at 20 ± 0.5 °C, before analysis. An aliquot of the sample was syringe filtered through a 0.45 µm PTFE filter and diluted with THF to be within the calibration line for the method.

The test material appeared to have reacted with the water as there was an oily top layer with a suspension of white particulates hanging from it, and small particles in motion in the supernatant. When the stirring was stopped these particulates quickly rose to the surface. When the sample was shaken after standing for about an hour it was clear to the naked eye.

The unfiltered samples gave a solubility of about 3.3 to 27.2 µg/mL and the filtered samples gave a solubility of about 0.03 to 1.0 µg/mL. There was a large variation in the results for both filtered (% RSD 110.91) and unfiltered (% RSD 70.91) both between vessels and time points. The mean pH of the unfiltered samples was 7.96.

Turbidity measurements on subsequent samples from all three vessels gave a wide range of turbidity across the vessels, with the filtered samples (0.215 to 0.803 NTU) being a lot lower than that of the unfiltered (3.47 to 12.0 NTU). Both filtered and unfiltered samples were clear to the naked eye. The results were also stable, suspended particulate’s would give very variable results; this might suggest a micro dispersion. This evidence suggests that an actual value for the water solubility of the test material cannot be measured, but based on the results from the filtered samples it was < 1 µg/mL.

Under the conditions of the study, the water solubility of the test material was determined to be < 1 µg/mL.