Pentaerythritol tetrakis(3-mercaptopropionate)

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008.04.01-2008.04.11

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

GLP compliance:

yes (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom

Type of method:

flask method

Water solubility:

ca. 3.68 mg/L

Temp.:

20 °C

pH:

ca. 7.3

Water solubility:

ca. 3.89 mg/L

Temp.:

20 °C

pH:

ca. 7.6

Water solubility:

ca. 3.51 mg/L

Temp.:

20 °C

pH:

ca. 7.8

Details on results:

To remove dissolved oxygen from the glass double-distilled water, to reduce the effects of oxidation of the test material, a volume was boiled and sparged with nitrogen and stored in a closed vessel with a nitrogen headspace. The prepared samples were sealed with a nitrogen purged headspace for shaking at 30 °C and equilibration at 20 °C.

As the Sponsor indicated the test material hydrolysed in water, it was decided to carry out the test with reduced shaking/equilibration times. This would then reduce the extent of hydrolysis occurring and also oxidation. Therefore, the solution would contain less hydrolysis products, which often being more water soluble than the test material, would possibly act as a co-solvent in helping to dissolve more test material than would otherwise occur.

The ion masses were chosen for the analysis to monitor the ions with different adducts and to give a representative profile of the test material. The peak at 6 minutes represents the main component of the test material and the one used to calculate the water solubility value. The other 2 main peaks at 3 and 8.5 minutes are the tri-ester and penta-ester impurities respectively.

The estimated water solubility using WSKOW v1.41, © 2000 US Environmental Protection Agency was calculated at 5.224 mg/l at 25 °C. Using a partition coefficient of 3.03 in the calculations, as determined in Safepharm Project 1158/0056, amended the value to 2.188 mg/l at 25 °C.

Concluding, triplicate experimental determinations resulted in the following concentrations of test material in water solution: 3.68 mg/L (pH~7.3), 3.89 mg/L (pH~7.6) and 3.51 mg/L (pH~7.8), mean concentration was reported 3.69 mg/L at 20.0+/-0.5 °C and range of concentrations: 3.51 mg/L to 3.89 mg/L.
The water solubility of the test material has been determined to be 3.69 mg/l of solution at 20.0+/-0.5 °C.

The prelimianry test of water solubility waas 6.71 mg/l.

The mean peak areas relating to the standard and sample solutions are shown in the following table (Table 1):

Table 1:

solution	mean peak area
standard 0.274 mg/l	1.680x10^6
standard 0.292 mg/l	1.971x10^6
blank	none detected
sample 1A	2.385x10^5
sample 1B	2.355x10^5
sample 2A	2.520x10^5
sample 2B	2.489x10^5
sample 3A	1.666x10^5 (not used in calculations due to inconsistency)
sample 3B	2.260x10^5

The concentration (g/l) of the test material in the sample solutions is shown in the following table (Table 2):

Table 2:

sample number	time shaken at ~ 30 °C (hours)	time equilibrated at 20 °C (hours)	concentration (g/l)	solution pH
1	1	1	3.68x10^-3	7.3
2	2	1	3.89x10^-3	7.6
3	3	1	3.51x10^-3	7.8

Mean concentration: 3.69x10 ^-3 g/l at 20 +/-0.5 °C.

Range: 3.51x10^-3to 3.89x10^-3g/l.

Conclusions:

Interpretation of results: slightly soluble (0.1-100 mg/L)
The water solubility of the test material THIOCURE PETMP has been determined to be ~3.69 mg/l of solution at 20.0+/-0.5°C and pH~7.57.

Executive summary:

The test material THIOCURE PETMP has been determined to have a water solubility ~3.69 mg/l of solution at 20.0 +/-0.05 °C (at pH~7.57) by using flask method with concentration determination by high performance liquid chromatography – mass spectrometry (HPLC-MS), according to method 105 OECD Guideline for Testing of Chemicals, 27 July 1995 and Method A6 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC).

Description of key information

Water solubility: ~3.69 mg/l of solution at 20.0 +/-0.05 °C (at pH~7.57). (Fox, J.M. (2008))
Water solubility determined to <8.4 mg/l (consilab (2023)) based on no available analytical method to determine lower concentrations.

Key value for chemical safety assessment

Water solubility:

3.69 mg/L

at the temperature of:

20 °C

Additional information

In the experimental laboratory study the water solubility of the test substance THIOCURE PETMP has been determined to be ~3.69 mg/l of solution at 20.0 +/-0.05 °C (at pH~7.57) by using flask method with concentration determination by high performance liquid chromatography – mass spectrometry (HPLC-MS), according to method 105 OECD Guideline for Testing of Chemicals, 27 July 1995 and Method A6 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC).

In another study, according to OECD 105 column elution method, water solubility of PETMP was determined to be <8,4 mg/L. Test could not be completed due to limited sensitivity of analytical methods.