2-methylpentyl 2-hydroxybenzoate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

31-03-2020 to 05-08-2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Guideline study performed under GLP. All relevant validity criteria were met.

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

Determination of the water solubility of the test item employing the flask method with slow stirring approach.The decision of the slow stirring method was made due to the test item properties. The test guideline was consistent with OECD Guideline 105 (water solubility) modified according to Letinski et. al. (2002) and OECD TG 123 (2006).

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7840 (Water Solubility)

Deviations:

no

GLP compliance:

yes

Type of method:

flask method

Key result

Water solubility:

1.59 mg/L

Conc. based on:

test mat.

Temp.:

20 °C

pH:

>= 7.4 - <= 7.5

Remarks on result:

other: mean 72, 120, 168, 240, 288 and 336 hour test samples (the maximum difference of the concentrations determined were ≤ 15%).

Preliminary test:

According to predictions and expert judgement the water solubility of the test item is expected to be < 10 mg/L. Therefore, no preliminary test was performed, and the slow-stirring flask method was chosen for the main study.

 

Definitive test – Slow Stir Method (main study 1):

The water solubility of the test item in the first main study at 20°C was considered to be 0.805 mg/L. However, the maximum difference of the concentrations determined in three different vessels at different time points was above the target of ≤ 15% (i.e. 79%) described in OECD Guideline 105. Water Solubility. July 27, 1995. On the basis of the observed results, not fulfilling the equilibrium criterion the test was repeated with modified conditions (including test vessel design incorporating a sampling tap).

 

Definitive test – Slow Stir Method (main study 2):

The maximum difference of the concentrations determined in 72, 120, 168, 240, 288 and 336 hour test samples was ≤ 15%. On this basis, the water solubility of the test item is given as the mean value of the analysed concentrations. No test item was detected in the pre-treated sample from the blank water mixture.

The solubility of the test item in double distilled water was determined to be 1.59 mg/L at 20 ± 0.5 °C and pH ca. 7.4.

 

Table 1.0. Results of the Slow Stir Method

Stirring time [hours]	Analyzed concentration [mg/L]	Mean [mg/L]	Maximum difference [%]	pH
72	1.65	1.59	11	7.4
120	1.67			7.5
168	1.49			7.4
240	1.61			7.5
288	1.56			7.5
366	1.59			7.4

Conclusions:

Interpretation of results: slightly soluble (0.1-100 mg/L)
The test item water solubility was determined to be 1.59 mg/L at pH ca. 7.4 and 20.0 °C.

Executive summary:

The water solubility of the test item was determined according to OECD Method 105 and EU Method A.6, flask method with the slow-stirring adaptation (Letinksi et al 2002) in accordance with GLP. Three containers were filled with 1000 mL of double distilled water. A volume of 482 μL of test item was added to the glass vessels avoiding turbulent mixing of the two phases. The vessels were placed on a magnetic stirring device at 20.2 ± 0.3°C where the content of each vessel was gently stirred at 100 rpm for 72, 120, 168, 240, 288 and 336 hours. In the blank, 1000 mL double distilled water was stirred for 336 hours. After the stirring period, subsamples of 100 μL were taken from via the tap close to the bottom of the water phases thereby avoiding sampling of undissolved test item. The samples were 10-fold further diluted with 50/50 (v/v) acetonitrile/ Milli-Q water to obtain concentration levels within the calibrated range and analysed. The blank sample was diluted in a 1:1 (v:v) ratio with acetonitrile and analysed. The analytical method (UPLC-MS, external standard) for the determination of the test item was validated and tested with satisfactory results in regard to linearity, accuracy, precision and specificity. The maximum difference of the concentrations determined in 72, 120, 168, 240, 288 and 336 hour test samples was ≤ 15%. On this basis, the water solubility of the test item is given as the mean value of the analysed concentrations. No test item was detected in the pre-treated sample from the blank water mixture. All acceptability criteria were considered to be met. Under the conditions of this study, the mean water solubility of the test item in double distilled water was determined to be 1.59 mg/L at 20 ± 0.5 °C and pH ca. 7.4.

Description of key information

Water Solubility: 1.59 mg/L at pH ca. 7.4 and 20 °C, OECD TG 105, flask method: slow-stirring adaptation, 2020

Key value for chemical safety assessment

Water solubility:

1.59 mg/L

at the temperature of:

20 °C

Additional information

Key study : OECD TG 105, 2020 : The water solubility of the test item was determined according to OECD Method 105 and EU Method A.6, flask method with the slow-stirring adaptation (Letinksi et al 2002) in accordance with GLP. Three containers were filled with 1000 mL of double distilled water. A volume of 482 μL of test item was added to the glass vessels avoiding turbulent mixing of the two phases. The vessels were placed on a magnetic stirring device at 20.2 ± 0.3°C where the content of each vessel was gently stirred at 100 rpm for 72, 120, 168, 240, 288 and 336 hours. In the blank, 1000 mL double distilled water was stirred for 336 hours. After the stirring period, subsamples of 100 μL were taken from via the tap close to the bottom of the water phases thereby avoiding sampling of undissolved test item. The samples were 10-fold further diluted with 50/50 (v/v) acetonitrile/ Milli-Q water to obtain concentration levels within the calibrated range and analysed. The blank sample was diluted in a 1:1 (v:v) ratio with acetonitrile and analysed. The analytical method (UPLC-MS, external standard) for the determination of the test item was validated and tested with satisfactory results in regard to linearity, accuracy, precision and specificity. The maximum difference of the concentrations determined in 72, 120, 168, 240, 288 and 336 hour test samples was ≤ 15%. On this basis, the water solubility of the test item is given as the mean value of the analysed concentrations. No test item was detected in the pre-treated sample from the blank water mixture. All acceptability criteria were considered to be met. Under the conditions of this study, the mean water solubility of the test item in double distilled water was determined to be 1.59 mg/L at 20 ± 0.5 °C and pH ca. 7.4.