N1,N2-dimethyl-N1-{2-[methyl(propan-2-yl)amino]ethyl}-N2-(propan-2-yl)ethane-1,2-diamine

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

February 04, 2021 - March 23, 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Version / remarks:

2008

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

2004

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source (i.e. manufacturer or supplier) and lot/batch number of test material: Source: Sponsor; Batch number:
- Purity, including information on contaminants, isomers, etc.: 98.2%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature, protection from light (discoloration will occur at sun light), dry and protected from longer air contact and stron oxidants; keep in tightly closed container in a dry, cool, well-ventilated place away from heat and ignition sources

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products: Samples were taken at test start (0 h) and test end (120 h).
- Sampling method: LC-MS/MS
- Test samples: 0.1 mL of each sample were filled up to volume with acetonitrile : water (50 : 50) containing 1% TFA in 10 mL volumetric flasks, corresponding to a dilution factor of 100.

Buffers:

Sterile buffer solutions with pH value 4, 7 and 9

Buffer solutions were prepared from chemicals with analytical grade or better quality following the composition guidance given in “KÜSTER-THIEL, Rechentafeln für die Chemische Analytik” and the OECD Guideline No. 111, respectively, by direct weighing of the buffer components. Buffers were purged with nitrogen for 5 min and then the pH was checked to a precision of at least 0.1 at the test temperatures. Buffers were sterilized by filtration through 0.2 μm.

Buffer solution pH 4: 0.18 g of sodium hydroxide and 5.7555 g of mono potassium
citrate were dissolved in 500 mL purified water.

Buffer solution pH 7: 3.854 g of ammonium acetate were dissolved in 500 mL purified
water.

Buffer solution pH 9: 0.426 g sodium hydroxide, 1.8638 g potassium chloride and 1.5458 g boric acid were dissolved in 500 mL purified water.

Reason for the selection The buffer systems are suitable for their pH value.

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: Test container (sterile) HPLC vials, volume: 2 mL
- Lighting: Photolytic effects were avoided by using an opaque water bath.
TEST MEDIUM
- Volume used/treatment : 1 mL
- Kind and purity of water: Purified water; Purity: ≥ 18.2 MΩ/cm ≤ 50 ppb TOC
- Preparation of test medium: The test solution was prepared at test start via stock solution. Sterile buffer solutions were spiked with the spiking solution and filled into the test containers. After the vials were sealed, they were transferred into the thermostat. The time between test item application and transfer to thermostat / analysis did not exceed 30 min.
- Stock solution: Nominal 1 g/L in methanol
- Spiking solution: 800 mg/L in methanol
- Identity and concentration of co-solvent: Methanol, 1% (v/v)
OTHER TEST CONDITIONS
- Incubation time. 120 h
- Temperature: 50 ± 0.5 °C

Duration:

120 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

8.07 mg/L

Remarks:

Loss of Test Item: 0

Duration:

0 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

7.54 mg/L

Duration:

0 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

8.07 mg/L

Duration:

120 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

7.51 mg/L

Remarks:

Loss of Test Item: 0

Duration:

120 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

8.34 mg/L

Remarks:

loss of tet item: 0.832%

Duration:

0 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

8.41 mg/L

Number of replicates:

Duplicates per pH and sampling date,

Positive controls:

no

Remarks:

According to the guidelines no reference item is necessary

Negative controls:

yes

Remarks:

Buffer solutions (pH value 4, 7 and 9) and co-solvent

Preliminary study:

The test item PU-2019-872 was found to be hydrolytically stable at all pH conditions

Transformation products:

not measured

Remarks on result:

hydrolytically stable based on preliminary test

Details on results:

There was not loss of the test item (No significant elimination was observed) at pH 4, 7, and 9

Check of the pH-Value

Table 1. pH-Value of the Test System (50°C)

Intended pH-value	Measured pH-value at 50 °C
4.0 ± 0.1	4.076
7.0 ± 0.1	6.924
9.0 ± 0.1	9.091

Temperature Monitoring

The temperature was in good agreement with the nominal range throughout the test. The mean temperature was 50.0 °C with a minimum of 49.9 °C and a maximum of 50.1 °C during the study.

Hydrolysis Results

Table 2. Hydrolysis Results for test item at pH 4 and 50 °C

Hydrolysis Time [hours]	Replicate	Concentration [mg/L]	Mean [mg/L]	Loss of   Test Item [%]
0	1	4.73 ^1	7.54	-
	2	7.54
120	1	8.12	8.10	-7.4^2
	2	8.08

1) Injection failure, not taken into account

2) Deemed to be no loss of test item and treated as “0%”

 

Table 3. Hydrolysis Results for test item at pH 7 and 50 °C

Hydrolysis Time [hours]	Replicate	Concentration [mg/L]	Mean [mg/L]	Loss of   Test Item [%]
0	1	7.31	7.51	-
	2	7.71
120	1	8.21	8.07	-7.5^1
	2	7.92

• Deemed to be no loss of test item and treated as “0%”

 

 

Table 4. Hydrolysis Results for test item at pH 9 and 50 °C

Hydrolysis Time [hours]	Replicate	Concentration [mg/L]	Mean [mg/L]	Loss of   Test Item [%]
0	1	8.40	8.41	-
	2	8.41
120	1	8.04	8.34	0.832
	2	8.64

 

 

 

Validity criteria fulfilled:

yes

Conclusions:

Hydrolysis as a function of pH was determined according to OECD Guideline No. 111 and Council Regulation (EC) No. 440/2008, Method C.7 for the test item PU-2019-872 (batch number: 10/16/2019) from 2021-02-18 to 2021-02-23 at the test facility.
Analyses of the test item PU-2019-872 were performed via LC-MS/MS on a reversed phase analytical column using the test item as external standard. The analytical method was validated with satisfactory results with regard to linearity, accuracy, precision and specificity.
The study was conducted with test item concentration of 8 mg/L in buffer solutions at pH 4, 7 and 9 at a test temperature of 50 °C (preliminary test). Samples were taken at test start (0 hours) and test end (120 hours). Pure test systems (buffer solution pH 4, 7 and 9) were analysed at test start and test end and there was no analytical interference with the test item.
No significant elimination was observed and therefore the test item was considered as hydrolytically stable under this condition and a half -life of > 1 year could be assumed for environmental typical temperatures.

Description of key information

Hydrolysis as a function of pH was determined according to OECD Guideline No. 111 and Council Regulation (EC) No. 440/2008, Method C.7 for the test item.

Analyses of the test item were performed via LC-MS/MS on a reversed phase analytical column using the test item as external standard. The analytical method was validated with satisfactory results with regard to linearity, accuracy, precision and specificity.

The study was conducted with test item concentration of 8 mg/L in buffer solutions at pH 4, 7 and 9 at a test temperature of 50 °C (preliminary test). Samples were taken at test start (0 hours) and test end (120 hours). Pure test systems (buffer solution pH 4, 7 and 9) were analysed at test start and test end and there was no analytical interference with the test item.

No significant elimination was observed and therefore the test item was considered as hydrolytically stable under this condition and a half -life of > 1 year could be assumed for environmental typical temperatures.