2-morpholinoethanesulphonic acid

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-11-30 to 2018-08-29

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

adopted 13 April 2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

31 May 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

The reaction solutions were analysed at the start of the test and after five days with six replicate samples each. Two replicate tubes filled with control buffers were analysed at the start and at the end of the incubation.

Buffers:

pH 4.0: 76.5 mL 0.1 M sodium acetate and 423.5 mL 0.1 M acetic acid;
pH 7.0: 74 mL 0.2 M sodium hydroxide and 125 mL 0.2 M potassium dihydrogen phosphate diluted to 500 mL with ultra-pure water;
pH 9.0: 53.5 mL 0.2 M sodium hydroxide and 125 mL 0.2 M boric acid and potassium chloride diluted to 500 mL with ultra-pure water

Details on test conditions:

TEST SYSTEM
- Type, material: 20 mL headspace-vials
- Measures to exclude oxygen: test tubes were filled up with test solutions
- Is there any indication of the test material adsorbing to the walls of the test apparatus? None was reported

PREPARATION OF TEST SAMPLES
About 250 mg of test item was weighed to the nearest 0,01 mg into a volumetric flask and dissolved in the buffer solutions to a total volume of 250 mL. The pH of each test solution was checked with a calibrated pH meter to a precision of 0.001. Deviation was higher than 0.05 in every test solution, therefore pH was set by the addition of base.

TEST MEDIUM
- Volume used/treatment: 20 mL
- Kind and purity of water: ultra-pure sterile water

Duration:

120 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

1.04 µg/L

Duration:

120 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

1.2 µg/L

Duration:

120 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

1.03 µg/L

Number of replicates:

Six replicates each

Positive controls:

not specified

Negative controls:

yes

Preliminary study:

Recovery after 120h at 50°C:
- pH 4: 112%
- pH 7: 91%
- pH 9: 92%
Therefore, it was concluded that the substance is hydrolytically stable and no further experiments were conducted.

Transformation products:

not measured

% Recovery:

112

pH:

4

Temp.:

50 °C

Duration:

120 h

Remarks on result:

hydrolytically stable based on preliminary test

% Recovery:

91

pH:

7

Temp.:

50 °C

Duration:

120 h

Remarks on result:

hydrolytically stable based on preliminary test

% Recovery:

92

pH:

9

Temp.:

50 °C

Duration:

120 h

Remarks on result:

hydrolytically stable based on preliminary test

Key result

Remarks on result:

hydrolytically stable based on preliminary test

Details on results:

TEST CONDITIONS
- pH, sterility, temperature, and other experimental conditions maintained throughout the study: Yes

Results of the Preliminary Test (Tier 1)

The hydrolysis test was performed at 50 ± 0.5 °C, at pH 4, 7 and 9.  Measured concentrations and pH values are summarised in in the table below.

Measured data of pH=4 test solution

pH	Sampling time (hour)	Concentration of Test item				Measured pH
		Results of the replicates (mg/mL)	Mean (mg/mL)	Measured/ Nominal (%)	End/Start (%)
4	0 (Start)	Control buffers		-	-	4.00
		1.02	1.104	104	-	4.00
		1.05
		1.04
		0.99
		1.03
		1.14
	120	Control buffers		-	-	3.90
		1.15	1.17	117	112	4.00
		1.25
		1.17
		1.18
		1.10
		1.17
7	0 (Start)	Control buffers		-	-	7.00
		1.24	1.20	120	-	7.00
		1.11
		1.26
		1.27
		1.47
		1.17
	120	Control buffers		-	-	6.53
		1.25	1.10	110	91	7.04
		1.11
		1.20
		1.05
		0.99
		0.98
9	0 (Start)	Control buffers		-	-	9.00
		1.14	1.03	102	-	9.00
		1.05
		1.02
		0.99
		1.01
		0.97
	120	Control buffers		-	-	8.99
		0.894	0.945	94	92	9.02
		1.03
		0.936
		0.945
		0.953
		0.915
		1.896*

* Wrong dilution; this value was not taken into consideration for further calculations.

Validity criteria fulfilled:

yes

Conclusions:

In the preliminary test, the test item was found to be hydrolytically stable at pH 4, 7 and 9 at 50 °C. Thus, no further hydrolysis test was investigated further.

Executive summary:

The hydrolysis of the substance as a function of pH was determined in a preliminary test according to OECD Test Guideline 111 under GLP conditions. As no hydrolysis was observed at pH 4, 7 and 9 at 50°C for 120-h, it was concluded that the substance is hydrolytically stable and the hydrolysis was not investigated further.

Description of key information

In the preliminary test, the test item was found to be hydrolytically stable at pH 4, 7 and 9 at 50 °C. Thus, no further hydrolysis test was investigated further (reference 5.1.2-1).

Additional information

The hydrolysis of the substance as a function of pH was determined in a preliminary test according to OECD Test Guideline 111 under GLP conditions. As no hydrolysis was observed at pH 4, 7 and 9 at 50°C for 120-h, it was concluded that the substance is hydrolytically stable and the hydrolysis was not investigated further.