Blue MGi 1037-Na (notification presscake)

Hydrolysis

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 2000-06-06 to 2000-11-08

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:

1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

1981

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Sample Preparation: After incubation 10 µL aliquots of the test solutions at each pH value were analysed without dilution by measuring the UV signal of BLUE MGi 1037 after HPLC separation of the injected sample solution.

Buffers:

Composition of buffer:
- Buffer pH 4, Biphthalate
- Buffer pH 7, Phosphate
- Buffer pH 9, Borate/Potassium chloride/NaOH

The buffer solutions were sterilized for 25 minutes in an autoclave prior to first use. Nitrogen was passed through the buffer solutions for 5 minutes except when freshly sterilized.

Details on test conditions:

TEST SYSTEM
- Test vessels: Glassware. All glassware, which must be inert in the pH range applied, were rinsed with sterile buffer. The hydrolysis was carried out in flasks which were stoppered or sealed with an inert material (e.g. PTFE).
The test vessels were labelled with the following information: RCC study number and the additional information necessary to assure unmistakable identification.

TEST MEDIUM
- Preparation of test solutions:
Hydrolysis at 50 °C (Preliminary Test and main test)
- pH 4.0: 21.83 mg of BLUE MGi 1037 were dissolved in 100 mL buffer solution (pH 4.0) to prepare a test solution of 218.3 µg/mL. This solution was treated in an ultrasonic bath for 5 minutes, filtrated (0.45 µm) and diluted in a 1:2 ratio with buffer solution pH 4.0. Two aliquots of this test solution of approximately 50 mL each were transferred into 50 mL Erlenmeyer flasks in order to perform a duplicate test.
- pH 7.0: 22.79 mg of BLUE MGi 1037 were dissolved in 100 mL buffer solution (pH 7.0) to prepare a test solution of 227.9 µg/mL. This solution was treated in an ultrasonic bath for 5 minutes, filtrated (0.45 µm) and diluted in a 1:2 ratio with buffer solution pH 7.0. Two aliquots of this test solution of approximately 50 mL each were transferred into 50 mL Erlenmeyer flasks in order to perform a duplicate test.
- pH 9.0: 21.14 mg of BLUE MGi 1037 were dissolved in 100 mL buffer solution (pH 9.0) to prepare a test solution of 211.4 µg/mL. This solution was treated in an ultrasonic bath for 5 minutes, filtrated (0.45 µm) and diluted in a 1:2 ratio with buffer solution pH 9.0. Two aliquots of this test solution of approximately 50 mL each were transferred into 50 mL Erlenmeyer flasks in order to perform a duplicate test.

Hydrolysis at 60 °C
- pH 4.0: 22.29 mg of BLUE MGi 1037 were dissolved in 100 mL buffer solution (pH 4.0) to prepare a test solution of 222.9 µg/mL. This solution was treated in an ultrasonic bath for 5 minutes, filtrated (0.45 µm) and diluted in a 1: 2 ratio with buffer solution pH 4.0. Two aliquots of this test solution of approximately 50 mL each were transferred into 50 mL Erlenmeyer flasks in order to perform a duplicate test.
- pH 9.0: 21.93 mg of BLUE MGi 1037 were dissolved in 100 mL buffer solution (pH 9.0) to prepare a test solution of 219.3 µg/mL. This solution was treated in an ultrasonic bath for 5 minutes, filtrated (0.45 µm) and diluted in a 1: 2 ratio with buffer solution pH 9.0. Two aliquots of this test solution of approximately 50 mL each were transferred into 50 mL Erlenmeyer flasks in order to perform a duplicate test.

Hydrolysis at 70 °C
- pH 4.0:
22.01 mg of BLUE MGi 1037 were dissolved in 100 mL buffer solution (pH 4.0) to prepare a test solution of 220.1 µg/mL. This solution was treated in an ultrasonic bath for 5 minutes, filtrated (0.45 µm) and diluted in a 1: 2 ratio with buffer solution pH 4.0. Two aliquots of this test solution of approximately 50 mL each were transferred into 50 mL Erlenmeyer flasks in order to perform a duplicate test.

Hydrolysis at 75 °C
- pH 9.0: 23.09 mg of BLUE MGi 1037 were dissolved in 100 mL buffer solution (pH 9.0) to prepare a test solution of 230.9 µg/mL. This solution was treated in an ultrasonic bath for 5 minutes, filtrated (0.45 µm) and diluted in a 1: 2 ratio with buffer solution pH 9.0. Two aliquots of this test solution of approximately 50 mL each were transferred into 50 mL Erlenmeyer flasks in order to perform a duplicate test.

OTHER TEST CONDITIONS
- Adjustment of pH: No

Number of replicates:

2 replicates per pH and temperature measured.

Positive controls:

no

Negative controls:

no

Preliminary study:

- Hydrolysis at 50 °C: The hydrolysis preliminary test was performed with BLUE MGi 1037 at 50.0 °C ± 0.1 °C at each of pH 4.0, pH 7.0, and pH 9.0 in duplicate. The test solutions of BLUE MGi 1037 were thermostated to 50.0 °C and analysed in time intervals.
- pH 4.0: The results of the preliminary test show, that BLUE MGi 1037 is not stable at pH 4.0. Therefore the test at 50 °C was repeated in the range of 20 % to 70 % degradation.

Test performance:

The preliminary hydrolysis tests were performed at 50.0 °C ± 0.1 °C at pH 4.0, pH 7.0 and pH 9.0, each.
Aliquots of each test solution were analysed at the beginning and after 2.4 and 120 hours using the analytical method as described later in this report.
Further hydrolysis tests were performed at 50 °C, 60 °C and 70 °C in the buffered test solution at pH 4.0 and at 50 °C, 60 °C and 75 °C in the buffered test solution at pH 9.0, due to the instability of the test item found in the preliminary test at 50.0 °C.
At pH 7.0 the test item was found to be stable at 50 °C. Therefore no further testing was performed at this pH-value.The vailidity criteria were fulfilled

Transformation products:

not specified

Details on hydrolysis and appearance of transformation product(s):

Not specified

Key result

pH:

4

Temp.:

25 °C

Hydrolysis rate constant:

0 s-1

DT50:

2 250 h

Remarks on result:

other: No preliminary test was performed

pH:

4

Temp.:

50 °C

Hydrolysis rate constant:

0 s-1

DT50:

236 h

Remarks on result:

other: No preliminary test was performed

pH:

4

Temp.:

60 °C

Hydrolysis rate constant:

0 s-1

DT50:

113 h

Remarks on result:

other: No preliminary test was performed

pH:

4

Temp.:

70 °C

Hydrolysis rate constant:

0 s-1

DT50:

50 h

Remarks on result:

other: No preliminary test was performed

pH:

7

Temp.:

25 °C

Remarks on result:

other: No preliminary test was performed

Key result

pH:

9

Temp.:

25 °C

Hydrolysis rate constant:

0 s-1

DT50:

3 536 h

Remarks on result:

other: No preliminary test was performed

pH:

9

Temp.:

50 °C

Hydrolysis rate constant:

0 s-1

DT50:

123 h

Remarks on result:

other: No preliminary test was performed

pH:

9

Temp.:

60 °C

Hydrolysis rate constant:

0 s-1

DT50:

36 h

Remarks on result:

other: No preliminary test was performed

pH:

9

Temp.:

70 °C

Hydrolysis rate constant:

0 s-1

DT50:

7 h

Remarks on result:

other: No preliminary test was performed

Details on results:

The concentration of the read across test substance BLUE MGi 1037 decreases at pH 4.0 and 50.0 °C (main test). The linear plots prove that the hydrolysis reaction is of pseudo first order in the range from 20 % to 70 % hydrolysis at pH 4.0. The half-life time of BLUE MGi 1037 at 50.0 °C and pH 4.0 was calculated to be 236 hours (10 days).
- pH 9.0: The results of the preliminary test show, that BLUE MGi 1037 is not stable at pH 9.0. Therefore the test at 50 °C was repeated in the range of 20 % to 70 % degradation. The concentration of the read across test substance BLUE MGi 1037 decreases at pH 9.0 and 50.0 °C (main test). The linear plots prove that the hydrolysis reaction is of pseudo first order in the range from 20 % to 70 % hydrolysis at pH 9.0. The half-life time of BLUE MGi 1037 at 50.0 °C and pH 4.0 was calculated to be 123 hours (5 days).
- pH 7: The results of pH 7.0 showed no significant degradation of BLUE MGi 1037 at 50 °C. According to the EEC Directive 92/69, Section C.7, it can be concluded, that the estimated half-life time is higher than one year under representative environmental conditions (25 °C). Therefore, BLUE MGi 1037 can be considered to be hydrolytically stable at pH 7.0 and no further testing was necessary at this pH-value.

Hydrolysis at pH4 and different temperatures
- Calculation of the Half-Life Time at pH 4.0:
The hydrolysis reaction at pH 4.0 is relatively slow. Therefore, the further hydrolysis tests at pH 4.0 were performed at 60 °C and 70 °C, each in duplicate. Each buffered test solution was analysed in time intervals.
The half-life time at pH 4.0 and 60 °C was calculated to be 113 hours (5 days).
The half-life time at pH 4.0 and 70 °C was calculated to be 50 hours (2 days).
- Evaluation of the Half-Life Time at 25 °C at pH 4.0: The half-life time of the hydrolysis reaction of BLUE MGi 1037 at 25 °C and pH 4.0 was calculated to be 2250 hours (94 days).

Hydrolysis at pH9 and different temperatures:
The hydrolysis reaction at pH 9.0 is relatively slow. Therefore, the further hydrolysis tests at pH 9.0 were performed at 60 °C and 75 °C, each in duplicate. Each buffered test solution was analysed in time intervals.
The half-life time at pH 9.0 and 60 °C was calculated to be 36 hours (1.5 days).
The half-life time at pH 9.0 and 75 °C was calculated to be 7 hours (0.28 days).

Evaluation of the Half-Life Time at 25 °C at pH 9.0
The half-life time of the hydrolysis reaction of BLUE MGi 1037 at 25 °C and pH 9.0 was calculated to be 3536 hours (147 days).

Results with reference substance:

Not performed

Validity criteria fulfilled:

yes

Conclusions:

At pH 4 the half-life of the test substance was determined to be 2250 hours at 25 °C.
At pH 7 the half-life of the test substance was determined to be longer than one year at 25 °C.
At pH 9 the half-life of the test substance was determined to be 3536 hours at 25 °C.

Reference 2

Endpoint:

hydrolysis

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reason / purpose for cross-reference:

read-across source

Transformation products:

not specified

Key result

pH:

4

Temp.:

25 °C

Hydrolysis rate constant:

0 s-1

DT50:

2 250 h

Remarks on result:

other: No preliminary test was performed

pH:

4

Temp.:

50 °C

Hydrolysis rate constant:

0 s-1

DT50:

236 h

Remarks on result:

other: No preliminary test was performed

pH:

4

Temp.:

60 °C

Hydrolysis rate constant:

0 s-1

DT50:

113 h

Remarks on result:

other: No preliminary test was performed

pH:

4

Temp.:

70 °C

Hydrolysis rate constant:

0 s-1

DT50:

50 h

Remarks on result:

other: No preliminary test was performed

Key result

pH:

7

Temp.:

25 °C

Remarks on result:

other: No preliminary test was performed

Key result

pH:

9

Temp.:

25 °C

Hydrolysis rate constant:

0 s-1

DT50:

3 536 h

Remarks on result:

other: No preliminary test was performed

pH:

9

Temp.:

50 °C

Hydrolysis rate constant:

0 s-1

DT50:

123 h

Remarks on result:

other: No preliminary test was performed

pH:

9

Temp.:

60 °C

Hydrolysis rate constant:

0 s-1

DT50:

36 h

Remarks on result:

other: No preliminary test was performed

pH:

9

Temp.:

70 °C

Hydrolysis rate constant:

0 s-1

DT50:

7 h

Remarks on result:

other: No preliminary test was performed

Details on results:

- BLUE MGi 1037 at pH 4.0 has a half-life time of 2250 hours (94 days) at 25 °C.
- BLUE MGi 1037 is stable at pH 7.0. Its half-life time is longer than one year at 25 °C.
- BLUE MGi 1037 at pH 9.0 has a half-life time of 3536 hours (147 days) at 25 °C.

Validity criteria fulfilled:

yes

Conclusions:

A study was conducted with the read across substance Blue MGi 1037 according to EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH). The hydrolysis of the test item was performed at 50.0 °C ± 0.1 °C at each of pH 4.0, pH 7.0 and pH 9.0. BLUE MGi 1037 was found to be stable at pH 7.0 and 50 °C but BLUE MGi 1037 was determined to be not stable at pH 4.0 and pH 9.0. At pH 4 the half-life of the test substance was determined to be 2250 hours (94 days) at 25 °C. At pH 9 the half-life of the test substance was determined to be 3536 (147 days) hours at 25 °C.

Description of key information

A study was conducted with the read across substance Blue MGi 1037 according to EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH). At pH 4 the half-life of the test substance was determined to be 2250 hours at 25 °C. At pH 9 the half-life of the test substance was determined to be 3536 hours at 25 °C.

Key value for chemical safety assessment

Half-life for hydrolysis:

3 536 h

at the temperature of:

25 °C

Additional information

A study was conducted with the read across substance Blue MGi 1037 according to EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH). The hydrolysis of the test item was performed at 50.0 °C ± 0.1 °C at each of pH 4.0, pH 7.0 and pH 9.0. BLUE MGi 1037 was found to be stable at pH 7.0 and 50 °C but BLUE MGi 1037 was determined to be not stable at pH 4.0 and pH 9.0. At pH 4 the half-life of the test substance was determined to be 2250 hours (94 days) at 25 °C. At pH 9 the half-life of the test substance was determined to be 3536 (147 days) hours at 25 °C.