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Administrative data

Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
11th December 2018 to 19th December 2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2019
Report date:
2019

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: The Guidelines for the Testing of Chemicals No. 111 'Hydrolysis as a function of pH (MEP, 2013|)
GLP compliance:
yes

Test material

Study design

Analytical monitoring:
yes
Buffers:
- pH: 4.0, 7.0 and 9.0

- Composition of buffers:
pH 4.0 - 500ml of 0.1 mol/L Potassium Dihydrogen Citrate + 90ml 0.1 mol/L of NaOH, made up to 1000ml with pure water
pH 7.0 - 500ml of 0.1 mol/L KH2PO4 + 296.3 of 0.1 mol/L of NaOH, made up to 1000ml with pure water
pH 9.0 - 500ml of 0.1 mol/L Boracic Acid(dissolved in 0.1 mol/L KCl + 213ml 0.1 mol/L of NaOH, made up to 1000ml with pure water

All buffer solutions and glassware were sterilised for 20mins at 121oC.
Details on test conditions:
500μL of stock solution of 400mg/L was added to 100ml of the buffer solutions of pH 4.0, 7.0 and 9.0 to generate a test solution of 20mg/L. The solutions were divided in 3 and placed at 50± 0.5oC in the dark. The residual concentration was measured on Day 5
Duration of testopen allclose all
Duration:
5 d
pH:
9
Temp.:
50 °C
Initial conc. measured:
18.3 mg/L
Duration:
5 d
pH:
7
Temp.:
50 °C
Initial conc. measured:
21 mg/L
Duration:
5 d
pH:
4
Temp.:
50 °C
Initial conc. measured:
20.6 mg/L
Number of replicates:
Three
Positive controls:
no
Negative controls:
no

Results and discussion

Preliminary study:
The average initial concentrations of pH 4, 7 and 9 were 20.6, 21.0 and 18.3 mg/L respectively. The residual concentration of pH 4, 7 and 9 on Day 5 were 19.0, 20.2 and 19.5 mg/L respectively. Therefore, the hydrolysis rates of pH 4, 7 and 9 on Day 5 were 7.8%, 1.7% and 5.4% respectively.
The hydrolysis rate at pH 4.0, 7.0 and 9.0 were all less than 10% on the 5th day at 50oC ± 0.5oC so the definitive test was terminated. 
Transformation products:
no
Dissipation DT50 of parent compoundopen allclose all
Key result
pH:
4
Temp.:
50 °C
Remarks on result:
hydrolytically stable based on preliminary test
Key result
pH:
7
Temp.:
50 °C
Remarks on result:
hydrolytically stable based on preliminary test
Key result
pH:
9
Temp.:
50 °C
Remarks on result:
hydrolytically stable based on preliminary test
Details on results:
The hydrolysis rate at pH 4.0, 7.0 and 9.0 were all less than 10% on the 5th day at 50oC ± 0.5oC so the definitive test was terminated. 

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The test item E Stage 3 Intermediate is hydrolytically stable. The DT50 cannot be calculated but is estimated to be >1 year at 2.5oC based on Test Guideline MEP 111. 
Executive summary:

HPLC was employed to determine the Test Item E Stage 3 Intermediate. The recovery test in buffer solution used two concentrations, 2mg/L and 50 mg/L. The mean recovery rate was in the range 87.8- 106.1% with RSD in the range of 0.6 -4.4%. The analytical method used met the quality criteria. The hydrolysis rate at pH 4.0, 7.0 and 9.0 were all less than 10% on the 5th day at 50oC ± 0.5oC so the definitive test was terminated. 


The test item E Stage 3 Intermediate is hydrolytically stable. The DT50 cannot be calculated but is estimated to be >1 year at 2.5oC based on Test Guideline MEP 111.