Registration Dossier

Administrative data

Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2016-02-29 to 2017-07-17
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report Date:
2017

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Version / remarks:
(2004)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
Version / remarks:
30 May, 2008
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Radiolabelling:
no

Study design

Analytical monitoring:
yes
Details on sampling:
- Sampling intervals for the parent/transformation products:
For the preliminary test, samples were taken at test start (0 h) and test end (120 h)
For the advanced test, samples were taken at test start (0 h) and at a minimum of 8 spaced points for pH 4 and 7 (actual 10 for pH 4 and 9 for pH 7), normally between 10 and 90% of hydrolysis. Due to the rapid hydrolysis at pH 9, only 1 to 5 additional samples could be obtained.
- Sampling intervals/times for sterility check:
As the test duration was 120 h for each test condition, no determination of CFU was deemed necessary.
Buffers:
- pH: 4, 7, 9
- Type and final molarity of buffer:
Buffer solution pH 4:
0.18 g of NaOH and 5.7555 g of mono potassium citrate were dissolved in 500 mL double distilled water.
Buffer pH 7 (preliminary test):
0.7358 g of NaOH and 4.3012 g of KH2PO4 were dissolved in 500 mL double distilled water.
Buffer solution pH 7 (advanced test):
3.854 g of ammonium acetate were dissolved in 500 mL double distilled water.
Buffer pH 9:
0.426 g NaOH, 1.8638 g KCI and 1.5458 g H3BO3 were dissolved in 500 mL double distilled water.
Details on test conditions:
TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: HPLC vials, volume: 4 mL
- Measures taken to avoid photolytic effects: Photolytic effects were avoided by using opaque water baths.
- If no traps were used, is the test system closed/open: closed

TEST MATERIAL
- Volume used/treatment: 2 mL
- Kind and purity of water: Double distilled water, ROTH; batches: 335233316, 415234632, 086239961; conductivity: ≤ 2.0 µS/cm, for Transformation products: HPLC grade water, VWR
- Preparation of test medium: 30 mg/L buffer pH 4, 7 and 9 with 1% acetonitrile, respectively. The test concentration was fixed at 30 mg/L, due to the sensitivity of the analytical method.
- Identity and concentration of co-solvent: Acetonitrile, ≤ 1 % (v/v)

OTHER TEST CONDITIONS
- Adjustment of pH: No
Duration of testopen allclose all
Duration:
54.8 h
pH:
4
Temp.:
20 °C
Initial conc. measured:
31.4 mg/L
Duration:
34.8 h
pH:
4
Temp.:
30 °C
Initial conc. measured:
30.5 mg/L
Duration:
8.83 h
pH:
4
Temp.:
50 °C
Initial conc. measured:
30.9 mg/L
Duration:
24.3 h
pH:
7
Temp.:
20 °C
Initial conc. measured:
30.7 mg/L
Duration:
8.33
pH:
7
Temp.:
30 °C
Initial conc. measured:
30.7 mg/L
Duration:
1.78 h
pH:
7
Temp.:
50 °C
Initial conc. measured:
32 mg/L
Duration:
1.22 h
pH:
9
Temp.:
5 °C
Initial conc. measured:
18.9 mg/L
Duration:
0.717 h
pH:
9
Temp.:
10 °C
Initial conc. measured:
17.4 mg/L
Duration:
0.18 h
pH:
9
Temp.:
20 °C
Initial conc. measured:
11.5 mg/L
Number of replicates:
Duplicates per pH value and sampling date, single injected
Positive controls:
no
Remarks:
according to guideline not necessary
Negative controls:
yes
Remarks:
Buffer solutions (pH value 4, 7 and 9 with 1% acetonitrile)

Results and discussion

Preliminary study:
In the preliminary test, no significant signal could be obtained for any pH condition after incubation at 50 °C for 120 h, corresponding to a degradation of 100%.
Transformation products:
yes
Identity of transformation productsopen allclose all
No.:
#1
Reference
Reference substance name:
Unnamed
No.:
#2
Reference
Reference substance name:
Unnamed
No.:
#3
Reference
Reference substance name:
Unnamed
No.:
#4
Reference
Reference substance name:
Unnamed
No.:
#5
Reference
Reference substance name:
Unnamed
No.:
#6
Reference
Reference substance name:
Unnamed
No.:
#8
Reference
Reference substance name:
Unnamed
No.:
#9
Reference
Reference substance name:
Unnamed
No.:
#10
Reference
Reference substance name:
Unnamed
No.:
#11
Reference
Reference substance name:
Unnamed
Details on hydrolysis and appearance of transformation product(s):
- Formation and decline of each transformation product during test:
For all test conditions the In concentration vs. time plots have regression graphs with slopes significantly non zero (perfect line for pH 9 at 20 “C). Therefore first order reaction kinetics was applied for data computation. A confirmation of pseudo first order reaction kinetics with coefficients of determination > 0.8 could be obtained for all test conditions.
Total recovery of test substance (in %)open allclose all
% Recovery:
11
pH:
4
Temp.:
20 °C
Duration:
54.8 h
% Recovery:
5
pH:
4
Temp.:
30 °C
Duration:
34.8 h
% Recovery:
7
pH:
4
Temp.:
50 °C
Duration:
8.83 h
% Recovery:
1
pH:
7
Temp.:
20 °C
Duration:
24.3 h
% Recovery:
2
pH:
7
Temp.:
30 °C
Duration:
8.33 h
% Recovery:
1
pH:
7
Temp.:
50 °C
Duration:
1.78 h
% Recovery:
2
pH:
9
Temp.:
5 °C
Duration:
1.22 h
% Recovery:
1
pH:
9
Temp.:
10 °C
Duration:
0.717 h
% Recovery:
4
pH:
9
Temp.:
20 °C
Duration:
0.183 h
Dissipation DT50 of parent compoundopen allclose all
Key result
pH:
4
Temp.:
20 °C
Hydrolysis rate constant:
0 s-1
DT50:
16.7 h
Type:
(pseudo-)first order (= half-life)
Key result
pH:
4
Temp.:
30 °C
Hydrolysis rate constant:
0 s-1
DT50:
8.08 h
Type:
(pseudo-)first order (= half-life)
Key result
pH:
4
Temp.:
50 °C
Hydrolysis rate constant:
0 s-1
DT50:
2.28 h
Type:
(pseudo-)first order (= half-life)
Key result
pH:
7
Temp.:
20 °C
Hydrolysis rate constant:
0 s-1
DT50:
3.58 h
Type:
(pseudo-)first order (= half-life)
Key result
pH:
7
Temp.:
30 °C
Hydrolysis rate constant:
0 s-1
DT50:
1.39 h
Type:
(pseudo-)first order (= half-life)
Key result
pH:
7
Temp.:
50 °C
Hydrolysis rate constant:
0.001 s-1
DT50:
0.262 h
Type:
(pseudo-)first order (= half-life)
Key result
pH:
9
Temp.:
5 °C
Hydrolysis rate constant:
0.001 s-1
DT50:
0.238 h
Type:
(pseudo-)first order (= half-life)
Key result
pH:
9
Temp.:
10 °C
Hydrolysis rate constant:
0.002 s-1
DT50:
0.11 h
Type:
(pseudo-)first order (= half-life)
Key result
pH:
9
Temp.:
20 °C
Hydrolysis rate constant:
0.005 s-1
DT50:
0.041 h
Type:
(pseudo-)first order (= half-life)
Details on results:
TEST CONDITIONS
- pH, sterility, temperature, and other experimental conditions maintained throughout the study: Yes
- Anomalies or problems encountered (if yes): no

MAJOR TRANSFORMATION PRODUCTS
Major transformation products were observed at all pH values and temperatures.
At pH 4 and 20 “C Trans 10 and at 30 and 50 °C Trans 10 and 11 were identified as major transformation products.
At pH 7 and 20 °C Trans 2, 6 and 8, at 30 °C Trans 2 and 8 and at 50 °C Trans 2, 8 and 11 were identified.
At pH 9 and 5 and 10 °C Trans 8 and at 20 °C Trans 2 and 8 was identified.

PATHWAYS OF HYDROLYSIS
- Figures of chemical structures attached: No

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
In the present study conducted according to OECD guideline 111 (2004), 30 mg/L of the test substance were dissolved in three buffers, pH 4, 7 and 9 and incubated at different temperatures (5, 10, 20, 30, and 50°C). The test item showed a moderate hydrolysis rate (2.4 h ≤ t1/2 ≤ 30 d) for pH 4 at 20 and 30 °C as well as for pH 7 at 20 °C and a fast hydrolysis rate (t1/2 ≤ 2.4 h) for the remaining test conditions (pH 4 at 50 °C, pH 7 at 30 and 50 °C as well as for pH 9 at 5, 10 and 20°C), with the higher half-lives at acidic conditions. Major transformation products were observed at all pH values and temperatures.