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Hydrolysis

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Reference
Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From October 01, 2018 to November 20, 2018
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Qualifier:
according to
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Qualifier:
according to
Guideline:
EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
GLP compliance:
no
Remarks:
conducted at the company internal.
Buffers:
Acetate buffer pH 4, 0.1 M: solution of 0.1 M acetic acid adjusted to pH 4 using 10 N sodium hydroxide. The buffer contains 0.002% (w/v) PREVENTAL BIT 20.
Phosphate buffer pH 7, 0.1 M: solution of 0.1 M potassium dihydrogen phosphate adjusted to pH 7 using 10 N sodium hydroxide. The buffer contains 0.002% (w/v) PREVENTAL BIT 20.
Borate buffer pH 9, 0.1 M: solution of 0.1 M boric acid and 0.1 M potassium chloride adjusted to pH 9 using 10 N sodium hydroxide. The buffer contains 0.002% (w/v) PREVENTAL BIT 20.
Number of replicates:
two
Statistical methods:
System control, data acquisition and data processing were performed using the following programme: Empower version 3.00 (Waters)
Transformation products:
no
% Recovery:
ca. 96.9
pH:
4
Temp.:
50 °C
Remarks on result:
hydrolytically stable based on preliminary test
% Recovery:
ca. 99.6
pH:
7
Temp.:
50 °C
Remarks on result:
hydrolytically stable based on preliminary test
% Recovery:
ca. 99.4
pH:
9
Temp.:
50 °C
Remarks on result:
hydrolytically stable based on preliminary test
pH:
4
Temp.:
25 °C
Hydrolysis rate constant:
0 h-1
DT50:
671 d
Type:
(pseudo-)first order (= half-life)
pH:
7
Temp.:
25 °C
Hydrolysis rate constant:
0 h-1
DT50:
1 099 d
Type:
(pseudo-)first order (= half-life)
pH:
9
Temp.:
25 °C
Hydrolysis rate constant:
0 h-1
DT50:
2 194 d
Type:
(pseudo-)first order (= half-life)

Table 1. Rate constants (kobs) and half-life times (t1/2) of the test substance

Temperature

[°C]

kobs

[hours-1]

t1/2

[days]

pH 4

pH 7

pH 9

pH 4

pH 7

pH 9

20

2.30 × 10-5

1.61 × 10-5

6.91 × 10-6

1254

1791

4179

25

4.30 × 10-5

2.63 × 10-5

1.32 × 10-5

671

1099

2194

50

6.91 × 10-4

2.30 × 10-4

2.30 × 10-4

42

125

125

Validity criteria fulfilled:
yes
Conclusions:
According to OECD 111 and EC C.7 test method, the rate constant of CJ302 at 25°C are 4.30× 10-5 hour-1 at pH=4, 2.63× 10-5 hour-1 at pH=7 and 1.32× 10-5 hour-1 at pH=9. And the half-life time of CJ302 at 25°C are 671 days at pH=4, 1099 days at pH=7 and 2194 days at pH=9.
Executive summary:

This test using the procedures outlined in the ECIC Study Plan for 180709-09, OECD 111 (OECD, 2004) and EC C.7 (EC no. 440/2008). In Main study, the mean recoveries of the buffer solutions at t=0 fell within the criterion range of 90-110 % . It demonstrated that the analytical method was adequate to support the hydrolysis study on the test substance. For testing of pseudo-first order kinetics the mean logarithms of the relative concentrations between 70% and 115% were plotted against time. At all temperatures linear relationships were obtained. The half-life times of the test substance were determined according to the model for pseudo-first order reactions. All logarithms of the relative concentrations were correlated with time using linear regression analysis. The rate constant and half-life time of the test substance at 20 and 50 °C was obtained and the Arrhenius equation was used to determine the rate constant and half-life time at 25°C. Therefore, the rate constant of CJ302 at 25°C are 4.30× 10-5hour-1at pH=4, 2.63× 10-5hour-1at pH=7 and 1.32× 10-5hour-1at pH=9. And the half-life time of CJ302 at 25°C are 671 days at pH=4, 1099 days at pH=7 and 2194 days at pH=9.

Description of key information

The rate constant of CJ302 at 25°C are 4.30× 10-5hour-1at pH=4, 2.63× 10-5hour-1at pH=7 and 1.32× 10-5hour-1at pH=9. And the half-life time of CJ302 at 25°C are 671 days at pH=4, 1099 days at pH=7 and 2194 days at pH=9 (OECD TG 111).

Key value for chemical safety assessment

Half-life for hydrolysis:
1 099 d
at the temperature of:
25 °C

Additional information

In Main study, the mean recoveries of the buffer solutions at t=0 fell within the criterion range of 90-110 % . It demonstrated that the analytical method was adequate to support the hydrolysis study on the test substance. For testing of pseudo-first order kinetics the mean logarithms of the relative concentrations between 70% and 115% were plotted against time. At all temperatures linear relationships were obtained. The half-life times of the test substance were determined according to the model for pseudo-first order reactions. All logarithms of the relative concentrations were correlated with time using linear regression analysis. The rate constant and half-life time of the test substance at 20 and 50 °C was obtained and the Arrhenius equation was used to determine the rate constant and half-life time at 25°C. Therefore, the rate constant of CJ302 at 25°C are 4.30× 10-5hour-1at pH=4, 2.63× 10-5hour-1at pH=7 and 1.32× 10-5hour-1at pH=9. And the half-life time of CJ302 at 25°C are 671 days at pH=4, 1099 days at pH=7 and 2194 days at pH=9.