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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 March 13, 2017 to April 28, 2017
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Qualifier:
according to guideline
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Qualifier:
according to guideline
Guideline:
EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
GLP compliance:
no
Remarks:
conducted at the company internal.
Analytical monitoring:
yes
Remarks:
Digital Electronic Indictors + S.S.R. with PID automatic calculation capability
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 dihydrogenphosphate 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, Milford, MA, USA)
Transformation products:
no
% Recovery:
97.2
pH:
4
Temp.:
50 °C
Duration:
0 h
% Recovery:
98
pH:
7
Temp.:
50 °C
Duration:
0 h
% Recovery:
97.1
pH:
9
Temp.:
50 °C
Duration:
0 h
pH:
4
Temp.:
25 °C
Hydrolysis rate constant:
0 h-1
DT50:
336 d
Type:
(pseudo-)first order (= half-life)
pH:
7
Temp.:
25 °C
Hydrolysis rate constant:
0.001 h-1
DT50:
35.8 d
Type:
(pseudo-)first order (= half-life)
pH:
9
Temp.:
25 °C
Hydrolysis rate constant:
0 h-1
DT50:
100 d
Type:
(pseudo-)first order (= half-life)

 

Table Rate constants (kobs) and half-life time (t½) at pH 4, pH 7 and pH 9

 

Temperature

(°C)

kobs(hours-1)

t½

pH 4

pH 7

pH 9

pH 4

pH 7

pH 9

20

5.50 x 10-5

7.78 x 10-4

2.49 x 10-4

525 days

37.1 days

116 days

25

8.59 x 10-5

8.07 x 10-4

2.89 x 10-4

336 days

35.8 days

100 days

50

6.20 x 10-4

9.47 x 10-4

5.53 x 10-4

46.6 days

30.5 days

52.2 days
Validity criteria fulfilled:
yes
Conclusions:
According to OECD 111 and EC C.7 test method, the rate constant (kobs) of CJ301 at 25°C are 8.59× 10-5, 8.07× 10-4 and 2.89× 10-4 hour-1 respectively at pH=4, pH=7 and pH=9. And the half-life time of CJ301 at 25°C are 336 days, 35.8 days and 100 days respectively at pH=4, pH=7 and pH=9.
Executive summary:

This test using the procedures outlined in the Everlight Study Plan for 170302 -01, OECD 111 (OECD, 2004) and EC C.7 (EC no. 440/2008).

In Main study, the mean recoveries of the buffer solutions at pH=4 and 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. At pH=7, the mean recoveries of the buffer solutions at t=0 fell within the criterion range of 80-110%. At pH=9, the mean recovery of the buffer solutions at t=0fell within the criterion range of 90 -110%.For testing of pseudo-first order kinetics the mean logarithms of the relative concentrations between 10% and 90% 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 (kobs) and half-life time of the test substance at each temperature was obtained and the Arrhenius equation was used to determine the rate constant and half-life time at 25°C. Therefore, the rate constant (kobs) of CJ301 at 25°C are 8.59× 10 -5, 8.07× 10 -4 and 2.89× 10 -4 hour-1respectivelyat pH=4, pH=7 and pH=9. And the half-life time of CJ301 at 25°C are 336 days, 35.8 days and 100 days respectively at pH=4, pH=7 and pH=9.

Description of key information

The rate constant (kobs) of CJ301 at 25°C are 8.59× 10-5, 8.07× 10-4 and 2.89× 10-4 hour-1 respectively at pH=4, pH=7 and pH=9. And the half-life time of CJ301 at 25°C are 336 days, 35.8 days and 100 days respectively at pH=4, pH=7 and pH=9 (OECD TG111).

Key value for chemical safety assessment

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

Additional information

In Main study,the mean recoveries of the buffer solutions at pH=4 and 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. At pH=7, the mean recoveries of the buffer solutions at t=0 fell within the criterion range of 80-110%. At pH=9, the mean recovery of the buffer solutions at t=0 fell within the criterion range of 90 -110%. For testing of pseudo-first order kinetics the mean logarithms of the relative concentrations between 10% and 90% 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 (kobs) and half-life time of the test substance at each temperature was obtained and the Arrhenius equation was used to determine the rate constant and half-life time at 25°C.Therefore, the rate constant (kobs) of CJ301 at 25°C are

are 8.59× 10-5, 8.07× 10-4and 2.89× 10-4hour-1 respectivelyat pH=4, pH=7 and pH=9. And the half-life time of CJ301 at 25°C are 336 days, 35.8days and 100 days respectively at pH=4, pH=7 and pH=9.