CJ309

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 18 May 2017 to 24 July 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)

GLP compliance:

yes

Specific details on test material used for the study:

Hygroscopic: store in ziplock bag
Water solubility ≥ 330.94 g/L at 20°C

Analytical monitoring:

yes

Buffers:

Acetate buffer pH4, 0.1M: solution of 0.1M acetic acid adjusted to pH4 using 10N sodium hydroxide. The buffer contains 0.002% (w/) T203.

Phosphate buffer pH7, 0.1M: solution of 0.1M potassium dihydrogenphosphate adjusted to pH7 using 10N sodium hydroxide. The buffer contains 0.002% (w/v) T203.

Borate buffer pH9, 0.1M: solution of 0.1M boric acid and 0.1M potassium chloride adjusted to pH9 using 10N sodium hydroxide. The buffer contains 0.002% (w/v) T203.

Details on test conditions:

During the main study of the determination of the Hydrolysis as a function of pH7, pH4 and pH9 at 20°C, the temperature was controlled within ± 0.8°C (criterion was ±0.5°C).
Evaluation: The temperature range was slightly higher than the criterion. According to this it was considered not to significantly influence the degradation of the test substance at 20°C.
The study integrity was not adversely affected by the deviations.
Any deviations from standard operating procedures (SOPs) were evaluated and filed in the study file. There were no deviations from SOPs that affected the integrity of the study.

Duration:

168 h

pH:

4

Temp.:

20 °C

Initial conc. measured:

510 mg/L

Duration:

168 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

527 mg/L

Duration:

168 h

pH:

7

Temp.:

20 °C

Initial conc. measured:

503 mg/L

Duration:

168 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

500 mg/L

Duration:

168 h

pH:

9

Temp.:

20 °C

Initial conc. measured:

517 mg/L

Duration:

168 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

500 mg/L

Number of replicates:

2

Test performance:

The rate of hydrolysis of the test substance as a function of pH was determined at pH values normally found in the environment (pH4-9).
The buffer solutions were filter-sterilised through a 0.22µm PVDF filter (Merck Millipore Ltd.) and transferred into a sterile vessel. The test substance was spiked to the solutions at a target concentration of 1000 mg/l using a spiking solution in water. For each sampling time, duplicate sterile vessels under vacuum were filled with 20mL test solution.
The concentration of the test substance in the test samples was determined immediately after preparation (t=0) and at several sampling points after t=0. The samples after t=0 days were cooled to room temperature using running tap water, if necessary.
The samples not analysed on the sampling day were stored in the freezer. Storage stability under these conditions was determined by the analysis of additional accuracy samples prepared at half the nominal concentration of the test samples. On the days of analysis, the frozen samples were defrosted at room temperature, treated and analysed. The stored samples were found to be stable if the mean accuracy was in the range 70-110%. Based on the results obtained the samples were stable when stored in the freezer for 7 days (results are archived in the raw data).
Blank buffer solutions were treated similarly as the test samples and analysed at t=0.
The pH of each of the test solutions (except for the blanks) was determined at least at the beginning and at the end of the test.

Transformation products:

no

% Recovery:

ca. 100

pH:

4

Temp.:

20 °C

Duration:

168 h

Remarks on result:

hydrolytically stable based on preliminary test

% Recovery:

ca. 100

pH:

4

Temp.:

50 °C

Duration:

168 h

Remarks on result:

hydrolytically stable based on preliminary test

% Recovery:

97.2

pH:

7

Temp.:

20 °C

Duration:

168 h

Remarks on result:

hydrolytically stable based on preliminary test

% Recovery:

97.7

pH:

7

Temp.:

50 °C

Duration:

168 h

Remarks on result:

hydrolytically stable based on preliminary test

% Recovery:

98.6

pH:

9

Temp.:

20 °C

Duration:

168 h

Remarks on result:

hydrolytically stable based on preliminary test

% Recovery:

95

pH:

9

Temp.:

50 °C

Duration:

168 h

Remarks on result:

hydrolytically stable based on preliminary test

pH:

4

Temp.:

20 °C

Hydrolysis rate constant:

0.001 h-1

DT50:

29.6 d

Type:

(pseudo-)first order (= half-life)

Remarks on result:

hydrolytically stable based on preliminary test

pH:

4

Temp.:

25 °C

Hydrolysis rate constant:

0.001 h-1

DT50:

24.2 d

Type:

(pseudo-)first order (= half-life)

Remarks on result:

hydrolytically stable based on preliminary test

pH:

4

Temp.:

50 °C

Hydrolysis rate constant:

0.003 h-1

DT50:

9.87 d

Type:

(pseudo-)first order (= half-life)

Remarks on result:

hydrolytically stable based on preliminary test

pH:

7

Temp.:

20 °C

Hydrolysis rate constant:

0 h-1

DT50:

142 d

Type:

(pseudo-)first order (= half-life)

Remarks on result:

hydrolytically stable based on preliminary test

pH:

7

Temp.:

25 °C

Hydrolysis rate constant:

0 h-1

DT50:

143 d

Type:

(pseudo-)first order (= half-life)

Remarks on result:

hydrolytically stable based on preliminary test

pH:

7

Temp.:

50 °C

Hydrolysis rate constant:

0 h-1

DT50:

146 d

Type:

(pseudo-)first order (= half-life)

Remarks on result:

hydrolytically stable based on preliminary test

pH:

9

Temp.:

20 °C

Hydrolysis rate constant:

0 h-1

DT50:

567 h

Type:

(pseudo-)first order (= half-life)

Remarks on result:

hydrolytically stable based on preliminary test

pH:

9

Temp.:

25 °C

Hydrolysis rate constant:

0 h-1

DT50:

501 d

Type:

(pseudo-)first order (= half-life)

Remarks on result:

hydrolytically stable based on preliminary test

pH:

9

Temp.:

50 °C

Hydrolysis rate constant:

0 h-1

DT50:

287 h

Type:

(pseudo-)first order (= half-life)

Remarks on result:

hydrolytically stable based on preliminary test

1. Hydrolysis of the test substance at pH4

No test substance was detected in the blank buffer solutions.

 

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.

 

Table 1. Main test – hydrolysis of the test substance at pH4 and 20°C

Sampling time (hrs)	Analysed concentration(mg/L)	Relativee concentration (%)	Logarithm relative concentration	Actual pH
0	510	99.9	2.00	3.7
0	510	100	2.00	3.7
2	514	101	2.00	3.7
2	525	103	2.01	3.8
4	523	103	2.01	3.7
4	519	102	2.01	3.8
27	508	99.7	2.00	3.7
27	511	100	2.00	3.7
47	502	98.4	1.99	3.7
47	504	98.9	2.00	3.7
51	493	96.7	1.99	3.7
51	485	95.2	1.98	3.8
123	462	90.7	1.96	3.7
123	464	90.9	1.96	3.7
142	445	87.2	1.94	3.7
142	454	89.0	1.95	3.7
147	446	87.5	1.94	3.8
147	449	88.1	1.94	3.7
168	431	84.5	1.93	3.6
168	434	85.1	1.93	3.7

 

Table 2. Main test – hydrolysis of the test substance at pH4 and 50°C

Sampling time (hrs)	Analysed concentration(mg/L)	Relativee concentration (%)	Logarithm relative concentration	Actual pH
0	527	99.9	2.00	3.7
0	528	100	2.00	3.7
2	531	101	2.00	3.7
2	523	99.2	2.00	3.7
4	531	101	2.00	3.6
4	514	97.4	1.99	3.7
27	490	92.8	1.97	3.7
27	485	92.0	1.96	3.7
47	469	88.9	1.95	3.6
47	459	87.0	1.94	3.7
51	445	84.3	1.93	3.7
51	441	83.6	1.92	3.7
123	374	70.9	1.85	3.6
123	367	69.5	1.84	3.7
142	350	66.4	1.82	3.6
142	346	65.5	1.82	3.7
147	348	65.9	1.82	3.7
147	346	65.5	1.82	3.7
168	323	61.2	1.79	3.7
168	318	60.3	1.78	3.7

 

Dye solutions in the concentration range 994-1028 mg/L were prepared from stock solutions. 0.426mL pH4 buffer, 0.5mL dye solutions and 0.074 mL 1N NaOH mixed to pH6.0-7.5 to terminate the hydrolysis reaction and avoid dye condensation.

 

Table 3. Recoveries

Temperature (°C)	Nominal concentration (mg/L)	Analysed concentration (mg/L)	Recovery (%)	Mean recovery (%)
20	994	510	103	103
	994	510	103
50	1028	527	103	104
	1014	528	104

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.

 

Table 4. Statistical parameters of the regression curves

Temperature (°C)	Slope (1/hours)	Intercept	Coefficient of correlation
20	-0.000424	2.01	0.947
50	-0.00127	2.00	0.992

 

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).

 

Table 5. Rate constants (kobs) and half-life time (t_1/2)

Temperature (°C)	kobs (1/hours)	t1/2
20	9.76 x 10^-4	29.6 days
25	1.19 x 10^-3	24.2 days
50	2.92 x 10^-3	9.87 days

 

2. Hydrolysis of the test substance at pH7

No test substance was detected in the blank buffer solutions.

 

The mean recoveries of the buffer solutions at t=0 fell within the criterion range of 80-110%. It demonstrated that the analytical method was adequate to support the hydrolysis study on the test substance.

 

Table 6. Main test – hydrolysis of the test substance at pH7 and 20°C

Sampling time (hrs)	Analysed concentration(mg/L)	Relativee concentration (%)	Logarithm relative concentration	Actual pH
0	503	99.7	2.00	7.1
0	505	100	2.00	7.1
2	493	97.8	1.99	7.1
2	494	98.0	1.99	7.1
5	494	98.0	1.99	7.1
5	494	98.1	1.99	7.0
17	469	93.1	1.97	7.1
17	464	92.1	1.96	7.1
66	529	105	2.02	7.1
66	524	104	2.02	7.1
71	502	99.6	2.00	7.0
71	502	99.6	2.00	7.1
165	502	99.6	2.00	7.1
165	508	101	2.00	7.1
168	505	100	2.00	7.1
168	511	101	2.01	7.1

 

Table 7. Main test – hydrolysis of the test substance at pH7 and 50°C

Sampling time (hrs)	Analysed concentration(mg/L)	Relativee concentration (%)	Logarithm relative concentration	Actual pH
0	500	100	2.00	7.1
0	501	100	2.00	7.1
2	487	97.4	1.99	7.1
2	504	101	2.00	7.0
5	484	96.7	1.99	7.1
5	499	99.7	2.00	7.1
17	452	90.3	1.96	7.1
17	466	93.0	1.97	7.0
66	512	102	2.01	7.1
66	517	103	2.01	7.1
71	497	99.2	2.00	7.1
71	508	102	2.01	7.0
165	498	99.5	2.00	7.1
165	516	103	2.01	7.0
168	492	98.3	1.99	7.1
168	508	102	2.01	7.1

 

Dye solutions in the concentration range 1010-1048 mg/L were prepared from stock solutions. 0.5mL pH7 buffer and 0.5mL dye solutions mixed to pH6.0-7.5 to terminate the hydrolysis reaction and avoid dye condensation.

 

Table 8. Recoveries

Temperature (°C)	Nominal concentration (mg/L)	Analysed concentration (mg/L)	Recovery (%)	Mean recovery (%)
20	1028	503	97.9	97.2
	1048	505	96.4
50	1010	500	99.0	97.7
	1040	501	96.3

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.

 

Table 9. Statistical parameters of the regression curves

Temperature (°C)	Slope (1/hours)	Intercept	Coefficient of correlation
20	8.84 x 10^-5	1.99	0.172
50	8.58 x 10^-5	1.99	0.138

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).

 

Table 10. Rate constants (kobs) and half-life time (t_1/2)

Temperature (°C)	kobs (1/hours)	t1/2
20	2.04 x 10^-4	142 days
25	2.02 x 10^-4	143 days
50	1.98 x 10^-4	146 days

 

3. Hydrolysis of the test substance at pH9

No test substance was detected in the blank buffer solutions.

 

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.

 

Table 11. Main test – hydrolysis of the test substance at pH9 and 20°C

Sampling time (hrs)	Analysed concentration(mg/L)	Relativee concentration (%)	Logarithm relative concentration	Actual pH
0	517	101	2.01	8.9
0	504	98.7	1.99	8.9
21	503	98.5	1.99	8.9
21	515	101	2.00	8.9
28	501	98.0	1.99	8.8
28	509	99.5	2.00	8.8
93	495	96.9	1.99	8.9
93	504	98.6	1.99	8.9
99	496	97.1	1.99	8.8
99	501	98.2	1.99	8.8
117	493	96.5	1.98	8.9
117	501	98.2	1.99	8.9
123	496	97.1	1.99	8.8
123	503	98.4	1.99	8.8
140	512	100	2.00	8.7
140	519	102	2.01	8.6
146	504	98.7	1.99	8.6
146	510	99.9	2.00	8.9
168	502	98.2	1.99	8.7
168	506	99.1	2.00	8.8

 

Table 12. Main test – hydrolysis of the test substance at pH9 and 50°C

Sampling time (hrs)	Analysed concentration(mg/L)	Relativee concentration (%)	Logarithm relative concentration	Actual pH
0	500	101	2.00	8.8
0	490	99.1	2.00	8.8
21	519	105	2.02	8.8
21	506	102	2.01	8.8
28	501	101	2.01	8.7
28	510	103	2.01	8.7
93	495	100	2.00	8.8
93	501	101	2.01	8.8
99	489	98.9	2.00	8.7
99	499	101	2.00	8.7
117	487	98.5	1.99	8.8
117	496	100	2.00	8.8
123	489	98.7	1.99	8.7
123	495	100	2.00	8.7
140	501	101	2.01	8.6
140	516	104	2.02	8.6
146	492	99.3	2.00	8.7
146	499	101	2.00	8.7
168	489	98.7	1.99	8.7
168	493	99.7	2.00	8.8

 

Dye solutions in the concentration range 994-1028 mg/L were prepared from stock solutions. 0.426mL pH9 buffer, 0.5mL dye solutions and 0.074 mL 1N HCl mixed to pH6.0-7.5 to terminate the hydrolysis reaction and avoid dye condensation.

 

Table 13. Recoveries

 

Temperature (°C)	Nominal concentration (mg/L)	Analysed concentration (mg/L)	Recovery (%)	Mean recovery (%)
20	1038	517	99.6	98.6
	1034	504	97.5
50	1036	500	96.5	95.0
	1048	490	93.5

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.

 

Table 14. Statistical parameters of the regression curves

Temperature (°C)	Slope (1/hours)	Intercept	Coefficient of correlation
20	-0.0000221	2.00	0.0320
50	-0.0000437	2.01	0.0873

 

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).

Table 15. Rate constants (kobs) and half-life time (t_1/2)

Temperature (°C)	kobs (1/hours)	t1/2
20	5.09 x 10^-5	567 days
25	5.77 x 10^-5	501 days
50	1.01 x 10^-4	287 days

 

Validity criteria fulfilled:

yes

Conclusions:

The main study were performed for the determination of the rate of hydrolysis of CJ309 at pH values normally found in the environment (pH4-9).
The half-life times of the test substance were:
pH4 pH7 pH9
Temperature t1/2 t1/2 t1/2
20 29.6 days 142 days 567 days
25 24.0 days 143 days 501 days
50 9.87 days 146 days 287 days

Executive summary:

The results of the physico-chemical properties of the test substance are given below.

Parameter	Result
Hydrolysis at pH4	t1/2=29.6 days at 20°C
	t1/2=24.2 days at 25°C
	t1/2=9.87 days at 50°C
Hydrolysis at pH7	t1/2=142 days at 20°C
	t1/2=143 days at 25°C
	t1/2=146 days at 50°C
Hydrolysis at pH9	t1/2=567 days at 20°C
	t1/2=501 days at 25°C
	t1/2=287 days at 50°C

Description of key information

The main study were performed for the determination of the rate of hydrolysis of CJ309 at pH values normally found in the environment (pH4-9). The half-life times of the test substance were:

                        pH4             pH7            pH9

Temperature       t_1/2             t_1/2             t_1/2

       20          29.6 days     142 days     567 days

       25          24.0 days     143 days     501 days

       50          9.87 days     146 days     287 days

Key value for chemical safety assessment

Half-life for hydrolysis:

168 h

at the temperature of:

20 °C