4-[(4-chloro-6-{[(3 or 4)-sulfophenyl]amino}-1,3,5-triazin-2-yl)amino]-2-{[1-ethyl-2-hydroxy-4-methyl-6-oxo-5-(sulfonatomethyl)-1,6-dihydropyridin-3-yl]diazenyl}benzenesulfonic acid, lithium sodium salts

Hydrolysis

Link to relevant study record(s)

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 (k_obs) and half-life time (t_½) 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 (k_obs) 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 (k_obs) 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 (k_obs) 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 (k_obs) 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 (k_obs) 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.