Pentasodium 2-(bis{halo-[(halo- sulfonatoaryl)diazenyl]-2-(sulfonatoalkoxy)anilino}-triazin-ylamino)alkanesulfonate

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 February 2011 – 27 April 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study has been performed according to OECD and EC guidelines and in compliance with GLP principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

(2004)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Version / remarks:

(Official Journal of the European Union no. L142, May 31, 2008)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Details on test material:

- Name of test material (as cited in study report): E-Y110
- Description: Orange powder
- Batch: MB-1
- Test substance storage: At room temperature protected from light
- Stability under storage conditions: Stable
- Expiry date: 23 December 2015

Radiolabelling:

no

Study design

Analytical monitoring:

yes

Details on sampling:

The concentration of the test substance in the test samples was determined immediately after preparation (t=0) and after 5 days. The samples taken at t=5 days were cooled to room temperature using running tap water. The samples were diluted in a 1:1 (v:v) ratio with 10 mM TBABr in acetonitrile and analysed.

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 each sampling time.

Buffers:

- pH: 4
- Type and final molarity of buffer: Acetate buffer, 0.1 M
- Composition of buffer: solution of 16.6% 0.1 M sodium acetate and 83.4% 0.1 M acetic acid. The buffer contains 0.0009% (w/v) sodium azide.

- pH: 7
- Type and final molarity of buffer: Phosphate buffer, 0.1 M
- Composition of buffer: solution of 0.1 M potassium dihydrogenphosphate adjusted to pH 7 using 10 N sodium hydroxide. The buffer contains
0.0009% (w/v) sodium azide.

- pH: 9
- Type and final molarity of buffer: Borate buffer, 0.1 M
- Composition of buffer: 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 0.0009% (w/v) sodium azide.

Details on test conditions:

All solutions containing the test substance were protected from light.

Test substance solutions were prepared in the buffer solutions at a target concentration of 100 mg/l. Each solution was filter-sterilised through a 0.2 μm FP 30/0.2 CA-S filter (Whatman, Dassel, Germany) and transferred into a sterile vessel. To exclude oxygen, nitrogen gas was purged through the solution for 5 minutes. For each sampling time, duplicate sterile vessels under vacuum were filled with 6 ml test solution and placed in the dark in a temperature controlled environment at 49.8°C +/- 0.1°C.

Duration of test

Duration of test 1

Duration:

5 d

pH:

4

Initial conc. measured:

81 - 83 mg/L

Duration of test 2

Duration:

5 d

pH:

7

Initial conc. measured:

112 mg/L

Duration of test 3

Duration:

5 d

pH:

9

Initial conc. measured:

108 mg/L

Number of replicates:

2 measurements at each pH (separate vessels)

Results and discussion

Preliminary study:

At pH 4, pH 7 and pH 9 a degree of hydrolysis of < 10% was observed after 5 days. It demonstrated that the half-life time of the test substance at 25°C is > 1 year. According to the guideline, no further tests were required.

A small peak at the retention time of the test substance was detected in the blank buffer solutions. The maximum contribution to the samples based on peak area was 0.4%. This was also observed in blank water and 5 mM TBABr in 50/50 (v/v) acetonitrile/water solutions (see also section 8, HPLC-UV: specificity). Therefore, it was considered that the response did not derive from the test substance.

Test performance:

The mean recoveries of the buffer solutions (all pH tested) fell within the acceptable range for non labelled chemicals of 70-110%. It demonstrated that the analytical method was adequate to support the hydrolysis study on the test substance.

Total recovery of test substance (in %)

Total recovery of test substance (in %) 1

% Recovery:

81 - 83

pH:

4

Temp.:

50 °C

Total recovery of test substance (in %) 2

% Recovery:

110

pH:

7

Temp.:

50 °C

Total recovery of test substance (in %) 3

% Recovery:

105

pH:

9

Temp.:

50 °C

Any other information on results incl. tables

Preliminary test – hydrolysis of the test substance at pH 4, pH 7 and pH 9

pH code	Sampling time	Analysed concentration [mg/l]	Degree of hydrolysis [%]		Actual pH
			Individual	Mean
pH 4	0 hours	83			4.0
		81			4.0
	5 days	86	- 4.5	- 4.2	4.0
		85	- 4.0		4.0
pH 7	0 hours	112			7.1
		112			7.1
	5 days	110	1.6	1.8	7.1
		110	1.9		7.1
pH 9	0 hours	108			9.0
		108			9.0
	5 days	109	- 0.7	- 1.2	9.0
		110	- 1.6		9.0

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The preliminary test (Tier 1) was performed for the determination of the rate of hydrolysis of E-Y110 at pH values normally found in the environment (pH 4-9).

At each pH value a degree of hydrolysis of < 10% was observed after 5 days. According to the guideline, performance of the main study (Tier 2) was not required.

From the results it was concluded that the half-life times of E-Y110 at 25°C are > 1 year at pH4, pH7 and pH9.