Disodium hydrogen bis[3-hydroxy-4-[(2-hydroxy-1-naphthyl)azo]naphthalene-1-sulphonato(3-)]chromate(3-)

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

2012-08-22 to 2012-08-27

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study with GLP statement performed on a similar substance

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Trisodium bis[3-hydroxy-4-[(2-hydroxy-1-naphthyl)azo]-7-nitronaphthalene-1-sulphonato(3-)]chromate(3-)

EC Number:

260-906-9

EC Name:

Trisodium bis[3-hydroxy-4-[(2-hydroxy-1-naphthyl)azo]-7-nitronaphthalene-1-sulphonato(3-)]chromate(3-)

Cas Number:

57693-14-8

Molecular formula:

C40H20CrN6O14S2.3Na

Test material form:

other: solid and liquid preparations

Radiolabelling:

no

Study design

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products: Samples were taken at 0 h and after 120 h. All samples were analysed directly. All test item containing samples were analysed immediately (max. 30 minutes until start of analyses) via HPLC with UV (DAD) detection.- Sample storage conditions before analysis: Direct analyses

Buffers:

Buffer solution pH 445 mL of 0.1 mol/L NaOH were mixed with 250 mL 0.1 mol/L KH2-Citrate and diluted to 500 mL with double distilled water.Buffer solution pH 7148.15 mL of 0.1 mol/L NaOH were mixed with 250 mL 0.1 mol/L KH2PO4, diluted to 500 mL with double distilled water.Buffer solution pH 9106.5 mL of 0.1 mol/L NaOH were mixed with 250 mL 0.1 mol/L H3BO3 in 0.1 mol/L KCL, diluted to 500 mL with double distilled water.Buffers were prepared on 2012-08-01, purged with nitrogen for 5 minutes and the pH was checked. Afterwards the buffer solutions were sterilised by filtration through 0.2 µm.

Details on test conditions:

TEST SYSTEM- Type, material and volume of test flasks, other equipment used: Amber HPLC vials, 4 mL- Measures taken to avoid photolytic effects: Photolytic effects were avoided by exclusion of direct light- Measures to exclude oxygen: Buffers were purged with nitrogen for 5 minutes and the pH was checked. Afterwards the buffer solutions were sterilised by filtration through 0.2 µm.- Is there any indication of the test material adsorbing to the walls of the test apparatus? NoTEST MEDIUM- Volume used/treatment: 4 mL - Preparation of test medium: 3.6 mL of the respective sterile buffer were spiked to 10 mg/L with the test item stock solution into the test containers, sealed and transferred into the thermostat. The time between test item application and transfer to laboratory incubator/analysis did not exceed 30 minutes.- Renewal of test solution: None

Duration of test

Duration of test 1

Duration:

120 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

9.3 mg/L

Duration of test 2

Duration:

120 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

9.14 mg/L

Duration of test 3

Duration:

120 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

9.11 mg/L

Number of replicates:

Two replicate at each sampling interval

Positive controls:

no

Negative controls:

yes

Remarks:

buffer solutions (pH 4, 7 and 9)

Results and discussion

Preliminary study:

The analogue substance was found to be stable in the preliminary test at pH 4, 7 and 9 at 50 °C. Reaction rate constants and half lives could not be calculated due to the fact that the test item undergoes no significant hydrolysis. According to the guideline a half life of > 1 year under environmental conditions can be assumed.

Transformation products:

no

Dissipation DT50 of parent compound

Remarks on result:

hydrolytically stable based on preliminary test

Details on results:

TEST CONDITIONS- pH, sterility, temperature, and other experimental conditions maintained throughout the study: Yes

Any other information on results incl. tables

Hydrolysis Results for analogue substance at pH 4 and 50 °C

Hydrolysis Time [hours]	Replicate	Concentration [mg/L]	Mean	Degradation [%]
0	1	10.2	10.1	-
	2	10.0
120	1	9.22	9.30	7.92
	2	9.38

Hydrolysis Results for analogue substance at pH 7 and 50 °C

Hydrolysis Time [hours]	Replicate	Concentration [mg/L]	Mean	Degradation [%]
0	1	10.0	10.0	-
	2	10.0
120	1	9.09	9.14	8.60
	2	9.18

Hydrolysis Results for analogue substance at pH 9 and 50 °C

Hydrolysis Time [hours]	Replicate	Concentration [mg/L]	Mean	Degradation [%]
0	1	10.1	10.1	-
	2	10.0
120	1	9.00	9.11	9.80
	2	9.21

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The analogue substance was found to be stable in the preliminary test at pH 4, 7 and 9 at 50 °C. Reaction rate constants and half lives could not be calculated due to the fact that the test item undergoes no significant hydrolysis. According to the guideline a half life of > 1 year under environmental conditions can be assumed.

Executive summary:

Hydrolysis as a function of pH was determined according to OECD Guideline No. 111 and Council Regulation (EC) No. 440/2008, Method C.7 for the analogue substance from 2012-08-22 to 2012-08-27 at Dr.U.Noack-Laboratorien, 31157 Sarstedt, Germany.

The study was conducted with test item concentrations of 10 mg/L in buffer solutions at pH 4, 7 and 9 at a test temperature of 50 °C (preliminary test).

Samples were taken at test start (0 hours) and test end (120 hours) and analysed via HPLC with UV (DAD) detection on a cyano-propyl column using an external standard. Buffer solutions were analysed at test start and test end and indicated no interference with the test item. The analytical method for determination of the test item was validated and tested with satisfactory results in regard to linearity, accuracy, precision and specificity.

Degradation was calculated as the percentage loss of the test item over the time. In the preliminary test, the test item was found to be stable at pH 4, 7 and 9, respectively. No further testing was deemed necessary as less than 10 % of the applied test item was transformed after 120 hours (5 days) at a temperature of 50 °C and each of the three pH values (Table 1). Reaction rate constants and half lives could not be calculated because the test item undergoes no significant hydrolysis. With respect to the guidelines a half life of > 1 year could be assumed for environmental typical temperature conditions.

Degradation [%] at 50 °C after 120 Hours

Hydrolysis Time [hours]	Degradation [%]
	pH 4	pH 7	pH 9
120	7.92	8.60	9.80