hexasodium 5-[(4-{3-[(8-benzamido-1-hydroxy-3,6-disulfonato-2-naphthyl)diazenyl]-4-sulfonatoanilino}-6-[(2-sulfonatoethyl)amino]-1,3,5-triazin-2-yl)amino]isophthalate

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was conducted between 24 October 2007 and 14 November 2007.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Magenta T-43

IUPAC Name:

Magenta T-43

Test material form:

solid: particulate/powder

Details on test material:

Sponsor's identification: MAGENTA T-43
Description: dark red solid
Storage conditions: room temperature, in the dark
Lot number: H186-5

Radiolabelling:

no

Study design

Analytical monitoring:

yes

Details on sampling:

Analysis of sample solutions:
Aliquots of the sample solutions were taken from the flasks at various times and the pH of each solution recorded. The concentration of the sample solution was determined by high performance liquid chromatography (HPLC).

Samples:
Duplicate samples (A and B) were analysed neat.

Buffers:

The specification of buffered solutions were as follows:

Potassium hydrogen phthalate; pH 4; conc. 0.005 mol dm-3
Disodium hydrogen orthophophate (anhydrous); pH 7; conc. 0.003 mol dm-3
Potassium dihydrogen orthophosphate; pH 7; conc. 0.002 mol dm-3
Sodium chloride; pH 7; conc. 0.002 mol dm-3
Disodium tetraborate; pH 9; conc. 0.001 mol dm-3
Sodium chloride; pH 9; conc. 0.002 mol dm-3


The buffer solutions were filtered through a 0.2 µm membrane filter to ensure they were sterile before commencement of the test. Also these solutions were subjected to ultrasonication and degassing with nitrogen to minimise dissolved oxygen content.

Estimation method (if used):

Not applicable

Details on test conditions:

Preparation of samples:
Sample solutions were prepared in stoppered glass flasks at a nominal concentration of 0.2 g/l in the three buffer solutions.

The solutions were shielded from light whilst maintained at the test temperature.

Preliminary test:
Sample solutions at pH 4, 7 and 9 were maintained at 50.0 ± 0.5°C for a period of 5 days.

Duration of test

Duration of test 1

Duration:

120 h

pH:

4

Temp.:

50

Duration of test 2

Duration:

120 h

pH:

7

Temp.:

50

Duration of test 3

Duration:

120 h

pH:

9

Temp.:

50

Number of replicates:

Samples:
Duplicate samples (A and B)

Standards:
Duplicate standard solutions

Positive controls:

no

Negative controls:

no

Results and discussion

Transformation products:

not specified

Dissipation DT50 of parent compound

Dissipation DT50 of parent compound 1

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Dissipation DT50 of parent compound 2

pH:

7

Temp.:

25 °C

DT50:

> 1 yr

Dissipation DT50 of parent compound 3

pH:

9

Temp.:

25 °C

DT50:

> 1 yr

Details on results:

Results:
For pH 4, 7 and 9 the results show that less than 10% hydrolysis was achieved after 5 days at 50 °C, equivalent to a half-life greater than 1 year at 25 °C.

Any other information on results incl. tables

Validation:

The linearity of the detector response with respect to concentration was assessed over the nominal concentration range of 0 to 500 mg/l. This was satisfactory with a correlation coefficient of 1.00 being obtained.

Preliminary Test Results

Solution	Mean Peak Area
Standard 202 mg/l Standard 200 mg/l Initial Sample A, pH4 Initial Sample B, pH 4	2032 2001 2049 2068
Standard 202 mg/l Standard 200 mg/l Initial Sample A, pH 7 Initial Sample B, pH 7	2036 2014 2064 2058
Standard 202 mg/l Standard 200 mg/l Initial Sample A, pH 9 Initial Sample B, pH 9	2027 2017 2037 2037
Standard 201 mg/l Standard 203 mg/l 24 Hour Sample A, pH 4 24 Hour Sample B, pH 4	1656 1679 1693 1703
Standard 201 mg/l Standard 203 mg/l 24 Hour Sample A, pH 7 24 Hour Sample B, pH 7	1664 1680 1702 1716
Standard 201 mg/l Standard 203 mg/l 24 Hour Sample A, pH 9 24 Hour Sample B, pH 9	1659 1689 1691 1688
Standard 202 mg/l Standard 202 mg/l 48 Hour Sample A, pH 4 48 Hour Sample B, pH 4	1692 1694 1709 1695
Standard 202 mg/l Standard 202 mg/l 48 Hour Sample A, pH 7 48 Hour Sample B, pH 7	1700 1685 1706 1689
Standard 202 mg/l Standard 202 mg/l 48 Hour Sample A, pH 9 48 Hour Sample B, pH 9	1699 1685 1686 1686
Standard 202 mg/l Standard 202 mg/l 120 Hour Sample A, pH 4 120 Hour Sample B, pH 4	1669 1679 1711 1707
Standard 202 mg/l Standard 202 mg/l 120 Hour Sample A, pH 7 120 Hour Sample B, pH 7	1684 1692 1718 1721
Standard 202 mg/l Standard 202 mg/l 120 Hour Sample A, pH 9 120 Hour Sample B, pH 9	1670 1691 1686 1682

 

Main Test Results:

pH 4 at 50.0 ± 0.5°C

 

Time (Hours)
	0	24	48	120
Concentration (g/l)	0.206	0.206	0.203	0.206
% of initial	100	100	98.9	100

 

Result: Less than 10% hydrolysis after 5 days at 50 °C, equivalent to a half-life greater than 1 year at 25 °C.

pH 7 at 50.0 ± 0.5°C

 

Time (Hours)
	0	24	48	120
Concentration (g/l)	0.205	0.206	0.203	0.206
% of initial	100	100	98.9	100

 

Result: Less than 10% hydrolysis after 5 days at 50 °C, equivalent to a half-life greater than 1 year at 25 °C.

pH 9 at 50.0 ± 0.5°C

 

Time (Hours)
	0	24	48	120
Concentration (g/l)	0.203	0.204	0.201	0.202
% of initial	100	100	99.3	99.6

 

Result: Less than 10% hydrolysis after 5 days at 50 °C, equivalent to a half-life greater than 1 year at 25 °C.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The estimated half-life at 25 °C of the test material at pH 4, pH 7 and pH 9 has been shown to be >1 year.

Executive summary:

The estimated half-life of the test substance Magenta T-43 was shown to be >1 year at pH 4, 7 and 9 at 25 °C according to method C7 of Commission Directive 92/69/EEC using the Hydrolysis as a Function of pH test method.