Octasodium 2-(8-(4-chloro-6-(3-((4-chloro-6-(3,6-disulfonato-2-(1,5-disulfonatonaphthalen-2-ylazo)-1-hydroxynaphthalen-8-ylamino)-1,3,5-triazin-2-yl)aminomethyl)phenylamino)-1,3,5-triazin-2-ylamino)-3,6-disulfonato-1-hydroxynaphthalen-2-ylazo)naphthalene-1,5-disulfonate

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

January 1992 to February 1992

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to recent EU test guidance in compliance with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Directive 84/449/EEC

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Octasodium 2-(8-(4-chloro-6-(3-((4-chloro-6-(3,6-disulfonato-2-(1,5-disulfonatonaphthalen-2-ylazo)-1-hydroxynaphthalen-8-ylamino)-1,3,5-triazin-2-yl)aminomethyl)phenylamino)-1,3,5-triazin-2-ylamino)-3,6-disulfonato-1-hydroxynaphthalen-2-ylazo)naphthalene-1,5-disulfonate

EC Number:

413-550-5

EC Name:

Octasodium 2-(8-(4-chloro-6-(3-((4-chloro-6-(3,6-disulfonato-2-(1,5-disulfonatonaphthalen-2-ylazo)-1-hydroxynaphthalen-8-ylamino)-1,3,5-triazin-2-yl)aminomethyl)phenylamino)-1,3,5-triazin-2-ylamino)-3,6-disulfonato-1-hydroxynaphthalen-2-ylazo)naphthalene-1,5-disulfonate

Cas Number:

142068-96-0

Molecular formula:

Hill formula: C53H28Cl2N14Na8O26S8

IUPAC Name:

octasodium 5-[(4-chloro-6-{[4-({[4-chloro-6-({7-[2-(1,5-disulfonatonaphthalen-2-yl)diazen-1-yl]-8-hydroxy-3,6-disulfonatonaphthalen-1-yl}amino)-1,3,5-triazin-2-yl]amino}methyl)phenyl]amino}-1,3,5-triazin-2-yl)amino]-3-[2-(1,5-disulfonatonaphthalen-2-yl)diazen-1-yl]-4-hydroxynaphthalene-2,7-disulfonate

Details on test material:

- Name of test material (as cited in study report): H112339
- Physical state: Powder
- Analytical purity: 71.6%
- Lot/batch No.: NBY 405/74

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Radiolabelling:

no

Study design

Analytical monitoring:

yes

Details on sampling:

Not specified.

Buffers:

pH 4.0 Buffer Solution
4ml of 0.1N sodium hydroxide solution added to 500ml of 0.1M potassium biphthalate and diluted to 1 litre with distilled water.

pH 7.0 Buffer Solution
296ml of 0.1N sodium hydroxide solution added to 500ml of 0.1M monopotassium phosphate and diluted to 1 litre with distilled water.

pH 9.0 Buffer Solution
213ml of 0.1N sodium hydroxide solution added to 500ml of Q.1M boric acid in 0.1M potassium chloride and diluted to 1 litre with distilled water.

All buffer solutions were prepared in distilled water which had been degassed with helium. The pH of each solution was measured and adjusted as required with the appropriate reagent as detailed above.

Estimation method (if used):

Not applicable.

Details on test conditions:

Not specified.

Duration of test

Duration of test 1

Duration:

7 d

pH:

4

Temp.:

50

Initial conc. measured:

1.066 g/L

Duration of test 2

Duration:

7 d

pH:

7

Temp.:

50

Initial conc. measured:

1.03 g/L

Duration of test 3

Duration:

7 d

pH:

9

Temp.:

50

Initial conc. measured:

1.09 g/L

Number of replicates:

2

Positive controls:

no

Negative controls:

no

Results and discussion

Preliminary study:

Less than 10% hydrolysis was obtained at pH's 7.0 and 9,0 so no further testing was required. At pH 4.0 approximately 50% hydrolysis occurred and the linear plot obtained indicates that the reaction is pseudo-first order. Further testing at pH 4.0 was therefore carried out at 35°C to obtain an extrapolated value for the rate constant at 25°C.

Test performance:

None specified.

Transformation products:

not measured

Details on hydrolysis and appearance of transformation product(s):

Not measured

Dissipation DT50 of parent compound

Dissipation DT50 of parent compound 1

pH:

4

Temp.:

25 °C

Hydrolysis rate constant:

0.013 d-1

DT50:

53.72 d

Type:

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

Remarks on result:

other: Calculated from data at 50deg C and 35 Deg C

Dissipation DT50 of parent compound 2

pH:

4

Temp.:

35 °C

Hydrolysis rate constant:

0.035 d-1

DT50:

19.69 d

Type:

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

Dissipation DT50 of parent compound 3

pH:

4

Temp.:

50 °C

Hydrolysis rate constant:

0.138 d-1

DT50:

5 d

Type:

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

Dissipation DT50 of parent compound 4

pH:

7

Temp.:

50 °C

DT50:

> 1 yr

Type:

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

Dissipation DT50 of parent compound 5

pH:

9

Temp.:

50 °C

DT50:

> 1 yr

Type:

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

Details on results:

The hydrolysis of the test substance was studied at pH's 4, 7 and 9. Solutions of substance were prepared in the buffer solutions and these were stored in amber coloured flasks at 50°C. The concentration of the main component of substance was monitored over several days by high performance liquid chromatography (HPLC).   Duplicate tests were carried out at each pH.   Less than 10% hydrolysis was obtained at pH's7.0 and 9,0 so no further testing was required. At pH 4.0 approximately 50% hydrolysis occurred and the linear plot obtained indicates that the reaction is pseudo-first order.  Further testing at pH 4.0 was therefore carried out at 35°C to obtain an extrapolated value for the rate constant at 25°C.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Result

kobs - 13.84 x 10-2 days-1 in pH 4 buffer at 50°C
t½ =5.01 days in pH 4 buffer at 50⁰C
kobs- 3.52 x 10-2 days-1 in PH 4 buffer at 35°C
t½ - 19.69 days in pH 4 buffer at 35°C

Extrapolated values
kobs - 1,29 x 10-2 days-1 in PH 4 buffer at 25°C
t½ - 53.72 days in pH 4 buffer at 25°C

Less than 10% hydrolysis was obtained at pH's 7.0 and 9,0 so no further testing was required

Executive summary:

The substance is considered to be stable to hydrolysis at neutral and basic pH’s. At acidic pH’s a moderate amount of degradation occurs.

  

Result  

k_obs- 13.84 x 10^-2days^-1in pH 4 buffer at 50°C

t_½     =5.01 days in pH 4 buffer at 50^⁰C

k_OBS- 3.52 x 10^-2days^-1in pH 4 buffer at 35°C

t_½    - 19.69 days in pH 4 buffer at 35°C

 

Extrapolated values

k_obs- 1,29 x 10^-2days^-1in pH 4 buffer at 25°C

t_½   - 53.72 days in pH 4 buffer at 25°C

 

The hydrolysis of the test substance was studied at pH's 4, 7 and 9. Solutions of Substance were prepared in the buffer solutions and these were stored in amber coloured flasks at 50°C. The concentration of the main component of Substance was monitored over several days by high performance liquid chromatography (HPLC).   Duplicate tests were carried out at each pH.   Less than 10% hydrolysis was obtained at pH's7.0 and 9,0 so no further testing was required. At pH 4.0 approximately 50% hydrolysis occurred and the linear plot obtained indicates that the reaction is pseudo-first order.  Further testing at pH 4.0 was therefore carried out at 35°C to obtain an extrapolated value for the rate constant at 25°C.