N,N'-bis(5,5-dimethyl-1,3,2-dioxaphosphinane-2-oxide-2-yl)ethane-1,2-diamine

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

October 14,2016 to November 29, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

OECD Guidelines for Testing of Chemicals, No.111, April 13, 2004, "Hydrolysis as a Function of pH"

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

C.7. DEGRADATION -ABIOTIC DEGRADATION HYDROLYSIS AS A FUNCTION OF pH (EU)

Deviations:

not specified

GLP compliance:

yes

Specific details on test material used for the study:

No further details specified in the study report.

Radiolabelling:

no

Analytical monitoring:

yes

Buffers:

pH 4.0: The solution was prepared by mixing 2.0 mL o f 0.1 mol/L sodium hydroxide solution and 50 mL o f 0.5 mol/L potassium hydrogen phthalate solution and then filling up to 500 mL with purified water.
pH 7.0: The solution was prepared by mixing 14.8 mL o f 1 mol/L sodium hydroxide solution and 50 mL o f 0.5 mol/L potassium dihydrogenphosphate solution and then filling up to 500 mL with purified water.
pH 9.0: The solution was prepared by mixing 10.7 mL o f 1 mol/L sodium hydroxide solution and 50 mL o f 0.5 mol/L potassium chloride and 0.5 mol/L boric acid solution, and then filling up to 500 mL with purified water. The solution was adjusted to pH 9.0 with 1 mol/L hydrochloric acid.

Details on test conditions:

Preparation for solution of test item
About 50 mg of the test sample was precisely weighed with an electronic analytical balance and dissolved in purified water to obtain 500 mg/L solution of the test item.

Preparation of test solution
Forty millilitre of the test item solution (test item: about 20 mg) was taken out and filled up to 200 m L with each buffer solution. Each solution was filtrated with a sterile filter (0.2 μm) and aerated for about 5 minutes with helium gas, and then about 10 mL of the solution was taken out into a test vessel to prepare a test solution. The test procedures described above were performed in the clean bench. The glassware (test vessels, etc.) was preliminaiy sterilized with ethanol. About 5 mL of the test solution was taken out and measured its pH.

Test conditions
a) Test equipment
Dzy thermo bath: MG-I (TOKYO RIKAKIKAI CO, LTD)
DRY THERMO UNIT: TAH-IB (Taiyo science industries, Ltd.)

b) Test conditions
Test concentration: About 100 mg/L
pH of test solution: pH4.0, pH7.0 and pH9.0

Test temperature:
pH4.0 50±0.5°C
pH7.0 50±0.5°C
pH9.0 50±0.5°C, 60±0.5°C, 70±0.5°C

Test duration:
pH4.0 5 days
pH7.0 5days
pH9.0 30 days (50°C), 24 days (60°C), 6 days (70°C)

Measurement point: pH4.0 At initiation and after 5 days
pH7.0 At initiation and after 5 days
pH9.0 6 points in test duration at each temperature

Number of test repetition: 2 (at each measurement point)
Light condition: Light-free condition
Test vessel: 10-mL test tube covered with aluminum foil

Analysis of test solution
Pre-treatment of test solutions for analysis
The test solutions were pre-treated to prepare samples for liquid chromatography-mass spectrometry (LC-MS) analysis as follows.

Test solution
• Taking out 1 mL(transferpipette)
• Filling up to 20 mL (eluent for LC-MS analysis, volumetric flask)
• Taking out 1 mL(transferpipette)
• Filling up to 10 mL (eluent for LC-MS analysis, volumetric flask)
Sample for LC-MS analysis

Quantitative analysis
The main component of the test item was analyzed by LC-MS.

a) Method of determination
The main component of the test item was determined by the absolute calibration curve method
using one concentration of the standard solution.
In order to confirm the validity of this determination method, a calibration curve was made using
four concentrations of the standard solution, 0.100, 0.250, 0.500 and 1.00 mg/L. It was confirmed
that the regression line of the calibration curve was a straight line from the origin.

b) Analytical conditions
Instrument: Liquid chromatograph-mass spectrometer
HPLC system: ACQUITYUPLC (Waters Corporation)
Mass spectrometer: Quattro Premier XE (Waters Corporation)

Conditions of liquid chromatograph
Column: ACQUITY UPLC BEH Cl8 (50 mm x 2.1 mm I.D., particle size 1.7 μm, Waters Corporation)
Column temperature: 40°C
Eluent: Methanol/purified water (1/1 v/v) containing 5 mmol/L ammonium acetate
Flowrate: 0.3mUmin
Injection volume: 1 μL (Partial Loop With Needle Overfill)

Conditions of mass spectrometer
Ionization mode: Electrospray ionization (ESI)
Detection ion: Positive
Detection mode: Selected ion monitoring (SIM)
Monitoring ion: mlz 357.0 (see Fig. 14)
Cone voltage: 20V
Ion source temperature: 120°C
Desolvation temperature: 400°C

c) Preparation for standard solution and calculation of concentration
The test sample (10.00 mg) was weighed with an electronic analytical balance and dissolved in methanol to obtain 500 mg/L solution of the test item. The standard solution (0.500 mg/L) was prepared from this solution by dilution with the eluent for LC-MS analysis.
The concentration of the test item in the sample for LC-MS analysis was calculated proportionally by comparing the peak area on the chromatogram of the sample for LC-MS analysis with that on the chromatogram of 0.500 mg/L standard solution.

Confirmation of sterile conditions (pH 9.0)
The sterile conditions were confirmed for one of the test solutions at the final measurement point of each test temperature in pH9 .0 according to the plate culture method using agar medium.

a) Instruments and apparatus
Incubator: IS-42 (Yamato Scientific)
Autoclave: SP510 (Yamato Scientific)
Sterilised petri dish: Made of resin

b) Test procedures
1) The mixture of 4 g of TSA medium and 100 mL of purified water was sterilised with autoclave (121 °C) for 15 min to prepare an agar medium, and then the agar medium was maintained at about 50°C in a water bath.
2) The test solution (1 mL) and about 15 mL of the agar media were mixed in a sterilised petri dish, and the mixture was cooled to room temperature. These procedures were performed in the clean bench.
3) After the agar medium became hard, the petri dish was made reverse and maintained at 25 ± 1 °C for more than 5 days in the incubator.
4) The number of the colony on the agar medium was recorded.

Identification of hydrolysis product (pH 9.0)
The hydrolysis product of the test item in pH9.0 was identified by LC-MS.
a) Preparation of test solution for qualitative analysis
One of the test solutions (1 mL) was pipetted into a 2-mL volumetric flask and filled with the
eluent for LC-MS analysis to prepare the test solution for qualitative analysis.

b) Preparation of standard solution for qualitative analysis
The test sample (10.00 mg) was weighed with an electronic analytical balance and dissolved in methanol to obtain 500 mg/L solution of the test item. The standard solution (50.0 mg/L) was prepared from this solution by dilution with the eluent for LC-MS analysis.

c) Analytical conditions
Instrument: Liquid chromatograph-mass spectrometer
HPLC system: ACQUITYUPLC (Waters Corporation)
Mass spectrometer: Quattro Premier XE (Waters Corporation)

Conditions of liquid chromatograph
Column: ACQUITY UPLC BEH Cl8 (50 mm x 2.1 mm I.D., particle size 1.7 μm, Waters Corporation)
Column temperature: 40°C
Eluent
A: 5 mmol/L Ammonium acetate solution
B: Methanol containing 5 mmol/L ammonium acetate
Flowrate: 0.3mUmin
Injection volume: 5 μL (Partial Loop With Needle Overfill)

Conditions of mass spectrometer
Ionization mode: Electrospray ionization (ESI)
Detection ion: Positive
Detection mode: Scan
Mass range (111/z): 100-800
Cone voltage: 20V
Ion source temperature: 120°C
Desolvation temperature: 400°C

d) Test procedures
The test solution for qualitative analysis in a), the standard solution in b) and solvent blank (the eluent for LC-MS analysis) was used) were analyzed according to the analytical conditions. The mass spectrum of the detected hydrolysis product was obtained.

Duration:

0.5 d

pH:

4

Temp.:

50 °C

Initial conc. measured:

100 mg/L

Duration:

0.5 d

pH:

7

Temp.:

50 °C

Initial conc. measured:

100 mg/L

Duration:

30 d

pH:

9

Temp.:

50 °C

Initial conc. measured:

100 mg/L

Duration:

24 d

pH:

9

Temp.:

60 °C

Initial conc. measured:

100 mg/L

Duration:

6 d

pH:

9

Temp.:

70 °C

Initial conc. measured:

100 mg/L

Number of replicates:

2 (at each measurement point)

Positive controls:

no

Negative controls:

no

Statistical methods:

Not specified

Transformation products:

not measured

Key result

pH:

9

Temp.:

25 °C

Hydrolysis rate constant:

0 h-1

DT50:

595 d

Type:

not specified

Details on results:

a) Hydrolysis test in pH4.0, pH7.0 (Tier 1)
The residual percentage of the test item in each solution (pH4.0, pH7.0) at 50°C was larger than 90%.
Therefore, it is considered that each half life of the test item at 25°C is more than a year.
b) Hydrolysis test in pH9.0 (Tier 2)
It is considered that the measurement point at each test temperature was set appropriately because the residual percentages of the test item were within approximately 10 to 90%. It is also considered that the test duration at each temperature was appropriate because the measurement points were set until approximately 90 % hydrolysis of the test item was observed. Therefore, it is concluded that this study was conducted according to the OECD Guidelines for Testing of Chemicals, No.111.
The results of hydrolysis rate constant and half life at 25°C (pH 9 .0) were considered to be acceptable because the regression equation about logarithm values of the hydrolysis rate constants versus reciprocal number of the respective absolute temperature (1/T) was confirmed a straight line. And, it is considered that the hydrolysis rate o f the test item in pH9 .0 is quite slow because the half life at 25°C was more than a year.
c) Identification of hydrolysis product (pH9.0)
As the results of the qualitative analysis of hydrolysis products, it was confirmed that phosphoester linkages (-P-O-) of the main component was cleaved. The phosphoester linkages was stable at pH4.0 and pH7.0,
It was not confirmed that unknown hydrolysis products were derived from either main component or subcomponents.

pH of test solutions

The test results are shown as follows

Test solution		pH of test solution (measured value)
pH 4.0		4.0
pH 7.0		7.0
pH 9.0	50 °C	9.0
	60 °C	9.0
	10 °C	9.0

 

Residual percentage of test item (pH 4.0 and pH 7.0)

The test results are shown as follows. It was concluded that test item was judged to be hydrolytically stable at pH 4.0 and pH 7.0 because each residual percentage of the test item was larger than 90%

Test solution	Concentration (mg/L)			Residual percentage (%)
	At initiation		After days	Measured value	Average
	Measured value	Average
pH 4.0	98.1	97.3	99.7	103	103
	96.5		100	103
pH 7.0	98.5	98.7	101	102	102
	99.0		100	101

 

Hydrolysis rate constant and half-life if test item (pH 9.0)

The test results are shown as follows.

Hydrolysis rate constant and half-life at test temperature

		Rate constant (hour^-1)		Half-life (hour)
		Measured value	Average	Measured value	Average
pH 9.0	50 °C	1.30 x 10^-3	1.23 x 10^-3	533	565
		1.16 x 10^-3		597
	60 °C	4.15 x 10^-3	4.14 x 10^-3	167	167
		4.13 x 10^-3		168
	10 °C	1.17 x 10^-2	1.17 x 10^-2	59.0	59.0
		1.17 x 10^-2		59.0

 

Hydrolysis rate constant and a half-life at 25 °C (extrapolated value)

	Rate constant (hour^-1)	Half-life (day)
pH 9.0	4.85 x 10^-5	595

 

Validity criteria fulfilled:

yes

Conclusions:

The test item is hydrolytically stable at pH 4.0, pH 7.0 and hydrolyzed at pH 9.0. The hydrolysis rate constant and half life of the test item at pH9.0 (25°C, extrapolated value) are shown as follows.
Hydrolysis rate: 4.85e-5 hour-1
Half life: 595 days
It is considered that the hydrolysis rate of the test item in pH9.0 is quite slow because the half life at 25°C was more than a year.

Executive summary:

Test item: DAIGUARD-850

Objective: The test is performed to obtain the information about hydrolysis of DAIGUARD-850.

Test methods: OECD Guidelines for Testing of Chemicals, No.111, April 13, 2004, "Hydrolysis as a Function of pH" and C.7. DEGRADATION -ABIOTIC DEGRADATION HYDROLYSIS AS A FUNCTION OF pH (EU)

 

Test conditions

Test concentration: 100mg/L

pH of test solution: pH 4.0, pH 7.0 and p H9.0

 

Test temperature:

pH 4.0: 50 ± 0.5 °C

pH 7.0: 50 ± 0.5 °C

pH 9.0: 50 ± 0.5 °C, 60 ± 0.5 °C, 70 ± 0.5 °C

 

Test duration:

pH 4.0: 5 days

pH 7.0: 5 days

pH 9.0: 30 days (50°C), 24 days (60°C), 6 days (70°C)

 

Measurement point:

pH 4.0: At initiation and after 5 days

pH 7.0: At initiation and after 5 days

pH 9.0: 6 points in test duration at each temperature

 

Number of test repetition: 2 (at each measurement point)

Light condition: Light-free condition

Test vessel: 10-mL test tube covered with aluminum foil

 

Results

The test item is hydrolytically stable at pH 4.0, pH 7.0 and hydrolyzed at pH 9.0. The hydrolysis rate constant and half-life of the test item at pH 9.0 (25°C, extrapolated value) are shown as follows.

Hydrolysis rate: 4.85 x 10^-5 hour^-1

Half-life: 595 days

It is considered that the hydrolysis rate of the test item in pH9.0 is quite slow because the half-life at 25°C was more than a year.

Description of key information

Hydrolysis rate: 4.85 x 10^-5 hour^-1

Half-life: 595 days

It is considered that the hydrolysis rate of the test item in pH9.0 is quite slow because the half-life at 25°C was more than a year.

Key value for chemical safety assessment

Half-life for hydrolysis:

595 d

at the temperature of:

25 °C

Additional information

Test conditions

Test concentration: 100mg/L

pH of test solution: pH 4.0, pH 7.0 and p H9.0

 

Test temperature:

pH 4.0: 50 ± 0.5 °C

pH 7.0: 50 ± 0.5 °C

pH 9.0: 50 ± 0.5 °C, 60 ± 0.5 °C, 70 ± 0.5 °C

 

Test duration:

pH 4.0: 5 days

pH 7.0: 5 days

pH 9.0: 30 days (50°C), 24 days (60°C), 6 days (70°C)

 

Measurement point:

pH 4.0: At initiation and after 5 days

pH 7.0: At initiation and after 5 days

pH 9.0: 6 points in test duration at each temperature

 

Number of test repetition: 2 (at each measurement point)

Light condition: Light-free condition

Test vessel: 10-mL test tube covered with aluminum foil

 

Results

The test item is hydrolytically stable at pH 4.0, pH 7.0 and hydrolyzed at pH 9.0. The hydrolysis rate constant and half-life of the test item at pH 9.0 (25°C, extrapolated value) are shown as follows.

Hydrolysis rate: 4.85 x 10^-5hour^-1

Half-life: 595 days

It is considered that the hydrolysis rate of the test item in pH9.0 is quite slow because the half-life at 25°C was more than a year.