Registration Dossier

Administrative data

Endpoint:
dissociation constant
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2002-04-30 - 2002-07-09
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
There are three possible methods for the determination of dissociation constant referenced in the OECD Guideline 112: Spectroscopic method, conductometric method and titration method.

The spectroscopic method has been shown to be of no use for this test material. There were no appreciable differences in spectra under strongly acidic and basic conditions. In any case, the test material absorbs UV light at only very low wavelengths where there was far too much interference from pH adjusting media (acid/base). Finally, this was expected for this material since there are no significant UV absorbing groups present in the test material such as aromatic rings for example.

The conductometric method was predicted to be of no use for this material since it has complex overlapping dissociation constants. Test material purity is only approximately 87% pure and hense, impurity influence would be high, especially since some impurities are salts as well, significantly contributing to conductivity readings.

The titration method has also been predicted to be of no use for this test material due to the purity issue. Additionally and more importantly however, the predicted dissociation constants of the test material overlap (refer to computer-based estimations). For this method (and the conductometric method) to work successfully, the dissociation constants should be ideally 2 units away from each other. The predicted values are only approximately 1.2 units apart and hence, on titration, certain ions will be in various states of ionization.

Finally, predominantly due to the overlapping dissociation constants and the above reasons, the dissociation constants of the test material are extremely complex and outside the range and scope of all the methods detailed in OECD Guideline 112.

As no experimental testing was deemed possible, it was therefore considered appropriate to estimate dissociation constants of the test material through computer-based estimation software and replacing sodium ions with protons. Estimation software used: Advanced Chemistry Development (ACD), pKa calculator, version 6.0
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2002-04-30 - 2002-07-09
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))
GLP compliance:
yes (incl. certificate)
Remarks:
2000-04-26
Type of method:
HPLC estimation method
Media:
soil
Specific details on test material used for the study:
- Synonyms: ITC 908, vinylidenephosphonic acid tetrasodium salt (VDPA tetrasodium salt)
- Lot/batch No.of test material: 562CH/646
- Purity: > 85%
- Storage condition of test material: Room temperature, in the dark
Type:
Koc
Value:
< 17.8 dimensionless
pH:
7
Type:
log Koc
Value:
< 1.25 dimensionless
pH:
7
Conclusions:
The adsorption coefficient (Koc) of the test material has been determined to be less than 17.8, log10 Koc < 1.25.
Executive summary:

The adsorption coefficient (Koc) of the test material has been determined to be less than 17.8, log10 Koc < 1.25.

Reason / purpose:
reference to same study
Reference
Endpoint:
relative density
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2002-04-30 - 2002-07-09
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
EU Method A.3 (Relative Density)
Qualifier:
according to
Guideline:
EPA OPPTS 830.7300 (Density / Relative Density / Bulk Density)
GLP compliance:
yes (incl. certificate)
Remarks:
2000-04-26
Type of method:
air comparison pycnometer (for solids)
Specific details on test material used for the study:
- Synonyms: ITC 908, vinylidenephosphonic acid tetrasodium salt (VDPA tetrasodium salt)
- Lot/batch No.of test material: 562CH/646
- Purity: 87.33%
- Storage condition of test material: Room temperature, in the dark
Key result
Type:
relative density
Density:
2.19
Temp.:
20.5 °C

A stainless steel ball of known volume was used to calibrate the instrument prior to measurement of the test sample.

Conclusions:
The relative density of the test material has been determined to be 2.19 at 20.5 +- 0.5 °C.
Executive summary:

The relative density of the test material has been determined to be 2.19 at 20.5 +- 0.5 °C.

Reason / purpose:
reference to same study
Reference
Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2002-04-30 - 2002-07-09
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
Qualifier:
according to
Guideline:
EPA OPPTS 835.2110 (Hydrolysis as a Function of pH)
GLP compliance:
yes (incl. certificate)
Remarks:
2000-04-26
Specific details on test material used for the study:
- Synonyms: ITC 908, vinylidenephosphonic acid tetrasodium salt (VDPA tetrasodium salt)
- Lot/batch No.of test material: 562CH/646
- Purity: 87.33%
- Storage condition of test material: Room temperature, in the dark
Analytical monitoring:
yes
Buffers:
pH 4; Potassium hydrogen phthalate; 0.05 mol dm-³
pH 7; Disodium hydrogen orthophosphate (anhydrous), Potassium dihydrogen orthophosphate, Sodium chloride; 0.03, 0.02 and 0.02 mol dm-³ respectively
pH 9; Disodium tetraborate, Sodium chloride; 0.01 and 0.02 mol dm-³ respectively

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.
Duration:
5 d
Number of replicates:
2
Preliminary study:
Sample solutions at pH 4, 7 and 9 were maintained at 50.0 °C for a period of 5 days.
Less than 10% hydrolysis was observed after 5 days at 50 °C, equivalent to a half-life greater than 1 year at 25 °C.
Test performance:
No second test performed based on the results of the preliminary study.
Transformation products:
not measured
pH:
4
Temp.:
25 °C
DT50:
> 1 yr
pH:
7
Temp.:
25 °C
DT50:
> 1 yr
pH:
9
Temp.:
25 °C
DT50:
> 1 yr

Duplicate standard solutions of test material were prepared in water:relevant buffer at a nominal concentration of 200 mg/L.

Conclusions:
The estimated half-life at 25 °C of the test material is > 1 year for pH 4, 7 and 9.
Executive summary:

The estimated half-life at 25 °C of the test material is > 1 year for pH 4, 7 and 9.

Reason / purpose:
reference to same study
Reference
Endpoint:
particle size distribution (granulometry)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2002-04-30 - 2002-07-09
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
OECD Guideline 110 (Particle Size Distribution / Fibre Length and Diameter Distributions) - Method B: Fibre Length and Diameter Distributions
GLP compliance:
yes (incl. certificate)
Remarks:
2000-04-26
Type of method:
cascade impaction
Type of particle tested:
primary particle
Type of distribution:
mass based distribution
Specific details on test material used for the study:
- Synonyms: ITC 908, vinylidenephosphonic acid tetrasodium salt (VDPA tetrasodium salt)
- Lot/batch No.of test material: 562CH/646
- Purity: 87.33%
- Storage condition of test material: Room temperature, in the dark
Remarks on result:
not determinable because of methodological limitations
Remarks:
Too few particles were of a size less than 10 µm to allow accurate assessment of mass median aerodynamic diameter.
No.:
#1
Size:
< 100 µm
Distribution:
79.8 %
No.:
#2
Size:
< 10 µm
Distribution:
2.38 %
Conclusions:
The results indicated that the proportion by mass of particles which, if inhaled, can be expected to achieve deposition throughout the respiratory tract is 2.38%.
Executive summary:

Proportion of test material having a particle size less than 100 µm: 79.8% (sieve)

Proportion of test material having a particle size less than 10 µm: 2.38% (cascade impactor)

The results indicated that the proportion by mass of particles which, if inhaled, can be expected to achieve deposition throughout the respiratory tract is 2.38%.

Reason / purpose:
reference to same study
Reference
Endpoint:
surface tension
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2002-04-30 - 2002-07-09
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
EU Method A.5 (Surface Tension)
Deviations:
yes
Remarks:
The surface tension result was not corrected using the Harkins-Jordan correction table as the correction is not applicable to the apparatus used.
Principles of method if other than guideline:
The determination was carried out using a White Electrical Institute interfacial tension balance and a procedure based on the ISO 304 ring method. Once calibrated, the balance and ring assembly used in this test give a direct reading for surface tension that is within the required accuracy (+- 0.5 mN/m), this is a result of the reduced ring dimensions.
This deviation has been considered not to have affected the integrity of the study.
GLP compliance:
yes (incl. certificate)
Remarks:
2000-04-26
Type of method:
ring method
Specific details on test material used for the study:
- Synonyms: ITC 908, vinylidenephosphonic acid tetrasodium salt (VDPA tetrasodium salt)
- Lot/batch No.of test material: 562CH/646
- Purity: 87.33%
- Storage condition of test material: Room temperature, in the dark
Surface tension:
71.9 mN/m
Temp.:
22 °C
Conc.:
1.02 g/L
Conclusions:
The surface tension of a 1.02 g/L solution of test material has been determined to be 71.9 mN/m at 22.0 +- 0.5 °C. The test material is considered not to be a surface-active material.
Executive summary:

The surface tension of a 1.02 g/L solution of test material has been determined to be 71.9 mN/m at 22.0 +- 0.5 °C. The test material is considered not to be a surface-active material.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2002
Report Date:
2002

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
QSAR
GLP compliance:
yes (incl. certificate)
Remarks:
2000-04-26

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid
Specific details on test material used for the study:
- Synonyms: ITC 908, vinylidenephosphonic acid tetrasodium salt (VDPA tetrasodium salt)

Results and discussion

Dissociating properties:
yes
Dissociation constantopen allclose all
No.:
#1
pKa:
7.19
Temp.:
25 °C
Remarks on result:
other:
Remarks:
Assumed temperature in the model
No.:
#2
pKa:
5.87
Temp.:
25 °C
Remarks on result:
other:
Remarks:
Assumed temperature in the model
No.:
#3
pKa:
1.14
Temp.:
25 °C
Remarks on result:
other:
Remarks:
Assumed temperature in the model
No.:
#4
pKa:
0.61
Temp.:
25 °C
Remarks on result:
other:
Remarks:
Assumed temperature in the model

Applicant's summary and conclusion

Conclusions:
The test material was predicted to have four dissociation constants of 7.19 +- 0.30, 5.87 +- 0.30, 1.14 +- 0.10 and 0.61 +- 0.10.
Executive summary:

No determination of dissociation constant was carried out for the test material. The test material has complex overlapping dissociation constants and is unsuitable for use with the methods detailed in OECD Guideline 112. However, using specialist chemical estimation software (Advanced Chemistry Development (ACD), pKa calculator, version 6.0, obtained using ACD (I-Lab web services)) and replacing all sodium ions with protons, the test material was predicted to have four dissociation constants of 7.19 +- 0.30, 5.87 +- 0.30, 1.14 +- 0.10 and 0.61 +- 0.10.