Registration Dossier
Registration Dossier
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EC number: - | CAS number: -
Dissociation constant
Administrative data
- Endpoint:
- dissociation constant
- Type of information:
- calculation (if not (Q)SAR)
- Remarks:
- Migrated phrase: estimated by calculation
- Adequacy of study:
- key study
- Study period:
- 16 Jan 2008 - 14 May 2008
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- other: The study has been performed according toOECD guidelines and according to GLP principles.
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 2 008
- Report date:
- 2008
Materials and methods
Test guideline
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 112 (Dissociation Constants in Water)
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
Test material
- Details on test material:
- - Name of test material (as cited in study report): S-500
- Physical state: yellow powder
- Lot/batch No.: MF1456-2345
- Expiration date of the lot/batch: 18 August 2011
- Storage condition of test material: At room temperature in the dark
- Stability under storage conditions: Stable
Constituent 1
Results and discussion
Any other information on results incl. tables
It proved not possible to determine the dissociation constants of S-500 experimentally. As an alternative, the pKa values were calculated using the pKalc version 5.0 computer program. Based on the calculation method, it was concluded that component A of the test substance has two basic pKa values, whereas the neutral species of component B has two acidic and two basic pKa values. For the major component A, two pKa values were calculated: 0.36 and 0.96. It was assumed that these pKa values derive from the subsequent protonation of the amide groups. For the neutral species of component B, four pKa values were calculated: -4.48, 0.13, 0.66 and 19.4. It was assumed that these pKa values derive from the subsequent protonation or deprotonation of the amide groups as well as the deprotonation of the sulfonic acid group.
Applicant's summary and conclusion
- Conclusions:
- It proved not possible to determine the dissociation constants of S-500 experimentally. As an alternative, the pKa values were calculated using the pKalc version 5.0 computer program. Based on the calculation method, it was concluded that component A of the test substance has two basic pKa values, whereas the neutral species of component B has two acidic and two basic pKa values.
For the major component A, two pKa values were calculated: 0.36 and 0.96. It was assumed that these pKa values derive from the subsequent protonation of the amide groups.
For the neutral species of component B, four pKa values were calculated: -4.48, 0.13, 0.66 and 19.4. It was assumed that these pKa values derive from the subsequent protonation or deprotonation of the amide groups as well as the deprotonation of the sulfonic acid group.
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