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Physical & Chemical properties

Dissociation constant

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Endpoint:
dissociation constant
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Justification for type of information:
structural similarity
Reason / purpose:
read-across source
Dissociating properties:
no
No.:
#1
pKa:
-0.75
Remarks on result:
other: QSAR ChemAxon

The source substance has the same functional groups when compared to the target substance. Hence, the result is considered relevant for the target substance as well.

Conclusions:
pKa is outside pH 5 to 9.
Executive summary:

The dissociation constant of docusate sodium as calculated with the QSAR ChemAxon is given as -0.75. Based on the same functional groups of the source and target substance the result is considered to be relevant for the target substance as WoE approach.

The pkA can be predicted to be outside the range of 5 - 9 which is given as criterion in R.7.a. Hence, the study is not needed.

Endpoint:
dissociation constant
Type of information:
not specified
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Principles of method if other than guideline:
Assessment of the pKa based on the molecular structure of the registered substance.
GLP compliance:
no
Dissociating properties:
yes
Remarks on result:
other: The registered substance is a salt. Salts are reaction products of acids and bases that retain their ionic character.  So salts are never undissociated. The dissociation constant is only relevant for substances with a acid or basic character.

The dissociation constant study does not need to be conducted as the substance is a salt. Salts are reaction products of acids and bases that retain their ionic character.  So salts are never undissociated. The dissociation constant is only relevant for substances with a acid or basic character.

For salts, the pkA can be predicted to be outside the range of 5 - 9 which is given as criterion in R.7.a. Hence, the study is not needed.

Conclusions:
The dissociation constant is not relevant since the substance is a salt.
Executive summary:

The dissociation constant study does not need to be conducted as the substance is a salt. Salts are reaction products of acids and bases that retain their ionic character.  So salts are never undissociated. The dissociation constant is only relevant for substances with a acid or basic character.

For salts, the pkA can be predicted to be outside the range of 5 - 9 which is given as criterion in R.7.a. Hence, the study is not needed.

Endpoint:
dissociation constant
Type of information:
not specified
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification
Principles of method if other than guideline:
Assessment of the pKa based on the molecular structure of the registered substance.
GLP compliance:
no
Dissociating properties:
no
Remarks:
The registered substance has no dissociating groups.

The registered substance has no dissociating groups. Hence, a study for the determination of the dissociation constant is not needed.

Conclusions:
The registered substance has no dissociating groups.
Executive summary:

The registered substance has no dissociating groups.Hence, a study for the determination of the dissociation constant is not needed.

Endpoint:
dissociation constant
Type of information:
not specified
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification
Principles of method if other than guideline:
Assessment of the pKa based on the molecular structure of the registered substance.
GLP compliance:
no
Dissociating properties:
no
Remarks:
The registered substance has no dissociating groups.

The registered substance is a salt. As stated in Guidance R.7a section R.7.1.17.1 "It is important to note that the dissolution of salts from their crystal lattice into individual ions is not intended to be covered by the endpoint dissociation constant. Therefore this section refers only to acid dissociation (pKa)."

Conclusions:
The registered substance is a salt. As stated in Guidance R.7a section R.7.1.17.1 "It is important to note that the dissolution of salts from their crystal lattice into individual ions is not intended to be covered by the endpoint dissociation constant. Therefore this section refers only to acid dissociation (pKa)."
Executive summary:

The registered substance is a salt. As stated in Guidance R.7a section R.7.1.17.1 "It is important to note that the dissolution of salts from their crystal lattice into individual ions is not intended to be covered by the endpoint dissociation constant. Therefore this section refers only to acid dissociation (pKa)."

Description of key information

The dissociation constant is not relevant since the substance is a salt.

The registered substance has no dissociating groups.Hence, a study for the determination of the dissociation constant is not needed.

Evidence that that the pKa about -0.75.

pKa is definitively out of pH 5 to 9.

Key value for chemical safety assessment

Additional information