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Physical & Chemical properties

Dissociation constant

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Reference
Endpoint:
dissociation constant
Type of information:
(Q)SAR
Adequacy of study:
supporting study
Study period:
Not applicable
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 adequate and reliable documentation / justification
Justification for type of information:
Accepted calulation method
Reference:
Composition 0
Qualifier:
according to
Guideline:
other:
Version / remarks:
Estimation Program "ACD/pKa DB" (Advanced Chemistry Development Inc.,
Toronto, Canada)' and "CAMEO" (Computer Assisted Mechanistic Evaluation of Organic Reactions)
Deviations:
no
GLP compliance:
no
Test material information:
Composition 1
Dissociating properties:
no

The substance can be considered as a neutral molecule in the pH range 2-10, which is of relevance for biological systems.

For the hydrogen atoms in the neighbourhood of the conjugated double bounds, pKa value above 19 and for the alcoholic hydroxyl groups pKa values > 13 were calculated.

Conclusions:
The substance can be considered as a neutral molecule in the pH range 2-10, which is of relevance for biological systems.
Executive summary:

The chemical structure of the substance does not show any groups, which can be protonated or deprotonated. This fact was supported by calculation with the computer programs ACD/pKa DB and CAMEO, which did not calculate for the test substance any pKa value in the pH range 0-13.Therefore it can be considered as a neutral molecule in the pH range 2-10, which is of relevance for biological systems.

Description of key information

The substance can be considered as a neutral molecule in the pH range 2 to 10, which is of relevance for biological systems.

Key value for chemical safety assessment

Additional information

The substance does not contain any functional group which can be protonated or deprotonated significantly in aqueous solution. This fact was supported by calculations with the computer programs ACD/pKa DB and Cameo, which didn't calculate any pKa in the range 0 to 13. Therefore, norethisterone is to be considered as a neutral molecule in the pH range 2 to 10, which is of relevance for aqueous biological systems.