1,4-dimethylpiperazine

Dissociation constant

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

dissociation constant

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2011/04/20-2011/06/01

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Study report in Japanese

Qualifier:

no guideline followed

Principles of method if other than guideline:

No guideline followed but data is required for CSCL-LVE registration

GLP compliance:

no

Specific details on test material used for the study:

- Name of test material (as cited in study report): DMP
- Analytical purity: 99.82 wt %
- Lot/batch No.: 1901/2011

The HPLC method was carried out at various pH values (pH 5.0, 7.0, 9.0, 10.0 and 11.0)

The retention time obtained its maximum value and became stable in equal to and above pH10.

Conclusions:

The retention time obtained its maximum value and became stable in equal to and above pH10.

Reference 2

Endpoint:

dissociation constant

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2013-10-21

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 112 (Dissociation Constants in Water)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Lot/batch number of test material: 1903-3/2012
- Purity: not indicated
- Appearance: clear liquid

Dissociating properties:

yes

No.:

#1

pKa:

9.78

Temp.:

20 °C

Remarks on result:

other: No details on temperature are provided, however ambient temperature is anticipated

No.:

#2

pKa:

8.31

Temp.:

20 °C

Remarks on result:

other: No details on temperature are provided, however ambient temperature is anticipated

During the preliminary test, inflection points were observed after 2 mL and 34 mL of titrant had been added. The mid-points of 1 mL and 17 mL of titrant addition were investigated for full testing.

Conclusions:

The dissociation constants of the substance were determined to be 9.78 and 8.31 at ambient temperature.

Description of key information

The dissociation constants of the test substance were determined to be 9.78 and 8.31 at ambient temperature following a GLP study conducted in accordance with guideline OECD 112 using the titration method (Younis, 2013) which was assigned as key study.

Key value for chemical safety assessment

pKa at 20°C:

9.78

Additional information

The pKa values were determined to be 9.78 and 8.31 at 20°C.

The supporting study (K4) showed that the retention time obtained its maximum value and became stable in equal to and above pH10 using the HPLC method.