1-[bis[3-(dimethylamino)propyl]amino]propan-2-ol

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

other: Estimation

Adequacy of study:

key study

Study period:

2012-30-04 to 2012-05-14

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

Well documented estimation of the log P under GLP conditions.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Log P is estimated based on the use of empirically derived atomic or group fragment constants and structural factors which when summed for the whole molecule estimate the partition coefficient directly. Reference is made to the Handbook of Chemical Property Estimation methods, fourth edition by W.J. Lyman et al., 1990.

GLP compliance:

yes (incl. QA statement)

Type of method:

other: Estimation based on chemical structure

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch number of test material: PFW100207
- Purity: contains 0.03% water
- Physical state: Liquid

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: in cool, well-ventilated area

Analytical method:

other:

Type:

log Pow

Partition coefficient:

-1.68

Remarks on result:

other: Log P is estimated, temperature and pH are not applicable. A temperature of 20°C can be assumed.

Details on results:

From the molecular structure, the test substance contains 13 carbon atom fragments, 30 hydrogen atom fragments, 3 tertiary amine fragments and 1 OH fragment. Thus fragment constants of value 0.20 (-C- fragment), 0.23 (-H fragment), - 2.18 (tertiary amine fragment) and -1.64 (-OH fragment) applies. The sum of the fragments in the molecule was therefore calculated as 1.32.

Also present in the molecule are 16 bonds radiating from the tertiary amines, therefore the fbYN factor must be applied. This is applied as (16-1) (-0.20). The sum of the factors was therefore obtained as -3.00.

From the sum of fragments and factors the partition coefficient was estimated by calculation as -1.68 log units.

The estimation refers to the uncharged molecule.

Conclusions:

The estimated log Pow value for the test substance is -1.68. The estimation refers to the uncharged molecule.

Reference 2

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012-07-23 to 2012-08-25

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch number of test material: PFW100207
- Purity: >99%
- Description: pale yellow liquid
- Expiry date: December 2013

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature in the dark

Analytical method:

gas chromatography

Type:

Pow

Partition coefficient:

3.88

Temp.:

22.6 °C

pH:

12

Key result

Type:

log Pow

Partition coefficient:

0.587

Temp.:

22.6 °C

pH:

12

Details on results:

Duplicate log Pow values of 0.615/0.615, 0.623/0.562 and 0.503/0.607 were calculated for the octanol/water ratio 1:2, 1:1 and 2:1, respectively.

The test item contains three ionizable nitrogen atoms in the structure with computer estimated pKa values of 5.74, 9.11 and 9.94. Therefore the n-octanol saturated water was adjusted to pH 12 to ensure the test item was paritioned in its non-ionized form. As testing was carried out at pH 12 this does not truly reflect the properties of the test item at an environmentally relevant pH (pH5-pH9). In this pH range either some or all the ionizable groups would be charged which would increase the water solubility and lower the partition coefficient for the test item. For this reason the result can be taken as a worst-case and in most environmentally relevant situations the partition coefficient would be lower than the value reported.

Conclusions:

The partition coefficient of the test substance has been determined to be 3.88 at 22.6 ± 1.0°C (log Pow 0.587) at pH 12.0, using the shake-flask method.

Description of key information

The partition coefficient of the test substance was determined in a GLP-compliant study according to OECD method 107, to be 0.587 (Log value), following the shake flask method (Tarran, 2012).

Key value for chemical safety assessment

Log Kow (Log Pow):

0.587

at the temperature of:

22.6 °C

Additional information

The log Pow of the test substance was determined in two studies. In one study, the log Pow of the test substance was determined following a scientifically accepted calculation method. In the other study, the log Pow of the test substance was experimentally determined according to OECD Guideline 107 and EC A.8 to be 0.587 at 22.6 °C and pH 12, following the shake flask method (Tarran, 2012). The latter study was selected as the key study.