Reaction mass of 3-[(2-aminoethyl)ammonio]propane-1-sulfonate and 3,3'-(ethane-1,2-diyldiammonio)dipropane-1-sulfonate and ethane-1,2-diamine

Partition coefficient

Administrative data

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study with GLP.

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

Principles of method if other than guideline:

The experimentally determined partition coefficient is outside the range of the two main methods (shake flask method and HPLC-method) described in the guidelines. The determination of the partition coefficient of the non dissociated test substance is not possible because at each pH-value the acidic and/or the basic groups dissociate. Therefore the estimation of the partition coefficient was performed from the solubilities of the test substance in the pure solvents water and n-octanol was performed, as decribed in the guideline.
The determination of the partition coefficient of the non dissociated test substance is not possible because at each pH-value the acidic and/or the basic groups dissociate and therefore no further tests were performed.

GLP compliance:

yes

Type of method:

other: Estimation from the solubilities in the pure solvents.

Partition coefficient type:

octanol-water

Test material

Test material information

Constituent 1

Reference substance name:

3-[(2-aminoethyl)amino]propane-1-sulfonic acid

Cas Number:

14235-54-2

Molecular formula:

C5H14N2O3S

IUPAC Name:

3-[(2-aminoethyl)amino]propane-1-sulfonic acid

Details on test material:

- Physical state: solid
- Analytical purity: approx. 95 %
- Impurities (identity and concentrations): water approx 5%
- Lot/batch No.: 06060423/101
- Stability under test conditions: stable
- Storage condition of test material: room temperature in the dark

Study design

Analytical method:

other: visually for the estimation of the solubilities in water and n-octanol.

Results and discussion

Partition coefficient

Key result

Type:

log Pow

Partition coefficient:

< -3

Temp.:

20 °C

Remarks on result:

other: see remarks

Remarks:

The test substance contains acidic and basic groups (zwitterion). The acidic and basic groups dissociate, depending on the pH. The determination of the partition coefficient of the non-dissociated test substance is not possible because at each pH-value the acidic and/or the basic groups of the zwitterion dissociate. The dissociation constants of the test substance were estimated by an atom/fragment contribution method using the software PALLAS© Version 3.4.1.3, pKa Prediction Module 5.1 (CompuDrug International Inc., San Francisco, USA). The pKa values of the test substance are -1.9 (acidic) and 7.6 (basic) and 10.4 (basic). Therefore a pH correction at the determination of the partition coefficient is not necessary.

Details on results:

The solubility in water at 21 °C is > 1000 g/L, see Section 4.8 "Water solubility".
The solubility in n-octanol was estimated to <1 g/L.

Any other information on results incl. tables

The estimated partition coefficient is outside the range for which methods are published in the guidelines. The determination of the partition coefficient of the non dissociated test substance is not possible because at each pH-value the acidic and/or the basic groups dissociate and therefore no further tests were performed.

Applicant's summary and conclusion

Conclusions:

The log Pow of the test substance is <-3.0.

Executive summary:

The log Pow of the test substance was determined from the solubility in water and in n-octanol according to OECD- and EU-methods. This method was used as it was estimated that the log Pow will fall outside the range of the shake flask method or the HPLC-method. The determination of the partition coefficient of the non dissociated test substance is not possible because at each pH-value the acidic and/or the basic groups dissociate.

The log Pow of the test substance is <-3.0.