Tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2012

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

Justification for type of information:

QSAR calculation: detailed information see "any other information on materials and methods" and "any other information on results"

Guideline:

other: REACH guidance QSARs R6, May/July 2008

Principles of method if other than guideline:

Estimation Program Interface (EPI) Suite v4.10: KOWWIN for estimating the logarithmic octanol-water partition coefficient (log Kow).
The Estimation Programs Interface was developed by the US Environmental Agency's Office of Pollution Prevention and Toxics and Syracuse Research Corporation (SRC).© 2000 - 2011 U.S. Environmental Protection Agency for EPI SuiteTM (Published online in January 2011).

GLP compliance:

no

Type of method:

other: QSAR

Partition coefficient type:

octanol-water

Key result

Type:

log Pow

Partition coefficient:

-5.45

Remarks on result:

other: temperature and pH not reported

Details on results:

The estimated value refers to the dissociated form of tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate.

Validity of model:

1. Defined Endpoint: Octanol-water partition coefficient

2. Unambiguous algorithm: KOWWIN estimates apply to compounds that are predominantly in a non-ionized form. There are exceptions; in particular, estimates for compounds considered "ion pairs" such as sodium salts. KOWWIN considers tetrasodium hydrogen 2- phosphonatobutane-1,2,4-tricarboxylate an "ion pair" compound and gives a corresponding estimate; effectively, the estimate for tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate is an estimate for ionized 2-phosphonobutane-1,2,4-tricarboxylic acid. In conclusion, the estimated value refers to the dissociated form of tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate. The molecule is separated into distinct atom/fragments using an Atom/Fragment Contribution method. Based on structure of the molecule, the following fragments were applied: -CH2 -, -C(=O)O, -O-P, O=P, -tert carbon and -OH and a factor [ C(=0)-0-{Na,K,Li}]and three correction factors [ -P(=0)-C-C(=0)- correction, Misc-0-{Na,K,Li} and MOOC-C-C-COOM {M=metal} correction] are applied. The number of times of the fragments that occurs in the structure of the substance applied by the program is verified.

3. Applicability domain: With a molecular weight of 358.07 g/mole the substance is within the range of the training set (18.02 - 719.92) as well as in the range of the validation set (27.03 - 991.15).

4. Statistical characteristics: Correlation coefficient of the total training set r² = 0.982; Correlation coefficient of the total validation set r² = 0.943.

5. Mechanistic interpretation: The structural fragments used as descriptors reflect the lipophilic or hydrophobic properties of the substances, and so the octanol-water partition coefficient.

6. Adequacy of prediction: The result for tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate falls within the applicability domain described above and the estimation rules applied for the substance appears appropriate. Therefore the predicted value can be considered reliable yielding a useful result for further assessment.

Conclusions:

The QSAR determination of the logarithmic octanol-water partition coefficient for tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate using the model KOWWIN included in the Estimation Program Interface (EPI) Suite v4.10 revealed a value of -5.45 of the dissociated form of the substance. The predicted value can be considered reliable yielding a useful result for further assessment.

Executive summary:

The logarithmic octanol-water partition coefficient (log Kow) for tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate was predicted using the QSAR calculation of the Estimation Program Interface (EPI) Suite v 4.10. The log Kow for the dissociated form of the substance was estimated to be -5.45. The predicted value can be considered reliable yielding a useful result for further assessment.

Description of key information

The QSAR determination of the logarithmic octanol-water partition coefficient for tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate using the model KOWWIN included in the Estimation Program Interface (EPI) Suite v4.10 revealed a value of -5.45 of the dissociated form of the substance. The predicted value can be considered reliable yielding a useful result for further assessment.

Key value for chemical safety assessment

Log Kow (Log Pow):

-5.45

at the temperature of:

25 °C

Additional information

The corresponding parent acid 2-phosphonobutane-1,2,4-tricarboxylic acid has a calculated log Kow of -1.66 for the non-water based substance.