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Physical & Chemical properties

Partition coefficient

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Endpoint:
partition coefficient
Type of information:
other: Literature data
Adequacy of study:
supporting study
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
secondary literature
Principles of method if other than guideline:
Method: other (measured)
GLP compliance:
no
Type of method:
other: Extrapolation of literature data
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
-0.72
Temp.:
20 °C
pH:
7
Details on results:
Log Pow was extrapolated from literature data to 0% lactic acid. This is relevant since the concentration of monomeric lactic acid is dependent on the overall concentration due to spontaneous, reversible polymerisation of lactic acid.
Conclusions:
Log Kow of lactic acid is -0.72
Executive summary:

An overview is given of measured literature data for the log Kow of lactic acid. The reviewed literature indicates a log Kow of -0.72 for lactic acid, calculated as the concentration in octanol divided by nominal concentration in water rises linearly with the nominal concentration.

Endpoint:
partition coefficient
Type of information:
other: Expert statment
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Expert statement
Qualifier:
according to
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
GLP compliance:
no
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Analytical method:
high-performance liquid chromatography
Type:
log Pow
Partition coefficient:
-0.6
Temp.:
20 °C
Remarks on result:
other: pH not given
Details on results:
1. EPIWIN modeling
The n-octonal/water coefficient is given in the EPIWIN modeling 1) of the EPA. The log KOW calculated within the KOWWIN module is –0.65
2. IUCLID data
In the data generated under the European HPV program (IUCLID 2)), the POW is reported to be –0.62
3. IPCS data
The IPCS International program on Chemical Safety 3) reported the POW for lactic acid to be –0.6
4. Conclusion:
As the values reported are very close, the value –0.6 will be included in section A3 of the dossier.
Conclusions:
The log octanol-water partition coefficient of lactic acid is significantly lower than 0.
Executive summary:

The log octanol-water partition coefficient of lactic acid is significantly lower than 0 (mean of -0.61 for the logKow).

Endpoint:
partition coefficient
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Expert statement
Justification for type of information:
This information is used in a read-across approach in the assessment of the target substance.
Reason / purpose:
read-across source
Qualifier:
according to
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
GLP compliance:
no
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
-0.6
Temp.:
20 °C
Details on results:
1. EPIWIN modeling
The n-octonal/water coefficient is given in the EPIWIN modeling 1) of the EPA. The log KOW calculated within the KOWWIN module is –0.65
2. IUCLID data
In the data generated under the European HPV program (IUCLID 2)), the POW is reported to be –0.62
3. IPCS data
The IPCS International program on Chemical Safety 3) reported the POW for lactic acid to be –0.6
4. Conclusion:
As the values reported are very close, the value –0.6 will be included in section A3 of the dossier.
Conclusions:
The log octanol-water partition coefficient of lactic acid is significantly lower than 0.
Executive summary:

The log octanol-water partition coefficient of lactic acid is significantly lower than 0 (mean of -0.61 for the logKow).

This information is used in a read-across approach in the assessment of the target substance.

For details and justification of read-across please refer to the attached report in section 13 of IUCLID.

Description of key information

All available evidence indicates that the octanol-water partition coefficient of lactic acid is significantly below 0.

The review of literature data indicates that the log octanol-water partition coefficient of lactic acid is -0.72. An OECD 107 study according to GLP revealed that no suitable method for the detection of lactic acid in n-octanol and/or water in the required concentration range could be developed (technically not feasible). Therefore, the partition coefficient of the test substance was calculated using the Rekker calculation method by the software PrologP 6.0, module in Pallas 3.0, indicating a log Kow of –0.54. A log Kow of –0.6 was calculated with EPISUITE v3.20.

Therefore, a mean of –0.62 is considered appropriate.

Key value for chemical safety assessment

Log Kow (Log Pow):
-0.62
at the temperature of:
20 °C

Additional information