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Physical & Chemical properties

Partition coefficient

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Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2016-07-29 - 2017-09-22
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
test procedure in accordance with generally accepted scientific standards and described in sufficient detail
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
other: no guideline available
Principles of method if other than guideline:
The partition coefficient of the test item was not determined, using a procedure designed to be compatible with Method A.8 Partition Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 117 of the OECD Guidelines for Testing of Chemicals, 13 April 2004, as the test item was demonstrated to be not applicable.
The partition coefficient of inorganic substances, as is the active ingredient of the test item, is not usually required. However, the Sponsor requested the endpoint to be determined, as in this case, the inorganic active was suspended in an organic medium. This may then have significantly affected its bioaccumulation potential. The flask-shake method was therefore attempted. The HPLC method to determine partition coefficient would not be applicable for pure inorganic substances or those in an organic medium.
GLP compliance:
yes (incl. certificate)
Remarks:
The Department of Health of the Government of the United Kingdom
Type of method:
flask method
Partition coefficient type:
octanol-water
Analytical method:
mass spectrometry
Key result
Type:
log Pow
Remarks on result:
not determinable

The following table shows the mean results from quadruple unfiltered stock and filtered stock:

 Solution     Concentration   
 Magnesium  Boron
 Unfiltered Stock  3.10  1.7
 Filtered Stock  0.177  0.434
 Matrix blanks  < LOQ  < LOQ

These results clearly demonstrated that the active ingredient precipitated out of water saturated octanol stock solution. The filtered stock had an observed Tyndall beam effect which suggested some fine precipitate still remained; if this had been filtered out then the filtered results may have been even lower. This all meant that the partition coefficient test by the flask-shake method was not applicable. As the test item was organic based, preparing a stock solution in octanol saturated water was not feasible either.

Conclusions:
The results clearly demonstrated that the active ingredient precipitated out of water saturated octanol stock solution. The filtered stock had an observed Tyndall beam effect which suggested some fine precipitate still remained; if this had been filtered out then the filtered results may have been even lower. This all meant that the partition coefficient test by the flask-shake method was not applicable. As the test item was organic based, preparing a stock solution in octanol saturated water was not feasible either.
Executive summary:

The partition coefficient of the test item was not determined, using a procedure designed to be compatible with Method A.8 Partition Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 117 of the OECD Guidelines for Testing of Chemicals, 13 April 2004, as the test item was demonstrated to be not applicable. The results clearly demonstrated that the active ingredient precipitated out of water saturated octanol stock solution. The filtered stock had an observed Tyndall beam effect which suggested some fine precipitate still remained; if this had been filtered out then the filtered results may have been even lower. This all meant that the partition coefficient test by the flask-shake method was not applicable. As the test item was organic based, preparing a stock solution in octanol saturated water was not feasible either.

Endpoint:
partition coefficient
Data waiving:
study technically not feasible
Justification for data waiving:
the study does not need to be conducted because the substance is inorganic

Description of key information

The partition coefficient of the test item was not determined, using a procedure designed to be compatible with Method A.8 Partition Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 117 of the OECD Guidelines for Testing of Chemicals, 13 April 2004, as the test item was demonstrated to be not applicable:

The partition coefficient of inorganic substances, as is the active ingredient of the test item, is not usually required.

The logPow of magnesium metaborate was determines using KOWWIN v1.68 implemented in EPIWIN v4.11. The logPow of magnesium metaborate was predicted to be -3.08. This prediction does not fall into the applicability domain of this model, since the query substance is inorganic.

Key value for chemical safety assessment

Log Kow (Log Pow):
-3.08

Additional information