Climbazole

Partition coefficient

Description of key information

A Partition Coefficient (logP) of 3.83 at 25 °C and pH10 was calculated from the solubilities in water presaturated n-octanol and n-octanol presaturated water.

As the test substance was expected to dissociate, the test was performed at pH 10 to ensure testing of the nonionised form.

A buffer (pH 10) presaturated with n-octanol and n-octanol presaturated with buffer were prepared using vortex mixing.

The buffer (pH 10) was prepared using 439 mL of 0.1 M sodium hydroxide and 500 mL of 0.1M boric acid in 0.1 M potassium chloride diluted to 1,000 mL with Milli Q Plus water.

Approximately 0.3 g of test substance was weighed in duplicate into a 100 mL conical flask and 100.0 mL buffer (pH 10) presaturated with n-octanolwas added to each. Approximately 10 g of test substance was weighed, in duplicate, into a 100 mL conical flask and 10.0 mL n-octanol presaturated with buffer (pH 10).

The flasks were stoppered and stirred in a 25°C water bath. After 1 h, each flask was visually assessed and undissolved test substance was observed. The flasks were then left to stir overnight and were subsequently left to equilibrate in the water bath for 30 min. The n-octanol solutions presaturated with buffer (pH 10) test solutions were filtered through 0.45 µm HVLP filters under vacuum. The buffer (pH 10) presaturated with n-octanol test solutions were filtered through 0.1 µm cellulose nitrate filters under vacuum. All filtrates were then analysed quantitatively by HPLC.

The buffer presaturated with n-octanol test solutions were analysed undiluted. n-Octanol presaturated with pH 10 buffer test solutions were diluted 1.0 mL to 100.0 mL acetonitrile, followed by a further dilution of 1.0 mL to 50.0 mL acetonitrile.

Key value for chemical safety assessment

Log Kow (Log Pow):

3.83

at the temperature of:

25 °C

Additional information

The partition coefficient of test substance was measured using EU method A8 (shake flask method) with the aid of quantitative HPLC analysis. The HPLC analysis was performed using a Waters Alliance LC instrument. Based on surface tension results of 58.0 ± 0.5 mN/m, the test substance is classified as being surface active. EU A8 Guideline indicates that the Shake Flask method is not applicable to surface active materials (for which a calculated value or an estimate based on the individual n-octanol and water solubilities should be provided). A Partition Coefficient (logP) of 3.83 at 25 °C and pH10 was then calculated from the solubilities in water presaturated n-octanol and n-octanol presaturated water.