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Physical & Chemical properties

Water solubility

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Reference
Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Qualifier:
according to
Guideline:
OECD Guideline 105 (Water Solubility)
Deviations:
no
GLP compliance:
yes
Type of method:
flask method
Water solubility:
1.31
Temp.:
25 °C
pH:
5
Remarks on result:
other: Average water solubility (mg active/l) of 14C-AHTN after 7 days of equilibration.
Water solubility:
1.22
Temp.:
25 °C
pH:
7
Remarks on result:
other: Average water solubility (mg active/l) of 14C-AHTN after 7 days of equilibration.
Water solubility:
1.22
Temp.:
25 °C
pH:
9
Remarks on result:
other: Average water solubility (mg active/l) of 14C-AHTN after 7 days of equilibration.
Water solubility:
1.25 mg/L
Temp.:
25 °C
pH:
> 5 - < 9
Remarks on result:
other: Overall average water solubility (mg active/L) of 14C-AHTN after 7 days of equilibration.
Details on results:
The average water solubility (+/- % relative standard deviation) of 14C-AHTN calculated after 7 days equilibration in pH buffer solutions of 5, 7, and 9 were 1.31 mg active/L +/-13.0%, 1.22 mg active/L +/-8.20%, and 1.22 mg active/L +/-14.8%, respectively, with an overall average water solubility of 1.25 mg active/L. pH did not seem to affect water solubility.

Table 1 Average Water Solubility (mg active/l). Average of three replicates for each pH/centrifuge speed.

pH 5 7 9
Centrifuge speed
Sampling day 0 5,000 10,000 0 5,000 10,000 0 5,000 10,000
1 1.15 1.02 1.04 1.06 0.96 1.08 0.98 1.03 1.08
2 1.17 1.12 1.30 1.11 1.14 1.07 1.15 1.18 1.31
5 1.19 1.30 1.28 1.07 1.20 1.15 1.22 1.29 1.29
7 1.44 1.32 1.18 1.24 1.19 1.22 1.33 1.29 1.06
Conclusions:
Interpretation of results (migrated information): slightly soluble (0.1-100 mg/L)
The water solubility is determined to be 1.25 mg/l (at 25°C) and seemed independent on the pH.
Executive summary:
A rough approx of water solubility was made by adding a series of masses of non-radiolabelled AHTN samples in deionised (DI) water and noting phase separation after overnight agitation. Using this procedure 10 mg active/l of (14)C-AHTN was estimated to be "well in excess" of the water solubility. The test apparatus consisted of 9 Teflon centrifuge tubes. AHTN was initially dissolved in ethanol (EtOH). The EtOH solution was added to tubes in volumes sufficient to deliver (14)C-AHTN in excess of the estimated water solubility (10 mg active/l). The EtOH was removed by evaporation, leaving the test material as tiny droplets on the bottom of the tubes. 3 buffer solutions (pH 5, 7 and 9) was added to triplicate tubes. Tubes were sealed and agitated overnight at 25°C. Agitation was ceased and water samples withdrawn from near bottom of tubes following 1 hour holding time, then following 30 min of centrifugation at 5,000 rpm (2,655 x g), and finally following 30 min of centrifugation at 10,000 rpm (10,620 x g). Concentration of test substance was determined by liquid scintillation counting. This procedure was repeated 2, 5, and 7 days after set-up. After 7 days of equilibration average water solubilities of (14)C-AHTN (±% relative standard deviation) were 1.31 mg active/l ±13.0%, 1.22 mg active/l ±8.20% and 1.22 mg active/l ±14.8% in pH buffers of pH 5, pH 7 and pH 9, respectively. pH of buffer solution did not appear to affect water solubility of (14)C-AHTN. Overall average water solubility was 1.25 mg active/l.

Description of key information

The water solubility of the test item has been established with radio labelled form of the test item in a OECD guideline 105 study under GLP compliance. Water solubilty was determined to be 1.25 mg/L.

Key value for chemical safety assessment

Water solubility:
1.25 mg/L
at the temperature of:
25 °C

Additional information