(R)-2-(2,4-Difluorphenyl)-1,1-difluor-3-(tetrazol-1-yl)-1-{5-[4-(2,2,2-trifluorethoxy)-phenyl]-2-pyridyl}-2-propanol-(R,R)-tartrate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2020-03-17 to 2020-06-04

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

GLP compliance:

no

Type of method:

flask method

Key result

Water solubility:

745 mg/L

Conc. based on:

test mat. (dissolved fraction)

Loading of aqueous phase:

100 g/L

Temp.:

20 °C

pH:

3.2

Remarks on result:

other: Mean water solubility of 24, 48 and 72 h experiment

Preliminary test:

In a stepwise procedure, increasing volumes of demineralized water were added at room temperature to a defined amount of the test item. After each addition of an amount of water the mixture was visually checked for any undissolved particles.

Table 1: Results of the preliminary test

Amount of test item / mg	Added volume of demineralized water / mL	Total volume of demineralized water / mL	Appearance of mixture
106.2	0.1	0.1	not dissolved
	0.4	0.5	not dissolved
	0.5	1.0	not dissolved
	1.0	2.0	not dissolved
	8.0	10.0	not dissolved

Three additional preliminary tests were carried out with specified amounts of the test item and 100 mL and 500 mL demineralized water, respectively. After each addition of an amount of water, the mixture was stirred for at least 24 hours, and visually checked for any undissolved particles.

Table 2: Results of additional preliminary test

Amount of test item / mg	Total volume of demineralized water / mL	Appearance of mixture
8.9	100	not dissolved, some light reflecting particles
9.6	500	not dissolved, some light reflecting particles
3.1	500	not dissolved, some light reflecting particles

Independent of the actual amount of water, visually nearly the same amount of light reflecting particles were seen, which could have been caused by insoluble impurities. Thus, as a conservative approach, the solubility of the test item was estimated to about 100 mg/L.

The preliminary test showed that the water solubility of the test item was > 10 mg/L. According to the preliminary test the water solubility was determined by the flask method in the main test. About 500 mg/L test item, which referred to five times that quantity of the preliminary test estimate, were used for the first test series. In this first main test the test item was almost completely dissolved at the end of stirring time (24 h, 48 h, 72 h at 30°C and 24 h at 20 °C). The aqueous phases (except the blank) had a pH value of 3.9. The HPLC analysis showed a mean water solubility of 547 mg/L.

Thus, two additional preliminary tests were run in order to estimate the amount of test item for the repetition of the flask method. Additionally, the stirrability of the test item water mixtures was checked. Therefore, the test item water mixtures were stirred at 30 °C for approx. 16 h and afterwards at 20 °C for about 6 h. The results are shown in Table 3.

Table 3: Results of the stirring test

Amount of test item / mg	Total volume of demineralized water / mL	Concentration of the test item / g/L	Observation
201.5	20	10.1	Slightly turbid, little precipitate, could be stirred
1993.3	20	99.7	Viscous suspension, much precipitate, could be stirred

In order to achieve reliably a saturated solution a concentration of approx. 100 g/L test item in demineralized water was used in the main test.

Flask method:

The data for the evaluation are given in Table 4. After the equilibration time precipitate was observed in the flasks of the experiments excluding the ones in the blank experiment. The water solubility was calculated from the measured and unrounded concentration values and not from the rounded values given in Table 4.

Table 4: Water solubility experiments of the test item

Experiment	24 h experiment	48 h experiment	72 h experiment	Blank experiment (72 h)
Amount of test item / g	2.08	2.06	2.08	-
Amount of demineralized water / mL	20	20	20	20
Stirring time at 30 °C / h	24	48	72	72
pH at ambient temperature	3.2	3.2	3.2	5.8
Dilution factor	10	10	10	10
Measured concentration / mg/L	72.19 / 71.44	74.74 / 77.23	74.88 / 76.59	- / -
Mean concentration / mg/L	71.82	75.98	75.74	-
Water solubility / mg/L	718.2	759.8	757.4	-

The mean water solubility of the test item at 20 °C was determined to be 745 mg/L (± 23 mg/L). This result was in the same range as in the first main test and the pH value of the test item solutions was comparable in both main tests. Therefore, it was concluded that the excess load of the test item did not influence the test result.

Conclusions:

The mean water solubility of the test item at 20 °C was determined to be 745 mg/L (± 23 mg/L).

Executive summary:

The water solubility of the test item was determined according to OECD guideline 105 by the flask method. The mean water solubility of the test item at 20 °C was determined to be 745 mg/L (± 23 mg/L).

Description of key information

The water solubility of the test item was determined according to OECD guideline 105 by the flask method. The mean water solubility of the test item at 20 °C was determined to be 745 mg/L (± 23 mg/L).

Key value for chemical safety assessment

Water solubility:

745 mg/L

at the temperature of:

20 °C