1,3,3-trimethyl-2-[[methyl(p-tolyl)hydrazono]methyl]-3H-indolium methyl sulphate

Water solubility

Administrative data

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012-12-11 to 2013-02-04

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

no

Type of method:

flask method

Test material

Test material information

Constituent 1

Reference substance name:

2-[[(4-methoxyphenyl)methylhydrazono]methyl]-1,3,3-trimethyl-3H-indolium methyl sulphate

EC Number:

258-946-7

EC Name:

2-[[(4-methoxyphenyl)methylhydrazono]methyl]-1,3,3-trimethyl-3H-indolium methyl sulphate

Cas Number:

54060-92-3

Molecular formula:

C20H24N3O.CH3O4S C21H27N3O5S

IUPAC Name:

2-{[2-(4-methoxyphenyl)-2-methylhydrazin-1-ylidene]methyl}-1,3,3-trimethyl-3H-indol-1-ium methyl sulfate

Test material form:

solid

Results and discussion

Water solubility

Water solubility:

8.8 g/L

Conc. based on:

test mat.

Temp.:

23 °C

pH:

5.6

Details on results:

see below

Any other information on results incl. tables

 Preliminary Visual Estimation of the Water Solubility

Different amounts of the test item and water were stirred at room temperature until the mixture appeared dissolved or the water solubility could be estimated to be below 10 mg/L.

Table 1: Appearance of the test mixtures

Amount of test item in mg	Total volume in ml	Appearance of mixture
104.7	0.1	undissolved^1)
	0.5	undissolved^1)
	1.0	undissolved^1)
	2.0	undissolved^1)
	10	undissolved (low turbidity)^1)

¹⁾: After adding the indicated amount of water, the solution was treated with ultrasound for 15 minutes.

Table 2: Appearance of the test mixtures

Amount of the test item in mg	Total volume in ml	Appearance of mixture
12.1	100	low turbidity^2)
11.2	500	low turbidity^2)
4.9	500	very low turbidity^2)

²⁾: After adding the indicated amount of water, the solution was stirred at room temperature for about 1 day.

According to the preliminary visual estimation the water solubility seems to be lower than 10 mg/l. However, in the test item water mixtures with a concentration of about 10 mg/l only a low turbidity was observed. It is assumed that this low turbidity results from impurities of the test item with a lower solubility. Therefore the water solubility of the test item is assumed to be > 10 mg/l. Consequently the flask method was performed as main test.

Table 3: Water solubility of the test item – experiments A to D

Experiment	A	B	C	D (blank)
Amount of test item (g)	6.18	6.20	6.11	--
Amount of distilled water (mL)	30	30	30	30
Stirring time at 30 °C (h)	24	48	72	72
pH at 23 °C	5.4	5.6	5.7	6.5
Aliquot of the flasks (mL)	0.5	0.5	0.5	0.5
Dilution with methanol to volume (mL)	50	50	50	50
Aliquot of the diluted sample (mL)	0.1	0.1	0.1	0.1
Dilution with methanol / dist. water 90 : 10 % to volume (mL)	1	1	1	1
Dilution factor	1000	1000	1000	1000
Measured concentration (mg/L)	8.81 / 8.83	8.56 / 8.57	8.93 / 9.01	-- / --
Mean concentration (mg/L)	8.82	8.57	8.97	--
Water solubility (g/L)	8.82	8.57	8.97	--

The water solubility of the test item at 20 °C was determined to be 8.8 g/l.

Table 4: Accuracy test

Standard	Measured concentration (mg/l)	% Recovery (mean values)
Standard C (c = 35.68 mg/L)	36.90 / 36.89	103.4
Standard E (c = 7.14 mg/L)	7.05 / 7.08	99.0
Standard G (c = 1.43 mg/L)	1.34 / 1.35	94.1

Recoveries of the ‘standard samples’ ranged from 94.1 % to 103.4 %, indicating a good accuracy of the analytical method.

Applicant's summary and conclusion

Conclusions:

soluble (1000-10000 mg/L)
In conclusion, the water solubility of the test item at 20 °C was determined to be 8.8 g/L.

Executive summary:

A study was performed according to EU method A.5 and OECD guideline 105 without GLP.

Initially a pre-test by visual estimation of the water solubility was performed which indicated a poor water solubility of < 10 mg/L because the solution was turbid at this low concentration. Considering that the turbidity might result from impurities of the test item the main test was performed.

In the main test the flask method was used in combination with HPLC and an external calibration (external standard method with the test item). The water solubility of the test item at a temperature of 20 °C was determined to be (without correction for the purity): Cs = 8.8 g/L.