Registration Dossier

Administrative data

Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
28-Sep-2018 to 19-Oct-2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report date:
2018

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 105 (Water Solubility)
GLP compliance:
not specified
Type of method:
flask method
Remarks:
The flask method was followed by a kinetic study

Test material

Constituent 1
Chemical structure
Reference substance name:
N-[2-[(4-amino-m-tolyl)ethylamino]ethyl]methanesulphonamide
EC Number:
202-124-2
EC Name:
N-[2-[(4-amino-m-tolyl)ethylamino]ethyl]methanesulphonamide
Cas Number:
92-09-1
Molecular formula:
C12H21N3O2S
IUPAC Name:
N-{2-[(4-amino-3-methylphenyl)(ethyl)amino]ethyl}methanesulfonamide

Results and discussion

Water solubility
Water solubility:
ca. 4 g/L
Temp.:
25 °C
pH:
7
Remarks on result:
other: The substance is not stable in contact with water.
Details on results:
Within 2 hours of contact with water a water solubility of approximately to 4 g/L at pH 7 and 20°C could be estimated, but clear deterioration of the sample occurred with 24 hours.

Any other information on results incl. tables

Results of preliminary test

The preliminary test proved that the amount of dissolved active substance falls in the range between 1-10 g/L.

Unfortunately, the water solubility test of the test item was compromised by its stability problems. Indeed, during this visual test a marked variation in the colour of the solution (from pink to black) was detected.

 

Results of main test

Session 1

At time = 0 the chromatographic response showed no evident differences between the solution in diluted methanol and the solution diluted in HP water.

The analysis of the same solutions after 24 hours showed the solution in water had degraded by ca. 34% compared to the solution in methanol, which remained stable.

Session 2

The degradation in this case was even more marked than the first test. After 24 hours the solution in water had reached ca. 58% of the initial sample area.

Along with the area decrease, other substantial changes occurred to the appearance of both the stock solution in water and the preliminary test samples in water. The solutions changed in colour from pink to black, thus confirming degradation of the active ingredient.

The chromatograms obtained from solutions at different time points compared with the solution at time = 0 showed a continuous decrease in the concentration of the analyte in all the tested solutions.

 

Time (hour)

mg found

REC% vs T30min

Solubility (g/L)

0.5

38.12

-

3.81

1

35.94

94.3

3.59

1.5

35.76

93.8

3.58

2

35.11

92.1

3.51

3

32.74

85.9

3.27

4

29.12

76.4

2.91

24

22.06

57.9

2.21

 

The study results showed that the test item is unstable in aqueous solutions, as well as being severely light sensitivity. For this reason no quantification of the water solubility was possible. The times required by the OECD 105 guideline covers a range of several days, while this study showed a clear deterioration within 24 hours.

 

As reported in the guideline, the solubility in water can be performed on “…essentially pure substances which are stable in water and not volatile”. Since this statement cannot be applied to the test item, the guideline cannot be followed in this case.

 

Conclusion

Study results showed that the test item N-(2 -4 -amino-n-ethyl-m-toluidino)ethyl)methanesulphonamide is unstable in aqueous solutions and is also severely light sensitive.

Within 2 hours of contact with water a water solubility of approximately 4 g/L at pH 7 and 25°C could be estimated, but clear deterioration of the sample occurs with 24 hours.

For this reason it was not possible to quantify the water solubility.

Applicant's summary and conclusion