N-[3-(dimethylamino)propyl]dodecanamide N-oxide

Partition coefficient

Administrative data

Endpoint:

partition coefficient

Remarks:

by estimation method

Type of information:

experimental study

Adequacy of study:

key study

Study period:

07 Jan - 17 Feb 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Cross-reference

Reason / purpose for cross-reference:

assessment report

Reference

Endpoint:

water solubility

Remarks:

by critical micelle concentration (CMC)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

05 Feb - 20 Feb 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: EC A.5

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

other: OECD 115

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

other: ISO 4311

Deviations:

not specified

GLP compliance:

yes

Type of method:

other: OECD harmonised ring method for CMC determination

Water solubility:

68 mg/L

Conc. based on:

test mat.

Temp.:

20 °C

Remarks on result:

other: CMC measurement

Results:

Preliminary test--

The results of the test solutions prepared on the first day to estimate the CMC, are summarized below. The individual measurements were obtained with a coefficient of variation of < 0.2 mN/m. The estimated critical micelle concentration was 69 mg/L.

 

Surface tension was measured at 1.002 mg/L, 10.018 mg/L, 100.86 mg/L, 1005.9 mg/L, and 10016 mg/L. Measured average values, respectively, were: 71.34 mN/m, 54.39 mN/m, 22.35 mN/m, 27.95 mN/m, and 29.67 mN/m.

 

Main study--

The results of the main study on the determination of the CMC on the second day, are summarized below. The individual measurements were obtained with a coefficient of variation of < 0.2 mN/m.

 

Surface tension was measured at 5.0017 mg/L, 25.029 mg/L, 50.273 mg/L, 201.94 mg/L, and 500.88 mg/L. Measured average values, respectively, were: 64.97 mN/m, 39.35 mN/m, 31.13 mN/m, 22.86 mN/m, and 25.43 mN/m.

 

Summary of the Determination of the Surface Tension of the Test Item Solutions:

Sample	Concentration C[mg/L]	Log C	Surface tension [mN/m]
1	5.0017	0.7	64.97
2	25.029	1.4	39.35
3	50.273	1.7	31.13
4	201.94	2.3	22.86
5	500.88	2.7	25.43
6	2031.7	3.3	28.97

The results above were used for calculation of the log C value. The plot of the surface tension of the test solutions as function of log C is summarized by 2 trendlines. The CMC was determined from the intersection of the two trendlines y1 and y2. Trendline y1 was obtained using the data of the test solutions with test item concentrations of 5.0017, 25.029 and 50.273 mg/L. Trendline y2 was obtained from the mean surface tension of the test solutions with test item concentrations of 201.94, 500.88 and 2031.7 mg/L. The intersection was calculated to be at a log C value of 1.83. It corresponded with a CMC of 68 mg/L.

 

Plot of Surface tension versus log C (concentration)-- 

Trendline y1 has equation: y1 = -34.267x + 88.542

Trendline y2 has equation: y2 = 25.753

 

Conclusion--

The CMC of the test item was determined by measuring the surface tension of test item solutions at different test item concentrations. The Critical Micelle Concentration (CMC) of the test item is 68 mg/L.

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Reference 2

Reference Type:

other: Amendment

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

Deviations:

not specified

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient - Shake Flask Method)

Deviations:

not specified

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7550 (Partition Coefficient, n-octanol / H2O, Shake Flask Method)

Deviations:

not specified

GLP compliance:

yes

Type of method:

estimation method (solubility ratio)

Partition coefficient type:

octanol-water

Test material

Test material information

Constituent 1

Reference substance name:

N-[3-(dimethylamino)propyl]dodecanamide N-oxide

EC Number:

263-218-7

EC Name:

N-[3-(dimethylamino)propyl]dodecanamide N-oxide

Cas Number:

61792-31-2

Molecular formula:

C17H36N2O2

IUPAC Name:

N-[3-(dimethylamino)propyl]dodecanamide N-oxide

Study design

Analytical method:

other: visual observation for n-octanol solubility

Results and discussion

Partition coefficient

Type:

log Pow

Partition coefficient:

>= 2.2 - < 3.2

Temp.:

20 °C

Remarks on result:

other: Gel forms at Log Pow = 3.2

Details on results:

Test sample at 102.78 g/L was not clear and formed a gel. This corresponds to Log Kow = 3.18, or 3.2 (rounded).

Any other information on results incl. tables

Results:

n-octanol solubility:

After the stirring period, the test sample at concentration of 0.096 g/L, 1.31 g/L, 5.54 g/L and

11.34 g/L were clear, and no undissolved test item was observed. The test sample at concentration of 102.78 g/L was not clear and formed a gel. Due to the formation of the gel, it was not possible to determine the n-octanol solubility by using the validated analytical method. From this, it was concluded that the n-octanol solubility determined by visual evaluation was ≥ 11.34 g/L at 20°C.

Critical micelle concentration:

Critical micelle concertation has determined to be 0.068 g/L (see water solubility endpoint).

Partition coefficient-estimation method:

The Pow, calculated as the quotient of the n-octanol and critical micelle concertation, is ≥ 1.7E2 and < 1.5E4 at 20 deg C. It corresponds with a log Pow value of ≥ 2.2 and < 3.2. (Note: upper limit is indicated in report amendment).

Justification (from Final Report Amendment No. 1):

For the risk assessment it is necessary to establish the upper limit for the partition coefficient. Since at 102.78 g/L solubility of test item in n-octanol was exceeded (gel was formed) this value is used for the estimation of the upper limit of the partition coefficient.

Conclusion:

The test item is a surface active compound. Therefore it was considered that the estimation method was the best suited method for the determination of the Pow of N-[3- (dimethyloxidoamino)propyl]-dodecanamide, using the solubility in n-octanol and critical micelle concentration (CMC) as a solubility limit in water. The partition coefficient (Pow) of N-[3-(dimethyloxidoamino)propyl]-dodecanamide by applied estimation method at 20 °C was ≥ 1.7E2. It corresponds with a log Pow value of ≥ 2.2.