(2-hydroxy-3-sulphopropyl)dimethyl[3-[(1-oxododecyl)amino]propyl]ammonium hydroxide

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 4 October 2012 to 25 January 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 123 (Partition Coefficient (1-Octanol / Water), Slow-Stirring Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

2012-12-15

Type of method:

slow-stirring method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

2.1

Temp.:

25 °C

pH:

>= 7.6 - <= 7.85

Remarks on result:

other: log Pow of the C12 fraction (weighted average value)

Results:

Calibration curve for 1 -octanol phases analysis

Reference of calibration solution	Peak area (area units)	Conc (mg/L)	Response factor	Final Volume (ml)	Dilution factor	Sample weight (mg)	Conc back-calc	Diff
	A	C= (w*P)/(V*Df)	RF = A/C	V	Df	w	C'= (A-b)/a	%
Lin 25%	1830264	19.31	9.48048E+04	100	4.0	20.11	18.49	-4.25%
Lin 25%	1845749	19.31	9.56069E+04	100	4.0	20.11	18.65	-3.37%
Lin 50%	3905839	39.71	9.83700E+04	100	1.0	10.34	40.46	1.89%
Lin 50%	3915468	39.71	9.86125E+04	100	1.0	10.34	40.56	2.14%
Lin 75%	5574447	57.14	9.75591E+04	100	1.0	14.88	58.12	1.72%
Lin 75%	5493480	57.14	9.61421E+04	100	1.0	14.88	57.26	0.21%
REF05	7463735	78.84	9.46752E+04	100	1.0	20.53	78.11	-0.91%
REF05	7502554	78.84	9.51676E+04	100	1.0	20.53	78.52	-0.39%
Lin 125%	9176261	96.38	9.52052E+04	100	1.0	25.10	96.24	-0.16%
Lin 125%	9169449	96.38	9.51346E+04	100	1.0	25.10	96.16	-0.23%
Lin 150%	10797715	112.59	9.59040E+04	100	1.0	29.32	113.40	0.72%
Lin 150%	10661311	112.59	9.46925E+04	100	1.0	29.32	111.95	-0.57%

Response function Peak Area = 94488.13*Concentration + 83143.53

The graph of the calibration curve is shown in Attachment 1.

Calibration curve for water phase analysis:

Reference of calibration solution	Peak area (area units)	Conc (mg/L)	Response factor	Final Volume (ml)	Dilution factor	Sample weight (mg)	Conc back-calc	Diff
	A	C= (w*P)/(V*Df)	RF = A/C	V	Df	w	C'= (A-b)/a	%
REF 05 dil20	369203	3.94	9.36645E+04	100	20	20.53	3.90	-1.01%
REF 05 dil20	351222	3.94	8.91028E+04	100	20	20.53	3.69	-6.34%
REF 05 dil10	699817	7.88	8.87696E+04	100	10	20.53	7.74	-1.78%
REF 05 dil10	710573	7.88	9.01340E+04	100	10	20.53	7.86	-0.25%
REF 05 dil5	1413337	15.77	8.96387E+04	100	5	20.53	16.03	1.65%
REF 05 dil5	1437975	15.77	9.12013E+04	100	5	20.53	16.32	3.49%
REF 05 dil4	1720595	19.71	8.73009E+04	100	4	20.53	19.60	-0.56%
REF 05 dil4	1733152	19.71	8.79380E+04	100	4	20.53	19.75	0.20%
REF 05 dil2,5	2735643	31.53	8.67520E+04	100	2.5	20.53	31.40	-0.44%
REF 05 dil2,5	2734947	31.53	8.67299E+04	100	2.5	20.53	31.39	-0.48%

Response function Peak Area = 86061.61*Concentration + 33709.60

The graph of the calibration curve is shown in Attachment 1.

Main test results:

The three filtered aliquots of 50 mL obtained from the 1-octanol saturated phase were analyzed and the concentrations of the C12 fraction were found to be equal to 1.86 g/L (4.84 g/L of test item). This value is lower than the theoretical one and shows a weak dissolution of test item during the two hours of preparation.

The results for the C12 fraction concentration in the two phases at each time are given in the following table:

Vessel number and sampling time	Concentration in the aqueous phase (mg/l)	Concentration in the 1-octanol phase (mg/l)	Pow ratio	log Pow
12-091 Z1T=93H	12.70	1499	118.00	2.07
12-091 Z2T=93H	11.44	1524	133.20	2.12
12-091 Z3T=93H	12.14	1558	128.30	2.11
12-091 Z1T=117H	11.24	1497	133.20	2.12
12-091 Z2T=117H	11.94	1539	128.90	2.11
12-091 Z3T=117H	11.78	1582	134.30	2.13
12-091 Z1T=137H	11.54	1503	130.20	2.11
12-091 Z2T=137H	12.18	1601	131.40	2.12
12-091 Z3T=137H	13.38	1629	121.70	2.09
12-091 Z1T=144H	11.48	1511	131.60	2.12
12-091 Z2T=144H	12.78	1513	118.40	2.07
12-091 Z3T=144H	13.26	1569	118.30	2.07
12-091 Z1T=163H	12.02	1489	123.90	2.09
12-091 Z2T=163H	12.14	1552	127.80	2.11
12-091 Z3T=163H	12.34	1599	129.60	2.11

The pH of the saturated water phase at the start of the test was 7.88 at 21 °C.The measured pH of the aqueous phases were between 7.60 and 7.85 at 21 °C.

The average value of log Pow of the different vessel units is calculated as the average of the results of the individual experimental units weighed with their respective variances.The results are shown in the following table.

Vessel Z1	Mean value Z1	Standard deviation Z1	Vessel Z2	Mean value Z2	Standard deviation Z2	Vessel Z3	Mean value Z3	Standard deviation Z3
2,07	2,102	0,02	2,12	2,106	0,02	2,11	2,102	0,02
2,12			2,11			2,13
2,11			2,12			2,09
2,12			2,07			2,07
2,09			2,11			2,11

	Mean / Vessel	Average	Standard deviation
Vessel Z1	2,102	2,103	0,02
Vessel Z2	2,106
Vessel Z3	2,102

Using the low stirring method, it was shown that the weighed average value of the 1-octanol/water partition coefficient log10 Pow of the C12 fraction present in test item is equal to 2.10 ± 0.02 at 25 ± .1°C.

Demonstration of attainment of equilibrium:

Achievement of chemical equilibrium is demonstrated by plotting for each vessel unit log Pow against time as shown in the figures shown in Attachment 2 where the slopes are very near to 0.

Conclusions:

Using the low stirring method, it was shown that the weighed average value of the 1-octanol/water partition coefficient log10 Pow of the C12 fraction present in test item is equal to 2.10 ± 0.02 at 25 ± 1°C.

Executive summary:

The n-octanol/water partition coefficient of the substance EC 939-455-3 (freeze-dried) was investigated in a GLP-compliant study performed in accordance with OECD Guideline 123 (Partition Coefficient (1-Octanol / Water), Slow-Stirring Method). The mean n-octanol/water partition coefficient log10 Pow of the C12 fraction present in test item was 2.10 ± 0.02 at 25°C.

Reference 2

Endpoint:

partition coefficient

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
C8-C18 AAPHS and C12 AAPHS have the same functional groups, and general composition. The main variable resides in the alkyl chain distribution.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source chemical = C8-18 cocamidopropyl hydroxysultaine (EC 939-455-3)
Target chemical = C12 cocamidopropyl hydroxysultaine (EC 242-893-1)

3. ANALOGUE APPROACH JUSTIFICATION
The alkyl C-chain distribution of the source chemical significantly overlaps with the one of the target chemical, the C12-alkyl derivative being the major constituent in both chemicals. The structural differences in side C-chains is not expected to lead to significant differences on phys-chem properties.

4. DATA MATRIX: see "Documentation and scientific justification of the read-across approach" in section 13.2.

Reason / purpose for cross-reference:

read-across source

Key result

Type:

log Pow

Partition coefficient:

2.1

Temp.:

25 °C

pH:

>= 7.6 - <= 7.85

Remarks on result:

other: log Pow of the C12 fraction (weighted average value)

Remarks:

read-across from EC 939-455-3

Conclusions:

By analogy with the source substance EC 939-455-3, a n-octanol/water partition coefficient log10 Pow of 2.10 ± 0.02 at 25°C was reported for the target substance (2-Hydroxy-3-sulphopropyl) dimethyl[3-[(1-oxododecyl) amino]propyl]ammonium hydroxide (EC 242-893-1).

Description of key information

As the n-octanol/water partition coefficient of the REACh substance (2-Hydroxy-3-sulphopropyl) dimethyl[3-[(1-oxododecyl) amino]propyl]ammonium hydroxide (EC 242-893-1) has not been determined experimentally, a read-across approach was followed to fill in the endpoint. The n-octanol/water partition coefficient of a structural analogue substance (= source substance EC 939-455-3, C8-18 AAPHS) was investigated in a GLP-compliant study (Meriaux, 2013) performed in accordance with OECD Guideline 123 (Partition Coefficient (1-Octanol / Water), Slow-Stirring Method). The mean n-octanol/water partition coefficient log10 Pow of the analogue substance was 2.10 ± 0.02 at 25°C. By analogy, a n-octanol/water partition coefficient log10 Pow of 2.10 ± 0.02 at 25°C is reported for the target REACh substance (EC 242-893-1, C12 AAPHS).

The alkyl C-chain distribution of the source substance EC 939-455-3 significantly overlaps with the one of the target substance EC 242-893-1, the C12-alkyl derivative being the major constituent in both chemicals. The structural differences in side C-chains is not expected to lead to significant differences on phys-chem properties.

Key value for chemical safety assessment

Log Kow (Log Pow):

2.1

at the temperature of:

25 °C

Additional information

The n-octanol/water partition coefficient of the structural analogue substance (= source substance EC 939-455-3) was investigated in a GLP-compliant study (Meriaux, 2013) performed in accordance with standard methods, without deviations. The study is considered as reliable (Klimisch 1) and was selected as key study for the endpoint of the target substance EC 242-893-1.