Benzenesulfonic acid, 4-C10-13-alkyl derivs.-, salts with amines, C16-C18 (even numbered) alkyl

Endpoint summary

Description of key information

Benzenesulfonic acid, 4-C10-13-alkyl derivs.-, salts with amines, C16-C18 (even numbered) alkyl is a UVCB with a Log Kow > 3.5. Consequently, it is not technically feasible or relevant to conduct in vitro skin sensitisation testing using the OECD Testing Guidelines 442C (Direct Peptide Reactivity Assay) and 442E (h-CLAT and U-SENS assays).

 

The skin sensitisation potential of the registered substance was investigated in accordance with the OECD Testing Guideline 442D (KeratinoSens). The study was GLP-compliant and provided a negative result.

 

The capacity of Benzenesulfonic acid, 4-C10-13-alkyl derivs.-, salts with amines, C16-C18 (even numbered) alkyl to be sensitising to the skin can be expected to be driven by the properties of its individual constituents, which belong either to the Primary Aliphatic Amines or Linear Alkylbenzene Sulphonates categories.
Testing conduct on two representative members of the Primary Aliphatic Amines category concluded that these substances are not sensitising to the skin, therefore, it can be predicted that the amine constituents of Benzenesulfonic acid, 4-C10-13-alkyl derivs.-, salts with amines, C16-C18 (even numbered) alkyl are not skin sensitisers.
Testing conduct on the C10-13 Alkylbenzene sulfonic acid, sodium salt indicated that it was not sensitising to the skin, therefore, it can be predicted that the acid constituents of Benzenesulfonic acid, 4-C10-13-alkyl derivs.-, salts with amines, C16-C18 (even numbered) alkyl are not skin sensitisers.

 

While only one key event out of three was investigated, available information on the amine and acid constituents of the substance supports the conclusion that Benzenesulfonic acid, 4-C10-13-alkyl derivs.-, salts with amines, C16-C18 (even numbered) alkyl is not sensitising to the skin and does not meet the criteria for classification in accordance with Regulation (EC) No 1272/2008.

 

It is not considered relevant to conduct subsequent animal testing on the substance to further assess its capacity to induce skin sensitisation.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vitro

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 10 Feb 2021 to 16 Apr 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 442D (In Vitro Skin Sensitisation: ARE-Nrf2 luciferase KeratinoSens™ test method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

ARE-Nrf2 luciferase KeratinoSens™ test method

Details of test system:

Keratinoses transgenic cell line [442D]

Details on the study design:

PREPARATION OF TEST SOLUTIONS
- Preparation of the test chemical stock solution: The test item was dissolved in DMSO to a final concentration of 40 mg/mL (clear colourless solution). The stock solution was treated with ultrasonic waves until the test item had completely dissolved.
- Preparation of the test chemical serial dilutions: From the stock 11 spike solutions in DMSO were prepared (2-fold dilution series). The stock and spike solutions were diluted 25-fold with exposure medium.
- Preparation of the positive controls: A 2-fold dilution series ranging from 0.78 to 25 mM were prepared in DMSO and diluted, so that the final concentration of the positive control ranges from 7.8 to 250 µM (final concentration DMSO of 1%).
- Preparation of the vehicle control: The vehicle control was 1% DMSO in exposure medium. Eighteen wells were tested per plate.
- Stable dispersion obtained: YES

APPLICATION OF THE TEST CHEMICAL AND CONTROL SUBSTANCES
- Number of experiments: Three
- Test chemical concentrations: 100, 50, 25, 13, 6.3, 3.1, 1.6, 0.78, 0.39, 0.20, 0.10 and 0.05 µg/mL (final concentration DMSO of 1%) in the first experiment and in final test concentrations of 25, 13, 6.3, 3.1, 1.6, 0.78, 0.39, 0.20, 0.10, 0.05, 0.02 and 0.01 µg/mL (final concentration DMSO of 1%)
- Application procedure: The medium was removed and replaced with fresh exposure medium (150 µL culture medium containing serum but without Geneticin) to which 50 µL of the 25-fold diluted test chemical and control items were added.
- Exposure time: 48 hours ± 1
- Study evaluation and decision criteria used: In accordance with the OECD TG 442D
- Description on study acceptance criteria: In accordance with the OECD TG 442D

SEEDING AND INCUBATION
- Seeding conditions: Distributed into 96-well plates (10,000 cells/well) in basic medium. Passage number used was P+4, P+10 and P+12 in experiment 1, 2 and 3, respectively
- Incubation conditions: Humid atmosphere of 80 - 100% (actual range 48 – 95%), containing 5.0 ± 0.5% CO2 in air in the dark at 37.0 ± 1.0°C (actual range 35.5 – 38.8°C)
- Precipitation noted: NO

LUCIFERASE ACTIVITY MEASUREMENTS
- Choice of luminometer: TECAN Infinite® M200 Pro Plate Reader
- Lysate preparation: Steady-Glo Luciferase Assay Substrat

DATA EVALUATION
- Cytotoxicity assessment: The IC50 and IC30 concentration values for 50% and 30% reduction of cellular viability

Vehicle / solvent control:

DMSO

Negative control:

not applicable

Positive control:

EGDMA (120 M) [442D]

Positive control results:

The EC1.5 of the positive control was within two standard deviations of the historical mean (35 µM, 45 µM and 27 µM in experiment 1, 2 and 3, respectively). A dose response was observed and the induction at 250 µM was higher than 2-fold (2.65-fold, 5.08-fold and 3.59-fold in experiment 1, 2 and 3, respectively).

Group:

test chemical

Run / experiment:

run/experiment 1

Parameter:

IC30 [442D]

Value:

2 µg/mL

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Group:

test chemical

Run / experiment:

run/experiment 2

Parameter:

IC30 [442D]

Value:

2.2 µg/mL

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Group:

test chemical

Run / experiment:

run/experiment 3

Parameter:

IC30 [442D]

Value:

4.3 µg/mL

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Group:

test chemical

Run / experiment:

run/experiment 1

Parameter:

IC50 [442D]

Value:

2.5 µg/mL

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Group:

test chemical

Run / experiment:

run/experiment 2

Parameter:

IC50 [442D]

Value:

3.7 µg/mL

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Group:

test chemical

Run / experiment:

run/experiment 3

Parameter:

IC50 [442D]

Value:

6.6 µg/mL

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Group:

test chemical

Run / experiment:

run/experiment 1

Parameter:

Imax [442D]

Value:

1.92 %

Cell viability:

89%

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Group:

test chemical

Run / experiment:

run/experiment 2

Parameter:

Imax [442D]

Value:

1.1 %

Cell viability:

96%

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Group:

test chemical

Run / experiment:

run/experiment 3

Parameter:

Imax [442D]

Value:

1.22 %

Cell viability:

96%

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Outcome of the prediction model:

negative [in vitro/in chemico]

Other effects / acceptance of results:

All tests passed the acceptance criteria:
• The luciferase activity induction obtained with the positive control, Ethylene dimethacrylate glycol, was statistically significant above the threshold of 1.5-fold in at least one concentration.
• The EC1.5 of the positive control was within two standard deviations of the historical mean (35 µM, 45 µM and 27 µM in experiment 1, 2 and 3, respectively). A dose response was observed and the induction at 250 µM was higher than 2-fold (2.65-fold, 5.08-fold and 3.59-fold in experiment 1, 2 and 3, respectively).
• Finally, the average coefficient of variation of the luminescence reading for the vehicle (negative) control DMSO was below 20% (6.3%, 8.2% and 11% in experiment 1, 2 and 3, respectively).
Overall it is concluded that the test conditions were adequate and that the test system functioned properly.

Table 1          
Overview Luminescence Induction and Cell Viability of the test item in Experiment 1, 2 and 3

Concentration (µg/mL)	0.05	0.10	0.20	0.39	0.78	1.6	3.1	6.3	13	25	50	100
Exp 1 luminescence	1.85^***	1.86^***	1.92^***	1.70^***	1.65^***	1.45	1.04	0.11	0.00	0.00	0.01	0.00
Exp 1 viability (%)	92	90	89	88	88	86	25	0.14	-0.15	-0.06	-0.08	-0.07
Concentration (µg/mL)	0.01	0.02	0.05	0.10	0.20	0.39	0.78	1.6	3.1	6.3	13	25
Exp 2 luminescence	0.93	0.94	0.97	1.07	1.05	1.10	0.96	0.96	0.73	0.29	0.00	0.00
Exp 2 viability (%)	124	103	103	98	95	96	87	76	60	7.2	0.05	0.11
Exp 3 luminescence	0.98	1.05	1.11	1.18	1.16	1.22	1.09	0.99	0.84	0.57	0.36	0.00
Exp 3 viability (%)	92	91	91	92	90	96	89	88	81	52	11	0.47

^*** p<0.001 Student’s t test

 

Table 2          
Overview Luminescence Induction and Cell Viability Positive Control EDMG in Experiment 1, 2 and 3

Concentration (µM)	7.8	16	31	63	125	250
Exp 1 luminescence	1.08	1.30	1.47	1.77^***	2.10^***	2.65^***
Exp 1 viability (%)	107	110	108	114	117	111
Exp 2 luminescence	1.05	1.05	1.17	1.93	1.93^*	5.08
Exp 2 viability (%)	128	127	122	117	113	106
Exp 3 luminescence	1.07	1.33	1.57^***	2.02^***	2.77^***	3.59^***
Exp 3 viability (%)	99	96	99	110	107	109

^*** p<0.001 Student’s t test, ^* p<0.05 Student’s t test

 

Table 3          
Overview EC_1.5, I_max, IC₃₀ and IC₅₀ Values

	EC1.5 (µg/mL)	Imax	IC30 (µg/mL)	IC50 (µg/mL)
Test item Experiment 1	0.03	1.92	2.0	2.5
Test item Experiment 2	NA	1.10	2.2	3.7
Test item Experiment 3	NA	1.22	4.3	6.6
	EC1.5 (µM)	Imax	IC30 (µM)	IC50 (µM)
Pos Control Experiment 1	35	2.65	NA	NA
Pos Control Experiment 2	45	5.08	NA	NA
Pos Control Experiment 3	27	3.59	NA	NA

NA = Not applicable

 

Table 4          
Historical Control Data for the KeratinoSens Studies

	Positive control
	EC1.5 (µM)	Imax
Range (mean ± 2x SD)	-3.0 – 120	-5.65 – 12.15
Mean	58.5	3.25
SD	30.7	4.45
n	503	503

SD = Standard deviation

n = Number of observations

The above mentioned historical control data range of the controls were obtained by collecting all data over the period of November 2017 to November 2020.

 

Interpretation of results:

GHS criteria not met

Conclusions:

Benzenesulfonic acid, 4-C10-13-alkyl derivs.-, salts with amines, C16-C18 (even numbered) alkyl (EC 953-378-2) is classified as negative (no activation of the antioxidant/electrophile responsive element (ARE)-dependent pathway in keratinocytes) under the experimental conditions.

Executive summary:

The ability of Benzenesulfonic acid, 4-C10-13-alkyl derivs.-, salts with amines, C16-C18 (even numbered) alkyl (EC 953-378-2) to activate the antioxidant/electrophile responsive element (ARE)-dependent pathway in the KeratinoSens assay was investigated.

The test item was dissolved in dimethyl sulfoxide (DMSO) at 10 in the first experiment and 2.5 mg/mL in the second and third experiment. From this stock 11 spike solutions in DMSO were prepared. The stock and spike solutions were diluted 100-fold in the assay resulting in test concentrations of 0.05 – 100 µg/mL (2-fold dilution series) in the first experiment and in test concentrations of 0.01 – 25 µg/mL (2-fold dilution series) in the second and third experiment. The highest test concentration was considered to be the limit of solubility. No precipitate was observed at any dose level tested. Three independent experiments were performed.

All tests passed the acceptance criteria:

• The luciferase activity induction obtained with the positive control, Ethylene dimethacrylate glycol, was statistically significant above the threshold of 1.5-fold in at least one concentration.


• The EC₅ of the positive control was within two standard deviations of the historical mean (35 µM, 45 µM and 27 µM in experiment 1, 2 and 3, respectively). A dose response was observed and the induction at 250 µM was higher than 2-fold (2.65-fold, 5.08-fold and 3.59-fold in experiment 1, 2 and 3, respectively).


• Finally, the average coefficient of variation of the luminescence reading for the vehicle (negative) control DMSO was below 20% (6.3%, 8.2% and 11% in experiment 1, 2 and 3, respectively).

Overall it is concluded that the test conditions were adequate and that the test system functioned properly.

In the first experiment, the test item showed toxicity (IC₃₀ value of 2.0 µg/mL and IC₅₀ value of 2.5 µg/mL). An induction of the luciferase activity (EC_1.5 values of 0.03 µg/mL) was measured. The maximum luciferase activity induction (I_max) was 1.92-fold leading to an individual run conclusion of positive since positive results (>1.5-fold induction) were observed at test concentrations < 200 µg/mL with a cell viability of >70% compared to the vehicle control.

In the second experiment, the test item showed toxicity (IC₃₀ value of 2.2 µg/mL and IC₅₀ value of 3.7 µg/mL). No biologically relevant induction of the luciferase activity (no EC_1.5 value) was measured at any of the test concentrations The maximum luciferase activity induction (I_max) was 1.10-fold leading to an individual run conclusion of negative since negative results (<1.5-fold induction) were observed at test concentrations < 200 µg/mL with cell viability < 70% compared to the vehicle control.

Since the first two experiments were not concordant, a third experiment was performed to provide a final conclusion. 

In the third experiment, the test item showed toxicity (IC₃₀ value of 4.3 µg/mL and IC₅₀ value of 6.6 µg/mL). No biologically relevant induction of the luciferase activity (no EC_1.5 value) was measured at any of the test concentrations. The maximum luciferase activity induction (I_max) was 1.22-fold leading to an individual run conclusion of negative since negative results (<1.5-fold induction) were observed at test concentrations < 200 µg/mL with cell viability
< 70% compared to the vehicle control.

Overall, the test item is classified as negative in the KeratinoSens assay since negative results (<1.5-fold induction) were observed in two out of three experiments at test concentrations < 200 µg/mL with cell viability < 70% compared to the vehicle control.

In conclusion, Benzenesulfonic acid, 4-C10-13-alkyl derivs.-, salts with amines, C16-C18 (even numbered) alkyl (EC 953-378-2) is classified as negative (no activation of the antioxidant/electrophile responsive element (ARE)-dependent pathway in keratinocytes) under the experimental conditions.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In vitro skin sensitisation

The ability of Benzenesulfonic acid, 4-C10-13-alkyl derivs.-, salts with amines, C16-C18 (even numbered) alkyl (EC 953-378-2) to activate the antioxidant/electrophile responsive element (ARE)-dependent pathway in the KeratinoSens assay was investigated.

The test item was dissolved in dimethyl sulfoxide (DMSO) at 10 in the first experiment and 2.5 mg/mL in the second and third experiment. From this stock 11 spike solutions in DMSO were prepared. The stock and spike solutions were diluted 100-fold in the assay resulting in test concentrations of 0.05 – 100 µg/mL (2-fold dilution series) in the first experiment and in test concentrations of 0.01 – 25 µg/mL (2-fold dilution series) in the second and third experiment. The highest test concentration was considered to be the limit of solubility. No precipitate was observed at any dose level tested. Three independent experiments were performed.

All tests passed the acceptance criteria:

• The luciferase activity induction obtained with the positive control, Ethylene dimethacrylate glycol, was statistically significant above the threshold of 1.5-fold in at least one concentration.


• The EC₅ of the positive control was within two standard deviations of the historical mean (35 µM, 45 µM and 27 µM in experiment 1, 2 and 3, respectively). A dose response was observed and the induction at 250 µM was higher than 2-fold (2.65-fold, 5.08-fold and 3.59-fold in experiment 1, 2 and 3, respectively).


• Finally, the average coefficient of variation of the luminescence reading for the vehicle (negative) control DMSO was below 20% (6.3%, 8.2% and 11% in experiment 1, 2 and 3, respectively).

Overall it is concluded that the test conditions were adequate and that the test system functioned properly.

In the first experiment, the test item showed toxicity (IC₃₀ value of 2.0 µg/mL and IC₅₀ value of 2.5 µg/mL). An induction of the luciferase activity (EC_1.5 values of 0.03 µg/mL) was measured. The maximum luciferase activity induction (I_max) was 1.92-fold leading to an individual run conclusion of positive since positive results (>1.5-fold induction) were observed at test concentrations < 200 µg/mL with a cell viability of >70% compared to the vehicle control.

In the second experiment, the test item showed toxicity (IC₃₀ value of 2.2 µg/mL and IC₅₀ value of 3.7 µg/mL). No biologically relevant induction of the luciferase activity (no EC_1.5 value) was measured at any of the test concentrations The maximum luciferase activity induction (I_max) was 1.10-fold leading to an individual run conclusion of negative since negative results (<1.5-fold induction) were observed at test concentrations < 200 µg/mL with cell viability < 70% compared to the vehicle control.

Since the first two experiments were not concordant, a third experiment was performed to provide a final conclusion. 

In the third experiment, the test item showed toxicity (IC₃₀ value of 4.3 µg/mL and IC₅₀ value of 6.6 µg/mL). No biologically relevant induction of the luciferase activity (no EC_1.5 value) was measured at any of the test concentrations. The maximum luciferase activity induction (I_max) was 1.22-fold leading to an individual run conclusion of negative since negative results (<1.5-fold induction) were observed at test concentrations < 200 µg/mL with cell viability
< 70% compared to the vehicle control.

Overall, the test item is classified as negative in the KeratinoSens assay since negative results (<1.5-fold induction) were observed in two out of three experiments at test concentrations < 200 µg/mL with cell viability < 70% compared to the vehicle control.

In conclusion, Benzenesulfonic acid, 4-C10-13-alkyl derivs.-, salts with amines, C16-C18 (even numbered) alkyl (EC 953-378-2) is classified as negative (no activation of the antioxidant/electrophile responsive element (ARE)-dependent pathway in keratinocytes) under the experimental conditions

 

Additional information

Testing was conducted to investigate the skin sensitisation properties of three relevant analogues of Benzenesulfonic acid, 4-C10-13-alkyl derivs.-, salts with amines, C16-C18 (even numbered) alkyl.

The study on Coco alkyl amines conducted by Schropp (2008) can be considered as reliable without restrictions. Ten female guinea pigs along with five control animals were treated with the test substance using cotton seed oil as a vehicle. Based on the results of a pretest, a test substance concentration of 0.1% was used for intradermal induction (0.1 mL), followed by a 1% concentration at epidermal induction. Challenge was performed using a 0.5% substance concentration. For epidermal treatments, patches were loaded with 0.5 mL. In contrast to results of the pretest, no dermal irritation was observed after epidermal induction. After challenge treatment, 2/10 animals showed grade 1 erythema at the 24h reading (positive rate = 20%). One out of these positive animals showed scaling after 48 and 72h. It was concluded that the substance was not sensitising to the skin.

The study on Amines, hydrogenated tallow alkyl performed by Cuthbert (1979) can be considered as reliable with restrictions. Ten female guinea pigs along with five control animals were treated with the test item. At the intradermal induction stage, 0.5 ml test substance emulsified with 0.05ml Freund's adjuvant was injected s.c. (additional injections: 0.1 ml Freund's adjuvant alone + 0.1 ml test agent). Prior to injection, the test substance was diluted with water to 1% w/w. 6 days after injections, the skin at the treatment site was shaved once again and treated with 10% sodium lauryl sulfate to provoke an inflammatory reaction. 24 hours later, the treatment sites were occlusively covered with a 2 x 2 cm filter patch, saturated with 5% aqueous hydrogenated tallow alkylamines for 48 hours (topical induction). A 2% concentration of Amine HBG was selected for the final challenge. 14 days after the first challenge, the second challenge was performed (24h closed patch exposure). No positive responses were observed in the ten induced and rechallenged animals. It was concluded that the substance was not sensitising to the skin.

The potential of the analogue C10-13 Alkylbenzene sulfonic acid, sodium salt to be sensitising to skin was investigated (RBM, 1985). The study can be considered as reliable without restrictions. Ten male and ten female guinea pigs were given intradermal injections of 25% test solution. Control animals (5 male and 5 female) were given injections of vehicle only. One week later, a second induction was done by dermal exposure to 25% test solution for 24 hrs. Control animals were again exposed to vehicle only. On day 21, the challenge exposure was performed. All animals were exposed to 12.5% test solution dermally. Exposure was for 24 hrs, with observations made at 48 and 72 hrs after the start of exposure. No positive reactions were noted. It was concluded that the substance was not sensitising to the skin.

 

Justification for classification or non-classification

An in vitro skin sensitisation study was conducted on Benzenesulfonic acid, 4-C10-13-alkyl derivs.-, salts with amines, C16-C18 (even numbered) alkyl in accordance with the OECD Testing Guideline 442D. It provided a negative result.

A read-across approach was used to further assess the capacity of Benzenesulfonic acid, 4-C10-13-alkyl derivs.-, salts with amines, C16-C18 (even numbered) alkyl to induce skin sensitisation, in accordance with Annex XI of REACH.

It was concluded that the Benzenesulfonic acid, 4-C10-13-alkyl derivs.-, salts with amines, C16-C18 (even numbered) alkyl does not meet the criteria for classification in accordance with Regulation (EC) No 1272/2008.