Registration Dossier

Administrative data

Description of key information

Read-across: Guinea pig, Buehler test, occlusive, not sensitising

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH
Please refer to the Read-across statement attached under section 13.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
This Read-Across is based on the hypothesis that the target and the source substances have similar environmental fate and (eco)toxicological properties because both substances have the same common compound octyl sulfonate while another main constituent of the target substance octyl disulfonate is considered to have similar level of toxicity as octyl sulfonate. Other non-common compounds represented by impurities are considered not to influence the read-across validity because they are either structurally identical in the target and in the source substances or, if different, do not contribute to the toxicity effects because they are also anionic sulfonates with the same functional groups and their content is very low.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Please refer to the Read-across statement attached under section 13.

3. ANALOGUE APPROACH JUSTIFICATION
PAS category members are predicted to be non-sensitising based on structural and chemical similarity with the other two sub-groups of ANS category - alkyl sulfates and the α-olefin sulfonates (SIDS, 2007). The source chemical was also non-sensitising in the skin sensitisation test.
Since the main constituents and most of the impurities of the target substance are also anionic surfactants with the same functional groups and the same length of hydrophobic carbon octyl chain, the same mode of toxicological action is expected for the target and the source substances. The constituents of the target substance do not possess functional groups associated with other modes of action or toxicity effects. Toxicokinetic behavior of the constituents of the target substance is expected to be essentially the same as for the source substance. The second main constituent octyl disulfonate does not bear a skin sensitisation hazard because it has no functional groups associated with hypersensitivity reactions to skin. This constituent does not possess ability to bind to proteins as profiled by the general mechanistic profiling method “Protein binding by OECD” and by “Protein binding by OASIS” and by all endpoint specific profiling methods related to protein binding included into the OECD QSAR Toolbox. Thus a skin sensitisation is not likey. The impurities are also structurally similar to the main constituents with octyl rest and sulfonate groups at different positions. They have also no functional groups leading to protein binding and subsequently to a hapten formation. The minor amounts of other impurities (hexadecyl sulfonate, octyl sulfinosulfonate, benzoic acid and tert-butyl alcohol) are not expected to induce skin sensitisation because they have no functional groups participating in a hapten formation and eliciting skin sensitisation as well.
Therefore, it is predicted that the target substance would not possess skin sensitisation potential if it was tested in a skin sensitisation study.

4. DATA MATRIX
Please refer to the Read-across statement attached under section 13.
Reason / purpose:
read-across source
Positive control results:
no positive control
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
5 % w/v
No. with + reactions:
5
Total no. in group:
19
Clinical observations:
not specified
Remarks on result:
other: contradictory information on challenge concentration in report (reported as 5 %w/v and 10 % w/v)
Remarks:
predicted result from the source substance
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
5 % w/v
No. with + reactions:
5
Total no. in group:
19
Clinical observations:
not specified
Remarks on result:
other: contradictory information on challenge concentration in report (reported as 5 %w/v and 10 % w/v)
Remarks:
predicted result from the source substance
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
5 % w/v
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
not specified
Remarks on result:
other: contradictory information on challenge concentration in report (reported as 5 %w/v and 10 % w/v)
Remarks:
predicted result from the source substance
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
5 % w/v
No. with + reactions:
3
Total no. in group:
10
Clinical observations:
not specified
Remarks on result:
other: contradictory information on challenge concentration in report (reported as 5 %w/v and 10 % w/v)
Remarks:
predicted result from the source substance
Group:
positive control
Remarks on result:
not measured/tested

Table 1: Skin grades following primary challenge of the test item in guinea pigs

Animal No.

Sex

Numerical Score

24-hour

48-hour

Test Material (10 % w/v in distilled water) in Induced Animals

T-1 YL327

M

0

0

T-2 YL327

M

0

0

T-3 YL327

M

0

0

T-4 YL327

M

0

0

T-5 YL327

M

0

0

T-6YL327

M

0

0

T-7 YL327

M

0

±

T-8 YL327

M

0

0

T-9YL327

M

0

0

T-10YL327

M

0

±

T-11YL327

F

0

0

T-12YL327

F

0

0

T-13YL327

F

0

0

T-14YL327

F

0

±

T-15YL327

F

±

±

T-16YL327

F

0

0

T-17 YL327

F

0

0

T-18 YL327

F

0

0

T-19YL327

F

FD

FD

T-20 YL327

F

0

±

 

 

Mean 0.03

Mean 0.1

Test Material (10 % w/v in distilled water) in Naive Animals

C-21YL327

M

0

0

C-22 YL327

M

0

0

C-23 YL327

M

0

0

C-24YL327

M

0

±

C-25 YL327

M

0

0

C-26YL327

F

0

±

C-27 YL327

F

0

0

C-28 YL327

F

0

0

C-29YL327

F

0

±

C-30YL327

F

0

0

 

 

Mean 0.0

Mean 0.2

±=slight patchy erythema (Grades of + are equal to 0.5 for calculating the mean)

FD = Animal found dead following third induction.Necropsy showed lungs pale, liver pale, abdominal cavity filled with a red blood-like material, and slight post-mortem autolysis.

Interpretation of results:
GHS criteria not met
Conclusions:
The potential of the source substance sodium octane-1-sulphonate monohydrate (EC 226-195-4; CAS 5324-84-5) as a 25 % w/v formulation in distilled water to produce a delayed contact hypersensitivity response in guinea pigs was evaluated in a modification of the Buehler test.
The incidence of grade + responses in the test group (5 of 19) was compared to that of the naive control group, (3 of 10) at primary challenge. The incidence and severity of the responses in the test group was essentially comparable to that produced by the naive control group indicating that sensitisation had not been induced. The same result is predicted for the target substance.
Executive summary:

The potential of the source substance sodium octane-1-sulphonate monohydrate (EC 226-195-4; CAS 5324-84-5) to produce delayed contact hypersensitivity in guinea pigs was evaluated by a modification of the Buehler test. The test material, as a 25 % w/v formulation in distilled water, was applied to the backs of male and female Hartley guinea pigs for three six-hour periods at weekly intervals. Group sizes were 20 animals for the test group and 10 animals for the naive control group. Approximately two weeks after the last induction session, the test material prepared as a 5 % w/v formulation in distilled water was reapplied to the test animals for six hours. The test material was also applied to ten naive control animals. The next day the sites were depilated and scored for severity of response 24-hours and 48-hours after removal of the patches. The incidence of grade + responses in the test group (5 of 19) was compared to that of the naive control group, (3 of 10) at primary challenge. The incidence and severity of the responses in the test group was essentially comparable to that produced by the naive control group indicating that sensitisation had not been induced.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available
Additional information:

The potential of sodium octane-1-sulphonate monohydrate (EC 226-195-4; CAS 5324-84-5) to produce delayed contact hypersensitivity in guinea pigs was evaluated by a modification of the Buehler test. The test material, as a 25 % w/v formulation in distilled water, was applied to the backs of male and female Hartley guinea pigs for three six-hour periods at weekly intervals. Group sizes were 20 animals for the test group and 10 animals for the naive control group. Approximately two weeks after the last induction session, the test material prepared as a 5 % w/v formulation in distilled water was reapplied to the test animals for six hours. The test material was also applied to ten naive control animals. The next day the sites were depilated and scored for severity of response 24-hours and 48-hours after removal of the patches. The incidence of grade + responses in the test group (5 of 19) was compared to that of the naive control group, (3 of 10) at primary challenge. The incidence and severity of the responses in the test group was essentially comparable to that produced by the naive control group indicating that sensitisation had not been induced.

Justification for classification or non-classification

Based on the available data on the source substance, the registered substance does not need to be classified according to Regulation (EC) No 1272/2008.