(benzothiazol-2-ylthio)acetic acid

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Remarks:

The Maximization test was selected since the test substance is a surfactant and the Local Lymph Node Assay as preferred alternative has shown to provide false positive results for surfactants.

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2014-08-19 to 2014-09-19

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

The Maximization test was selected since the test substance is a surfactant and the Local Lymph Node Assay as preferred alternative has shown to provide false positive results for surfactants.

Test material

Test material information

Constituent 1

Reference substance name:

(benzothiazol-2-ylthio)acetic acid

EC Number:

228-565-0

EC Name:

(benzothiazol-2-ylthio)acetic acid

Cas Number:

6295-57-4

Molecular formula:

C9H7NO2S2

IUPAC Name:

2-(1,3-benzothiazol-2-ylsulfanyl)acetic acid

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Study design: in vivo (non-LLNA)

Induction

Route:

intradermal and epicutaneous

Vehicle:

polyethylene glycol

Concentration / amount:

induction, intra dermal: 2%
induction, epidermal: 50%

Day(s)/duration:

Day 1: intra dermal injection, Day 7: SDS 10% skin treatment, Day 8: epicutaneous, exposure 48h,

Adequacy of induction:

non-irritant substance, but skin pre-treated with 10% SDS

Challenge

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

polyethylene glycol

Concentration / amount:

50%

Day(s)/duration:

Day 23: epidermal challenge, exposure 24h

Adequacy of challenge:

not specified

No. of animals per dose:

10 females (Experimental group)
5 females (control group)

Details on study design:

Test substance formulations (w/w) were prepared within 4 hours prior to each treatment. No correction was made for purity/composition of the test substance and no adjustment was made for specific gravity of the vehicle. Homogeneity was obtained to visually acceptable levels. In order to obtain homogeneity, the test substance (formulations) were heated in a water bath with a maximum temperature of 79.9 ºC for a maximum of 53 minutes. The test substance (formulations) were allowed to cool down to a temperature of maximally 40 ºC prior to dosing.
A preliminary irritation study was conducted in four animals in order to select test substance concentrations to be used in the main Study. The selection of concentrations were 50%, 20%, 10%, 5%, 2%, 1% in propylene glycol as vehicle. The test system and procedures were identical to those used during the main study, unless otherwise specified.

Challenge controls:

vehicle

Positive control substance(s):

yes

Remarks:

ALPHA-HEXYLCINNAMICALDEHYDE

Results and discussion

Positive control results:

The skin reactions observed in nine experimental animals in response to the 20% test substance (ALPHA-HEXYLCINNAMICALDEHYDE) concentration in the challenge phase were considered indicative of sensitisation, based on the absence of any response in the control animals. These results lead to a sensitization rate of 90 per cent to the 20% concentration. From these results, it was concluded that the female guinea pig of the Dunkin Hartley strain is an appropriate animal model for the performance of studies designed to evaluate the sensitizing potential of a substance in a Maximization type of test.

In vivo (non-LLNA)

Results

Results 1

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

20% ALPHA-HEXYLCINNAMICALDEHYDE

No. with + reactions:

8

Total no. in group:

10

Clinical observations:

Discrete or patchy erythema in one animal and moderate and confluent erythema in 7 animals

Remarks on result:

positive indication of skin sensitisation

Results 2

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

20% ALPHA-HEXYLCINNAMICALDEHYDE

No. with + reactions:

8

Total no. in group:

10

Clinical observations:

Discrete or patchy erythema in two animal and moderate and confluent erythema in 6 animals.

Remarks on result:

positive indication of skin sensitisation

Results 3

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

vehicle

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

no effects

Remarks on result:

no indication of skin sensitisation

Results 4

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

vehicle

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

no effects

Remarks on result:

no indication of skin sensitisation

Results 5

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

50% Test substance

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

no effects

Remarks on result:

no indication of skin sensitisation

Results 6

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

50% Test substance

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

no effects

Remarks on result:

no indication of skin sensitisation

Any other information on results incl. tables

Preliminary irritation study:

The necrosis seen at intradermal injection of the lowest concentration (2%) was considered to be caused mainly by polyethylene glycol rather than the test substance.

Based on the results, the test substance concentrations selected for the main study were a 2% concentration for the intradermal induction and a 50% concentration for the epidermal induction exposure.

No signs of irritation were observed to the highest test substance concentration epidermally tested. Therefore, the test site of all animals was treated with 10% SDS approximately 24 hours before the epidermal induction in the main study, to provoke a mild inflammatory reaction. A 50% test substance concentration was selected for the challenge phase.

Main study results:

-Induction phase:

The signs of necrosis seen in the control animals after the intradermal injection with vehicle only were in consistency with the results in the preliminary irritation study after injection of polyethylene glycol.

The reactions noted in the experimental and control animals after the epidermal induction exposure were considered to be enhanced by the SDS treatment.

-Challenge phase

No skin reactions were evident after the challenge exposure in the experimental and control animals.

No mortality occurred and no symptoms of systemic toxicity were observed in the experimental and control animals. Body weights and body weight gain of experimental animals remained in the same range as controls over the study period.

Tables:

Challenge treatment - control and treatment group

Test substance concentration: 50 % in polyethylene glycol (day 22)

Treated area: one flank

A.    Challenge treatment: individual values (day 24)

Time of observation: approx. 24 hours after removal of the patches (day 24)

Controls Animal no.	1	2	3	4	5
Value	0	0	0	0	0

 

Treated Animal no.	6	7	8	9	10	11	12	13	14	15
value	0	0	0	0	0	0	0	0	0	0

 

B.    Challenge treatment: individual values (day 25)

Time of observation: approx. 48 hours after removal of the patches (day 25)

Controls Animal no.	1	2	3	4	5
Value	0	0	0	0	0

 

Treated Animal no.	6	7	8	9	10	11	12	13	14	15
value	0	0	0	0	0	0	0	0	0	0

SCALE FOR GRADING CHALLENGE REACTIONS

According to the scale of EEC-Guideline B.6: Magnusson/Kligman grading scale for the evaluation of challenge patch test reactions

 

No visible change	0
Discrete or patchy erythema	1
Moderate and confluent erythema	2
Intense erythema and swelling	3
Not assessable	*

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Based on these results (Benzothiazol-2-ylthio)acetic acid does not have to be classified for skin sensitizing.

Executive summary:

In order to determine the sensitizing potential of the test substance an OECD 406 Magunsson &Kligman test in guinea pigs was performed. Test substance concentrations selected for the main study were based on the results of a preliminary study. In the main study, ten experimental animals were intradermally injected with a 2% concentration and epidermally exposed to a 50% concentration. Five control animals were similarly treated, but with vehicle alone (polyethylene glycol). Approximately 24 hours before the epidermal induction exposure all animals were treated with 10% SDS. Two weeks after the epidermal application all animals were challenged with a 50% test substance concentration and the vehicle. No skin reactions were evident after the challenge exposure in the experimental and control animals.

There was no evidence that (Benzothiazol-2-ylthio)acetic acid had caused skin hypersensitivity in the guinea pig, since no responses were observed in the experimental animals in response to a 50% test substance concentration in the challenge phase. This result indicates a sensitization rate of 0 per cent. Based on these results (Benzothiazol-2-ylthio)acetic acid does not have to be classified.