2,6-Diamino-4,5,6,7-tetrahydrobenzothiazole

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

from 21 november 1994 to 15 december 1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted in GLP compliance and in accordance with several internationally established guidelines (OECD, EEC, EPA guidelines, see below).

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Test guideline 1

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Study has been performed in 1985. LLNA method was not available at that time.

Test material

Test material information

Constituent 1

Reference substance name:

SND 919 CL2 Y

IUPAC Name:

SND 919 CL2 Y

Test material form:

other: solid

Details on test material:

- Name of test material (as cited in study report): SND 919 CL2 Y precursor 2; 2,6-Diamino-4,5,6,7-tetrahydro-benzothiazol
- Physical state: solid
- Purity test date: 12 July 1994
- Lot/batch No.: KRÖ 27

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

not specified

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Interfauna
- Age at study initiation: approx. 10 weeks
- Weight at study initiation: 636.8 +- 53.9 g
- Housing: individually in makrolon cages
- Diet (e.g. ad libitum): ad libitum, sniff guinea pig feed, Soest
- Water (e.g. ad libitum): ad libitum, demineralized water adjusted to pH 2.6 with HCl
- Acclimation period: 10 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23°C +- 2°C
- Humidity (%): 55 (50 to 65%)
- Photoperiod (hrs dark / hrs light): 12 : 12 hours light : dark

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal

Vehicle:

other: ethanol

Induction 2

Concentration / amount:

25% in ethanol

Challenge

Challenge 1

Route:

epicutaneous, occlusive

Vehicle:

other: ethanol

Challenge 2

Concentration / amount:

25% in ethanol

No. of animals per dose:

Group 1: 10 animals, negative control group
Group 2: 20 animals, 0.1 ml of 0.25 % test suspension

Details on study design:

RANGE FINDING TESTS: a preliminary dose-finding study was performed.
Test item was applied at concentrations of 0.25 % (w/v) for intra-dermal injection and 25% (w/v) for dermal application.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 6 for intradermal test, 1 for epicutaneous test.
- Exposure period: 24h (intradermal), 48h (epicutaneous)
- Test groups: 1 group, 20 animals per group
- Control group: 1 group, 10 animals per group

B. CHALLENGE EXPOSURE
- No. of exposures: 1 (epicutaneous)
- Day(s) of challenge: day 22 after first induction test
- Exposure period: 24 hours
- Test groups: 1 group, 10 animals per group
- Control group: 1 group, 5 animals per group
- Evaluation (hr after challenge): 24 and 48 hrs after exposure.

Challenge controls:

Challenge controls were treated with the text substance at c=25%

Positive control substance(s):

no

Results and discussion

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

25 % compound in ethanol

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 25 % compound in ethanol. No with. + reactions: 0.0. Total no. in groups: 10.0.

Results 2

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

25 % compound in ethanol

No. with + reactions:

2

Total no. in group:

10

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 25 % compound in ethanol. No with. + reactions: 2.0. Total no. in groups: 10.0.

Results 3

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

25 % test compound in ethanol

No. with + reactions:

17

Total no. in group:

20

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 25 % test compound in ethanol . No with. + reactions: 17.0. Total no. in groups: 20.0.

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

25 % test compound in ethanol

No. with + reactions:

17

Total no. in group:

20

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 25 % test compound in ethanol . No with. + reactions: 17.0. Total no. in groups: 20.0.

Any other information on results incl. tables

On the 24th and 25th day of the study, i. e. 24 and 48 hours after the removal of the occlusive dressings, both areas of applicatioin (left and right flanks) were evaluated on the basis of the following points system:

0 - no reaction

1 - slight reddening (points and spots)

2 - moderate reddening of the whole area of application

3 - severe reddening and swelling

In the presensitized animals of the test group the following skin reactions were observed at the observation times of the 24th and 25th day of the study (see table below): On the 24th day slight reddening in seven animals and moderate reddening in seven animlas. Nine animals showed additionally slight swelling and one animal a moderate swelling. On day 25th slight reddening in five animals, moderate reddening in seven animals and severe reddening in two animals. Five animals showed additionally slight swelling and eight animals moderate swelling.

As allergic skin reactions are counted all skin reactions scored 2 or >2 in the points system used.

Skin reactions of test group at challenge exposure time

	Animal number	Left flank		Right flank
		25% SND 919 CL2 Y, Precursor 2    suspension in absolute ethanol		absolute ethanol
		Skin reaction
		24th day		25th day
		left flank	right flank	left flank	right flank
	1	2	0	2	0
	2	2	0	2**	0
	3	1	0	1	0
	4	2*	0	2*	0
	5	1	0	1*	0
	6	0	0	1	0
	7	death	0
	8	0	0	0	0
	9	1*	0	0*	0
	10	death	0
	11	2*	0	3**	0
	12	2*	0	2**	0
	13	1*	0	2**	0
	14	2**	0	3**	0
	15	death	0
	16	2*	0	2**	0
	17	1*	0	1**	0
	18	0	0	0*	0
	19	1*	0	2**	0
	20	1*	0	1*	0

*slight swelling

** moderate swelling

Applicant's summary and conclusion

Interpretation of results:

sensitising

Remarks:

Migrated information Criteria used for interpretation of results: expert judgment

Conclusions:

In the sensitization test based on Magnusson and Kligman's "Guinea Pig Maximisation Test', the substance 2,6-Diamino-4,5,6,7-tetrahydrobenzothiazol (SND 919 CL2 Y, precursor 2) induced an allergic reaction by skin contact in nine of 17 guinea pigs treated.
According to the Magnusson and Kligman classification scheme 2,6-Diamino-4,5,6,7-tetrahydrobenzothiazol has to be classified as a substance with a moderate sensitizing potential (Grade III) based on the 53 % positive reactions registered under the stated study conditions.

Executive summary:

According to the German Chemicals Act (Chemikaliengesetz) the compound 2,6 -Diamino-4,5,6,7 -tetrahydrobenzothiazol has to be classified as a sensitizer and labelled with the Risk Phrase R 43 "Sensibilisierung durch Hautkontakt möglich" (may cause sensitization by skin contact).