1,3-di-o-tolylguanidine

Endpoint summary

Description of key information

A GLP guideline study (OECD 406) is available for the evaluation of the skin sensitisation of DOTG. DOTG is not a skin sensitizer in the modified test of Magnuson and Kligman.

Moreover negative results were obtained in the patch test : no skin sensitisation observed in human.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

A guinea pigs study was performed prior REACH regulation.

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan, Gannat, France
- Age at study initiation: 1-3 months
- Weight at study initiation: 405+/-21 g (males), 415+/-26g (females)
- Housing: individually in polycarbonate cages with stainless steel lid (48 cm x 27 cm x 20 cm) equipped with a polypropylene bottle.
- Diet (e.g. ad libitum): free access to 106 pelleted diet (UAR Villemoisson, France)
- Water (e.g. ad libitum): filtered water, free access
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22+/-2°C
- Humidity (%): 30 to 70%
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light): 12/12

Route:

epicutaneous, occlusive

Vehicle:

other: ethanol/water (80/20, for induction) and acetone (for challenge)

Concentration / amount:

50% ; The test substance was finely pulverised being incorporated in the vehicle.

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

other: ethanol/water (80/20, for induction) and acetone (for challenge)

Concentration / amount:

50% ; The test substance was finely pulverised being incorporated in the vehicle.

No. of animals per dose:

30

Details on study design:

RANGE FINDING TESTS:
According to the results of the preliminary test, which showed that the test substance is not well-tolerated after intradermal injections, a modified method was used: during the induction period, only Freund's complete adjuvant was administered by intradermal route and the test substance was administered twice by cutaneous route (on days 1 and 8).

MAIN STUDY
The application sites were clipped on days -1 and 7 (interscapular region 4 cm x 2 cm), clipped and shaved on day 21 (each flank 2 cm x 2 cm).

A. INDUCTION EXPOSURE
- Intradermal route : On day 1, injections were made into the dermis of a 4 cm x 2 cm clipped interscapular area, using a needle mounted on a 1 ml plastic syringe. four intradermal injections of 0.1 ml of freund's complete adjuvant diluted to 50% (v/v) with 0.9% NaCl were made into the shaved nuclal region of all animals of the treated and control groups.
- Cutaneous route : On day 1, a pad of filter paper (8 cm²) was fully-loaded with the test substance at the concentration of 50% (w/w) and was then applied to the interscapular region of the animals of the treated group. The pad was held in place for 48 hours by means of an adhesive hypoallergenic dressing and an adhesive anallergenic waterproof plaster.
As the test substance was shown to be non-irritant during th e preliminary test, the animals were treated on day 7 with 0.5 ml de sodium lauryl sulfate at the concentration of 10% (w/w) in vaseline, in order to induce local irritation.
On day 8, a pad of filter paper (8 cm²) was fully-loaded with the test substance at the concentration of 50% (w/w) and was then applied to the interscapular region of the animals of the treated group. The pad was held in place for 48 hours by means of an adhesive hypoallergenic dressing and an adhesive anallergenic waterproof plaster.

B. CHALLENGE EXPOSURE
On day 22, the animals of treated and control groups received an application of the test susbtance and vehicle. The filter paper of the chamber was fully-loaded with the test substance at the concentation of 50% (w/w) and was then applied to a clipped area of the skin of the posterior right flank of all animals. the vehicle was applied under the same experimental conditions to the skin of the posterior left flank.
The chambers were held in contact with the skin for 24 hours by means of an adhesive anallergenic waterproof plaster.

Challenge controls:

yes

Positive control substance(s):

yes

Remarks:

Mercaptobenzothiazole

Positive control results:

see below

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

0%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

none

Remarks on result:

no indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

none

Remarks on result:

no indication of skin sensitisation

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

50%

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

no indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

50%

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

none

Remarks on result:

no indication of skin sensitisation

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

20%

No. with + reactions:

10

Total no. in group:

10

Clinical observations:

none

Remarks on result:

positive indication of skin sensitisation

Clinical examinations:

One animal of the treated group was found dead on day 7. no clinical signs were observed prior death. As such spontaneous mortality is sometimes observed in this species, it was not attributed to treatment with the test substance.

No clinical signs and no other deaths occurred during the study. No cutaneous reactions were observed.

Body weight:

The body weight gain of the treated animals was similar to that of the control animals.

Interpretation of results:

GHS criteria not met

Remarks:

Not skin sensitizer

Conclusions:

Under these experimental conditions, the test substance DOTG does not induce delayed contact hypersensitivity in guinea pigs.

Executive summary:

The potential of DOTG to induce delayed contact hypersensitivity was evaluated in guinea pigs according to a modified method of Magnusson and Kligman. The study was conducted in compliance with the OECD 406 guideline and the principles of GLP.

No clinical signs and no deaths related to treatment were noted during the study. No cutaneous reactions were observed after the challenge application. Under these experimental conditions, the test substance DOTG (50%) does not induce delayed contact hypersensitivity in guinea pigs.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

The potential of DOTG to induce delayed contact hypersensitivity was evaluated in guinea pigs according to a modified method of Magnusson and Kligman. The study was conducted in compliance with the OECD 406 guideline and the principles of GLP.

No clinical signs and no deaths related to treatment were noted during the study. No cutaneous reactions were observed after the challenge application. Under these experimental conditions, the test substance DOTG (50%) does not induce delayed contact hypersensitivity in guinea pigs.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the available data, 1,3-di-o-tolylguanidine should not be classified as skin sensitizer according to the Regulation EC N°1272/2008.