Benzyltoluene

Endpoint summary

Description of key information

For that endpoint, three studies are available and of good quality. Two were Guinea Pig Maximisation Tests and two were Buehler tests (or similar). These tests were conducted according to OECD 406 guideline or according to similar protocol.

 

One study was chosen as key study (Kaufmann, 1990). 20 Guinea pigs animals were used as treated group and 20 other animals were used as negative control. The concentrations used for induction were, for intradermal treatment: 5%; and for dermal treatment: 100%. The concentration used in Freund’s Complete Adjuvant (FCA) was 5 %. For challenge, the concentration used was 100 %. No skin reaction was observed for none of the animals. Benzyl toluene was considered as non-sensitizing in the Guinea Pigs Maximalisation Test.

 

In another Guinea Pig Maximisation Tests (Mürmann, 1990), in a Buehler test (Eisele, 1995) and a modified Buehler test (Guillot, 1981), there were no signs of skin sensitisation.

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:

not mentioned

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

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:

Study perfromed before the implementation of the REACH regulation

Species:

guinea pig

Strain:

other: Pirbright white DHPW (SPF)

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: F. Winkelmann, Borchen, Germany
- Age at study initiation: not mentioned
- Weight at study initiation: 301 - 398 g
- Housing: collective housing up to maximum of 5 animals per cage in Makrolon cages type IV
- Diet (e.g. ad libitum): Ssniff G complete feed for guinea pigs ad libitum, supplied by Ssniff Spezialfutter GmbH, Soest, Germany
- Water (e.g. ad libitum): drinking water ad libitum
- Acclimation period: at least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.5 ± 3.5
- Humidity (%): 50 - 85
- Air changes (per hr): not mentioned
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: not mentioned

Route:

intradermal

Vehicle:

paraffin oil

Concentration / amount:

5%

Route:

epicutaneous, occlusive

Vehicle:

unchanged (no vehicle)

Concentration / amount:

100%

Route:

epicutaneous, occlusive

Vehicle:

unchanged (no vehicle)

Concentration / amount:

100%

No. of animals per dose:

test group: 20 animals (10 male, 10 female)
control group: 20 animals (10 male, 10 female)

Details on study design:

RANGE FINDING TESTS:
Intradermal injection: The test articel was diluted with water and FCA to give a final concentration of 5%. Two animals (1 male, 1 female) were employed, skin reactions being recorded 48 h after treatment.
Dermal application: A closed patch exposure was effected by means of an occlusive bandage. Two animals (1 male, 1 female each) were empoyed for each concentration tested (100%; 50%) and skin reactions were recorded 48 h p.a.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2
- Exposure period: 1st exposure: intracutaneous injections (0.1 mL); 2nd exposure: epicutaneous for 48 hours
- Concentration in Freunds Complete Adjuvants (FCA): 5 % test substance in a mixture of FCA and water (1:2)
- Test group: dermal: 100 % test substance (2 x 4 cm patch)
- Control group: vehicle (2 x 4 cm patch)
- Frequency of applications: day 0: intradermal treatment, day 7: pretreatment with sodium lauryl sulfate (10% in petrolatum) and day 8: dermal treatment
- Duration: 3 weeks


B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: on day 21
- Exposure period: dermal application for 24 hours
- Test groups: test substance
- Control group: test substance
- Site: left flanks
- Concentrations: 100%
- Evaluation (hr after challenge): 24 and 48 hours after patch removal

Challenge controls:

see above B. Challenge exposure

Positive control substance(s):

yes

Remarks:

2,4 dinitrochlorobenzene, historical control

Positive control results:

The last periodic use of the positive control substance (2,4 dinitrochlorobenzene) resulted in an acceptable level of response in the test animals, not tested in parallel (no further details mentioned).

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

100 %

No. with + reactions:

0

Total no. in group:

20

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

100 %

No. with + reactions:

0

Total no. in group:

20

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

100 %

No. with + reactions:

0

Total no. in group:

20

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

100 %

No. with + reactions:

0

Total no. in group:

20

Group:

positive control

Remarks on result:

positive indication of skin sensitisation

RESULTS OF PILOT STUDY:

Intradermal treatment: no specific findings

Dermal application: no skin irritation

Interpretation of results:

GHS criteria not met

Conclusions:

Benzyltoluene was considered as non-sensitizing in the Guinea Pigs Maximalisation Test.

Executive summary:

The delayed contact hypersensivity of Benzyltoluene was evaluated in Guinea pigs according to OECD N°406 guideline. 20 animals were used as treated group and 20 other animals were used as negative control. The concentrations used for induction were, for intradermal treatment: 5%; and for dermal treatment: 100%. The concentration used in Freund's Complete Adjuvant (FCA) was 5 %. For challenge, the concentration used was 100 %. No skin reaction was observed for none of the animals. Benzyltoluene was considered as non-sensitizing in the Guinea Pigs Maximalisation Test.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

According to EU Regulation (EC) N0. 1272/2008 (CLP), benzyltoluene is not classified for skin sensitisation.