4-tert-butylbenzoic acid

Endpoint summary

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: study performed in accordance with an official guideline; also a positive control test was performed with a known sensitzer that proved the validity of the test system; GLP-conformity is given

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

GLP compliance:

yes (incl. QA statement)

Type of study:

guinea pig maximisation test

Species:

guinea pig

Strain:

other: Ibm: GOHI; SPF-quality guinea pigs (synonym: Himalayan spotted)

Sex:

female

Details on test animals and environmental conditions:

Number of animals for main study/pretest: 15 females / 3 females (nulliparous and non-pregnant)
Age at pretest start / beginning of acclimatization period: 5-7 weeks
Body weight at pretest start: pretest groups 411-442 g; Body weight at beginning of acclimatization period: control and test group 378-426 g
Identification: by unique cage number and corresponding ear tags.
Randomization: selected by hand at time of delivery; no computer randomization.

Acclimatization: one week for the control and test group under test conditions after health examination. No acclimatization for the animals of the pre-
test. Only animals without any visible signs of illness were used for the study.

- Housing: individually in Makrolon type-4 cages with standard softwood bedding ("Lignocel", Schill AG, CH-4132 Muttenz)
- Diet: ad libitum, pelleted standard Provimi Kliba 3418, batch no. 64/02, guinea pig breeding / maintenance diet, containing Vitamin C (Provimi Kliba AG, CH-4303 Kaiseraugst). Results of analyses for contaminants are archived at RCC Ltd, Itingen, CH.
- Water: ad libitum, community tap water from Füllinsdorf. Results of bacteriological, chemical and contaminant analyses are archived at RCC Ltd, Itingen.

Environmental conditions:
- Temperature (°C): 20 +/- 3
- Humidity (%): 30-70
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 12 / 12 (music played during daytime light period)

Route:

intradermal and epicutaneous

Vehicle:

other: Polyethylene glycol 300 (PEG 300), Freund's Complete Adjuvant (FCA), physiological saline

Route:

epicutaneous, occlusive

Vehicle:

other: Polyethylene glycol 300 (PEG 300), Freund's Complete Adjuvant (FCA), physiological saline

No. of animals per dose:

control group: 5
test group: 10

Positive control substance(s):

yes

Remarks:

alpha-hexylcinnamaldehyde, purity 85 %, from Aldrich Chemicals Company Inc., USA

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Positive control results:

It is stated in the study report that based on the findings and in accordance with Commission Directive 96/54/EEC, alpha-hexylcinnamaldehyde does have to be classified and labelled as skin sensitizer and proved the sensitivity of the test system.

Results main study:

Skin effects after intradermal induction (Day 1):

Erythema, oedema, necrotizing dermatitis, encrustation and exfoliation of encrustation were observed as expected (effects of FCA)

Skin effects after epidermal induction (Day 8):

Control group: no erythematous or oedematous reaction was observed in the animals treated with PEG 300 only.

Test group: Discrete/patchy erythema (score = 1) was observed in six out of 10 animals at the 24- and 48-hour reading after treatment with the test item at 50 % in PEG 300.

Skin effects after the challenge (Day 22):

Control group: no skin reactions were observed in the animals when treated with PEG 300 only or when treated with the test item at 25 % in PEG 300.

Test group: no skin reactions were observed in the animals when treated with PEG 300 only or when treated with the test item at 25 % in PEG 300.

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

It was concluded in the study report:
Based on the findings of the study and in accordance with Commission Directive 96/54/EEC, p-tert-butyl benzoic acid does not have to be classified and labelled as a skin sensitizer.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

According to the study results there was a slight irritation after dermal induction. However, after the challenge treatment there were no skin reactions visible either in the test nor the control animals.

Migrated from Short description of key information:
Study according to OECD TG 406, guinea pigs (GOHI, SPF-quality (synonym: Himalayan spotted)), females, control group: 5, test group: 10, hexyl cinnamic aldehyde as positive control:

Skin effects after epidermal induction (Day 8):
Control group: no erythematous or oedematous reaction was observed in the animals treated with PEG 300 only.
Test group: Discrete/patchy erythema (score = 1) was observed in six out of 10 animals at the 24- and 48-hour reading after treatment with the test item at 50 % in PEG 300.

Skin effects after the challenge (Day 22): no skin reactions in control and test group

(RCC (2003))

Justification for selection of skin sensitisation endpoint:
Official testing procedure (OECD 406) according to todays standard.

Respiratory sensitisation

Endpoint conclusion

Additional information:

There is no data available about respiratory sensitisation of the substance.

Migrated from Short description of key information:
There is no data available about respiratory sensitisation of the substance.

Justification for classification or non-classification

It was concluded in the study report that based on the findings and in accordance with Commission Directive 96/54/EEC p-tert-butyl benzoic acid does not have to be classified and labelled as a skin sensitizer.

There is no data available about respiratory sensitisation of the substance. Therefore there is no basis for a classification.