2-tert-butylhydroquinone

Endpoint summary

Description of key information

The skin sensitization potential of test chemical was assessed in various experimental studies conducted on human subjects. The predicted data using the Danish QSAR database has also been compared with the experimental data. Based on the available data for the test chemical and supporting studies, it can be concluded that the test chemical is able to cause skin sensitization and thus can be considered as sensitizing. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Skin Sensitizer”.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Remarks:

in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Data is from experimental report

Qualifier:

according to guideline

Guideline:

other:

Principles of method if other than guideline:

Skin sensitization study was conducted to determine the skin sensitization potential of test chemical.

GLP compliance:

not specified

Type of study:

not specified

Justification for non-LLNA method:

not specified

Species:

human

Strain:

not specified

Sex:

not specified

Route:

other: not specified

Vehicle:

other: A+D+GP Fat

Concentration / amount:

500mg (0.5g) in 5 mL A+D+GP Fat

Day(s)/duration:

not specified

Adequacy of induction:

not specified

No.:

#1

Route:

other: not specified

Vehicle:

other: A+D+GP Fat

Concentration / amount:

1000mg (1.0g) in 10 mL A+D+GP Fat

Day(s)/duration:

not specified

Adequacy of challenge:

not specified

No. of animals per dose:

Not specified

Details on study design:

Not specified

Positive control substance(s):

not specified

Reading:

1st reading

Group:

test chemical

Dose level:

1000 mg (1.00g) in 10 mL A+D+GP Fat

Clinical observations:

Moderate risk for human sensitization

Remarks on result:

positive indication of skin sensitisation

SUMMARY
	HIGHEST AVERAGE			CONC. FOR CHALLENGE
Drop on	0			1.00 g IN 10mL A+D+GP Fat
	NUMBER POSITIVE				TOTAL SCORE
Sensitization	NORMAL	SLIGHT	MODERATE	SEVERE
Freund’s only	10					0
1% cpd in Freunds	1	1	8			41

Interpretation of results:

other: sensitising

Conclusions:

The test substance showed moderate risk for human skin sensitization.

Executive summary:

The skin sensitization study was conducted on human subjects to assess the skin sensitization potential of test chemical.

The subjects were treated at dose of 500 mg in 5 ml A+D+GP Fat during induction and challenged at concentration 1000mg in 10 ml A+D+GP Fat.

The test chemical induced moderate skin sensitization at tested concentrations. Hence the test material was considered to be sensitizing to the skin of human subjects.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

Various studies has been investigated for the test chemical to observe the potential for skin sensitization to a greater or lesser extent. The studies are based on in vivo experiments in human and guinea pigs for test chemical .The predicted data using the Danish QSAR database has also been compared with the experimental data and summarized as below;

 

The skin sensitization study was conducted on human subjects to assess the skin sensitization potential of test chemical. The subjects were treated at dose of 500 mg in 5 ml A+D+GP Fat during induction and challenged at concentration 1000mg in 10 ml A+D+GP Fat. The test chemical induced moderate skin sensitization at tested concentrations. Hence the test material was considered to be sensitizing to the skin of human subjects.

 

The above result was supported by two case reports conducted on one male and one female subject respectively as below;

In first case report, an occupational contact dermatitis from test chemical in a cutting fluid had been reported. A 40 year old male metalworker employed for 14 years in an elevator producing workshop developed dermatitis on his hands, forearms, and feet over the previous 3 to 4 years. Symptoms abated during vacations. The subject was patch tested with test chemical at dilution series 0.0005-1 % in alcohol.A positive reaction was observed to test chemical, 1% in alcohol; in a dilution series, a positive reaction was observed down to 0.0005%. Upon changing jobs and ceasing contact with cutting fluid, the dermatitis healed. Thus the author concludes that the test chemical can cause contact dermatitis and hence considered as sensitizing to the skin.

 

In second case report, a 37-year-old woman with no past history of allergy had patch tested with test chemical.1 day after the 2nd application of a new hair-colouring preparation (Excellence Chatain Clair, L’Ore´al, Clichy, France), she had developed an itchy inflammatory oedema of her scalp and face, with occipital lymph node swelling. The lesions cleared after 5 days on oral corticosteroids. She had regularly used hair dyes for several years, but with transient local discomfort only. The women was treated at 0. % concentration of test chemical in ahydro-alcoholic (50/50) solution under semi-occlusive condition for three days.The Patch testing was performed with the European standard series and a hairdressers series (TrolabA).The test chemical had developed a strong positive reaction. Hence the test chemical can be considered as sensitizing to the skin.

 

Further, a Repeated insult patch test was conducted in 114 participants to determine the skin sensitization eliciting capacity of test chemical. The subjects were treated with test chemical at a dose of 0.20% (02ml) in petrolatum. During induction, the patches were applied three times per week for 3 weeks. After a rest period of 2 weeks, a challenge patch was applied for 1 day and reactions were scored 1 and 3 days after path removal. The test chemical induced skin sensitization in one individual at tested concentration. Hence the test material was considered as weakly sensitizing to the skin.

 

The overall results were further supported by the patch test conducted on two individual to confirm the sensitivity and to determine the no observable effect level (NOEL) of test chemical. The individuals were exposed to ascending concentration of test chemical (0.0003-0.02%) in 0.2ml of petrolatum until a positive allergic response was elicited. Patches were left on for two days and sites were scored at 0.5h and 2 days post removal. The NOEL for eliciting a reaction to test chemical was determined to be 0.0050% (50ppm). Both the individual exhibited reactions indicative of contact sensitization at concentration of 0.010% and 0.20%. Hence the test chemical can be considered as sensitizing to the skin at theses concentrations.

 

According to Danish QSAR database, skin sensitization effects were estimated by using four different models i.e, Battery, Leadscope, SciQSAR and CASE Ultra for test chemical. Based on estimation, known Allergic Contact Dermatitis effects were observed when test chemical was exposed to human and guinea pig skin. Hence, the test chemical can be considered as sensitizing to the skin.

 

Thus based on the above key and supporting studies for test chemical, it can be concluded that the test chemical is able to cause skin sensitization. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Skin Sensitizer”.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The skin sensitization potential of test chemical was observed in various studies. The results obtained from these studies indicates that the chemical is likely to cause skin sensitization. Hence the test chemical can be classified under the category “Skin Sensitizer” per CLP.