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Toxicological information

Endpoint summary

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Administrative data

Description of key information

Skin Sensitization:

The results of the experimental studies from the structurally similar read across substances indicate a possibility that 2-naphthalenol, 1-[[2-methyl-4-[(2-methylphenyl)azo]phenyl]azo]-, ar-styrenated can be not sensitizing to skin.

Hence by applying the weight of evidence approach, 2-naphthalenol, 1-[[2-methyl-4-[(2-methylphenyl)azo]phenyl]azo]-, ar-styrenated can be considered to be not sensitizing to skin. It can be classified under the category “Not Classified” as per CLP regulation.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Weight of evidence based on structurally similar read across chemicals
Justification for type of information:
Weight of evidence based on structurally similar read across chemicals
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across: supporting information
Qualifier:
according to guideline
Guideline:
other: Weight of evidence based on structurally similar substances
Principles of method if other than guideline:
The weight of evidence report has been prepared based on the read across substances identified based on structural and functional similarity to assess the dermal sensitization potential of 2-naphthalenol, 1-[[2-methyl-4-[(2-methylphenyl)azo]phenyl]azo]-, ar-styrenated
GLP compliance:
not specified
Type of study:
other: Weight of evidence approach
Specific details on test material used for the study:
- Name of test material (as cited in study report): 2-Naphthalenol, 1-[[2-methyl-4-[(2-methylphenyl) azo] phenyl] azo]-, ar-styrenated- IUPAC name: 2-Naphthalenol, 1-[[2-methyl-4-[(2-methylphenyl) azo] phenyl] azo]-, ar-styrenated- Molecular formula: C40H36N4O1 - Molecular wt. : 588.76 g/mole- smiles : Cc1ccccc1N=Nc2ccc(c(C)c2)N=Nc3c4ccc(C(C)c5ccccc5)cc4cc(C(C)c6ccccc6)c3O- Substance type: Organic- Physical state: solid
Species:
guinea pig
Strain:
not specified
Sex:
not specified
Details on test animals and environmental conditions:
no data available
Route:
intradermal and epicutaneous
Vehicle:
olive oil
Concentration / amount:
(1) 0.1 ml emulsified mixture of Freund’s complete adjuvant (FCA: Iatron Co., Ltd., Tokyo) and saline (1:1); (2) 0.1 ml of 0.1% chemicals in olive oil; (3) 0.1 ml of the 0.1% test substance in FCA and saline mixture (1:1).
Adequacy of induction:
non-irritant substance, but skin pre-treated with 10% SDS
Route:
epicutaneous, occlusive
Vehicle:
petrolatum
Concentration / amount:
0.5 g of 1.0% test chemical
Day(s)/duration:
48 hours
Adequacy of induction:
non-irritant substance, but skin pre-treated with 10% SDS
Route:
epicutaneous, open
Vehicle:
propylene glycol
Concentration / amount:
0.1 ml of test chemical
Day(s)/duration:
3 weeks
Adequacy of induction:
not specified
Route:
intradermal
Vehicle:
water
Concentration / amount:
0.1 ml of a 2% aqueous solution of a 40% color paste.
Day(s)/duration:
3 times a day for 5 consecutive days
Adequacy of induction:
not specified
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: acetone
Concentration / amount:
0.03 ml aliquots of test chemicals in acetone
Day(s)/duration:
24 hours
Adequacy of challenge:
not specified
No.:
#2
Route:
epicutaneous, open
Vehicle:
propylene glycol
Concentration / amount:
10,5 and 2.5 % of the induction concentration
Day(s)/duration:
24 hours
Adequacy of challenge:
not specified
No.:
#3
Route:
intradermal
Vehicle:
water
Concentration / amount:
8% of 40% color paste.
Adequacy of challenge:
not specified
No. of animals per dose:
1. total - 62. total - 103. total - not specified
Details on study design:
The study is based on weight of evidence approach from the read across values
Challenge controls:
no data available
Positive control substance(s):
not specified
Reading:
1st reading
Group:
test chemical
Clinical observations:
no dermal reactions observed
Remarks on result:
no indication of skin sensitisation
Interpretation of results:
other: not sensitizing
Conclusions:
On the basis of available studies for the structurally similar read across substances, the weight of evidence approach is applied to assess the skin sensitization potential for target substance. 2-naphthalenol, 1-[[2-methyl-4-[(2-methylphenyl)azo]phenyl]azo]-, ar-styrenated was estimated to be not sensitizing to guinea pig skin.
Executive summary:

Based on the available studies for the structurally similar read across substances, the weight of evidence approach was applied to assess the skin sensitization potential for2-naphthalenol, 1-[[2-methyl-4-[(2-methylphenyl)azo]phenyl]azo]-, ar-styrenated.

 

Magnusson & Kligman guinea pig maximization test (GPMT) was conducted (Contact Dermatitis, 2000) on six Female Hartley strain albino guinea pigs to assess the dermal sensitization potential of the test chemical.

 Induction treatment consisted of 3 intra-dermal injections and one topical induction. On day 0, a row of 3 injections of 0.1 ml test material emulsified mixture of Freund’s complete adjuvant and saline (1:1) in olive oil was given on each side of the 2x4 cm clipped neck. In order to enhance the sensitization, sodium lauryl sulfate 10% in petrolatum was applied on induction area for 24 h before the topical induction. On day 7, 0.5 g of 1.0% test chemicals in petrolatum were occlusively applied for 48 h. The samples were covered with lint pads which were lining with Blenderm tape.

The challenge treatment was given by open topical application. On day 21, the flank regions of the animals were clipped and shaved, and then 0.03 ml of test material in acetone was applied to the skin for 72 hrs. Observations were made 48 hrs after challenge. No positive reaction was elicited at the concentrations tested.

Hence, the test chemical was considered to be not sensitizing to guinea pig’s skin.

This is supported by the experimental study summarized in JOURNAL OF COSMETIC SCIENCE, 2007 for the structurally similar chemical. Buehler and the Klecak method for open epicutaneous testing (OET) was performed to determine the degree of dermal sensitization caused by the test chemical in guinea pigs.

During the induction phase, the left flanks of ten albino guinea pigs were shaved and the dye test material applied three times weekly (Monday, Wednesday, Friday) for three consecutive weeks.

Each animal received 0.1 ml of the dye test material over a 1.8-cm circular area. Following the induction period, the guinea pigs entered the challenge phase. The challenge phase began after a two-week rest period when the right flank of each guinea pig was shaved and exposed to three different dye test material concentrations(10.0%, 5.0%, and 2 .5%). Twenty-four hours after the last induction and challenge application, the animals were depilated to clearly observe dermal reactions.

All test sites were graded for erythema and edema 24 and 48 hours post-application using a four-point ordinal scale. A positive control of 0.5% 2,4-dinitrochlorobenzene(DNCB) in ethanol was included for both the induction and challenge phases.

No positive skin irritation reactions. Hence, the test chemical was considered to be not sensitizing to guinea pig skin.

The above results are further supported by the experimental study summarized in Scientific Committee on Cosmetology (seventh series) for the structurally similar read across chemical. Guinea Pig Maximization test was performed to assess the dermal sensitization potential of the test chemical.

During the induction phase, 0.1 ml of a 2% aqueous solution of a 40% color paste of the test chemical was injected intra cutaneously three times a day for 5 consecutive days

Challenge treatment was provided 4 weeks after induction treatment in the concentration 8% of 40% color paste. No skin allergic reactions were observed in the guinea pigs. Hence, the test chemical was considered to be not sensitizing to skin.

Based on the available data for the structurally similar read across chemicals and applying the weight of

evidence approach, it can be concluded that2-naphthalenol, 1-[[2-methyl-4-[(2-methylphenyl)azo]phenyl]azo]-, ar-styrenatedwill also behave in similar manner that of the read across chemicals and was estimated to be not sensitizing to skin. Thus it can be further classified under the category “Not Classified” as per CLP regulation.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Based on the available studies for the structurally similar read across substances, the weight of evidence approach was applied to assess the skin sensitization potential for2-naphthalenol, 1-[[2-methyl-4-[(2-methylphenyl)azo]phenyl]azo]-, ar-styrenated.

 

Magnusson & Kligman guinea pig maximization test (GPMT) was conducted on six Female Hartley strain albino guinea pigs to assess the dermal sensitization potential of the test chemical.

 Induction treatment consisted of 3 intra-dermal injections and one topical induction. On day 0, a row of 3 injections of 0.1 ml test material emulsified mixture of Freund’s complete adjuvant and saline (1:1) in olive oil was given on each side of the 2x4 cm clipped neck. In order to enhance the sensitization, sodium lauryl sulfate 10% in petrolatum was applied on induction area for 24 h before the topical induction. On day 7, 0.5 g of 1.0% test chemicals in petrolatum were occlusively applied for 48 h. The samples were covered with lint pads which were lining with Blenderm tape.

The challenge treatment was given by open topical application. On day 21, the flank regions of the animals were clipped and shaved, and then 0.03 ml of test material in acetone was applied to the skin for 72 hrs. Observations were made 48 hrs after challenge. No positive reaction was elicited at the concentrations tested.

Hence, the test chemical was considered to be not sensitizing to guinea pig’s skin.

This is supported by the experimental study for the structurally similar chemical. Buehler and the Klecak method for open epicutaneous testing (OET) was performed to determine the degree of dermal sensitization caused by the test chemical in guinea pigs.

During the induction phase, the left flanks of ten albino guinea pigs were shaved and the dye test material applied three times weekly (Monday, Wednesday, Friday) for three consecutive weeks.

Each animal received 0.1 ml of the dye test material over a 1.8-cm circular area. Following the induction period, the guinea pigs entered the challenge phase. The challenge phase began after a two-week rest period when the right flank of each guinea pig was shaved and exposed to three different dye test material concentrations(10.0%, 5.0%, and 2 .5%). Twenty-four hours after the last induction and challenge application, the animals were depilated to clearly observe dermal reactions.

All test sites were graded for erythema and edema 24 and 48 hours post-application using a four-point ordinal scale. A positive control of 0.5% 2,4-dinitrochlorobenzene(DNCB) in ethanol was included for both the induction and challenge phases.

No positive skin irritation reactions. Hence, the test chemical was considered to be not sensitizing to guinea pig skin.

The above results are further supported by the experimental study summarized in Scientific Committee on Cosmetology (seventh series) for the structurally similar read across chemical. Guinea Pig Maximization test was performed to assess the dermal sensitization potential of the test chemical.

During the induction phase, 0.1 ml of a 2% aqueous solution of a 40% color paste of the test chemical was injected intra cutaneously three times a day for 5 consecutive days

Challenge treatment was provided 4 weeks after induction treatment in the concentration 8% of 40% color paste. No skin allergic reactions were observed in the guinea pigs. Hence, the test chemical was considered to be not sensitizing to skin.

Based on the available data for the structurally similar read across chemicals and applying the weight of

evidence approach, it can be concluded that2-naphthalenol, 1-[[2-methyl-4-[(2-methylphenyl)azo]phenyl]azo]-, ar-styrenatedwill also behave in similar manner that of the read across chemicals and was estimated to be not sensitizing to skin. Thus it can be further classified under the category “Not Classified” as per CLP regulation.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

The results of the experimental studies from the structurally similar read across substances indicate a possibility that 2-naphthalenol, 1-[[2-methyl-4-[(2-methylphenyl)azo]phenyl]azo]-, ar-styrenated can be not sensitizing to skin.

Hence by applying the weight of evidence approach, 2-naphthalenol, 1-[[2-methyl-4-[(2-methylphenyl)azo]phenyl]azo]-, ar-styrenated can be considered to be not sensitizing to skin. It can be classified under the category “Not Classified” as per CLP regulation.