1-(2,4-dimethylphenylazo)-2-naphthol

Endpoint summary

Description of key information

Skin sensitization:

Skin sensitization study was performed in human patients suffering from pigmented contact dermatitis caused by the commercial Brilliant Lake Red R to evaluate the skin sensitizing potential of the test substance 1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol (CAS No: 3118-97-6). The patch of 1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol was applied onto the back of each patient for 24 hours by using Finn Chambers® on Scanpor® (Epitest, Ltd. Oy). After removal of patch, skin reactions were assessed according to the ICDRG classification for 2 days. Twenty-eight healthy female volunteers, aged 20 and 21, were also tested with the sample as controls. None gave a positive reaction to Since the positive reactions were seen in 2 out of total 8 cases, the test chemical 1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol (CAS No: 3118-97-6) was considered to be sensitizing in human patients suffering from pigmented contact dermatitis caused by the commercial Brilliant Lake Red R.

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:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from peer reviewed journal

Qualifier:

according to guideline

Guideline:

other: as mentioned below

Principles of method if other than guideline:

Skin sensitization study was performed in human patients suffering from pigmented contact dermatitis caused by the commercial Brilliant Lake Red R to evaluate whether the test substance Sudan II is a potential skin sensitizer or not.

GLP compliance:

not specified

Type of study:

patch test

Justification for non-LLNA method:

Skin sensitization study was performed in human patients suffering from pigmented contact dermatitis.

Specific details on test material used for the study:

- Name of test material (as cited in study report): C.I. Solvent orange 7
- Molecular formula: C18H16N2O
- Molecular weight : 276.337 g/mol
- Substance type: Organic
- Physical state: Solid
- Smiles : Cc1ccc(N=Nc2c(O)ccc3ccccc23)c(C)c1
- InChI: 1S/C18H16N2O/c1-12-7-9-16(13(2)11-12)19-20-18-15-6-4-3-5-14(15)8-10-17(18)21/h3-11,21H,1-2H3/b20-19+

Species:

human

Strain:

other: not applicable

Sex:

not specified

Details on test animals and environmental conditions:

No data available

Route:

epicutaneous, occlusive

Vehicle:

petrolatum

Concentration / amount:

1% in petrolatum

Route:

epicutaneous, occlusive

Vehicle:

petrolatum

Concentration / amount:

1% in petrolactum

No. of animals per dose:

8

Details on study design:

OTHER: The tests were performed with Finn Chambers® on Scanpor® (Epitest, Ltd. Oy). The application was performed on the back for 2 days. Readings were made according to the ICDRG classification 24 h after the patches were removed.

Challenge controls:

No data available

Positive control substance(s):

not specified

Group:

test chemical

Dose level:

1%

No. with + reactions:

2

Total no. in group:

8

Clinical observations:

Positive effects observed

Remarks on result:

positive indication of skin sensitisation

Other details not known

Interpretation of results:

other: sensitising

Conclusions:

Positive reactions were seen in 2 out of total 8 cases. Thus the test chemical 1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol (CAS No: 3118-97-6) was considered to be sensitizing in human patients suffering from pigmented contact dermatitis caused by the commercial Brilliant Lake Red R.

Executive summary:

Skin sensitization study was performed in human patients suffering from pigmented contact dermatitis caused by the commercial Brilliant Lake Red R to evaluate the skin sensitizing potential of the test substance 1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol (CAS No: 3118-97-6).

 

The patch of 1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol was applied onto the back of each patient for 24 hours by usingFinn Chambers® on Scanpor® (Epitest, Ltd. Oy). After removal of patch, skin reactions were assessedaccording to the ICDRG classification for 2 days.

 

Twenty-eight healthy female volunteers, aged 20 and 21, were also tested with the sample as controls. None gave a positive reaction to

 

Since thepositive reactions were seen in 2 out of total 8 cases,the test chemical1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol (CAS No: 3118-97-6)was considered to be sensitizingin human patients suffering from pigmented contact dermatitis caused by the commercial Brilliant Lake Red R.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

Skin sensitization:

Various studies has been investigated for the test chemical1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol (CAS No: 3118-97-6)to observe the potential for skin sensitization to a greater or lesser extent. The studies are based on in vivo experiments in guinea pigs and humans for target chemical1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol (CAS No: 3118-97-6) and its structurally similar read across substances 1-(phenyldiazenyl)-2-naphthol (CAS No: 842-07-9) and in vivo mouse local lymphnode assay (LLNA) in another structurally similar read across substances1-[(2-methoxyphenyl)diazenyl]-2-naphthol(1229-55-6).The predicted data using the OECD QSAR toolbox has also been compared with the experimental data and summarized as below;

The Skin sensitization study was performed byTAKEHITO KGZUKA, MINORU TASHIR0, SHIGEHARU SANO, KEIICHI FUJIMOTO, YUMI NAKAMURA, SEIICHI HASHIMOTO AND GEN NAKAMINAM (1980) in human patients suffering from pigmented contact dermatitis caused by the commercial Brilliant Lake Red R to evaluate the skin sensitizing potential of the test substance 1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol (CAS No: 3118-97-6). The patch of 1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol was applied onto the back of each patient for 24 hours by usingFinn Chambers® on Scanpor® (Epitest, Ltd. Oy). After removal of patch, skin reactions were assessedaccording to the ICDRG classification for 2 days.Twenty-eight healthy female volunteers, aged 20 and 21, were also tested with the sample as controls. None gave a positive reaction. Since thepositive reactions were seen in 2 out of total 8 cases,the test chemical1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol (CAS No: 3118-97-6)was considered to be sensitizingin human patients.

In a prediction done by SSS (2017) using the OECD QSAR toolbox with log kow as the primary descriptor,skin sensitization potential estimated was 1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol (CAS No: 3118-97-6). The substance 1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol (CAS No: 3118-97-6) is to be sensitizing to the skin of guinea pig.

The above results were supported by experimental study conducted by DENISE M. SAILSTAD, JEFFREY S. TEPPER, DONALD L. DOERFLER, MOHAMMAD Qasim AND MARYJANE K. SELGRADE in 1994 forstructurally similar read across substances 1-[(2-methoxyphenyl)diazenyl]-2-naphthol(1229-55-6). This Skin sensitization study for 1-[(2-methoxyphenyl)diazenyl]-2-naphthol(1229-55-6) was observed in female Balb/c mice by using LLNA mode. Twenty-five microliters of the agent (acetone-dye solutions) or acetone (negative-vehicle control) was applied to the ears of Balb/c mice for 3 days. On the fourth day, mice were terminated by cervical dislocation and the auricular lymph nodes were removed. Aseptic techniques were used throughout the assay. Due to the sparse number of cells in each node, pools were made using the nodes of 3 mice. Three pools were used for each agent (dye or positive control) or acetone control group. Pooled nodes were homogenized to single-cellsuspension using glass tissue grinders. Cell viabilities were evaluated using trypan blue exclusion and were above 90% for each pool. Cell mixtures of 1.2 X 10* cells were added to the wells of a 96-well microtiter plate in an RPMI 1640 media containing L-glutamine, 25 mM Hepes, 10% fetal bovine serum, and2%penicillinstreptomycin (Gibco Laboratories). Triated [3H]thymidine (2 ^Ci/well) (NEN Dupont, Boston, MA) was added to each well and incubated for 24 hr at 37°C and 5% CO2. The cells from each well were harvested onto filter disks using a Skatron cell harvester. Incorporation of 3H was determined using a beta scintillation counter. Experimental and control groups each contained nine mice. Groups were divided into three subgroups or "pools" of three mice each. Auricular lymph nodes from each pooled subgroup were processed as previously described. The counts per minute were obtained from triplicates of each pool. The average of these triplicate readings was used as input for the statistical evaluation using an analysis of variance (ANOVA). Analysis of the individual dye compounds, in which two separate experiments were performed, was adjusted for differences between the two replicates. Pairwise comparisons among different agents were performed as subtests of the overall ANOVA. Significance levels were adjusted for multiple comparisons using a modified Bonferroni correction. However 1-[(2-methoxyphenyl)diazenyl]-2-naphthol(1229 -55-6) was statistically different from the control. The response to 3% glutaraldehyde was used as a positive control in this experiment. Differences in acetone controls indicate normal variability. Therefore 1-[(2-methoxyphenyl)diazenyl]-2-naphthol(1229-55-6) was considered to be sensitizing in mice by LLNA mode.

TAKEHITO KGZUKA, MINORU TASHIR0, SHIGEHARU SANO, KEIICHI FUJIMOTO, YUMI NAKAMURA, SEIICHI HASHIMOTO AND GEN NAKAMINAM (1980) performed same study (mentioned above for target CAS) for anotherstructurally similar read across substances 1-(phenyldiazenyl)-2-naphthol (CAS No: 842-07-9)in human patients suffering from pigmented contact dermatitis caused by the commercial Brilliant Lake Red Rwhich further supports the above results.All thehuman patients showed positive skin sensitizing reactions (8/8).Thusthe chemical1-(phenyldiazenyl)-2-naphthol (CAS No: 842-07-9) was considered to be sensitizingin human patients.

 

Based on the available data for the target substance 1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol (CAS No: 3118-97-6) and its structurally similar read across substances1-(phenyldiazenyl)-2-naphthol (CAS No: 842-07-9)and1-[(2-methoxyphenyl)diazenyl]-2-naphthol(1229-55-6) ,it can be concluded thatchemical 1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol (CAS No: 3118-97-6) is able to cause skin sensitization and thus can be considered as sensitizing .

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available (further information necessary)

Justification for classification or non-classification

The skin sensitization potential of test substance substance 1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol (CAS No: 3118-97-6) and its structurally similar read across substances1-(phenyldiazenyl)-2-naphthol (CAS No: 842-07-9)and1-[(2-methoxyphenyl)diazenyl]-2-naphthol(1229-55-6) were observed in various studies. From the results obtained from these studies it is concluded that the chemical 1-[(2,4-dimethylphenyl)diazenyl]-2-naphthol (CAS No: 3118-97-6) is able to cause skin sensitization and hence can be classified as skin sensitizing.