2-amino-6-chloro-4-nitrophenol

Endpoint summary

Description of key information

2 studies were available to evaluate the skin sensitization potential  of 2-Amino-6- chloro-4-nitrophenol:

•       In the study of Ravel (2004), a Local Lymph Node Assay  with ten week old female CBA/J mice, two vehicles were used for the preparation of test substance, vehicle 1 (dimethyl sulfoxide (DMSO) and vehicle 2 (acetone/water/olive oil). The test substance was prepared daily in vehicle 1 or 2 at concentrations of 0.5%, 1.5%, 5.0% and 10.0%.

There was no mortality as well as no treatment-related effects in body weight or body weight gains observed during the study. No treatment-related clinical signs were observed.

The mean SIs of the test substance at the concentrations of 0.5, 1.5, 5.0 and 10.0% in DMSO were 1.2, 1.2, 2.0 and 4.7, respectively. The mean SIs at the concentrations of 0.5, 1.5, 5.0 and 10.0% in acetone/water/olive oil were 2.8, 3.9, 3.7 and 5.2 respectively. Thus the test substance elicited a positive response.

EC3 values calculated were 6.85% in DMSO and 0.68% in acetone/water/olive oil. The EC3 value in acetone/water/olive oil of 0.68% was considered to be an underestimation due to the unusually low mean DPM value for the control.

Based on above, 2-Amino-6-chloro-4-nitrophenol was determined to be a skin sensitizer in the Local Lymph Node Assay (LLNA) when tested at concentrations of 0.5, 1.5, 5.0 and 10.0% in DMSO and acetone/water (1:1) mixed with olive oil.

•       In the study of Chibanguza (1988), The skin sensitization potential was determined following the OECD Guideline 406 (Skin Sensitisation-Guinea Pig Maximization Test).

40 guinea pigs were used in this study.

During the induction phase, all animals of test and control groups were treated with three pairs of intradermal injections (0.05 mL) at two skin areas situated bilateral of the spineas follows:

Treatment group:

Injection Pair 1: 10% test substance in propylene glycol

Injection Pair 2: 10% test substance in FCA

Injection Pair 3: Undiluted FCA

Control group:

Injection Pair 1: Undiluted FCA

Injection Pair 2: 10% propylene glycol in FC

Injection Pair 3: Undiluted propylene glycol

Seven days after intradermal treatment, the same sites were treated dermally with 0.5 g of undiluted test substance (test group) and 0.5 mL of undiluted Propylene glycol (control group).

Three weeks after the intradermal treatment a second dermal (challenge) treatment was carried out on both test and control groups using "HillTop" Chambers.Two chambers loaded with 0.5 mL of test substance per animal were adhered to the left clipped flank. Chamber A was provided with the maximum administration concentration of 2% and Chamber B with a 0.1% dilution. On the right clipped flank of the animals, chambers loaded with 0.5 mL of undiluted propylene glycol were applied. 24 hours post-application the bandages were removed.

No skin reactions were observed in the test and control groups on the areas treated with the 0.1% dilution. The areas treated with the maximum administration concentration (=2%) could not be evaluated due to the self coloration of the sample. The control areas of both test and control groups were without any skin reactions.

Under the conditions of test, Chlororange did not cause contact hypersensitivity and therefore test substance was considered as non-sensitising.

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Justification for classification or non-classification

Considering the EC3 values calculated: 6.85% in DMSO and 0.68% in acetone/water/olive oil, in the LLNA study, the substance was considered as skin sensitizer and should be classified as category 1A according to CLP regulation (1272/2008).