[7-hydroxy-8-[(2-methoxyphenyl)azo]-2-naphthyl]trimethylammonium chloride

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

GLP compliance:

not specified

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

other: CBA/CaOlaHsd mice

Sex:

female

Vehicle:

other: ethanol:water (7:3 v/v)

Concentration:

2.5%, 5% and 10% in ethanol:water (7:3 v/v)

No. of animals per dose:

4 female mice per groups

Details on study design:

The control group was treated with the vehicle exclusivelyRANGE FINDING TESTS:A dilution of the test item in a mixture of ethanol:water (7:3 v/v) was made shortly before each dosing. Although acetone:olive oil (4:1 v/v) is recommended, ethanol:water (7:3 v/v) was selected as the vehicle due to pre-tests on the solubility of the test item. The highest non-irritating, “technically applicable” test item concentration was determined in a pre-test with 4 mice. Based on these test results 2.5%, 5% and 10% solutions were chosen for the main study.MAIN STUDYANIMAL ASSIGNMENT AND TREATMENT- No. of exposures: single application for 3 consecutive days- Exposure period: 3 days- Test groups: 2.5%, 5% and 10% solutions- Control group: vehicle control, positive control- Site: topical application to the dorsal surface of each ear lobe (left and right)- Frequency of applications: The application volume, 25 μl, was spread over the entire dorsal surface of each ear lobe once daily for 3 consecutive days.- Duration: No data- Concentrations: The application volume, 25 μl of 2.5%, 5% and 10% solutions.OTHER: Five days after the first topical application, all mice were administered with radio-labelled thymidine (³H-TdR) by intravenous injection via the tail vein.Approximately 5 hours after ³H-TdR application all mice were euthanized. The draining lymph nodes were excised and pooled for each experimental group. After preparation of the lymph nodes, desegregation and overnight precipitation of macromolecules, these precipitations were re-suspended and transferred to scintillation vials.The level of ³H-TdR incorporation was then measured by scintillation counting. The proliferative response of lymph node cells is expressed as the ratio of ³H-TdR incorporation into lymph node cells of treated animals relative to that recorded in control mice (stimulation index).

Positive control substance(s):

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

Positive control results:

The positive control induced a distinct increase of the stimulation index and gave an EC3 of 11.7% w/v

Parameter:

SI

Remarks on result:

other: Calculation of the EC 3 value was not performed as none of the test concentrations produced a stimulation index of 3 or above.

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: no data

Table 1: Stimulation Index of the test chemical.

 

Test chemical concentration	Stimulation Index
2.5% (w/v)	0.9
5% (w/v)	1.1
10% (w/v)	1.3

 

Calculation of the EC 3 value was not performed as none of the test concentration produced a stimulation index of 3 or above.

Interpretation of results:

not sensitising

Remarks:

Migrated informationCriteria used for interpretation of results: EU

Conclusions:

The sensitization potential of Basic Red 76 was determined by Mouse Local Lymphnode Assay.Stimulation Index of the test chemical was determined to be in range 0.9-1.3 Calculation of the EC 3 value was not performed as no test concentration produced a stimulation index of 3 or above.Based on the criteria of the test system, Basic Red 76 was a non-sensitizer when tested up to a concentration of 10% (w/v) in ethanol:water (7:3 v/v) in mice.

Executive summary:

The sensitization potential of Basic Red 76 was determined by Mouse Lymphnode Assay.

 

A dilution of the test item in a mixture of ethanol:water (7:3 v/v) was made shortly before each dosing. Although acetone:olive oil (4:1 v/v) is recommended, ethanol:water (7:3 v/v) was selected as the vehicle due to pre-tests on the solubility of the test item. The highest non-irritating, “technically applicable” test item concentration was determined in a pre-test with 4 mice. Based on these test results 2.5%, 5% and 10% solutions were chosen for the main study.

Each test group of mice was treated by topical application to the dorsal surface of each ear lobe (left and right) with the different test item concentrations. The application volume, 25 precipitations were re-suspended and transferred to scintillation vials.Five days after the first topical application, all mice were administered with radio-labelled thymidine (³H-TdR)by intravenous injection via the tail vein.

Approximately 5 hours after ³H-TdR application all mice were euthanized. The draining lymph nodes were excised and pooled for each experimental group. After preparation of the lymph nodes, desegregation and overnight precipitation of macromolecules, these precipitations were re-suspended and transferred to scintillation vials.

The level of ³H-TdR incorporation was then measured by scintillation counting. The proliferative response of lymph node cells is expressed as the ratio of ³H-TdR incorporation into lymph node cells of treated animals relative to that recorded in control mice (stimulation index).

 

The positive control induced a distinct increase of the stimulation index and gave an EC3 of 11.7% w/v

 

Stimulation Index of the test chemical was determined to be in range 0.9-1.3.

Calculation of the EC 3 value was not performed as none of the test concentrations produced a stimulation index of 3 or above.

 

Based on the criteria of the test system, Basic Red 76 was a non-sensitizer when tested up to a concentration of 10% (w/v) in ethanol : water (7:3 v/v) in mice.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Skin sensitisation:

In an in vitro study by SØSTED et. al. (2004), the sensitization potential of Basic Red 76 was estimated by using a quantitative structure–activity relationship (QSAR) model.

The predicted sensitization potency numbers represent an arbitrary relative ranking scheme, which makes it possible to compare substances within the same group.

The predicted sensitizing potential of Basic Red 76 was estimated to be in the weak sensitizer group.

 

In a study reported in Scientific Committee on Consumer Safety SCCS - OPINION ON Basic Red 76 (2011), the sensitization potential of Basic Red 76 was determined by Mouse Local Lymph Node Assay.

Stimulation Index of the test chemical was determined to be in range 0.9-1.3

Calculation of the EC 3 value was not performed as no test concentration produced a stimulation index of 3 or above. Based on the criteria of the test system, Basic Red 76 was a non-sensitizer when tested up to a concentration of 10% (w/v) in ethanol: water (7:3 v/v) in mice.

In another study reported in Scientific Committee on Cosmetic Products (2003), The sensitization potential of Basic Red 76 was determined by Guinea Pig Maximization Assay.

The intradermal injection caused an irritation response that was still present at the time of the topical induction. Following the challenge, erythema was observed in 5 of the animals at 24 hours, but had resolved by 48 hours. Hence, the substance is considered to be non-sensitising.

Various studies were reported for similar substance (CAS: 68391-32-2) in Scientific Committee on Consumer Products SCCP Opinion on Basic Brown 17 (2003 and 2008)

Skin sensitization study was performed in mice for evaluation of whether the test substance (8-((4-Amino-3-nitrophenyl)azo)-7-hydroxy-2-naphthyl)trimethylammonium chloride.Water was used as a vehicle during the test solution preparation. Test chemical conc. used for the study was 1%, 5% and 25%, respectively.

Based on the stimulation index, the test material (8-((4-Amino-3-nitrophenyl)azo)-7-hydroxy-2-naphthyl)trimethylammonium chloride was evaluated to be non-sensitizer to mice.

 

Skin sensitization study was performed in mice for evaluation of whether the test substance (8-((4-Amino-3-nitrophenyl)azo)-7-hydroxy-2-naphthyl)trimethylammonium chloride.

No test item related findings, such as significant body weight loss or local/systemic findings were observed up to the concentration of 1 %. At the higher concentrations tested, i.e. 3 and 6%, some test item related signs, such as slight to moderate ear erythema, were observed at the local dosing sites but no clear change of dpm/LN was caused by this local irritant effect. All treated animals survived the scheduled study period. Thus, the test material (8-((4-Amino-3-nitrophenyl)azo)-7-hydroxy-2-naphthyl)trimethylammonium chloride was evaluated to be non-sensitizer to mice.

Overall reported skin sensitisation studies of Basic red 76 and its read-across substance, indicate that Basic Red 76 is not likely to exhibit skin sensitisation can be classified as 'non-hazardous' as per the CLP classification criteria.

Migrated from Short description of key information:
The sensitization potential of Basic Red 76 was determined by Mouse Local Lymphnode Assay. Stimulation Index of the test chemical was determined to be in range 0.9-1.3
Calculation of the EC 3 value was not performed as no test concentration produced a stimulation index of 3 or above. Based on the criteria of the test system, Basic Red 76 was a non-sensitizer when tested up to a concentration of 10% (w/v) in ethanol:water (7:3 v/v) in mice.

Justification for selection of skin sensitisation endpoint:
The sensitization potential of Basic Red 76 was determined by Mouse Local Lymphnode Assay.
Stimulation Index of the test chemical was determined to be in range 0.9-1.3
Calculation of the EC 3 value was not performed as no test concentration produced a stimulation index of 3 or above.
Based on the criteria of the test system, Basic Red 76 was a non-sensitizer when tested up to a concentration of 10% (w/v) in ethanol:water (7:3 v/v) in mice.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

On the basis of available data, the substance Basic red 76 is not likely to exhibit skin sensitisation and can be classified as 'non-hazardous' as per the CLP classification criteria.