5-nitroisophthalic acid

Endpoint summary

Description of key information

Positive erythema reactions (i.e., a score >= 2) were observed in only one test article–treated guinea pig, compared to no vehicle or sham control guinea pigs during the challenge phase. Since no sensitization reactions were observed in majority of treated animals, the chemical  was considered as not sensitizing to the skin of guinea pigs.

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:

data from handbook or collection of data

Remarks:

experimental data of read across substances

Justification for type of information:

Data for the target chemical is summarized based on the structurally similar read across chemicals

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

other: as mentioned below

Principles of method if other than guideline:

WoE derived based on the experimental data from structurally and functionally similar read across chemicals

GLP compliance:

not specified

Type of study:

other: 2. Buehler test 3.not specified

Justification for non-LLNA method:

Currently no LLNA study is available for assessment. The Guinea Pig Maximization Test (GPMT) has been carried out as an animal test to predict human sensitization for over a decade and is recommended by international test guidelines such as OECD.

Species:

guinea pig

Strain:

not specified

Sex:

male

Details on test animals and environmental conditions:

No data available

Route:

epicutaneous, occlusive

Vehicle:

DMSO

Concentration / amount:

30% (0.3mL)

Day(s)/duration:

3 weeks

Adequacy of induction:

other: not specified/2

Route:

epicutaneous, open

Vehicle:

other: 1% aqueous duponol

Concentration / amount:

50%

Day(s)/duration:

not specified

Adequacy of induction:

other: not specified/3

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

DMSO

Concentration / amount:

30% (0.3mL)

Day(s)/duration:

48 hours

Adequacy of challenge:

other: not specified / 2

No. of animals per dose:

2. 30 (10 guinea pigs/Group)
3. Not specified

Details on study design:

2. MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3
- Exposure period: no data
- Test groups: 10 guinea pigs
- Control group: 10 guinea pigs
- Site: shaved backs
- Frequency of applications: once a week
- Duration: 3 weeks
- Concentrations: 30% (0.3mL)

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: after 2 weeks
- Exposure period: 24 hours
- Test groups: 10 guinea pigs
- Control group: 10 guinea pigs
- Site: no data
- Concentrations: 30% (0.3mL)
- Evaluation (hr after challenge): 24 hours and 48 hours

3.The test chemical was applied as a 50% paste in 1% aqueous duponol to the intact skin of Guinea Pigs.

Challenge controls:

2. The sham control guinea pigs each received a challenge dose of 0.3 ml of the 30% test article/DMSO solution; the vehicle control guinea pigs each received a challenge dose of 0.3 ml of a 70% (w/w) aqueous DMSO solution.
3. Not specified

Positive control substance(s):

not specified

Reading:

1st reading

Hours after challenge:

48

Group:

test chemical

Dose level:

30% (0.3mL)

No. with + reactions:

1

Total no. in group:

10

Clinical observations:

Positive erythema reactions (i.e., a score >= 2) were observed in only one test article–treated guinea pig, compared to no vehicle or sham control guinea pigs during the challenge phase.

Remarks on result:

no indication of skin sensitisation

Remarks:

2

Reading:

1st reading

Group:

other: Not specified

Remarks on result:

no indication of skin sensitisation

Remarks:

3

The primary effect of treatment (treated vs. control) and the secondary effect of time of scoring (24 hr vs. 48 hr) were not statistically significant. These findings indicate that dermal sensitization did not result from repeated dermal application of Isophthalic acid.

Interpretation of results:

other: not sensitizing

Conclusions:

Positive erythema reactions (i.e., a score >= 2) were observed in only one test article–treated guinea pig, compared to no vehicle or sham control guinea pigs during the challenge phase. Since no sensitization reactions were observed in majority of treated animals, the chemical was considered as not sensitizing to the skin of guinea pigs.

Executive summary:

Skin sensitization study was performedcon guniea pig to dtermine the sensitization potential of test chemicals. The studies are summarized below:

A Buehler Test was conducted on ten male guinea pigs for chemical to assess its skin sensitization potential. Test chemical was applied once a week at a dose of 0.3ml of a 30% (w/w) solution in dimethylsulfoxide (DMSO) to the shaved backs of ten male guinea pigs during an induction period of three weeks. Another group of 10 male guinea pigs served as a vehicle control and was similarly dosed with 0.3ml of undiluted DMSO. A third group of ten sham control guinea pigs was handled in the same manner, but was not treated with test article or vehicle. Two weeks following application of the third induction dose, the treated andsham control guinea pigs each received a challenge dose of 0.3 ml of the 30% test article/DMSO solution; the vehicle control guinea pigs each received a challenge dose of 0.3 ml of a 70% (w/w) aqueous DMSO solution. All guinea pigs were scored for erythema approximately 24 and 48 hours following application of the first induction dose and the challenge dose. Positive erythema reactions (i.e., a score >= 2) were observed in only one test article–treated guinea pig, compared to no vehicle or sham control guinea pigs during the challenge phase. Since no sensitization reactions were observed in majority of treated animals, the chemical was considered as not sensitizing to the skin of guinea pigs.

In another study, Skin sensitization test was performed on Guinea pig to determine the sensitization potential of test chemical. The test chemical was applied as a 50% paste in 1% aqueous solution of Duponol to intact skin of Guinea pig. No indication of clinical signs suggests that the test chemical is not sensitizing to the skin of Guinea pig. Hence the test chemical is 'Not sensitizing' in nature.

Thus, comparing above studies it can be concluded that the test chemical is not sensitizing in nature.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Skin sensitization study was performedcon guniea pig to dtermine the sensitization potential of test chemicals. The studies are summarized below:

A Buehler Test was conducted on ten male guinea pigs for chemical to assess its skin sensitization potential. Test chemical was applied once a week at a dose of 0.3ml of a 30% (w/w) solution in dimethylsulfoxide (DMSO) to the shaved backs of ten male guinea pigs during an induction period of three weeks. Another group of 10 male guinea pigs served as a vehicle control and was similarly dosed with 0.3ml of undiluted DMSO. A third group of ten sham control guinea pigs was handled in the same manner, but was not treated with test article or vehicle. Two weeks following application of the third induction dose, the treated andsham control guinea pigs each received a challenge dose of 0.3 ml of the 30% test article/DMSO solution; the vehicle control guinea pigs each received a challenge dose of 0.3 ml of a 70% (w/w) aqueous DMSO solution. All guinea pigs were scored for erythema approximately 24 and 48 hours following application of the first induction dose and the challenge dose. Positive erythema reactions (i.e., a score >= 2) were observed in only one test article–treated guinea pig, compared to no vehicle or sham control guinea pigs during the challenge phase. Since no sensitization reactions were observed in majority of treated animals, the chemical was considered as not sensitizing to the skin of guinea pigs.

In another study, Skin sensitization test was performed on Guinea pig to determine the sensitization potential of test chemical. The test chemical was applied as a 50% paste in 1% aqueous solution of Duponol to intact skin of Guinea pig. No indication of clinical signs suggests that the test chemical is not sensitizing to the skin of Guinea pig. Hence the test chemical is 'Not sensitizing' in nature.

Thus, comparing above studies it can be concluded that the test chemical is not sensitizing in nature.

Justification for classification or non-classification

The skin sensitization potential of test substance and its structurally and functionally similar read across substances were observed in various studies. From the results obtained from these studies it is concluded that the chemical is not likely to cause skin sensitization and hence can be classified as non-skin sensitizer.