Pyridine-2,4-dicarboxylic acid

Skin sensitisation

Administrative data

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 from handbook or collection of data

Data source

Reference

Reference 1

Reference Type:

review article or handbook

Title:

Safety Assessment of Trimellitic Anhydride Copolymers as Used in Cosmetics

Author:

cosmetic ingredient review expert panel

Year:

2016

Bibliographic source:

cosmetic ingredient review expert panel; November 14, 2016

Reference 2

Reference Type:

secondary source

Title:

IUCLID Dataset for CAS 121-91-5

Author:

EUROPEAN COMMISSION – European Chemicals Bureau

Year:

2000

Bibliographic source:

IUCLID Dataset; EUROPEAN COMMISSION – European Chemicals Bureau; 18–FEB–2000

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: as mentioned below

Principles of method if other than guideline:

A Buehler Test was conducted on ten male guinea pigs for chemical isophthalic acid (CAS No: 121-91-5) to assess its skin sensitization potential.

GLP compliance:

not specified

Type of study:

Buehler test

Justification for non-LLNA method:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Isophthalic acid

EC Number:

204-506-4

EC Name:

Isophthalic acid

Cas Number:

121-91-5

Molecular formula:

C8H6O4

IUPAC Name:

1,3-benzenedicarboxylic acid

Test material form:

solid

Details on test material:

Name of the test chemical: Isophthtalic acid
Molecular Formula:C8H6O4
Molecular Weight: 166.1314 g/mol
InChI: 1S/C8H6O4/c9-7(10)5-2-1-3-6(4-5)8(11)12/h1-4H,(H,9,10)(H,11,12)
Substance Type: Organic
Physical State: Solid

Specific details on test material used for the study:

- Name of test material (as cited in study report): Isophthalic acid
- Molecular formula: C8H6O4
- Molecular weight: 166.1314
- Substance type: organic
- Physical state: solid
-Smiles: c1cc(cc(c1)C(=O)O)C(=O)O
-InChI: 1S/C8H6O4/c9-7(10)5-2-1-3-6(4-5)8(11)12/h1-4H,(H,9,10)(H,11,12)

In vivo test system

Test animals

Species:

guinea pig

Strain:

not specified

Sex:

male

Details on test animals and environmental conditions:

No data available

Study design: in vivo (non-LLNA)

Induction

Route:

epicutaneous, occlusive

Vehicle:

DMSO

Concentration / amount:

30% (0.3mL)

Day(s)/duration:

3 weeks

Adequacy of induction:

not specified

Challenge

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

DMSO

Concentration / amount:

30% (0.3mL)

Day(s)/duration:

48 hours

Adequacy of challenge:

not specified

No. of animals per dose:

30 (10 guinea pigs/Group)

Details on study design:

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

Challenge controls:

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.

Positive control substance(s):

not specified

Results and discussion

In vivo (non-LLNA)

Results

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

In vivo (LLNA)

Cellular proliferation data / 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.

Any other information on results incl. tables

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.

Applicant's summary and conclusion

Interpretation of results:

other: not sensitizing

Conclusions:

The test material isophthalic acid (CAS No: 121-91-5) was considered as not sensitizing to the skin of guinea pigs.

Executive summary:

A Buehler Test was conducted on ten male guinea pigs for chemicalisophthalic acid (CAS No:121-91-5) to assess its skin sensitization potential.

 

Isophthalic acid 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 isophthalicacid (CAS No:121-91-5) was considered as not sensitizing to the skin of guinea pigs.