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Diss Factsheets

Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Limited documentation, no positive control group, no historical data, study design does not accord to modern guidelines.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1974
Report date:
1974

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
A test for primary irritation was conducted on the shaved intact shoulder skin of male albino guinea pigs. To test for sensitization potential, a series of four sacral intradermal injections was given, one each week over a 3-week period. Following a 2-week rest period, the test animals were challenged for sensitization dermally on the shaved intact shoulder skin. A group of previously unexposed guinea pigs received similar applications at challenge to provide a comparison of the challenge reactions on skin of similar age.
GLP compliance:
not specified
Type of study:
other: skin sensitization study on Guinea pigs
Justification for non-LLNA method:
The Guinea pig test was performed in 1974.

Test material

Constituent 1
Chemical structure
Reference substance name:
Adipic acid
EC Number:
204-673-3
EC Name:
Adipic acid
Cas Number:
124-04-9
Molecular formula:
C6H10O4
IUPAC Name:
adipic acid
Details on test material:
- Purity: 99.99%

In vivo test system

Test animals

Species:
guinea pig
Strain:
other: albino
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: Not reported
- Weight at study initiation: 502-766 g
- Housing: Not reported
- Diet (e.g. ad libitum): Not reported
- Water (e.g. ad libitum): Not reported
- Acclimation period: Not reported

ENVIRONMENTAL CONDITIONS
- Temperature (°C): Not reported
- Humidity (%): Not reported
- Air changes (per hr): Not reported
- Photoperiod (hrs dark / hrs light): Not reported

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal
Vehicle:
propylene glycol
Concentration / amount:
Primary Irritation: One drop (~0.05 mL) of 50% and 25% suspension (wt./wt.) of test material in propylene glycol
Induction: 0.1 mL of a 1.0% solution (wt./vol) of test material in water
Challenge: One drop (~0.05 mL) of 50% and 25% suspension (wt./wt.) of test material in propylene glycol
Challengeopen allclose all
Route:
epicutaneous, open
Vehicle:
propylene glycol
Concentration / amount:
Primary Irritation: One drop (~0.05 mL) of 50% and 25% suspension (wt./wt.) of test material in propylene glycol
Induction: 0.1 mL of a 1.0% solution (wt./vol) of test material in water
Challenge: One drop (~0.05 mL) of 50% and 25% suspension (wt./wt.) of test material in propylene glycol
No. of animals per dose:
10
Details on study design:
RANGE FINDING TESTS: The test for primary irritation was conducted by applying and lightly rubbing one drop of test material on the shaved intact shoulder skin.


MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 4 intradermal injections
- Exposure period: 3 weeks
- Site: Not reported
- Frequency of applications: once per week
- Concentrations: 0.1 mL of a 10% solution (wt./vol.) of test material in water

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Site: Shoulder
- Concentrations: 1 drop (~0.05ml) of 50% and 25% suspensions of test material in propylene glycol
- Evaluation (hr after challenge): 24 and 48 hours
Challenge controls:
A group of 10 previously unexposed guinea pigs received similar applications at the time of challange to provide a direct comparison of the challange reaction on skin of similar age.
Positive control substance(s):
no

Results and discussion

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
25%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
25%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
48
Group:
test chemical
Dose level:
50%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
50%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
25% for challenge only
No. with + reactions:
2
Total no. in group:
10
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
25% for challenge only
No. with + reactions:
2
Total no. in group:
10
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
50% for challenge only
No. with + reactions:
1
Total no. in group:
10
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
50% for challenge only
No. with + reactions:
2
Total no. in group:
10
Group:
positive control
Remarks on result:
not measured/tested
Remarks:
not measured/tested

Any other information on results incl. tables

Table 1: Results

 

Test Area

Control Area for Challenge Test

Concentration in Propylene glycol

50%

25%

50%

25%

Primary Irritation Test

     24 hours

10 neg.

10 neg.

 

 

     48 hours

10 neg.

10 neg.

 

 

Challenge Test

     24 hours

10 neg.

10 neg.

1+, 9 neg.

2+, 8 neg.

     48 hours

10 neg.

10 neg.

2+, 8 neg.

2+, 8 neg.

Reaction Code: +, ++, +++ = mild, moderate, strong erythema; ++++ = erythema plus edema; +++++ = necrosis

Adipic acid produced very mild to no skin irritation when tested on the shaved intact skin of male albino guinea pigs at a concentration up to 50% in propylene glycol. It did not cause skin sensitization at concentrations of 25 and 50%.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Adipic acid produced very mild to no skin irritation when tested on the shaved intact skin of male albino guinea pigs at a concentration up to 50% in propylene glycol. It did not cause skin sensitization.
Executive summary:

Groups of 10 guinea pigs were given series of four sacral intradermal injections, one each week over a three-week period, which consisted of 0.1 ml of a 1.0 % solution of adipic acid (99.99 %) in water. Following a two-week rest period, the test animals were challenged for sensitisation by applying, and lightly rubbing in, approximately 0.05 ml of a 50 % and 25 % suspension of the test material in propylene glycol on the shaved intact shoulder skin. A group of 10 previously unexposed animals received similar applications at the time of challenge to provide direct comparison of the challenge reactions on the skin of similar age. The compound produced very mild to no skin irritation to previously unexposed guinea pigs and did not cause sensitisation (Haskell 1974). The study design does not accord to modern guidelines.