Registration Dossier

Diss Factsheets

Toxicological information

Skin sensitisation

Currently viewing:

Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1992
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report date:
1992

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
EPA OTS 798.4100 (Skin Sensitisation)
Deviations:
no
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
GLP compliance:
yes
Type of study:
Buehler test
Justification for non-LLNA method:
Albino guinea pigs were used in this study (conducted in 1992), because they have historically been used in skin sensitization tests and the guidelines have no alternative (non-animal) methods. The number of animals is recommended in the following reference: Identification of Contact Allergens, Dermatotoxicology, 3rd edtition, eds. F.N. Marzulli and H.I. Maibach, Hemisphere Publishing Corporation, Washington-New York-London, pp. 246-249, 1987.

Test material

Constituent 1
Chemical structure
Reference substance name:
2-pyridylamine
EC Number:
207-988-4
EC Name:
2-pyridylamine
Cas Number:
504-29-0
Molecular formula:
C5H6N2
IUPAC Name:
pyridin-2-amine
Test material form:
solid
Details on test material:
STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature
- Stability under test conditions: stable

In vivo test system

Test animals

Species:
guinea pig
Strain:
Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Elm Hill Breeding Labs, Chelmsford, MA.
- Females (if applicable) nulliparous and non-pregnant: not specified
- Age at study initiation: 21-43 days.
- Weight at study initiation: 250-400 g.
- Housing: animals were group housed in stainless steel cages. Hardwood chips (Sani-Chips, JP Murphy Forest Products, Montvale, NJ) were used as contact bedding within the cages.
- Diet: commercial guinea pig ration (Agway Prolab, Agway, Waverly, NY) ad libitum.
- Water: tap water ad libitum.
- Acclimation period: 6 days (preliminary irritation study) or 9 days (skin sensitization study).
- Indication of any skin lesions: no; animals selected for the study were from a larger pool of animals and were examined to insure their skin was free from irritation, trauma, and disease.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 1.7
- Humidity (%): 30-70
- Air changes (per hr): 10-13
- Photoperiod (hrs dark / hrs light): 12/12
- IN-LIFE DATES: From: To:

Study design: in vivo (non-LLNA)

Induction
Route:
epicutaneous, occlusive
Vehicle:
unchanged (no vehicle)
Concentration / amount:
100%
Day(s)/duration:
3 weeks treatment / 1 treatment per week / 6 hours exposure
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
Challenge
No.:
#1
Route:
epicutaneous, open
Vehicle:
water
Concentration / amount:
50%
Day(s)/duration:
1 / 24h
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
14 males and 14 females
Details on study design:
RANGE FINDING TESTS: A preliminary irritation study was performed with 4 previously unexposed animals. 0.4ml of the test item at concentrations of 100, 50, 25 and 10% were applied for 6h, by the closed patch technique, and the responses were read 24h and up to 72h after application. The test substance was found to be slightly to moderately irritating at a concentration of 100% and non-irritating at a concentration of 50% in the Preliminary Irritation study.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3 (weeks 01, 02, 03)
- Exposure period: 6h
- Test groups: 1
- Control group: yes
- Site: 4x3cm site on one side of the animal
- Frequency of applications: once per week
- Duration: 3 weeks
- Concentrations: 0.4 ml of 100% test item.

B. CHALLENGE EXPOSURE
- No. of exposures: 1 (week 05)
- Day(s) of challenge: 1
- Exposure period: 24h
- Test groups: 1
- Control group: yes
- Site: 4x3cm untreated site on the back of the animal
- Concentrations: 50% test item.
- Evaluation (hr after challenge): 26h

OTHER: It was not considered necessary to rechallenge the sensitized guinea pigs at 1 and 2 weeks after the primary challenge (weeks 06 and 07).
Positive control substance(s):
yes
Remarks:
Dinitrochlorobenzene.

Results and discussion

Positive control results:
All 4 animals in the positive control group exhibited signs of erythema (2.0 -3.0).

In vivo (non-LLNA)

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

Any other information on results incl. tables

- No systemic signs of toxicity were evident during the course of the study. Signs of erythema or edema (grade 1.0 or 2.0) were present in the test animals throughout the induction scoring phase. No signs of erythema were observed in any of the test animals in the challenge phase.

- No signes of erythema or edema were present in the control animals at any time point. All 4 animals in the positive control group exhibited signs of erythema (2.0 -3.0).

Table 3. Main Test. Body weight and Clinical Observations.

Group

Animal #

Sex

Day 0

06/18/92

Day 30

07/18/92

Weight

Change

Signs of

Toxicity

Test

article

1

Male

326.4

432.5

106.1

None

2

Male

318.9

425.9

107.0

None

3

Male

334.5

451.0

116.5

None

4

Male

392.3

536.8

144.5

None

5

Male

376.4

523.5

147.1

None

Mean

 

349.7

473.9

 

 

± SD

 

32.6

52.3

 

 

6

Female

382.1

516.4

134.3

None

7

Female

342.6

498.2

155.6

None

8

Female

339.3

453.6

114.3

None

9

Female

341.7

462.3

120.6

None

10

Female

330.0

459.7

129.7

None

Mean

 

347.1

478.0

 

 

± SD

 

20.2

27.7

 

 

Negative

Control

11

Male

357.1

473.2

116.1

None

12

Male

390.7

491.6

100.9

None

13

Male

319.4

436.4

117.0

None

14

Male

323.6

435.5

111.9

None

15

Male

350.4

463.8

113.4

None

Mean

 

348.2

460.1

 

 

± SD

 

28.8

24.2

 

 

16

Female

326.2

432.5

106.3

None

17

Female

334.7

461.0

126.3

None

18

Female

329.3

442.9

113.6

None

19

Female

341.6

458.6

117.0

None

20

Female

353.2

472.1

118.9

None

Mean

 

337.0

453.4

 

 

± SD

 

10.8

15.7

 

 

Positive

control

21

Male

325.0

432.6

107.6

None

22

Male

361.7

472.3

110.6

None

23

Female

390.5

506.4

115.9

None

24

Female

370.5

493.4

122.9

None

 

Table 4. Main Test. Draize Scoring at Induction.

Group

Animal #

Sex

Wk 1

06/19/92

Wk 2

06/26/92

Wk 3

07/03/92

Test

article

1

Male

2.0

2.0

1.0

2

Male

1.0

2.0

2.0

3

Male

2.0

2.0

2.0

4

Male

2.0

1.0

2.0

5

Male

2.0

2.0

2.0

6

Female

2.0

2.0

2.0

7

Female

1.0

2.0

2.0

8

Female

2.0

2.0

2.0

9

Female

1.0

1.0

2.0

10

Female

2.0

1.0

2.0

Positive

control

21

Male

0.0

0.0

0.0

22

Male

0.0

0.0

0.0

23

Female

0.0

0.0

0.0

24

Female

0.0

0.0

0.0

 

Table 5. Main test. Challenge scores.

Group

Animal #

24 h

07/17/92

48 h

07/18/92

Results

Test

article

1

0.0

0.0

Combined incidence = 0/10 (0%)

Combined severity (24h) = 0/10

Combined severity (48h) = 0/10

2

0.0

0.0

3

0.0

0.0

4

0.0

0.0

5

0.0

0.0

6

0.0

0.0

7

0.0

0.0

8

0.0

0.0

9

0.0

0.0

10

0.0

0.0

Negative

Control

11

0.0

0.0

Combined incidence = 0/10 (0%)

Combined severity (24h) = 0/10

Combined severity (48h) = 0/10

12

0.0

0.0

13

0.0

0.0

14

0.0

0.0

15

0.0

0.0

16

0.0

0.0

17

0.0

0.0

18

0.0

0.0

19

0.0

0.0

20

0.0

0.0

Positive

control

21

3.0

3.0

Combined incidence = 4/4 (100%)

Combined severity (24h) = 9/4 = 2.25

Combined severity (48h) = 12/4 = 3.00

22

2.0

3.0

23

2.0

3.0

24

2.0

3.0

 

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Challenge with the test item following 3 weeks of induction caused no erythema or edema in 10/10 treated animals.Therefore, the test item was not considered a skin sensitizer.
Executive summary:

The test item was assessed for skin sensitization potential using the Buehler topical closed patch technique, according to US EPA 798.4100 (GLP study). In a preliminary test, the test item was found to be slightly to moderately irritating at a concentration of 100% and non-irritating at a concentration of 50%. Based on these results, the test item at a concentration of 100% was applied for 6h under a closed patch, once a week for 3 weeks during the induction phase, and once for 24h during the challenge phase. Challenge with the test item following 3 weeks of induction caused no erythema or edema in 10/10 treated animals. No reactions were noted in the negative control group, and 4/4 animals reacted in the positive control group. Consequently, the test item was not considered a skin sensitizer.

Categories Display