2-pyridylamine

Skin sensitisation

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 guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EPA OTS 798.4100 (Skin Sensitisation)

Deviations:

no

Test guideline 2

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

Test material information

Constituent 1

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)

Results

Results 1

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

Results 2

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

Results 3

Reading:

rechallenge

Remarks on result:

not measured/tested

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Remarks on result:

no indication of skin sensitisation

Results 5

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.