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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: well conducted study (MEST) following the general recommendations of the OECD Guideline 406 (QAU)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1987
Report date:
1987

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
The procedures used were generally based on "Development and Validation of an Alternative Dermal Sensitization Test: Mouse Ear Swelling Test (MEST)," by Gad SC, Dunn BJ and Dobbs DW, in Toxicol. & Appl. Parmacol., 84: 93-114 (1986)
GLP compliance:
no
Remarks:
the report has been review by the QAU of Bio/dynamics Inc.
Type of study:
mouse ear swelling test
Justification for non-LLNA method:
Older study available

Test material

Constituent 1
Chemical structure
Reference substance name:
Dipropylamine
EC Number:
205-565-9
EC Name:
Dipropylamine
Cas Number:
142-84-7
Molecular formula:
C6H15N
IUPAC Name:
N-propylpropan-1-amine
Details on test material:
- Name of test material (as cited in study report): di-n-propylamine (C-896 received from Celanese Corp. on August 20, 1986)
- Physical state: clear liquid
- Analytical purity: no data
- Impurities (identity and concentrations): no data
- Composition of test material, percentage of components:
- Storage condition of test material: room temperature
- Other: the positive control substance used was 2,4-dinitrochlorobenzene (yellow granules; lot number A11E; from Eastman Kodak Company, Rochester, New York; storage at room temperature)

In vivo test system

Test animals

Species:
mouse
Strain:
CF-1
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: albino CF-1 (BR) mice from Charles River Breeding Laboratories, Inc., Kingston, New York
- Age at study initiation: approx. 6-8 weeks old at study initiation
- Weight at study initiation: 20-25 g
- Housing: group of 2-5/cage in suspended, etainless steel cages with wire mesh bottoms
- Diet (e.g. ad libitum): Purina Laboratory Chow, #5001
- Water (e.g. ad libitum): automatic watering system (Municipal water supply; Elizabethtown Water Co.)
- Acclimation period: 13 days

ENVIRONMENTAL CONDITIONS
- Temperature (°F): 67-76
- Humidity (%): 30-70%
- Photoperiod (hrs dark / hrs light): 12 / 12 (controlled by an automatic timer)

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
epicutaneous, open
Vehicle:
other: 70% ethanol
Concentration / amount:
1.0% at induction (maximum non-irritating concentration); 50.0% at challenge (maximum non-corrosive concentration)
Challengeopen allclose all
Route:
epicutaneous, open
Vehicle:
other: 70% ethanol
Concentration / amount:
1.0% at induction (maximum non-irritating concentration); 50.0% at challenge (maximum non-corrosive concentration)
No. of animals per dose:
10 in the test groups, 5 in the irritation control groups (see Table 1)
Details on study design:
RANGE FINDING TESTS:
Prior to the study initiation, a range –finding study was performed in order to evaluate the irritation potential of the test material. 18 mice (2 per concentration) were subjected to preliminary studies as follows:
- Doses: initially 0.3, 1, 5 and10% (ear and abdomen) then 25, 50 and 100% (ear only) or 0.05 and 0.1% (abdomen only)
- Amount: 100 µl (abdomen) or 10 µl (ear)
- Treatment period: day 0 (abdomen and ear) and days 1, 2 and 3 (only abdomen)
- Test site preparation: clipped with an electric clipper and then tape-stripped (19 consecutive times with a new piece of tape each time) for abdomen; the ear was not prepared.
- Evaluation of results: ear thickness was measured 18-24 hours after test material application (except in the 0.5, 1, 5 and 10% treatment groups, due to technical error); the abdomen was evaluated on day 4, 24 hours after the last exposure (for erythema or corrosion).

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 4 (days 0, 1, 2 and 4)
- Exposure period: days 0, 1, 2 and 4
- Test groups: clipping oh hair on the abdomen, stripping of the abdomen horny layer of tissue with tape, intradermal injection of a 50% concentration of FCA to 2 sites on the abdomen (1 left and 1 right; approximately 0.02 ml administered), then administration of 100 µl test substance preparation directly to the test site on day 0; on days 1, 2 and 3, tape-stripping of the abdominal skin for 5 consecutive times and administration of 100 µl test substance as described above.
- Control group: treated as test groups, except that 100 µl vehicle was used at the last step
- Site: topical application of the test and/or control material to the clipped abdomen
- Frequency of applications: daily
- Duration: each 24 hours
- Concentrations: 0.1%

B. CHALLENGE EXPOSURE
- No. of exposures: 1 (day 10); on the day before the challenge administration (day 9 for challenge and day 16 for re-challenge), both ears of each animal were examined for the presence of irritation
- Day(s) of challenge: day 10 (challenge) and day 17 (re-challenge
- Exposure period: each 24 hours
- Test groups: 10 µl of the appropriate material left each at challenge or right ear at re-challenge
- Control group: 10 µl of the appropriate vehicle was administrated to the opposing ear as described above, each at challenge or re-challenge
- Site: topical application to the dorsal and ventral surface of the ear
- Concentrations: 50%
- Evaluation (hr after challenge): 24 and 48 hours after challenge/re-challenge administration

OTHER: Animals were lightly anesthetized with ether and the ear thickness was measured and recorded, for both ears. Measurements were made using the ODITEST Series Gauge, D-1000 micrometer.
Challenge controls:
In order to differentiate reactions produced by irritation from those produced by sensitization, five irritation controls animals (previously treated with vehicle and FCA) were subjected to the same challenge procedure as the test animals).
Positive control substance(s):
yes
Remarks:
2,4-dinitrochlorobenzene 0.5% at induction, 1.0% at challenge (also prepared in 70% ethanol)

Results and discussion

Positive control results:
60% of the animals treated with DNBC (Group IA) exhibited a positive sensitization response at 24 hours (test ear at least 20% thicker than control ear) and 50% exhibited a positive response at 48 hours. There were no positive responders in the irritation control group (Group IB). This positive response to a known sensitizer demonstrated the susceptibility of this group of animals to sensitization.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
50%
No. with + reactions:
1
Total no. in group:
10
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 50%. No with. + reactions: 1.0. Total no. in groups: 10.0.
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:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 50%. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
other: rechallenge, 1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
50%
No. with + reactions:
1
Total no. in group:
10
Remarks on result:
other: Reading: other: rechallenge, 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 50%. No with. + reactions: 1.0. Total no. in groups: 10.0.
Reading:
other: rechallenge, 2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
50%
No. with + reactions:
1
Total no. in group:
10
Remarks on result:
other: Reading: other: rechallenge, 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 50%. No with. + reactions: 1.0. Total no. in groups: 10.0.
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
50%
No. with + reactions:
1
Total no. in group:
5
Clinical observations:
challenge irritation control group (Goup IIB)
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 50%. No with. + reactions: 1.0. Total no. in groups: 5.0. Clinical observations: challenge irritation control group (Goup IIB).
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
50%
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
challenge irritation control group (Goup IIB)
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 50%. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: challenge irritation control group (Goup IIB).
Reading:
other: rechallenge, 1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
50%
No. with + reactions:
1
Total no. in group:
5
Clinical observations:
rechallenge irritation control group (Goup IIC)
Remarks on result:
other: Reading: other: rechallenge, 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 50%. No with. + reactions: 1.0. Total no. in groups: 5.0. Clinical observations: rechallenge irritation control group (Goup IIC).
Reading:
other: rechallenge, 2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
50%
No. with + reactions:
1
Total no. in group:
5
Clinical observations:
rechallenge irritation control group (Goup IIC)
Remarks on result:
other: Reading: other: rechallenge, 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 50%. No with. + reactions: 1.0. Total no. in groups: 5.0. Clinical observations: rechallenge irritation control group (Goup IIC).
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
1%
No. with + reactions:
6
Total no. in group:
10
Clinical observations:
no positive reaction in the corresponding irritation control group (Group IB)
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: positive control. Dose level: 1%. No with. + reactions: 6.0. Total no. in groups: 10.0. Clinical observations: no positive reaction in the corresponding irritation control group (Group IB).
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
1%
No. with + reactions:
5
Total no. in group:
10
Clinical observations:
no positive reaction in the corresponding irritation control group (Group IB)
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: positive control. Dose level: 1%. No with. + reactions: 5.0. Total no. in groups: 10.0. Clinical observations: no positive reaction in the corresponding irritation control group (Group IB).

Any other information on results incl. tables

1/10 animals (10%) challenged with test substance (Group IIA) exhibited a positive response at 24 hours only. However, 1/5 challenge irritation control animals (Group IIB) also exhibited a positive response (test ear 135% thicker than control ear, necrosis present).

1/10 animal rechallenged with test substance (Group IIA) exhibited a positive response at 24 hours and 1/10 animal exhibited a positive response at 48 hours. But, one animal in the rechallenge irritation control group (Group IIC) exhibited a positive response at 24 hours (test ear 84% thicker than control ear, foci of necrosis present), and 1 animal exhibited a positive response at 48 hours.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information