Registration Dossier

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:
January 24, 1980 - February 21 , 1980
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
Challenge was done with a slightly irritating concentration and a challenge control was not included.
Justification for type of information:
Buehler test is available from 1980

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1980
Report Date:
1980

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
Study performed prior to introduction of guideline.
Deviations:
yes
Remarks:
irritant concentration (5%) used for challenge, the negative control group is not challenged with the test material and therefore irritation and sensitisation is difficult to distinguish; 15 instead of 20 animals used in treatment group.
GLP compliance:
no
Remarks:
pre-GLP
Type of study:
Buehler test
Justification for non-LLNA method:
A Bueler test from 1980 is available, which can be used for the assessment of skin sensitisation.

Test material

Reference
Name:
Unnamed
Test material form:
liquid

In vivo test system

Test animals

Species:
guinea pig
Strain:
Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Murphy Breeding Laboratories
- Females (if applicable) nulliparous and non-pregnant: not specified
- Weight: 200 - 300 grams
- Housing: singly in wire mesh cages suspended above the droppings
- Diet: Purina Guinea Pig Chow, ad libitum
- Water (e.g. ad libitum): The animals were maintained on medicated water containing 4% of sulfaethoxypyridazine (6.25% S.E.Z. , American Cyanamid) for four days. At the end of this period they were furnished with non-medicated water ad libitum
- Acclimation period: minimum 4 days

ENVIRONMENTAL CONDITIONS
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (non-LLNA)

Induction
Route:
epicutaneous, occlusive
Vehicle:
other: SDA39C
Concentration / amount:
5% v/v
Day(s)/duration:
3 exposures (once a week) of 6 hours per day
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
Challenge
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: SDA39C
Concentration / amount:
5% v/v
Day(s)/duration:
6 hours (2 weeks after last induction)
Adequacy of challenge:
other: same concentration as used for induction (slightly irritant) and therefore skin sensitisation results may also be due to skin irritation.
No. of animals per dose:
Dose-selection: 4
Test group: 15
Positive control: 10
Negative control: 5
Details on study design:
RANGE FINDING TESTS:
Prior to the induction phase of the study the test material was applied to four guinea pigs to determine the highest non-irritating concentration which could be applied for the induction and the primary challenge. For this purpose the test substance was tested as 10%, 5%, 2.5% and 1.3% v/v solutions in SDA39C. On the day before applications were made the backs of the guinea pigs were clipped with electric clippers. The four concentrations were tested the following day on each guinea pig (0.4 mL on each patch).

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3
- Exposure period: 3 weeks
- Test groups: 15 animals
- Control group: 10 animals for positive control, 5 for negative control
- Site: upper left quadrant of the back
- Frequency of applications: once/week
- Duration: 6 hours
- Concentrations: test material as a 5% v/v solution in SDA39C for test group and 100% SDA39C for negative control group

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 1
- Exposure period: 6 hours
- Test groups: 15 animals
- Control group: 10 animals for positive control, 5 for negative control
- Site: lower left quadrant of the back
- Concentrations: test material as a 5% v/v solution in SDA39C for test group and 100% SDA39C for negative control group
- Evaluation (hr after challenge): 24 and 48 hrs
Challenge controls:
Not included
Positive control substance(s):
yes
Remarks:
DNCB, for information on concentration see Positive control results.

Results and discussion

Positive control results:
At induction and challenge the positive control was tested as a 10% v/v solution in SDA39C as described in the report. However 0.1% positive control is also mentioned in the report. In view of DNCB being a strong sensitizer the latter seems applicable.

Results:
For the positive control animals one animal showed severe erythema (grade 3), in six animals moderate erythema was observed (grade 2), and three animals developed slight confluent or moderate patchy erythema (grade 1) at the 24-hour reading. At the 48-hour reading two cases of severe erythema (grade 3) were noted, three moderate erythema (grade 2) and five cases of slight confluent or moderate patchy erythema (grade 1) was noted at the 48-hour reading.

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
5% v/v
No. with + reactions:
9
Total no. in group:
15
Clinical observations:
Five animals with moderate erythema (grade 2), four animals with slight confluent or moderate patchy erythema (grade 1) and six slightly patchy erythema (grade +/-)
Remarks on result:
positive indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
5% v/v
No. with + reactions:
9
Total no. in group:
15
Clinical observations:
Two animals with moderate erythema (grade 2), seven animals with slight confluent or moderate patchy erythema (grade 1), five animals developed slightly patchy erythema (+/-) and one had no reaction (grade 0).
Remarks on result:
positive indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
0.1%
No. with + reactions:
10
Total no. in group:
10
Clinical observations:
One animal showed severe erythema (grade 3), in six animals moderate erythema was observed (grade 2), and three animals developed slight confluent or moderate patchy erythema (grade 1).
Remarks on result:
positive indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
0.1%
No. with + reactions:
10
Total no. in group:
10
Clinical observations:
Two cases of severe erythema (grade 3) were noted, three moderate erythema (grade 2) and five cases of slight confluent or moderate patchy erythema (grade 1).
Remarks on result:
positive indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
100%
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
100%
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation

Any other information on results incl. tables

A preliminary irritation test was performed with 10, 5, 2.5 and 1.3% test substance in SDA 39C. At 10%, 2/4 animals exhibited slight confluent or moderate patchy erythema (grade 1) and 1/4 animals exhibited slightly patchy erythema (grade +/-). At 5%, 2/4 animals exhibited slightly patchy erythema (grade +/-), while at 2.5% and 1.3% no effects were observed.

Induction and challenge concentrations were 5% test material in SDA 39C.

Under the conditions of the study, 5% test material in vehicle SDA 39C produced 9/15 positive responses (1 and 2 grades) at the 24 and 48 hour readings of the test animals. When considering ± responses (slightly patchy erythema) also as a positive result, 15/15 animals responded at the 24 hour reading and 14/15 at the 48 hour reading. In view of the irritation seen during the preliminary test at 5% and the fact that the challenge is also conducted at 5% the sensitization effects may be difficult to separate from irritation. Though the results indicate some sensitization, also because similar scores were seen at 24 and 48 hours, the severity of the sensitisation is inconclusive.

Applicant's summary and conclusion

Interpretation of results:
other: Skin sensitising, Category 1
Remarks:
in accordance with EU CLP (EC 1272/2008 and its updates)
Conclusions:
The results of this Buehler assay with Dimeth Cyclormol indicate that the material is a sensitiser in view of the positive results in at least 9/15 animals. Although this result may be confounded with irritancy the substance is considered a skin sensitiser because the erythema remained after 48 hours. The skin sensitisation potency is however inconclusive.
Executive summary:

A Buehler test was performed in accordance with a method similar to OECD TG 406 (performed prior to guideline introduction). The study was rated Klimisch 2, firstly because irritant concentrations were used during the challenge. Secondly because the animals in the challenge control (non-induced) animals were exposed to the vehicle instead of the 5% test substance concentration. The irritant effects cannot be distinguished from the skin sensitisation effects. A preliminary irritation test was performed with 10, 5, 2.5 and 1.3% test substance in SDA 39C. At 10%, 2/4 animals exhibited slight confluent or moderate patchy erythema and 1/4 animals exhibited slightly patchy erythema. At 5%, 2/4 animals exhibited slightly patchy erythema, while at 2.5% and 1.3% no effects were observed. Induction and challenge concentrations selected were 5% test material in SDA 39C, which were applied under occlusion. The challenge concentration of 5% test material produced 9/15 positive responses (grades 1: slight confluent or moderate patchy erythema and grades 2: moderate erythema) at the 24 and 48 hour readings of the test animals. When considering ± responses (slightly patchy erythema) also positive, 15/15 animals responded positive at the 24 hour reading and 14/15 at the 48 hour reading. The positive reactions in most animals and being consistent at 48 hours the substance is considered a sensitiser. The potency remains inconclusive because Buehler tests are not developed to present potency and because the irritation of the substance may have confounded the skin sensitisation.