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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
Study period:
1996-03-26 to 1996-07-12
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1996
Report date:
1996

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
GLP compliance:
yes (incl. QA statement)
Type of study:
Buehler test
Justification for non-LLNA method:
The in vivo study data were obtained in studies performed before any in vitro sensitization tests had been validated and accepted for regulatory purposes

Test material

Constituent 1
Reference substance name:
Reference substance 001
Cas Number:
91744-23-9
Molecular formula:
UVCB, not applicable
Test material form:
semi-solid (amorphous): gel
Remarks:
migrated information: paste
Details on test material:
- Substance type: product
- Physical state: viscous yellow paste
- Purity: 99.8%
- Stability under test conditions: > 1 year
- Storage condition of test material: at room temperatures in the dark
- Manufacture date: May 1995
- Lot/batch No.: 505024
- Expiration date of the lot/batch: not earlier than May 1996

In vivo test system

Test animals

Species:
guinea pig
Strain:
other: Dunkin Hartley, Pirbright White
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Winkelmann GmbH, Versuchstierzucht, Borchen, Germany
- Age at study initiation: young adults, no further details mentioned
- Weight at study initiation: 257 ± 19 g
- Housing: conventional, Makrolon Type IV cages (maximum 5 animals per cage)
- Diet (e.g. ad libitum): Ssniff G4 complete feed for guinea pigs ad libitum, supplied by Ssniff Spezialfutter GmbH, Soest, Germany
- Water (e.g. ad libitum): drinking water ad libitum, supplied by Gelsenwasser, Wasserwerk, Haltern, Germany
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 30 - 70
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 1996-03-26 To: 1996-03-29 (preliminary study)
From: 1996-06-12 To: 1996-07-12 (main study)

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
induction and challenge: 2, 25, 50 and 100 % in corn oil MEH 56
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
induction and challenge: 2, 25, 50 and 100 % in corn oil MEH 56
No. of animals per dose:
test animals: 20 (main experiment), 3 (pilot study), 3 (determination of challenge concentration)
control animals: 10
Details on study design:
RANGE FINDING TESTS:
Determination of the non-irritant concentration of the test substance with occlusive epicutaneous applications for 6 hours of test substance 5%, 25%, 50% in corn oil MEH 56 and undiluted 100% (delivery form). Reading at 30 and 54 hours after application.
Redetermination of the maximum non-irritant concentration for the challenge treatment in the 4th week with 3 additional guinea pigs which had not been treated up to this time. The concentrations and test conditions were the same as in the pilot study. This additional testing was carried out because it was suspected that the sensitivity of the skin changed as the weight of the animals increased. This ensured that the challenge concentration was determined on animals which had approx. the same weights as the 30 animals in the challenge phase.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3
- Exposure period: occlusive dermal applications for 6 hours, scoring at 30 hours after start of application
- Test group: receiving test substance (0.3 cm³/patch)
- Control group: receiving vehicle (0.3 cm³/patch)
- Site: left flanks
- Frequency of applications: induction on days 0, 7 and 14
- Duration: 3 weeks
- Concentrations: undiluted (delivery form)

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: on day 28
- Exposure period: occlusive dermal application for 6 hours
- Test groups: receiving test substance solution and vehicle (0.3 cm³/patch each)
- Control group: receiving test substance solution and vehicle (0.3 cm³/patch each)
- Site: right flanks (front: vehicle, back: test substance solution)
- Concentrations: undiluted (delivery form)
- Evaluation (hr after challenge): 24 and 48 hours
Challenge controls:
same treatment as test group animals
Positive control substance(s):
yes
Remarks:
2-Mercaptobenzothiazole

Results and discussion

Positive control results:
The sensitivity of the used guinea pig strain was checked from 1996-04-29 to 1996-05-30. The test compound was used as an well-known standard allergen. The maximisations method was carried out for this test. A test goup of 10 and a control group of 5 animals were used to test the sensitivity. 48 and 72 hours after challenge treatment all skin reaction were recorded:
Dermal irritation was found on the right flank of 3 of 10 test animals 48 and 72 hours after treatment with the allergen. Treatment of the test animals with the vehicle on the left flank likewise resulted in a slight or to distinct subcutaneous reaction after 48 and 72 hours in two animals.
There were no signs of irritation at these times on the skin on the left (standard allergen) and right (vehicle) flanks of the control animals.
It was necessary to pretreat the skin with 10% sodium dodecylsulphate in vaseline in order to cause slight to moderate cutaneous inflammation, because the highest allergen concentration which could be administered satisfactorily caused no dermal irritation.
On the basis of these results (30% of test animals showed evidence of delayed contact hypersensitivity), the guinea pig strain was judged to be sensitive under the test conditions described. In the maximisation method, a figure of 15% or more is regarded as positive result.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
100%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
no clinical effects observed
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 100%. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: no clinical effects observed.
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
100%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
no clinical effects observed
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 100%. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: no clinical effects observed.
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
100%
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no clinical effects observed
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 100%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no clinical effects observed.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
100%
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no clinical effects observed
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 100%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no clinical effects observed.
Reading:
other: Reliability
Group:
positive control
Remarks on result:
positive indication of skin sensitisation
Remarks:
The sensitivity of the used guinea pig strain was checked from 1996-04-29 to 1996-05-30. The test compound was used as an well-known standard allergen.

Any other information on results incl. tables

RESULTS OF PILOT STUDY

No irritant effects at any concentration of the test substance tested.

RESULTS OF TEST

- Sensitisation reaction: No sensitising effects observed.

- Clinical signs: No clinical effects observed. Body weight increase comparable to control.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The test substance is not sensitizing.
Executive summary:

The sensitizing potential of the test substance (CAS 91744-23-9) was investigated in a study according to OECD Guideline No. 406 "Skin Sensitization (maximization test)”.

The following animal numbers were used in the study: 20 (main experiment), 3 (pilot study), 3 (determination of challenge concentration), control animals: 10. The substance concentrations for induction and challenge were 2, 25, 50, and 100 % in corn oil MEH 56. 2 -Mercaptobenzothiazole served as positive control.

Experimental animals were epidermally exposed to undiluted test substance on days 0, 7, and 14 (occlusive dermal applications for 6 hours, scoring at 30 hours after start of application). Control animals were exposed to vehicle only. On day 28 animals were challenged with undiluted test substance (occlusive dermal application for 6 hours). Evaluations were made after 24 and 48 h.

Under the conditions of the test no sensitizing effects of the test substance could be observed. In addition, no clinical effects were observed. Body weight increase of the test animals was comparable to the control.

On the basis of the results with the positive control 2-mercaptobenzothiazole (30% of test animals showed evidence of delayed contact hypersensitivity), the guinea pig strain was judged to be sensitive under the test conditions described.