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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
no data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: valid with restrictions; meets generally accepted scientific standards, well documented and acceptable for assessment.
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
yes
Remarks:
: no information on use of 10% SDS
GLP compliance:
no
Type of study:
guinea pig maximisation test
Species:
guinea pig
Strain:
other: pirbright white
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Lippische Versuchstierzucht, Hagemann GmbH & Co, D-4923 Exertal 1
- Age at study initiation: 21-28 Tage
- Weight at study initiation: 250-300 g
- Housing: two animals in one cage
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: not reported

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C +/-1°C
- Humidity (%): 60% +/- 5%
- Air changes (per hr): not reported
- Photoperiod (hrs dark / hrs light): 12/12
Route:
intradermal
Vehicle:
no data
Concentration / amount:
0.5-10% induction; 20 % challenge
Route:
other: percutaneous
Vehicle:
no data
Concentration / amount:
0.5-10% induction; 20 % challenge
No. of animals per dose:
20 male animals were tested altogether; in the positive control additional 20 animals were tested
Details on study design:
RANGE FINDING TESTS: yes; 2-3 animals; estimation of the probable sentising effects; determination of dose to induce after intradermal treatment an irritation; percutaneous treat did not lead to irritation

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 1
- Exposure period: 24 h
- Test groups: 0.5-10% substance; 0.5%-10% substance + mixture containing of Freund`s adjuvant Complete and vehicle (1:1)
- Control group: Freund`s adjuvant Complete and vehicle (1:1)
- Site:at the back
- Frequency of applications: once
- Duration: 24 h
- Concentrations: 0.5-10%
Reading after 1 h and 24 h

B. CHALLENGE EXPOSURE
- No. of exposures: 2
- Day(s) of challenge: 7 days after first exposure
- Exposure period: 48 h (occlusive)
- Test groups: 2 ml 20% solution of test substance
- Control group: not reported
- Site: at the back between front and rear extremities
- Concentrations: 20 % solution
- Evaluation (hr after challenge): 72 h

OTHER: positive control: 20 animals treated with Penicllin G-Na
Positive control substance(s):
yes
Remarks:
Penicllin G-Na
Positive control results:
valid; 100% sensibilization
Reading:
other: 3rd
Hours after challenge:
72
Group:
test group
Dose level:
20 %
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
not reported
Remarks on result:
other: Reading: other: 3rd. . Hours after challenge: 72.0. Group: test group. Dose level: 20 %. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: not reported.
Reading:
other: 3rd
Hours after challenge:
72
Group:
positive control
Dose level:
5000 IE/ 0.1ml
No. with + reactions:
20
Total no. in group:
20
Clinical observations:
not reported
Remarks on result:
other: Reading: other: 3rd. . Hours after challenge: 72.0. Group: positive control. Dose level: 5000 IE/ 0.1ml. No with. + reactions: 20.0. Total no. in groups: 20.0. Clinical observations: not reported.
Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
In this study thiourea is not sensitising.
Executive summary:

In a dermal sensitization study with Thiourea (0.5-10%) male guinea pigs (pirbright white) were tested using the method of Magnusson and Kligman. Induction was performed intradermal. Penicillin G-Na was used as positive control.

In this study Thiourea is not a dermal sensitizer.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

In a dermal sensitization study with 0.1 ml Thiourea (0.5–10 %) male guinea pigs were tested using the method of Magnusson and Kligman. In this study Thiourea is not a dermal sensitizer. Several case reports on human exposure are available indication a low degree of sensitization. The number of reports are not considered to represent a "substantial number" as required for a classification under CLP. In addition it is not clear whether or not they are attributable to Thiourea derivatives. In several cases thiourea derivatives and not thiourea as such were reported to cause contact dermatitis.


Migrated from Short description of key information:
The dermal sensitization potential of Thiourea in Guinea Pigs was assessed in a Maximisation test in accordance with the guidance for skin sensitisation of the OECD short term toxicology group (31.12.1979). Thiourea was found to have no sensitizing potential in this study. Several case reports on human exposure are available indication a low degree of sensitization.

Justification for selection of skin sensitisation endpoint:
key study equivalent to OECD406

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Thiourea is not classified based on a negative Guinea Pig Maximisation Test.