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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Justification for type of information:
data is from peer reviewed journals

Data source

Reference
Reference Type:
publication
Title:
Final report of the safety assessment of Urea.
Author:
Cosmetic Ingredient Review Expert Panel
Year:
2005
Bibliographic source:
International Journal of Toxicology;24 Suppl 3:1-56;2005

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: as mentioned below
Principles of method if other than guideline:
To assess the dermal irritation potential of urea in mice
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid
Details on test material:
Name of the test chemical: Urea
Molecular Weight: 60.0556 g/mol
Molecular Formula:CH4N2O
InChI: 1S/CH4N2O/c2-1(3)4/h(H4,2,3,4)
Substance Type: Organic
Physical State: Solid
Specific details on test material used for the study:
Name of the test chemical: Urea
Molecular Weight: 60.0556 g/mol
Molecular Formula:CH4N2O
InChI: 1S/CH4N2O/c2-1(3)4/h(H4,2,3,4)
Substance Type: Organic
Physical State: Solid

Test animals

Species:
mouse
Strain:
Nude
Details on test animals and environmental conditions:
sex: male
housing: 3/cage

Test system

Type of coverage:
occlusive
Preparation of test site:
not specified
Vehicle:
unchanged (no vehicle)
Controls:
not specified
Amount / concentration applied:
1, 10, 25, 50, 75 or 100% urea
Duration of treatment / exposure:
24 hours
Observation period:
24 hours
Number of animals:
3 mice/ formulation
Details on study design:
TEST SITE
- Area of exposure: dorsal area, surface area 0.8 sq.cm
- Type of wrap if used: secured with surgical tape and fastened with super glue

Results and discussion

In vitro

Other effects / acceptance of results:
no data available

In vivo

Results
Irritation parameter:
overall irritation score
Basis:
mean
Time point:
24 h
Reversibility:
not specified
Remarks on result:
no indication of irritation
Irritant / corrosive response data:
Urea did not cause any microscopic changes over the 24 hour period at the concentrations tested

Applicant's summary and conclusion

Interpretation of results:
other: not irritating
Conclusions:
Urea did not cause any microscopic changes over the 24 hour period at the concentrations tested.
Hence, urea can be considered to be not irritating to the skin of male nude mice.
Executive summary:

A dermal irritation study was performed to assess the irritation potential of urea in mice.

1, 10, 25, 50, 75 or 100% urea was exposed to the skin of 3 male nude mice for 24 hours.3 animals were exposed to each formulation and maintained 3/cage. Urea was placed in a PVC (Polyvinyl chloride) cup with a surface area of 0.8 sq cm and surface volume of 0.3 cubic cm. The cup was fastened to the dorsal side of the animal using surgical tape and secured with Superglue. The mice were killed immediately after the 24 hours exposure period. Specimens of the exposed areas and of the adjacent untreated skin were taken for histological evaluation. Histological assessment included examination for epidermal changes, hyperkeratosis, spongiosis, destruction of the epidermis hyperemia, and increase in the cell layer of the stratum granulosum, increase in the density and thickness of the collagen bundles, fractured collagen, infiltration of the dermis and intracellular edema.

Urea did not cause any microscopic changes over the 24 hour period at the concentrations tested.

Hence, urea can be considered to be not irritating to the skin of male nude mice.