Urea

Exposure related observations in humans: other data

Administrative data

Endpoint:

exposure-related observations in humans: other data

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Conference proceedings cited in WHO document. Original report not available.

Data source

Reference

Reference 1

Reference Type:

publication

Title:

The chamber-scarification test for assessing irritancy of topically applied substances

Author:

Frosch, P.J. & Kligman, A.M.

Year:

1977

Bibliographic source:

Cutaneous Toxicity: Proceedings of the Conference on Cutaneous Toxicity, 127-153. Drill, V.A. & Lazar, P., eds. New York, Academic Press, 1977, 127-154.

Reference 2

Reference Type:

review article or handbook

Title:

Urea

Author:

Olsen, P.

Bibliographic source:

WHO / JECFA Monograph 798: urea (WHO Food Additives Series 32)

Materials and methods

Type of study / information:

Chamber-scarification test in human volunteers

Endpoint addressed:

skin irritation / corrosion

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Short description of test conditions: Human volunteers were exposed to three daily applications of urea (dissolved in water) at concentrations of between 7.5 - 30%; applications were made to intact and scarified skin. Comparison was made of hypo- and hyperactive individuals.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Urea

EC Number:

200-315-5

EC Name:

Urea

Cas Number:

57-13-6

Molecular formula:

CH4N2O

IUPAC Name:

urea

Details on test material:

No additional information available

Method

Details on exposure:

TYPE OF EXPOSURE: occlusive exposure on abraded skin

EXPOSURE LEVELS: 7.5% and 30% urea solutions in water (75 and 300 g/L respectively)

EXPOSURE PERIOD: 48 hours

POSTEXPOSURE PERIOD: 48 hours observation period

DESCRIPTION / DELINEATION OF EXPOSURE GROUPS / CATEGORIES: Comparison of hypo- and hyperactive individuals

Results and discussion

Results:

On the third day following daily application, a solution of 7.5% urea showed slight skin irritation, and a solution of 30% urea showed marked skin irritation. Comparison between hypo- and hyperactive individuals with 30% urea in water after 48 hours; 0.8 (slight) and 2.4 (moderate), respectively. A solution of 30% urea did not affect normal skin.

Any other information on results incl. tables

On abraded skin, slight irritation was seen with 7.5% urea; marked irritation was seen with 30% urea.

No effects were seen on intact skin.

Applicant's summary and conclusion

Conclusions:

No signs of irritation were seen on intact skin following daily exposures to 30% urea.

Executive summary:

Human volunteers were exposed to three daily applications of urea (dissolved in water) at concentrations of between 7.5 - 30%; applications were made to intact and scarified skin. On abraded skin, slight irritation was seen with 7.5% urea; marked irritation was seen with 30% urea. No effects were seen on intact skin.