thiourea; thiocarbamide

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

no data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1983

Report date:

1983

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

exposure 4h, no reading after 1 h and 48 h; animals are treated on intact and abraded skin

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Thiourea

EC Number:

200-543-5

EC Name:

Thiourea

Cas Number:

62-56-6

Molecular formula:

CH4N2S

IUPAC Name:

thiourea

Test material form:

solid: particulate/powder

Test animals

Species:

rabbit

Strain:

New Zealand White

Test system

Type of coverage:

occlusive

Preparation of test site:

abraded

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 g undiluted test material

Duration of treatment / exposure:

24 hours

Observation period:

72 hours

Number of animals:

12

Details on study design:

TEST SITE
- Area of exposure: 1 inch²
- Type of wrap if used: surgical patch, adhesive tape, impervious material to wrap

SCORING SYSTEM: Draize and CIVO grading

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Remarks:

of the animals with intact skin

Time point:

24 h

Score:

1

Max. score:

2

Reversibility:

fully reversible within: 72 h

Results 2

Irritation parameter:

erythema score

Basis:

mean

Remarks:

of the animals with intact skin

Time point:

48 h

Score:

1

Max. score:

2

Reversibility:

fully reversible

Results 3

Irritation parameter:

erythema score

Basis:

mean

Remarks:

of the animals with intact skin

Time point:

72 h

Score:

0

Max. score:

2

Reversibility:

fully reversible within: 72h

Results 4

Irritation parameter:

erythema score

Basis:

mean

Remarks:

of the animals with abraded skin

Time point:

24 h

Score:

1.5

Max. score:

2

Reversibility:

fully reversible within: 72 h

Remarks on result:

other: only in one animal very slight scaliness was observed after 72 hours

Results 5

Irritation parameter:

erythema score

Basis:

mean

Time point:

72 h

Score:

0.2

Max. score:

1

Reversibility:

fully reversible

Remarks on result:

other: one of six animals showed very slight scaliness after 72 hours

Results 6

Irritation parameter:

edema score

Basis:

mean

Time point:

24 h

Score:

1

Max. score:

2

Reversibility:

fully reversible within: 72h

Results 7

Irritation parameter:

edema score

Basis:

mean

Time point:

48 h

Score:

1

Max. score:

2

Reversibility:

fully reversible

Results 8

Irritation parameter:

edema score

Basis:

mean

Time point:

72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Results 9

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24 h

Score:

1.5

Max. score:

2

Reversibility:

not fully reversible within: 72h

Remarks on result:

probability of weak irritation

Results 10

Irritation parameter:

edema score

Basis:

animal #1

Time point:

48 h

Score:

1

Max. score:

2

Reversibility:

fully reversible

Remarks on result:

probability of weak irritation

Results 11

Irritation parameter:

edema score

Basis:

animal #1

Time point:

72 h

Score:

0.2

Max. score:

1

Reversibility:

fully reversible

Remarks on result:

probability of weak irritation

Other effects:

No other effects were observed

Any other information on results incl. tables

Table 1: Individual and average skin irritation scores of undiluted thiourea

Rabbit number	Intact skin			Rabbit number	Abraded skin
	24 hours		72 hours		24 hours		72 hours
	A	B			A	B
1	1	0	0	7	2	2	1
2	0	0	0	8	2	0	0
3	1	2	0	9	0	0	0
4	1	1	0	10	0	0	0
5	0	0	0	11	1	1	0
6	0	0	0	12	1	0	0
average	1.0		0	average	1.5		0.2

 

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

On the basis of the results it is concluded that undiluted thiourea is a very slight to slight primary skin irritant but not relevant for classification.

Executive summary:

In a primary dermal irritation study 12 healthy, adult New Zealand White albino rabbits were dermally exposed to 0.5 g of undiluted thiourea on 1 inch² of the body surface area on the back of the animals. Test sites were covered with an occlusive dressing for 24 hours. Animals were then observed for 72 hours. Irritation was scored by the method of Draize (1944) and the CIVO grading system. After 24 hours dermal effects were observed in seven out of twelve rabbits. These effects consisted of very slight to well-defined erythema with or without very slight or slight oedema. After 72 hours one rabbit treated on the abraded skin showed slight scaliness. No other dermal effects were observed. In this study, thiourea is very slightly to slightly irritatin but not relevant for classification.