1,1,1-trichloroethane

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation / corrosion

Remarks:

in vitro

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: 1b: comparable to guideline study. Conducted at well established laboratory

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1990

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

Remarks:

not GLP

Principles of method if other than guideline:

Secondary objective to reduce the number of rabbits required by the test by using more than one substance on each rabbit.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

1,1,1-trichloroethane

EC Number:

200-756-3

EC Name:

1,1,1-trichloroethane

Cas Number:

71-55-6

Molecular formula:

C2H3Cl3

IUPAC Name:

1,1,1-trichloroethane

Details on test material:

1,1,1-trichloroethane, stabilized with ethanol (0.5 % w/w)
purity > 99.95%

Test animals

Species:

rabbit

Details on test animals or test system and environmental conditions:

New Zealand White Albino rabbits, bwt 2.5 – 3.0 Kg
Housed individually in suspended, galvanised cages with a wire-mesh floor and front. Temperature maintained at 18 + 3 0C, humidity at least 40 %, 12 hours light/dark cycle and ventilation at 10 air changes/hour.

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

0.5 mL 1,1,1-trichloroethane, stabilized with ethanol (0.5 % w/w)

Duration of treatment / exposure:

4 hours

Observation period:

Observations made after 1, 24, 48 and 72 hours and 9 and 16 days.

Number of animals:

3 rabbits each treated individually with 1,1,1-trichloroethane.
In a second experiment, all three rabbits also had patches applied with 3 other test substances.

Details on study design:

0.5 mL test substance onto intact sikn over a 1 x 1 inch area to 3 rabbits. Patches occluded with tape and kept in place for 4 hours. Area then washed and scored 1 hour later and after 24, 48 and 72 hours and 9 and 16 days (Draize 1944). The primary irritation index was calculated by combining the scores for erythema/eschar formation and oedema after 24, 48 and 72 hours. Classification according to EEC Directive 83/467 (1983)

In a second experiment, all three rabbits also had patches applied with 3 other test substances.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

other: 24, 48 and 72 hours

Score:

5.2

Reversibility:

not fully reversible within: 16 days

Remarks on result:

other: Each rabbit treated with only one substance

Results 2

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

other: 24, 48 and 72 hours

Score:

5.5

Reversibility:

not fully reversible within: 16 days

Remarks on result:

other: Each of 3 rabbits treated with 4 substances

Any other information on results incl. tables

Table #: Irritant/corrosive response data for each animal at each observation time up to removal of each animal from the test (1 substance/animal)

Score at time point / Reversibility	Erythema	Edema
	Max. score: 4	Max. score: 2
60 min	2, 2, 1	2, 2, 2
24 h	4, 4, 4	2, 2, 2
48 h	4, 4, 4	2, 1, 1
72 h	4, 4, 1	2, 1, 1
Average 1h, 24h, 48h, 72h	1.7, 4.0, 4.0	2.0, 2.0, 1.3
Reversibility*)	nc	c
Average time (unit) for reversion	16	16
Primary Irritation Index	5.2

*) Reversibility: c. = completely reversible; n.c. = not completely reversible; n. = not reversible

On Day 16 the average score for erythema was 0.3

On Day 9 the average score for erythema was 1.3 and for oedema 1.0

Table #: Irritant/corrosive response data for each animal at each observation time up to removal of each animal from the test (4 substance/animal)

Score at time point / Reversibility	Erythema	Edema
	Max. score: 4	Max. score: 2
60 min	1, 2, 2	2, 2, 2
24 h	4, 4, 4	2, 2, 2
48 h	4, 4, 4	1, 2, 1
72 h	4, 4, 4	1, 1, 2
Average 1h, 24h, 48h, 72h	2.2, 4.0, 4.0, 4.0	1.7, 2.0, 1.3, 1.3
Reversibility*)	nc	nc
Average time (unit) for reversion	16	16
Primary Irritation Index	5.5

*) Reversibility: c. = completely reversible; n.c. = not completely reversible; n. = not reversible

On Day 16 the average score for erythema was 0.3 and for oedema was 0.3

On Day 9 the average score for erythema was 1.3 and for oedema 1.0

Applicant's summary and conclusion

Interpretation of results:

irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the experimental conditions, 1,1,1-trichloroethane, stabilized with ethanol (0.5 % w/w) was irritant when applied topically to rabbits

Executive summary:

The acute dermal irritation of 1,1,1-trichloroethane, stabilized with ethanol (0.5 % w/w) was evaluated in rabbits according to OECD 404 guideline. The test item was applied (undiluted) to the skin of 3 New-Zealand White albino rabbits and held in contact for 4 hours by means of a semi-occlusive dressing.  In a separate experiment, designed to look at reducing the number of animals required for testing, 1,1,1-trichloroethane was one of 4 substances each applied to the backs of 3 rabbits.

Irritation was scored after 1, 24, 48 and 72 hours for each animal.  1,1,1 trichloroethane resulted in severe erythma and oedema after 1 hour.  This was still apparent after 72 hours, but signs of reversibility were noted after 9 days.  Similar results were observed in both experiments.

The severity of the reaction in this experiment is greater than previously observed.

Under the experimental conditions, 1,1,1-trichloroethane, stabilized with ethanol (0.5 % w/w) was irritant when applied topically to rabbits.