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Toxicological information

Skin irritation / corrosion

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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:
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

Reference
Name:
Unnamed
Type:
Constituent
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 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

Resultsopen allclose all
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
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.