Chromium trioxide

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

15th-18th February 1983

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Proprietary guideline-compliant study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1983

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: US Department of Transport

Deviations:

no

Principles of method if other than guideline:

Corrosivity screening test in the rabbit in vivo

GLP compliance:

no

Remarks:

Pre-GLP study

Test material

Test material information

Constituent 1

Reference substance name:

Chromic acid mixture

IUPAC Name:

Chromic acid mixture

Constituent 2

Reference substance name:

chromium (VI) trioxide

IUPAC Name:

chromium (VI) trioxide

Details on test material:

Red powder: no further details provided. The test material was a mixture of chromium (VI) trioxide from different sources.

Test animals

Species:

rabbit

Strain:

New Zealand White

Test system

Type of coverage:

occlusive

Preparation of test site:

shaved

Vehicle:

physiological saline

Controls:

not required

Amount / concentration applied:

0.5 g, moistened with 0.5 ml saline

Duration of treatment / exposure:

Up to 30 minutes

Observation period:

Up to 1 hour

Number of animals:

Two

Details on study design:

Two animals were exposed for three minutes and observed at regular intervals for corrosive effects.

Results and discussion

In vivo

Results

Irritation parameter:

overall irritation score

Basis:

mean

Reversibility:

not reversible

Remarks on result:

other: signs of local tissue destruction

Irritant / corrosive response data:

Signs in both animals indicate local tissue destruction, which was confirmed by histopathology.

Other effects:

Histopathology showed coagulative necrosis of the epidermis and the outer dermis, with epidermal sloughing and capillary congestion.

Any other information on results incl. tables

Brown discoloration of the application site in the first animal after 3 minutes prevented the assessment of erythema; slight oedema (Grade 2) was apparent at this stage. Similar findings were noted at 15 minutes (following replacement of the patch). At 30 minutes Stage 3 oedema was observed and the animal showed signs of pain. The skin was noted to be hard and leathery. The animal was sacrificed at this point. The second animal showed signs of pain within 30 seconds of administration. Scoring of erythema was not possible after 3 minutes due to brown discoloration of the skin: the patch was not replaced at this point. Slight (Grade 2) oedema was apparent and the skin was hard. Moderate (Grade 3) oedema was seen at 30 and 60 minutes, at which point the animal was sacrificed.

Applicant's summary and conclusion

Interpretation of results:

other: corrosive based on EU GHS criteria

Conclusions:

The results of the study show that chromium (VI) trioxide is corrosive to skin.

Executive summary:

0.5 g chromic acid (moistened with 0.5 ml physiological saline) was applied under occlusive conditions to the shorn dorsal skin of two rabbits. The application time in the first animal was 30 minutes; observations were made at up to 30 minutes, when the animal was sacrificed for humane reasons. Application time in the second animal was 3 minutes; observations were made for up to 1 hour, when the animal was sacrificed for humane reasons. In both animals, the skin at the application site appeared hard and brown, preventing the assessment of erythema. Oedema and pain were observed in both animals from early timepoints. Histopathology of skin at the application site confirmed a corrosive effect.