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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Between 13 Nov 1978 and 16 Nov 1978
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with national standard methods with acceptable restrictions
Remarks:
Pre GLP, performed according to US D.O.T standards

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1979
Report date:
1979

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: US D.O.T. requirements
Version / remarks:
according to Section l73.240 (a) (1) Title 49 CFR and Section 1500.41 Title 16 CFR
Deviations:
no
Principles of method if other than guideline:
- Principle of test: For the D.O.T study. The methods employed in the testing, evaluation and scoring (according to Draize) of the results are similar to OECD 404. 0.5 g material is applied to the intact and abraded skin of 6 rabbits for 4 hours under closed conditions, with readings after end of exposure and at 24 and 48 hours..
For the irritation study however, exposure durtation is 24 hours, and readings are done after exposure (= 24 hours) and again at 72 hours after start of exposure.
- Parameters observed are Erythema and Eschar Formation, and Edema.
GLP compliance:
not specified
Remarks:
pre-GLP study

Test material

Constituent 1
Reference substance name:
Morwet B
IUPAC Name:
Morwet B
Test material form:
solid: granular
Details on test material:
Material: Petrochemicals Company, Inc. - Morwet B
Specific details on test material used for the study:
Commercial product

Test animals

Species:
rabbit
Strain:
not specified
Details on test animals or test system and environmental conditions:
A group of six albino rabbits were clipped over a wide area. One side of the animals' backs was abraded at two sites with a lancet sufficiently deep to penetrate the stratum corneum but not enter the derma to produce bleeding. The skin on the other side was allowed to remain intact.

Test system

Type of coverage:
occlusive
Preparation of test site:
other: clipped, and either intact or abraded
Vehicle:
unchanged (no vehicle)
Controls:
not required
Amount / concentration applied:
A 0.5 gm portion of the material was applied to two abraded and two intact skin sites on the same rabbit. Gauze patches were then placed over the treated areas and an impervious material was wrapped snuggly around the trunks of the animals to hold the patches in place.
Duration of treatment / exposure:
4 hours (D.O.T. corrosion) and 24 hours (primary irritation)
Observation period:
Up to 48 hours (D.O.T. corrosion) and 72 hours (primary irritation)
Number of animals:
6
Details on study design:
The primary skin irritation study was conducted on the intact and abraded skin sites adjacent to each other towards the head end of the animal while the D.O.T. study was conducted on the intact and abraded skin sites adjacent to each other towards the tail end of the animal.
The wrappings were removed at the end of a four hour period for the D.O.T. study and the treated areas were examined. Readings were also made after twenty-four and forty-eight hours. The Draize method of scoring was employed.
The wrappings were removed at the end of a twenty-four hour period for the primary skin irritation study and the treated areas were examined. Readings were also made after seventy-two hours. The Draize method of scoring was employed.

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
erythema score
Remarks:
4 hour exposure on intact (non-abraded) skin
Basis:
mean
Remarks:
of 6 animals
Time point:
24 h
Score:
0.33
Max. score:
1
Remarks on result:
probability of weak irritation
Remarks:
grade 1 eythema in 2/6 animals
Irritation parameter:
erythema score
Remarks:
4 hour exposure on intact (non-abraded) skin
Basis:
mean
Remarks:
of 6 animals
Time point:
48 h
Score:
0
Max. score:
0
Reversibility:
fully reversible within: 48 hour
Remarks on result:
no indication of irritation
Irritation parameter:
edema score
Remarks:
4 hour exposure on intact (non-abraded) skin
Basis:
mean
Remarks:
of 6 animals
Time point:
24/48 h
Score:
0
Max. score:
0
Irritant / corrosive response data:
The 4 hour exposure did not result to formation of edema in any of the 6 animals at any of the time points. Erythema grade 1 was only visible after 24 hours on the skin of 2/6 animals following application on the intact skin. Application to the abraded skin only resulted to grade 1 erythema in 5/6 animals immediately after 4-hour application, but no erythema was observed at any of the other time points.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Following application on the intact and abraded skin of 6 animals under occlusive conditions for 4 hours was practically non-rritating. Expsoures for 24 hours resulkted to mild irritation.
Executive summary:

Morwet B (Naphthalenesulfonic acid, methyl, butyl, sodium salt) was evaluated for dermal irritation and corrosion in a D.O.T. skin corrosion and a primary skin irritation study involving exposure to the intact and abraded skin of 6 albino rabbits.

Skin areas were clipped over a wide area. One side of the animals' backs was abraded at two sites with a lancet sufficiently deep to penetrate the stratum corneum but not enter the derma to produce bleeding. The skin on the other side was allowed to remain intact.

A 0.5 gram portion of the material was applied to two abraded and two intact skin sites on the same rabbit. Gauze patches were then placed over the treated areas and an impervious material was wrapped snuggly around the trunks of the animals to hold the patches in place.

 

The D.O.T. study was conducted on the intact and abraded skin sites adjacent to each other towards the tail end of the animal. The wrappings were removed at the end of a four hour period and the treated areas were examined. Readings were also made after twenty-four and forty-eight hours. The Draize method of scoring was employed.

 

The primary skin irritation study was conducted on the intact and abraded skin sites adjacent to each other towards the head end of the animal. The wrappings were removed at the end of a twenty-four hour period for the primary skin irritation study and the treated areas were examined. Readings were also made after seventy-two hours. The Draize method of scoring was employed.

 

Results:

The primary skin irritation study: Following 24 hour exposure to the intact skin under occlusive conditions resulted to only mild irritation. The erythema score was 1 or 2 in all animals at the 24 hour reading with a 1, 2 or 3 grade edema. At 72 hours only two animals still showed some signs of irritation with a grade 1 erythema and a grade 1 or 2 edema.

The results from 24 hour exposure to the abraded skin showed slightly higher reaction.

 

Average score Intact skin following 24 hour exposure:

- 24 h reading: erythema: 1.83; edema: 2.00

- 72 h reading: erythema: 0.33; edema: 0.50

Average score Intact skin following 24 hour exposure:

- 24 h reading: erythema: 1.83; edema: 2.17

- 72 h reading: erythema: 1.00; edema: 1.17

 

D.O.T. study for skin corrosion: The 4 hour exposure did not result to formation of edema in any of the 6 animals at any of the time points. Erythema grade 1 was only visible after 24 hours on the skin of 2/6 animals following application on the intact skin. Application to the abraded skin only resulted to grade 1 erythema in 5/6 animals immediately after 4-hour application, but no erythema was observed at any of the other time points.

 

Average score Intact skin following 4 hour exposure:

- 4 h reading: erythema: 0; edema: 0

- 24 h reading: erythema: 0.33; edema: 0

- 48 h reading: erythema: 0; edema: 0

Average score Intact skin following 4 hour exposure:

- 4 h reading: erythema: 0.83; edema: 0

- 24 h reading: erythema: 0; edema: 0

- 48 h reading: erythema: 0; edema: 0

 

The results from the 4-hour exposure can be used for GHS classification, and indicate that Morwet B does not need to be classified for skin erritation.