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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Acceptable, well-documented study report equivalent or similar to OECD guideline (404): GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): MRD-91-125
- Substance type: white crystalline solid
- Analytical purity: assumed 100%

Test animals

Species:
rabbit
Strain:
New Zealand White
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Hazleton Research Products
- Age at study initiation: approximately 13 weeks
- Weight at study initiation: 2.01 - 2.27 kg
- Housing: individually
- Diet (e.g. ad libitum): Agway certified R.C.A. rabbit feed, ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 8 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-22
- Humidity (%): 40-60
- Photoperiod (hrs dark / hrs light): 12/12

Test system

Type of coverage:
not specified
Preparation of test site:
shaved
Vehicle:
unchanged (no vehicle)
Controls:
no
Amount / concentration applied:
0.5 ml
Duration of treatment / exposure:
4
Observation period:
24, 48, and 72 hours and on day 7 post exposure
Number of animals:
6
Details on study design:
TEST SITE
- Area of exposure: lumbar region
- % coverage: n/a
- Type of wrap if used: gauze, semiocclusive


REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes
- Time after start of exposure: 4 hours


SCORING SYSTEM: Draize

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
erythema score
Basis:
mean
Time point:
other: 24 - 72 h
Score:
3.61
Reversibility:
not fully reversible within: 7 days
Irritation parameter:
edema score
Basis:
mean
Time point:
other: 24 - 72 h
Score:
1.83
Reversibility:
not fully reversible within: 7 days
Irritant / corrosive response data:
Topical application elicited severe erythema in one animal, moderate to severe erythema in two animals, well-defined erythema in one animals and very slight erythema in two animals at the 45 minute interval. Erythema increased after the 45 minute interval. At the 24 hours interval, four animals were noted with severe erythema, one animal was noted with well defined erythema and one was noted with slight erythema. An increase in erythema was seen again at 48 and 72 hours. Erythema increased slightly again at the day 7 interval where all animals were noted with severe erythema. Changes in erythema were accompanied by changes in edema.

Any other information on results incl. tables

  45 min 24 h  48 h  72 h  Day 7 
Erythema  2.33  3.17  3.83  3.83  4.0 
Edema  0.83  1.50  2.0  2.0  1.83 

Erythema and edema scores (mean).

Applicant's summary and conclusion

Executive summary:

In this study, rabbits were exposed to neopentanoic acid via a semioccluded patch for 4 hours. Topical application elicited severe erythema in one animal, moderate to severe erythema in two animals, well-defined erythema in one animals and very slight erythema in two animals at the 45 minute interval. Erythema increased after the 45 minute interval. At the 24 hours interval, four animals were noted with severe erythema, one animal was noted with well defined erythema and one was noted with slight erythema. An increase in erythema was seen again at 48 and 72 hours. Erythema increased slightly again at the day 7 interval where all animals were noted with severe erythema. Changes in erythema were accompanied by changes in edema.