Pivalic acid

Skin irritation / corrosion

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

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Pivalic acid

EC Number:

200-922-5

EC Name:

Pivalic acid

Cas Number:

75-98-9

Molecular formula:

C5H10O2

IUPAC Name:

2,2-dimethylpropanoic acid

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 or test system 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

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Time point:

other: 24 - 72 h

Score:

3.61

Reversibility:

not fully reversible within: 7 days

Results 2

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.