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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation / corrosion, other
Remarks:
in vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Between 12 August 1994 and 12 October 1994
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report date:
1994

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
EPA OTS 798.4470 (Acute Dermal Irritation)
Deviations:
no
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
no
GLP compliance:
yes

Test material

Constituent 1
Details on test material:
Sponsor's identification: N-(n-butyl) thiophosphoric triamide (NBPT)
Substance type: Organic
Physical state:: Light-tan, waxy solid
Analytical purity: 87 %
Batch number: Not reportded
Date received: Not reported
Storage conditions: The test material was stored refrigerated before the range-finding study, then was moved to room temperature storage

Test animals

Species:
other: Rabbit (New Zealand White)
Strain:
other: Hra:(NZW)SPF strain
Details on test animals or test system and environmental conditions:
Test Animals:
Animals:
Rabbit, Hra:(NZW)SPF strain

Rationale:
Historically, the New Zealand White albino rabbit has been the animal of choice because of the large amount of background information on this species.

- Source:
from HRP, Inc., Kalamazoo, Michigan

- Age at study initiation:
Adult albino rabbits

- Weight at study initiation:
2,371 to 2,913 g

-- Housing:
the animals were individually housed in screen-bottom stainless steel cage

- Fasting period before study: Not stated

- Housing:
animals were individually housed in screen-bottom stainless steel cage

- Diet:
a measured amount of Laboratory Rabbit Diet HF #5326, PMI Feeds,

- Water:
The animals were provided access to water ad libitum

- Acclimation period:
at least 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C):
19° to 23°C

- Humidity (%):
relative humidity of 50% ±20%

- Air changes (per hr):
Not stated

- Photoperiod (hrs dark / hrs light):
12-hour light/12-hour dark lighting cycle

IN-LIFE DATES: From: To:
In-life Start Date: 16 August 1994
In-life Termination Date: 19 August 1994

Test system

Type of coverage:
semiocclusive
Preparation of test site:
shaved
Vehicle:
unchanged (no vehicle)
Remarks:
was moistened with distilled water
Controls:
other: untreated skin of each animal was used for comparison.
Amount / concentration applied:
500 mg (0.5 g)
Duration of treatment / exposure:
4 h
Observation period:
approximately 24, 48, and 72 hour
Number of animals:
6
Details on study design:
TEST SITE
- Area of exposure: 6.25 cm2

- Type of wrap if used:
The area of application was covered with a 2.5-cm x 2.5-cm gauze patch secured with paper tape, loosely overwrapped with Saran Wrap®, and secured with Elastoplast® tape to provide a semiocclusive dressing.

REMOVAL OF TEST SUBSTANCE
- Washing (if done):
The test sites were washed using tap water and disposable paper towels. The test material was removed from the test sites as thoroughly as possible without irritating the skin.

- Time after start of exposure:
At the end of the 4-hour exposure period

SCORING SYSTEM:
based on the Draize scoring system

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
erythema score
Basis:
mean
Time point:
other: 24, 48, 72 hours
Score:
0.06
Max. score:
4
Reversibility:
fully reversible within: 48 hours
Irritation parameter:
edema score
Basis:
mean
Time point:
other: 24,48,72 hours
Score:
0
Max. score:
4
Irritant / corrosive response data:
The test material produced only a very slight erythema reaction in one animal. No other dermal irritation was observed The average of the 4-, 24-, 48- and 72-hour index scores is 0.04 (considered to be slightly irritating). All irritation cleared by the 48-hour observation.
Reversibility of any observed effect: Changes fully reversible within 48 hours (2 days).
Other effects:
None

Applicant's summary and conclusion

Interpretation of results:
other: Not classified
Remarks:
Criteria used for interpretation of results: EU
Conclusions:
Application of N-(n-butyl) thiophosphoric triamide (NBPT) to the skin of rabbits under 4-hour semioccluded conditions resulted in only a very slight erythema reaction in one animal. No other dermal irritation was observed. The average of the 4-, 24-, 48-, and 72-hour scores is 0.04 (considered to be slightly irritating). All irritation cleared by the 48-hour observation.
Executive summary:

The objective of this study was to assess the relative level of primary dermal skin irritation of a test material on rabbits under semioccluded conditions. The study was conducted according to EPA guidelines: EPA OTS 798.4470 (Acute Dermal Irritation)

The primary dermal irritation potential of N-(n-butyl) thiophosphoric triamide (NBPT) was evaluated in rabbits under 4-hour semioccluded conditions. The test material produced only a very slight erythema reaction in one animal. No other dermal irritation was observed The average of the 4-, 24-, 48- and 72-hour index scores is 0.04 (considered to be slightly irritating). All irritation cleared by the 48-hour observation.