N-butylphosphorothioic triamide

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Between 12 August 1994 and 12 October 1994

Reliability:

2 (reliable with restrictions)

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 guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EPA OTS 798.4470 (Acute Dermal Irritation)

Deviations:

no

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

(six animals were tested; first observation was done 4 hours after patch removal instead of 60 minutes)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

435-740-7

EC Name:

-

Cas Number:

94317-64-3

Molecular formula:

C4H14N3PS

IUPAC Name:

Phosphorothioic triamide, N-butyl-

Constituent 2

Reference substance name:

N-(n-butyl) thiophosphoric triamide (NBPT)

IUPAC Name:

N-(n-butyl) thiophosphoric triamide (NBPT)

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 it 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:
- Source: from HRP, Inc., Kalamazoo, Michigan
- Age at study initiation: Adult albino rabbits
- Weight at study initiation: 2.4 to 2.9 g
- Housing: the animals were individually housed in screen-bottom stainless steel cage
- Fasting period before study: Not stated
- 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 - 23°C
- Humidity (%): 50 ± 20
- Air changes (per hr): Not stated
- Photoperiod (hrs dark / hrs light): 12/12

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 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

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Remarks:

out of all six animals

Time point:

other: mean over 24, 48 and 72 h

Score:

0.06

Max. score:

4

Reversibility:

fully reversible within: 48 hours

Results 2

Irritation parameter:

edema score

Basis:

mean

Remarks:

out of all six animals

Time point:

other: mean over 24, 48 and 72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

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:

not irritating

Remarks:

Migrated information 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 of six animals. 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 of six animals. 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.