3,5-dimethylpyrazole

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

01 April 2002 to 16 April 2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

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. The study report was conclusive, done to a valid guideline and the study was conducted under GLP conditions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

yes

Remarks:

Animals were younger and lighter than specified by the guidelines.

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Deviations:

yes

Remarks:

Animals were younger and lighter than specified by the guidelines.

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1200 (Acute Dermal Toxicity)

Deviations:

yes

Remarks:

Animals were younger and lighter than specified by the guidelines.

Principles of method if other than guideline:

Deviation from guideline: Animals were younger and lighter than specified by the guidelines, however this deviation is not considered to have affected the outcome of the study.

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

3,5-dimethylpyrazole

EC Number:

200-657-5

EC Name:

3,5-dimethylpyrazole

Cas Number:

67-51-6

Molecular formula:

C5H8N2

IUPAC Name:

3,5-dimethyl-1H-pyrazole

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Physical state: An off white powder
- Storage condition of test material: In the dark at ambient temperature

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan UK Limited, Shaw's Farm, Blackhorn, Bicester, OX6 0TP. Animals arrived on 06 March 2002.
- Age at study initiation: Approximately 7 weeks old, on arrival.
- Weight at study initiation: 164 - 205g, on arrival.
- Housing: Individually in cages (dimensions 42 x 27 x 20 cm), with stainless steel grid tops and solid bottoms. Wood shavings were used as bedding.
- Diet: Rat and mouse no. 1 maintenance diet, supplied by Special Diets Services Limited. The diet was feed ad libitum throughout the study.
- Water: Supplied from the domestic mains and was available ad libitum throughout the study.
- Analysis for significant contaminants was performed on both the diet and water supplied to the test animals. Both were considered not to contain any additional substances in sufficient concentrations to have any influence on the outcome of the study.
- Acclimation period: Animals were allowed to acclimatise for at least 3 weeks.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): Mean minimum and maximum temperatures, 21 ºC and 19 ºC, respectively.
- Humidity (%): Mean relative humidity, 48% (ranged from 36 – 56%).
- Air changes (per hr): Minimum of 15 air charges per hour.
- Photoperiod (hrs dark / hrs light): 12 hr light/dark cycle (light 0700-1900 hrs).

Administration / exposure

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: The exact area was not recorded, however an area of approximately 7 cm x 8 cm was prepared for application on the dorsal trunk and a covering of 5 cm x 6 cm was used.
- Site preparation: The hair was clipped, taking care not to abrade the skin.
- Application: The test material was applied on to the water moistened skin of the test animals.
- Type of wrap if used: A water moistened gauze patch was secured with semi-occlusive tape, and a strip of non-irritating occlusive tape was wrapped around the trunk to secure the test site.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): The site was wiped with distilled water.
- Time after start of exposure: 24 hours, immediately after the patch was removed.

Duration of exposure:

24 hour in a single application.

Doses:

2000 mg/kg b.w.

No. of animals per sex per dose:

5 animals per sex per dose.

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
> Viability: Animals were checked twice daily,
> Clinical observations: Animals were examined for reaction to treatment frequently on the day of dosing and daily thereafter. The onset, intensity and duration of any signs were recorded.
> Bodyweights: Recorded weekly, on Day 1, Day 8 and Day 15.
- Necropsy of survivors performed: Yes, all animals were subjected to necropsy on Day 15.
> Sacrifice: Animals were killed by exposure to carbon dioxide and exsanguinated.
> Detailed examinations were made of the thoracic and abdominal organs and tissue in situ. All gross lesions were recorded in descriptive terms including location, size, shape, colour, consistency and number.

Statistics:

No formal statistical analysis was conducted.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality was observed during the observation period.

Clinical signs:

other: No clinical signs were noted during the study.

Gross pathology:

One male was noted to have developed an oval mass on the median lobe of the liver. This was not noted in any of the other test animals, and thus not considered to be related to treatment.

Any other information on results incl. tables

Table 1. Individual Body Weighs (g)

Dose Level (mg/kg)/Sex	Animal	Body weight (g)
		Day 1	Day 8	Day 15	Change (Days 1 – 15)
2000/M	1	301	308	317	16
	2	309	320	336	27
	3	302	312	321	19
	4	345	355	379	34
	5	311	320	335	24
	Mean	314	323	338	24
	SD	18	19	25	7
2000/F	1	229	229	232	3
	2	212	219	219	7
	3	258	255	270	12
	4	225	227	234	9
	5	236	237	247	11
	Mean	232	233	240	8
	SD	17	14	19	4

SD - standard deviation from the mean.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of the test, the LD50 of the test material was determined to be > 2000 mg/kg.

Executive summary:

The acute dermal toxicity of the test material was determined in a study conducted according to GLP and in line with the standardised guidelines OECD 402, EU Method B.3 and EPA OPPTS 870.1200.

Ten Sprague-Dawley rats, 5 male and 5 female, were exposed to the test material in a limit test at 2000 mg/kg. The animals were exposed in a single application for 24 hours under an occlusive dressing. Animals were observed for 14 days post application and then subjected to necropsy.

Under the conditions of the test, no mortalities, signs of toxicity or abnormal pathology were observed. Thus the LD₅₀ was determined to be greater than 2000 mg/kg. Consequentially the test material will not require classification according to Regulation (EC) No. 1272/2008.