2-methyl-3-butenenitrile

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Not stated

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to OECD 402. Study performed before GLP statemnt. Substance purity and composition are not stated.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1981

Report date:

1981

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

yes

Remarks:

: Occlusive condition, no details on test material and on test animals

Principles of method if other than guideline:

Not applicable.

GLP compliance:

no

Remarks:

Study performed before GLP statment

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2-methyl-3-butenenitrile

EC Number:

240-596-1

EC Name:

2-methyl-3-butenenitrile

Cas Number:

16529-56-9

Molecular formula:

C5H7N

IUPAC Name:

2-methylbut-3-enenitrile

Details on test material:

- Name of test material (as cited in study report): 2-methyl 3 butenenitrile (2M3BN)
- Substance type: no data
- Physical state: colorless liquid
- Impurities (identity and concentrations): no data
- Composition of test material, percentage of components: no data
- Isomers composition: no data
- Purity test date: no data
- Expiration date of the lot/batch: no data
- Stability under test conditions: no data
- Storage condition of test material: no data
- Other: no additional data

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: IFFRA CREDO
- Age at study initiation: no data
- Weight at study initiation: between 150 and 230 g.
- Fasting period before study: no data
- Housing: in cage of 37.5 x 23.5 x 16 cm, 2 or 5 rats per cage, with a dusted and sterilized and sawdust litter
- Diet (e.g. ad libitum): IFFARAT food ad libitum
- Water (e.g. ad libitum): ad libitum except a 17/18 hours diet before treatment
- Acclimation period: no data

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22° ± 1°C
- Humidity (%): 50 ± 10%
- Air changes (per hr): 8 per hour
- Photoperiod (hrs dark / hrs light): no data


IN-LIFE DATES: no data

Administration / exposure

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: no data
- % coverage: no data
- Type of wrap if used: silver foil and adhesive tape


REMOVAL OF TEST SUBSTANCE
- Washing (if done): no
- Time after start of exposure: 24 hours


TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0, 1.85, 2.16, 2.47, 3.09 mL/kg
- Concentration (if solution): no
- Constant volume or concentration used: no
- For solids, paste formed: no


VEHICLE
No vehicle

Duration of exposure:

24 hours

Doses:

0, 1500, 1750, 2000 and 2500 mg/kg

No. of animals per sex per dose:

5 animals/sex/dose

Control animals:

yes, concurrent no treatment

Details on study design:

- Duration of observation period following administration: 1, 2 and 6 hours after exposure and daily until 14 days of observation.
- Frequency of observations and weighing: on day 0, 1, 2, 4, 7 and 14 after exposure
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight

Statistics:

Probit method, Litchfield and Wilcoxon method and Arcsinus method were used.

Results and discussion

Preliminary study:

In a preliminary study, 2-methyl-3-butenenitrile was admistered by dermal way to 4 groups of 4 Sprague-Dawley rats (2 males and 2 females) at doses of 100, 500, 1000 and 2000 mg/kg. (See table 7.2.3/1)
At doses of 100 and 500 mg/kg, the test subtance was preliminary diluted in an aqueous dispersion of arabic gumm 10%.
Animals were observed and mortality noted at 1, 2 and 6 hours post-exposure and for 14 days (See table 7.2.3/3).
0% mortality was observed at dose level of 100, 500 and 1000 mg/kg, and 50% mortality was observed at dose level of 2000 mg/kg.

Effect levels

Effect levels 1

Sex:

male/female

Dose descriptor:

LD50

Effect level:

1 849 mg/kg bw

95% CL:

>= 1 533 - <= 2 231

Effect levels 2

Sex:

male

Dose descriptor:

LD50

Effect level:

1 560 mg/kg bw

Effect levels 3

Sex:

female

Dose descriptor:

LD50

Effect level:

2 368 mg/kg bw

Mortality:

See table 7.2.3/3
At 1500 mg/kg, there was 0% of mortality.
At 1750 mg/kg, there was 20% of mortality.
At 2000 mg/kg, there was 60% of mortality.
At 2500 mg/kg, there was 70% of mortality.

Clinical signs:

other: At 1500 mg/kg: Reduced spontaneous activity and apathy were observed at 1 hour post-exposure and persist on day 1 post-exposure. On day 2 post-exposure, spontaneous activity still be reduced but on day 4 post-exposure, survivors go back to a normal behavi

Gross pathology:

At all dose levels, in animals dead during experiment, haemorrhagic lungs, haemorragic thymus gland, ulcerated stomach and irritated intestine were observed at autopsy.
When survivors were sacrified, no macroscopic abnormalities were detected at all dose levels.

Other findings:

At all doses tested, no irritation was observed at the application site.

Any other information on results incl. tables

Table 7.2.3/3: Preliminary study results of dermal acute toxicity on rats

Administration			Animals		Cumulated mortality
Dose mg/kg	Volume mL/kg	Concentration (%)	Weight (g)	Number	1 hr	2 hr	6 hr	1d	2d	4d	7d	14d	%
100	1.00	10	M 168 F 167	2 2	0 0	0 0	0 0	0 0	0 0	0 0	0 0	0 0	0
500	5.00	10	M 225 F 185	2 2	0 0	0 0	0 0	0 0	0 0	0 0	0 0	0 0	0
1000	2.16	Undiluted	M 229 F 179	2 2	0 0	0 0	0 0	0 0	0 0	0 0	0 0	0 0	0
2000	2.47		M 179 F 175	2 2	0 0	0 0	0 0	1 1	1 1	1 1	1 1	1 1	50

Table 7.2.3/4: Dermal acute toxicity on rats

Administration			Animals		Cumulated mortality
Dose mg/kg	Volume mL/kg	Concentration	Weight (g)	Number	1 hr	2 hr	6 hr	1d	2d	4d	7d	14d	%
Control	-	-	M 173 F 176	5 5	0 0	0 0	0 0	0 0	0 0	0 0	0 0	0 0	0
1500	1.85	Undiluted	M 169 F 177	5 5	0 0	0 0	0 0	1 0	1 0	2 0	2 0	2 0	20
1750	2.16		M 174 F 179	5 5	0 0	0 0	0 0	2 0	2 1	3 2	4 2	4 2	60
2000	2.47		M 173 F 175	5 5	0 0	0 0	0 0	3 1	3 1	4 2	4 2	4 2	60
2500	3.09		M 168 F 177	5 5	0 0	0 0	0 0	3 0	5 0	5 0	5 1	5 2	70

Table 7.2.3/5: Body weight evolution after exposure of female Sprague-Dawley rats to 2 -methyl-3 -butenenitrile

Dose (mg/kg)	Mean weight (g)
	Day 0	Day 1	Day 2	Day 4	Day 7	Day 14
Control	176	164	174	184	203	223
1500	177	161	163*	170*	192*	220
1750	179	162	158*	174	192	217
2000	175	159	156*	161	191	206
2500	177	156	158*	161*	179	217

*Significant at threshold 95%

Table 7.2.3/5: Body weight evolution after exposure of male Sprague-Dawley rats to 2 -methyl-3 -butenenitrile

Dose (mg/kg)	Mean weight (g)
	Day 0	Day 1	Day 2	Day 4	Day 7	Day 14
Control	173	154	170	187	217	270
1500	169	145	146	148	186	243
1750	174	156	151	151	185	236
2000	173	149	145	153	184	231
2500	168*	150	-	-	-	-

*Significant at threshold 95%

Applicant's summary and conclusion

Interpretation of results:

Toxicity Category IV

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the test conditions of this study, the LD50 combined was 1849mg/kg bw, and the LD50 for males was 1560 mg/kg bw. thus 2-methyl-3-butenenitrile was considered in Category 4 (H312: Harmful in contact with skin) according to the Regulation 1272/2008/EC and as harmful in contact with skin (Xn, R21) according to the Directive 67/548/EEC.

Executive summary:

In an acute dermal toxicity study, 2-methyl-3-butenenitrile was administered by dermal route to 5 groups of 10 Sprague-Dawley rats (5 males and 5 females) at dose levels of 0, 1500, 1750, 2000 and 2500 mg/kg, undiluted. This study was equivalent or similar to OECD 402 guideline. A preliminary study was performed. Animals were observed and mortality was noted at 1, 2 and 6 hours post-exposure and for 14 days, and they were weighed on day 0, 1, 2, 4, 7 and 14.

At 1500, 1750, 2000 and 2500 mg/kg, there was respectively 20, 60, 60 and 70% of mortality. No death was observed in the control group with vehicle alone applied.

At 1500 mg/kg, reduced spontaneous activity and apathy were observed at 1 hour post-exposure and persist on day 1 post-exposure. on day 4 post-exposure, survivors got back to a normal behaviour. At 1750 and 2000 mg/kg, spontaneous activity was reduced or null, apathy and ptosis were observed from 1 hour post-exposure and up to day 6 post-exposure. At the highest dose, the same signs as at lower dose levels were observed. At all doses tested, no irritation was observed at the application site.

For male, significant weight decrease was observed at 1500 mg/kg and at 2500 mg/kg, but at 14 day post-exposure, animals got back to their normal body weight. For females, a significant bodyweight decrease was observed at all dose levels, but on day 14 post-exposure, no decrease was oberved anymore.

At all dose levels, in animals dead during experiment, haemorrhagic lungs, haemorragic thymus gland, ulcerated stomach and irritated intestine were observed at autopsy. When survivors were sacrified, no macroscopic abnormalities were detected at all dose levels.

Under the test conditions of this study, LD50 combined is 1849 mg/kg bw (1532 -2231 mg/kg bw) and the LD50 for males was 1560 mg/kg bw. Therefore, 2 -methyl-3 -butenenitrile is considered in Category 4 (H312: Harmful in contact with skin) according to the Regulation 1272/2008/EC and as harmful in contact with skin (Xn, R21) according to the Directive 67/548/EEC.