Methylcyclopentane

Endpoint summary

Description of key information

No studies are available for the registered substance Methylcyclopentane. Based on the read-across approach, information on the structural analogue n-Hexane is used.

Key read across studies of C-6 normal and iso paraffins (hexanes) and naphthenes (methyl-cyclohexane, dimethylcyclohexane), 25-35% n-hexane (Hine et al., 1970; Klimisch score = 2) were identified to support each acute toxicity endpoint (oral, dermal, and inhalation) for this substance.

Acute Toxicity Oral: LD₅₀ 15840 mg/Kg in rats

Acute Toxicity Dermal: LD₅₀ >3350 mg/Kg in rabbits (OECD TG 402)

Acute Toxicity Inhalation LC₅₀ >259354 mg/m³ in rats (OECD TG 403)

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

no guideline available

Principles of method if other than guideline:

not specified

GLP compliance:

not specified

Species:

rat

Strain:

Sprague-Dawley

Sex:

not specified

Route of administration:

oral: unspecified

Key result

Sex:

not specified

Dose descriptor:

LD50

Effect level:

ca. 15 840 mg/kg bw

Conclusions:

In an LD50 (lethal dose, 50% kill) test with Sprague-Dawley rats (sex not specified), an LD50 of 15,840 mg/Kg was reported for analogue substance n-Hexane.

Executive summary:

In an LD₅₀ (lethal dose, 50% kill) test with Sprague-Dawley rats (sex not specified), an LD₅₀ of 15,840 mg/Kg was reported for analogue substance n-Hexane.

Reference 2

Endpoint:

acute toxicity: oral

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across source

Qualifier:

no guideline available

Principles of method if other than guideline:

not specified

GLP compliance:

not specified

Species:

rat

Strain:

Sprague-Dawley

Sex:

not specified

Route of administration:

oral: unspecified

Key result

Sex:

not specified

Dose descriptor:

LD50

Effect level:

ca. 15 840 mg/kg bw

Conclusions:

In an LD50 (lethal dose, 50% kill) test with Sprague-Dawley rats (sex not specified), an LD50 of 15,840 mg/Kg was reported for analogue substance n-Hexane.

Executive summary:

In an LD₅₀ (lethal dose, 50% kill) test with Sprague-Dawley rats (sex not specified), an LD50 of 15,840 mg/Kg was reported for analogue substance n-Hexane.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

15 840 mg/kg bw

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1970

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This study is classified as reliable with restrictions because it is an acceptable well-documented publication which meets basic scientific principles.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

no

Remarks:

Pre-GLP study

Test type:

acute toxic class method

Species:

rat

Strain:

Long-Evans

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 150-300 g

Route of administration:

inhalation: vapour

Type of inhalation exposure:

not specified

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure chamber volume: 250 l
- Method of conditioning air: Sample was heated in a water bath at 77 degree F. Air was bubbled through the sample and entered the exposure chamber. For concentrations less than saturation, air flow was divided with part passing over the sample and part passing directly into the exposure chamber.

TEST ATMOSPHERE
- Brief description of analytical method used: GLC

Duration of exposure:

4 h

Concentrations:

73,680 ppm (30-40% of saturation at 25 degree C)
81,800 ppm

No. of animals per sex per dose:

10 males

Details on study design:

- Duration of observation period following administration: at least 6 days

Key result

Sex:

male

Dose descriptor:

LC50

Effect level:

73 860 ppm

Exp. duration:

4 h

Remarks on result:

other: 259354 mg/m3

Mortality:

All deaths occurred during exposure, except one rat in the 81800 ppm group that died on day 6.

Clinical signs:

other: Surviving rats were uncoordinated, prostrate or comatose during exposure but recovered within a few hours of removal from the chamber. The rat that died on day 6 had convulsions during and after exposure.

Interpretation of results:

study cannot be used for classification

Conclusions:

The 4-hr LC50 for rats exposed by inhalation was 73,680 ppm.

Executive summary:

This study examined that acute inhalation toxicity of hexane to male rats. Groups of 10 male rats exposed to various large concentrations of hexane vapor for 4 hrs. Animals were then observed for clinical signs and mortality for at least the next 6 days.

Several animals died during the exposure period. Surviving animals experienced severe toxicological effects during the exposure. One animal experienced convulsions during and after exposure, and died on day 6 post-exposure. The LC₅₀ was determined to be 73,680 ppm (259354 mg/m³). Due to the high concentration of the LC₅₀, the test substance would not be classified as toxic by inhalation according to OECD GHS guidelines.

Reference 2

Endpoint:

acute toxicity: inhalation

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

1970

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This study is classified as reliable with restrictions because it is an acceptable well-documented publication which meets basic scientific principles.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across source

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

no

Remarks:

Pre-GLP study

Test type:

acute toxic class method

Species:

rat

Strain:

Long-Evans

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 150-300 g

Route of administration:

inhalation: vapour

Type of inhalation exposure:

not specified

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure chamber volume: 250 l
- Method of conditioning air: Sample was heated in a water bath at 77 degree F. Air was bubbled through the sample and entered the exposure chamber. For concentrations less than saturation, air flow was divided with part passing over the sample and part passing directly into the exposure chamber.

TEST ATMOSPHERE
- Brief description of analytical method used: GLC

Duration of exposure:

4 h

Concentrations:

73,680 ppm (30-40% of saturation at 25 degree C)
81,800 ppm

No. of animals per sex per dose:

10 males

Details on study design:

- Duration of observation period following administration: at least 6 days

Key result

Sex:

male

Dose descriptor:

LC50

Effect level:

73 860 ppm

Exp. duration:

4 h

Remarks on result:

other: 259354 mg/m3

Mortality:

All deaths occurred during exposure, except one rat in the 81800 ppm group that died on day 6.

Clinical signs:

other: Surviving rats were uncoordinated, prostrate or comatose during exposure but recovered within a few hours of removal from the chamber. The rat that died on day 6 had convulsions during and after exposure.

Interpretation of results:

study cannot be used for classification

Conclusions:

The 4-hr LC50 for rats exposed by inhalation was 73,680 ppm.

Executive summary:

This study examined that acute inhalation toxicity of hexane to male rats. Groups of 10 male rats exposed to various large concentrations of hexane vapor for 4 hrs. Animals were then observed for clinical signs and mortality for at least the next 6 days.

Several animals died during the exposure period. Surviving animals experienced severe toxicological effects during the exposure. One animal experienced convulsions during and after exposure, and died on day 6 post-exposure. The LC₅₀ was determined to be 73,680 ppm (259354 mg/m³). Due to the high concentration of the LC₅₀, the test substance would not be classified as toxic by inhalation according to OECD GHS guidelines.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

259 354 mg/m³ air

Acute toxicity: via dermal route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1970

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This study is classified as reliable with restrictions because it is an acceptable well-documented publication which meets basic scientific principles.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

GLP compliance:

no

Remarks:

Pre-GLP study

Test type:

fixed dose procedure

Limit test:

yes

Species:

rabbit

Strain:

New Zealand White

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 2-3 kg

Type of coverage:

occlusive

Details on dermal exposure:

TEST SITE
- Type of wrap if used: saran wrap sleeve


REMOVAL OF TEST SUBSTANCE
- Washing (if done): skin was wiped with damp towels
- Time after start of exposure: 4 hrs


TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 5 ml/kg

Duration of exposure:

4 hrs

Doses:

up to 5.0 ml/kg

No. of animals per sex per dose:

3 males

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days
- Other examinations performed: clinical signs

Statistics:

method of Litchfield and Wilcoxen

Key result

Sex:

male

Dose descriptor:

LD50

Effect level:

> 5 mL/kg bw

Remarks on result:

other: 3.35 g/kg

Mortality:

No mortality was observed.

Clinical signs:

other: Animals showed signs of discomfort and were uncoordinated at the end of the exposure period.

Interpretation of results:

other: Not classified

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

The 4-hr LD50 for dermal exposure in rabbits is > 5.0 mL/Kg bw (3.35 g/Kg).

Executive summary:

This study examined the dermal toxicity of the hexane. Doses of up to 5.0 mL/Kg of test substance was placed on the shaved skin of 3 male rabbits. The test area was then covered with a saran wrap sleeve for 4 hrs. After the exposure period, the test substance washed off, and the animals observed for toxicity and mortality over the next 14 days.

No animals died, however, they did show signs of discomfort and uncoordination after the exposure. The LD₅₀ for dermal exposure is >5.0 mL/Kg (3.35 g/Kg). The test substance is not classified as toxic under EU GHS guidelines.

Reference 2

Endpoint:

acute toxicity: dermal

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

1970

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This study is classified as reliable with restrictions because it is an acceptable well-documented publication which meets basic scientific principles.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across source

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

GLP compliance:

no

Remarks:

Pre-GLP study

Test type:

fixed dose procedure

Limit test:

yes

Species:

rabbit

Strain:

New Zealand White

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 2-3 kg

Type of coverage:

occlusive

Details on dermal exposure:

TEST SITE
- Type of wrap if used: saran wrap sleeve


REMOVAL OF TEST SUBSTANCE
- Washing (if done): skin was wiped with damp towels
- Time after start of exposure: 4 hrs


TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 5 ml/kg

Duration of exposure:

4 hrs

Doses:

up to 5.0 ml/kg

No. of animals per sex per dose:

3 males

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days
- Other examinations performed: clinical signs

Statistics:

method of Litchfield and Wilcoxen

Key result

Sex:

male

Dose descriptor:

LD50

Effect level:

> 5 mL/kg bw

Remarks on result:

other: 3.35 g/kg

Mortality:

No mortality was observed.

Clinical signs:

other: Animals showed signs of discomfort and were uncoordinated at the end of the exposure period.

Interpretation of results:

other: Not classified

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

The 4-hr LD50 for dermal exposure in rabbits is > 5.0 mL/Kg bw (3.35 g/Kg).

Executive summary:

This study examined the dermal toxicity of the hexane. Doses of up to 5.0 mL/Kg of test substance was placed on the shaved skin of 3 male rabbits. The test area was then covered with a saran wrap sleeve for 4 hrs. After the exposure period, the test substance washed off, and the animals observed for toxicity and mortality over the next 14 days.

No animals died, however, they did show signs of discomfort and uncoordination after the exposure. The LD₅₀ for dermal exposure is >5.0 mL/Kg (3.35 g/Kg). The test substance is not classified as toxic under EU GHS guidelines.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

3 350 mg/kg bw

Additional information

There is no data available for Methylcyclopentane. Data is available from a structural analogue n-Hexane and used as read across.

Acute oral toxicity

In a key read across LD₅₀ (lethal dose, 50% kill) test with Sprague-Dawley rats (sex not specified), an LD₅₀ of 15,840 mg/Kg was reported for n-Hexane (US DHHS, 1999).

Acute inhalation toxicity

In a key read-across acute inhalation toxicity study (Hine et al., 1970; Klimisch score=2), groups of 10 male rats were exposed to concentrations of

C-6 normal and iso paraffins (hexanes) and naphthenes (methyl-cyclohexane, dimethylcyclohexane), 25-35% n-hexane for 4 hours. Animals were then observed for clinical signs and mortality for at least 6 days post-exposure. Several animals died during the exposure period. Surviving animals experienced severe toxicological effects during the exposure. One animal experienced convulsions during and after exposure and died on day 6 post-exposure. The LC₅₀ was determined to be 73,680 ppm (259354 mg/m³), and the test substance is therefore not classified under EU criteria.

Acute dermal toxicity

In a key read-across acute dermal toxicity study of C-6 normal and iso paraffins (hexanes) and naphthenes (methyl-cyclohexane, dimethylcyclohexane), 25-35% n-hexane (Hine et al., 1970; Klimisch score=2), 5.0 mL/Kg was placed on the shaved skin of 3 male rabbits. The test area was then covered with a saran wrap sleeve for 4 hrs. After the exposure period, the test substance washed off, and the animals observed for toxicity and mortality over the next 14 days. No animals died; however, they did show signs of discomfort and uncoordination after the exposure. The LD₅₀ for dermal exposure is >5.0 mL/Kg (3350 mg/Kg). Therefore, the test substance is not classified under EU criteria.

Justification for classification or non-classification

Based on available read across data, Methylcyclopentane does not warrant classification for acute oral, inhalation, or dermal toxicity under the Regulation (EC) 1272/2008 on classification, labelling and packaging of substances and mixtures (CLP).

On the basis of available read across physical and chemical property data (hydrocarbon fluid, viscosity ≤ 20.5 mm²/s), Methylcyclopentane is classified as a Category 1 aspiration hazard (H304) under the Regulation (EC) 1272/2008 on classification, labelling and packaging of substances and mixtures (CLP).

 

Additionally, acute exposure may result in non-lethal narcotic effects and therefore, Methylcyclopentane is classified as STOT Single Exposure Category 3 (H336: narcosis) under the Regulation (EC) 1272/2008 on classification, labelling and packaging of substances and mixtures (CLP).