2-methylpentane

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Data source

Reference

Reference Type:

review article or handbook

Title:

2-METHYLPENTANE (ISOHEXANE)

Author:

Galvin, Jennifer B.; Bond, Gary

Year:

1999

Bibliographic source:

Journal of Toxicology and Environmental Health, Part A, 58:1-2, pp. 81-92, DOI: 10.1080/009841099157449; http://dx.doi.org/10.1080/009841099157449

Materials and methods

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

2-methylpentane

EC Number:

203-523-4

EC Name:

2-methylpentane

Cas Number:

107-83-5

Molecular formula:

C6H14

IUPAC Name:

2-methylpentane

Specific details on test material used for the study:

98% pure 2-methylpentane

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male

Administration / exposure

Route of administration:

inhalation

Duration of treatment / exposure:

14 weeks

Frequency of treatment:

9 h/d, 5 d/wk

Doses / concentrations

Dose / conc.:

1 500 ppm

Results and discussion

Results of examinations

Clinical signs:

not specified

Mortality:

not specified

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

significant decrease in body weight gain

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

effects observed, treatment-related

Description (incidence and severity):

24-h urine sample, 1 metabolite, 2-methyl-2-pentanol

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

No significant differences in hindlimb spreads but high individual variability

Neuropathological findings:

no effects observed

Description (incidence and severity):

No signs of neuropathy

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

histology (glutaraldehyde perfusion): no pathological alterations of tissue

Histopathological findings: neoplastic:

not specified

Effect levels

Dose descriptor:

LOEL

Effect level:

< 1 500 ppm

Based on:

test mat.

Sex:

male

Basis for effect level:

body weight and weight gain

Applicant's summary and conclusion

Conclusions:

There were no signs of neuropathy in any of the animals in the Frontali et al. study on 2-methylpentane. After the exposure period ended, samples of nerves were processed for light microscopy. Sections of teased nerve fibers showed no pathological alterations of tissue from the 2-methylpentane-exposed animals. There was a significant decrease in body weight gain for 2-methylpentane. There were no significant differences in hindlimb spread but there was high individual variability. Rats treated with n-hexane developed the typical giant axonal degeneration. The 24-h urine sample from rats exposed to 1500 ppm 2-methylpentane showed only 1 metabolite, 2-methyl-2-pentanol.

Executive summary:

Frontali et al. (1981) designed a study to investigate whether the isomers of hexane caused axonal degeneration. Therefore, he studied inhalation exposures to n-heptane, 2-methylpentane, 3-methylpentane, n-pentane, cyclohexane, and n-heptane. He varied the exposure regimen for the different chemicals. In the case of 2-methylpentane (98% pure), rats were exposed to 1500 ppm for 9 h/d, 5 d/wk, for 14 wk.