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Diss Factsheets
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EC number: 203-523-4 | CAS number: 107-83-5
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
![](https://echa.europa.eu/o/diss-blank-theme/images/factsheets/A-REACH/factsheet/print_toxicological-information.png)
Repeated dose toxicity: oral
Administrative data
- Endpoint:
- short-term repeated dose toxicity: oral
- Type of information:
- experimental study
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- study well documented, meets generally accepted scientific principles, acceptable for assessment
Cross-reference
- Reason / purpose for cross-reference:
- read-across: supporting information
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 1 981
Materials and methods
Test guideline
- Qualifier:
- no guideline available
- Principles of method if other than guideline:
- 30 male Wistar rats were feeded with the test substance in olive oil for 8 weeks. The conduction velocity of the peripheral nerve was obtained in the rats tail.
Therefore the rat kept immobilized by wrapping into a towel, turned on his back and got electrodes inserted in his tail. Then the tail was immersed in a warm parrafin bath and the tail nerve was stimulated by a square pulse of 0.2 ms and supramaximal strenght. Biopotentials were observed with an adscope between two different distances.Then the conduction velocity was calculated. - GLP compliance:
- not specified
Test material
- 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
- Test material form:
- liquid
1
- Specific details on test material used for the study:
- The four chemicals (2-methylpentane, 3-methylpentane, methylcyclopentane and n-hexane) used were more than 99 % pure.
Test animals
- Species:
- rat
- Strain:
- Wistar
- Sex:
- male
- Details on test animals or test system and environmental conditions:
- thirty Wistar male rats: mean body weight 343 g, SD 27 g
Administration / exposure
- Route of administration:
- oral: unspecified
- Vehicle:
- olive oil
- Details on oral exposure:
- The solvents were diluted with olive oil and orally administered for 8 weeks. Weeks 1-4: 0.4 ml test substance + 0.6 ml olive oil, weeks 5-6: 0.6 ml test substance + 0.4 ml olive oil, weeks 7-8: 1.2 ml test substance + 0.8 ml olive oil
- Duration of treatment / exposure:
- 8 weeks
- Frequency of treatment:
- once daily
Doses / concentrationsopen allclose all
- Dose / conc.:
- 0.4 other: ml
- Remarks:
- wks. 1-4
- Dose / conc.:
- 0.6 other: ml
- Remarks:
- wks. 5+6
- Dose / conc.:
- 0.8 other: ml
- Remarks:
- wks. 7+8
- No. of animals per sex per dose:
- 5-7 (males only)
- Control animals:
- yes, concurrent vehicle
- Positive control:
- 5 different test substances tested
Examinations
- Observations and examinations performed and frequency:
- before administration and after 2, 4, 6 and 8 weeks; Body weight, conduction velocity, motor distal latency, mixed nerve conduction velocity
3 points at the rat´s tail were inserted with electrodes: A (3 cm down from the anus), B (7-10 cm down from A) and C (3-4 cm up from the tail`s end). Stimulating at A or B by a single stimulation and measuring the resulting EMGs at C were used to obtain the motor nerve conduction velocity (MCV) and the distal latency (DL). Stimulating the nerve at C by 100 times by 2 c/s and measuring the nerve impulses at A and B obtained the mixed nerve conduction velocity (MNCV).
Results and discussion
Results of examinations
- Clinical signs:
- not examined
- Mortality:
- not examined
- Body weight and weight changes:
- no effects observed
- Description (incidence and severity):
- The changes in body weight are shown in Fig. 2. There were no statistically significant differences between the solvent-administered groups and the control.
- Food consumption and compound intake (if feeding study):
- not examined
- Food efficiency:
- not examined
- Water consumption and compound intake (if drinking water study):
- not examined
- Ophthalmological findings:
- not examined
- Haematological findings:
- not examined
- Clinical biochemistry findings:
- not examined
- Urinalysis findings:
- not examined
- Behaviour (functional findings):
- no effects observed
- Description (incidence and severity):
- No abnormal changes in the behavior of rats were found in every group throughout the experiment.
- Immunological findings:
- not examined
- Organ weight findings including organ / body weight ratios:
- not examined
- Gross pathological findings:
- not examined
- Neuropathological findings:
- effects observed, treatment-related
- Description (incidence and severity):
- The changes in MCV are shown in Fig. 3 MCV in the n-hexane group was significantly less than the control after four and eight weeks of administration. MCV in methylcyclopentane group was significantly less than the control after eight weeks' administration. But there was no significant difference between MCVs in 2-methylpentane or 3-methylpentane group and the control.
DLs in every groups had a tendency to decrease as the rats grew. There were no statistically significant differences between the solvent-administered groups and the control. - Histopathological findings: non-neoplastic:
- not examined
- Histopathological findings: neoplastic:
- not examined
Any other information on results incl. tables
The changes in MNCV (distal) are shown in Fig. 4. MNCV (distal) in n-hexane group was significantly less than the control after four weeks' administration. But there was no significant difference between MNCVs (distal) in 2-methylpentane, 3-methylpentane or methylcyclopentane group and the control.
The changes in MNCV (proximal) are shown in Fig. 5. MNCV (proximal) in n-hexane group was significantly less than the control after six weeks' administration. MNCVs (proximal) in the 2-methylpentane and methylcyclopentane groups
were significantly less than the control after eight weeks' administration.
The summary of the results is shown in Fig. 6. The results demonstrated that the n-hexane group showed a distinct impairment of the functional states of the peripheral nerve, the methylcyclopentane and 2-methylpentane groups showed
only slight impairment of them, and 3-methylpentane group barely showed any impairment.
The ratios of the conduction velocities and distal latencies to the predosing ones were calculated and compared between each solvent-administered group and the control group (Fig. 7). MNCV (distal) significantly differed from that of the
control even in 3-methylpentane group after eight weeks' administration. There were no significant differences in distal latency.
Applicant's summary and conclusion
- Conclusions:
- The n-hexane group showed a distinct impairment of the functional states of the peripheral nerve Methylcyclopentane, 2-methylpentane and 3-methylpentane group had some significant differences in comparison with the control in the experiment, although these differences were not so distinct as those in n-hexane group. The results revealed that the neurotoxicity of the three chemicals was not so severe as that of n-hexane and were in the order of
n-hexane > methylcyclopentane > 2-methylpentane = 3-methylpentane. - Executive summary:
Commercial hexane which caused polyneuropathy in many workers contained 10-40 % of 2-methylpentane, 3-methylpentane and methylcyclopentane in addition to n-hexane. The hexacarbon compounds methyl n-butyl ketone, 2,5-hexanedione and etc were shown to be neurotoxic like n-hexane. Therefore, 2-methylpentane, 3-methylpentane and methylcyclopentane which are also hexacarbon compounds were suspected to be neurotoxic, but their neurotoxicity had not been sufficiently investigated.
The present experiment was performed to clarify their neurotoxicity by measuring the nerve conduction velocity in the rat's tail Thirty rats were divided into five groups of 5-7 rats. n-Hexane, 2 -methylpentane, 3-methylpentane and methylcyclopentane were diluted with olive oil and orally administered daily for eight weeks. The body weight, motor nerve conduction velocity, motor distal latency and mixed nerve conduction velocity were measured before administration, after two, four, six and eight weeks' administration.
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