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EC number: 936-414-1 | CAS number: -
- 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
Endpoint summary
Administrative data
Key value for chemical safety assessment
- Toxic effect type:
- dose-dependent
Effects on fertility
Description of key information
A screening study for effects on fertility does not need to be conducted because a pre-natal developmental toxicity study is available.
An extended one-generation reproductive toxicity study does not need to be conducted because there are no results from available repeated dose toxicity studies that indicate adverse effects on reproductive organs or tissues, or reveal other concerns in relation with reproductive toxicity.
Link to relevant study records
- Endpoint:
- extended one-generation reproductive toxicity - basic test design (Cohorts 1A, and 1B without extension)
- Data waiving:
- study scientifically not necessary / other information available
- Justification for data waiving:
- the extended one-generation reproductive toxicity study does not need to be conducted because there are no results from available repeated dose toxicity studies that indicate adverse effects on reproductive organs or tissues, or reveal other concerns in relation with reproductive toxicity
- Endpoint:
- screening for reproductive / developmental toxicity
- Data waiving:
- study scientifically not necessary / other information available
- Justification for data waiving:
- the study does not need to be conducted because a pre-natal developmental toxicity study is available
- Reason / purpose for cross-reference:
- data waiving: supporting information
Referenceopen allclose all
Effect on fertility: via oral route
- Endpoint conclusion:
- no study available
Effect on fertility: via inhalation route
- Endpoint conclusion:
- no study available
Effect on fertility: via dermal route
- Endpoint conclusion:
- no study available
Effects on developmental toxicity
Description of key information
A study assessing developmental toxicity after oral administration of MWCNT which was performed similar to OECD TG 414 in rats, resulted in decreased maternal thymus weights at the highest dose tested (1000 mg/kg bw/day). No effect on pregnancy outcome, fetal growth, viability, or morphological development was observed. Therefore, the respective NOAELs were considered to be 1000 mg/kg bw/day for fetal development and 200 mg/kg bw/day for maternal toxicity.
Link to relevant study records
- Endpoint:
- developmental toxicity
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- key study
- Justification for type of information:
- For details on endpoint specific justification please see read-across report in section 13 or find a link in cross-reference “assessment report”.
- Reason / purpose for cross-reference:
- assessment report
- Reason / purpose for cross-reference:
- read-across source
- Key result
- Dose descriptor:
- NOAEL
- Effect level:
- 200 mg/kg bw/day
- Based on:
- test mat.
- Basis for effect level:
- other: overall effects
- Key result
- Dose descriptor:
- LOAEL
- Effect level:
- 1 000 mg/kg bw/day
- Based on:
- test mat.
- Basis for effect level:
- organ weights and organ / body weight ratios
- Key result
- Abnormalities:
- effects observed, treatment-related
- Localisation:
- other: thymus
- Description (incidence and severity):
- Significant decrease in absolute and relative thymus weights in the 1000 mg/kg group compared to the control group.
Please refer to table 3 in section 'any other information on results incl. tables'. - Key result
- Dose descriptor:
- NOAEL
- Effect level:
- 1 000 mg/kg bw/day
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- other: overall effects
- Key result
- Abnormalities:
- no effects observed
- Key result
- Developmental effects observed:
- no
- Conclusions:
- This study assessing developmental toxicity after oral application of MWCNT and which was performed similar to OECD TG 414 in rats, showed decreased maternal thymus weight at the highest dose tested (1000 mg/kg bw/day). No effect on pregnancy outcome, fetal growth, viability, or morphological development was observed. Therefore, the repective NOAELs are considered to be 1000 mg/kg bw/day for fetal development and 200 mg/kg bw/day for maternal toxicity.
- Executive summary:
The study used as source investigated developmental toxicity of MWCNT in rats. The study results of the source compound were considered applicable to the target compound. Justification and applicability of the read-across approach (structural analogue) is outlined in the read-across report in section 13 or find a link in cross reference “assessment report”.
- Endpoint:
- developmental toxicity
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- published in 2011
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- guideline study without detailed documentation
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 414 (Prenatal Developmental Toxicity Study)
- Deviations:
- yes
- Remarks:
- fewer number of dams per group tested
- GLP compliance:
- not specified
- Remarks:
- Published study performed by University staff in the Republic of Korea
- Limit test:
- no
- Specific details on test material used for the study:
- SOURCE OF TEST MATERIAL
- Source: Hanwha Nanotech, Incheon Korea
- Purity: 95% carbon, 5% iron
TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: ultrasonication after suspension in vehicle for 3 minutes
- Final concentration of a dissolved solid: 2, 10, or 50 mg/ml - Species:
- rat
- Strain:
- Sprague-Dawley
- Remarks:
- Specific pathogen free
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Source: Orient Bio, Seoul, Korea
- Age at study initiation: 10 weeks
- Housing: clear polycarbonate cages with stainless steel wire lids. Mating: two females were cohabited with one male in the same cage overnight. Mated females: individually housed
- Diet (e.g. ad libitum): commercial rodent chow (Samyang Feed, Wonju, Republic of Korea), ad libitum
- Water (e.g. ad libitum): UV-irradiation sterilized tap water, ad libitum
- Acclimation period: 1 week (including quarantine)
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23 +/- 3°C
- Humidity (%): 50 +/- 10%
- Air changes (per hr): 13 - 18
- Photoperiod (hrs dark / hrs light): 12/12 - Route of administration:
- oral: gavage
- Vehicle:
- CMC (carboxymethyl cellulose)
- Remarks:
- 1% sodium carboxymethylcellulose solution
- Details on exposure:
- PREPARATION OF DOSING SOLUTIONS:
VEHICLE
- Justification for use and choice of vehicle (if other than water): Based on the report 'Takagi A, Hirose A, Nishimura T, Fukumori N, Ogata A, Ohashi N, et al. Induction of mesothelioma in p53+/- mouse by intraperitoneal application of multi-wall carbon nanotube. J Toxicol Sci 2008; 33(1): 105-116.'
- Amount of vehicle (if gavage): 20 ml/kg/day - Analytical verification of doses or concentrations:
- not specified
- Details on mating procedure:
- - Impregnation procedure: [cohoused]
- If cohoused:
- M/F ratio per cage: 1 : 2
- Length of cohabitation: overnight
- Proof of pregnancy: [sperm in vaginal smear] referred to as [day 0 ] of gestation - Duration of treatment / exposure:
- Gestation day (GD) 6 - GD19
- Frequency of treatment:
- once daily
- Duration of test:
- 14 days from GD 6 through GD 19
- Dose / conc.:
- 0 mg/kg bw/day
- Dose / conc.:
- 40 mg/kg bw/day
- Dose / conc.:
- 200 mg/kg bw/day
- Dose / conc.:
- 1 000 mg/kg bw/day
- No. of animals per sex per dose:
- 12 mated females per dosing group
- Control animals:
- yes, concurrent vehicle
- Details on study design:
- - Dose selection rationale: Preliminary study with 5 females per group for 10 days, no maternal toxicity or developmental toxicity observed. Therefore, the doses of 40, 200 and 1000 mg/kg bw/day were selected using a scaling factor of five.
- Maternal examinations:
- CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- Cage side observations checked: mortality, morbidity, general appearance, behaviour
BODY WEIGHT: Yes
- Time schedule for examinations: on GD 0, 6, 9, 12, 15, and 20
FOOD CONSUMPTION: Yes
- Food consumption for each animal determined and mean daily diet consumption calculated: Yes
POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20
- Organs examined: complete gross postmortem examination, absolute and relative (organ-to-body weight ratio) weights of
lung, adrenal glands, liver, spleen, kidneys, thymus, heart, and ovaries measured
OTHER:
- Analysis of Kidney Oxidation Damage
Kidney preparation: crushing of the kidney tissue (glass-teflon homogenous grinder, few seconds), centrifuging homogenized at 4°C, at 800 g for 10 minutes. Protein quantification according to Lowry method. Measurement of activity of antioxidant enzymes (catalase, glutathione reductase, glutathione peroxidase, glutathione-S-transferase), glutathione concentration, degree of lipid
peroxidation
- Serum Biochemical Examination
Blood samples were taken from posterior vena cava. Parameters examined: aspartate aminotransferase, alanine aminotransferase, total cholesterol, triglyceride, alkaline phosphatase, blood urea nitrogen, creatinine, glucose, total bilirubin, albumin, total protein
Animals were sacrificed by ether inhalation and exsanguination via the aorta - Ovaries and uterine content:
- The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Other: live and dead fetuses - Blood sampling:
- Yes, please refer to 'Maternal Examinations'
- Fetal examinations:
- - External examinations: Yes: [all per litter]
- Soft tissue examinations: Yes: [half per litter]
- Skeletal examinations: Yes: [half per litter]
- Head examinations:No
- fetal sex ratio calculated
- fetal weight
- placental weight - Statistics:
- Data are presented as means ± S.D.
The unit of statistical measurement is the pregnant female or the litter. Quantitative data (maternal body weight, food consumption, fetal body weight, placental weight): one-way analysis of variance followed by Scheffe's multiple comparison test when the differences were significant. Number of corpora lutea, total implantations, live and dead fetuses, fetal alterations: Kruskal-Wallis nonparametric analysis of variance, followed by Mann-Whitney U-test where applicable. Gender ratio and proportions of litters with malformations and developmental variations: chi-square tests and Fischer's exact probability tests. Computer program: GraphPad InStat version 3.0 (GraphPad Software Inc., CA, USA). P-value = 0.05: statistical significance attained. - Indices:
- Pre-implantation loss (%) = ([No. of corpora lutea - No. of implantation sites]/No. of corpora lutea) * 100.
Post-implantation loss (%) = ([No. of implantation sites - No. of live embryos]/No. of implantation sites) * 100 - Clinical signs:
- effects observed, treatment-related
- Description (incidence and severity):
- 1 of 10 dams in the 40 mg/kg group and 3 of 12 dams in the 1000 mg/kg group showed decreased locomotor activity and depression after treatment. These clinical signs were transient in nature, and not dose-dependent in either incidence or severity.
- Dermal irritation (if dermal study):
- not examined
- Mortality:
- no mortality observed
- Body weight and weight changes:
- no effects observed
- Description (incidence and severity):
- Please refer to table 1 in section 'any other information on results incl. tables'.
- Food consumption and compound intake (if feeding study):
- no effects observed
- Description (incidence and severity):
- Please refer to table 2 in section 'any other information on results incl. tables'.
- 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:
- no effects observed
- Endocrine findings:
- not examined
- Urinalysis findings:
- not examined
- Behaviour (functional findings):
- not examined
- Immunological findings:
- not examined
- Organ weight findings including organ / body weight ratios:
- effects observed, treatment-related
- Description (incidence and severity):
- Significant decrease in absolute and relative thymus weights in the 1000 mg/kg group compared to the control group.
Please refer to table 3 in section 'any other information on results incl. tables'. - Gross pathological findings:
- no effects observed
- Neuropathological findings:
- not examined
- Histopathological findings: non-neoplastic:
- not examined
- Histopathological findings: neoplastic:
- not examined
- Other effects:
- no effects observed
- Description (incidence and severity):
- No effects observed in the analysis of kidney oxidation damage.
Please refer to table 4 in section 'any other information on results incl. tables'. - Number of abortions:
- no effects observed
- Pre- and post-implantation loss:
- no effects observed
- Total litter losses by resorption:
- no effects observed
- Early or late resorptions:
- no effects observed
- Dead fetuses:
- no effects observed
- Changes in pregnancy duration:
- no effects observed
- Changes in number of pregnant:
- effects observed, non-treatment-related
- Description (incidence and severity):
- Number of pregnant females out of twelve (control, low dose, mid dose, high dose, respectively):
11, 10, 12, 11 - Details on maternal toxic effects:
- For more details please refer to table 5 in section 'any other information on results incl. tables'.
- Key result
- Dose descriptor:
- NOAEL
- Effect level:
- 200 mg/kg bw/day
- Based on:
- test mat.
- Basis for effect level:
- other: overall effects
- Key result
- Dose descriptor:
- LOAEL
- Effect level:
- 1 000 mg/kg bw/day
- Based on:
- test mat.
- Basis for effect level:
- organ weights and organ / body weight ratios
- Key result
- Abnormalities:
- effects observed, treatment-related
- Localisation:
- other: thymus
- Description (incidence and severity):
- Significant decrease in absolute and relative thymus weights in the 1000 mg/kg group compared to the control group.
Please refer to table 3 in section 'any other information on results incl. tables'. - Fetal body weight changes:
- no effects observed
- Reduction in number of live offspring:
- no effects observed
- Changes in sex ratio:
- no effects observed
- Changes in litter size and weights:
- no effects observed
- Anogenital distance of all rodent fetuses:
- not examined
- Changes in postnatal survival:
- not examined
- External malformations:
- no effects observed
- Skeletal malformations:
- no effects observed
- Visceral malformations:
- no effects observed
- Key result
- Dose descriptor:
- NOAEL
- Effect level:
- 1 000 mg/kg bw/day
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- other: overall effects
- Key result
- Abnormalities:
- no effects observed
- Key result
- Developmental effects observed:
- no
- Conclusions:
- This study assessing developmental toxicity of MWCNT and which was performed similar to OECD TG 414 in rats, showed decreased maternal thymus weight at the highest dose tested (1000 mg/kg bw/day). No effect on pregnancy outcome, fetal growth, viability, or morphological development was observed. Therefore, the repective NOAELs are considered to be 1000 mg/kg bw/day for fetal development and 200 mg/kg bw/day for maternal toxicity.
- Executive summary:
This study assessing developmental toxicity of MWCNT was conducted similar to OECD TG 414 in specific pathogen free Sprague-Dawley rats with the deviation that fewer dams (n = 12) were tested than required in the guideline.
The test material was administered in doses of 0, 40, 200 and 1000 mg/kg bw/day orally per gavage. Control animals received the same volume of pure vehicle (CMC solution).
Clinical signs, mortality, body weights, food consumption, serum biochemistry, kidney oxidation damage, gross findings, organ weights, and Caesarean section findings were examined.
In the high dose group, dams showed decreased thymus weights (absolute and body weight relative) when compared to control dams. Therefore, the maternal NOAEL was set to 200 mg/kg bw/day.
There were no effects on fetal development obsereved. Thus, the according NOAEL was set to 1000 mg/kg bw/day.
Referenceopen allclose all
Table 1: Body Weight Changes in Pregnant Rats Treated With Multi-Wall Carbon Nanotubes During Gestational Days 6–19
Multi-wall carbon nanotubes (mg/kg/day)
| ||||
Parameters | 0 | 40 | 200 | 1000 |
No. of rats mated | 12 | 12 | 12 | 12 |
No. of pregnant rats | 11 | 10 | 12 | 11 |
Gestational day 0 | 246.5+11.14a | 247.1+17.08 | 243.7+16.96 | 242.0+19.65 |
Gestational day 6 | 283.7+12.60 | 286.1+19.65 | 280.4+16.70 | 283.4+25.12 |
Gestational day 9 | 296.2+15.63 | 297.3+20.35 | 289.4+18.08 | 290.6+27.92 |
Gestational day 12 | 309.8+15.56 | 312.5+20.66 | 303.2+19.52 | 303.9+28.66 |
Gestational day 15 | 323.0+16.30 | 328.6+21.05 | 318.6+20.59 | 320.3+31.07 |
Gestational day 20 | 381.3+25.97 | 387.4+28.61 | 367.2+28.13 | 377.4+39.56 |
Body weight gain during pregnancy | 134.8+17.12 | 140.3+21.11 | 123.6+23.42 | 135.4+26.26 |
Corrected body weightb | 319.9+16.77 | 323.4+23.07 | 306.3+28.76 | 303.4+39.51 |
Gravid uterine weight | 61.4+16.72 | 63.9+21.99 | 60.9+20.35 | 74.0+9.79 |
aValues are presented as mean+SD (g).
bBody weight on gestational day 20—gravid uterine weight.
Table 2: Food Consumption by Pregnant Rats Treated With Multi-Wall Carbon Nanotubes During Gestational Days 6–19
Multi-wall carbon nanotubes (mg/kg/day) | ||||
Parameters | 0 | 40 | 200 | 1000 |
No. of dams | 11 | 10 | 12 | 11 |
Gestational day 0 | 19.6+3.06a | 19.4+3.14 | 18.2+1.63 | 19.5+3.78 |
Gestational day 6 | 23.9+3.61 | 24.3+2.87 | 22.7+3.21 | 22.2+2.82 |
Gestational day 9 | 22.1+2.65 | 23.0+3.81 | 21.4+2.54 | 21.8+4.33 |
Gestational day 12 | 22.2+3.87 | 25.8+3.78 | 22.8+6.32 | 23.0+4.94 |
Gestational day 15 | 23.3+3.04 | 24.4+2.66 | 22.8+2.23 | 23.4+5.15 |
Gestational day 19 | 23.7+2.70 | 29.8+8.30* | 22.9+4.48 | 23.7+6.04 |
aValues are presented as mean+SD (g).
Table 3: Absolute and Relative Organ Weights of Pregnant Rats Treated With Multi-Wall Carbon Nanotubes During Gestational Days 6–19
|
Multi-wall carbon nanotubes (mg/kg/day)
| |||
Parameters | 0 | 40 | 200 | 1000 |
No. of dams | 11 | 10 | 12 | 11 |
Body weight at term | 381.3+25.97a | 387.4+28.61 | 367.2+28.13 | 377.4+39.56 |
Lung (g) | 1.25+0.122 | 1.24+0.083 | 1.24+0.106 | 1.20+0.090 |
Per body weight (%) | 0.33+0.029 | 0.32+0.021 | 0.34+0.035 | 0.32+0.021 |
Adrenal glands (g) | 0.087+0.0078 | 0.076+0.0127 | 0.089+0.0142 | 0.087+0.0143 |
Per body weight (%) | 0.023+0.0017 | 0.020+0.0028 | 0.024+0.0048 | 0.023+0.0056 |
Liver (g) | 15.39+1.673 | 15.50+1.661 | 15.08+1.964 | 15.05+1.855 |
Per body weight (%) | 4.03+0.245 | 4.00+0.260 | 4.10+0.337 | 3.98+0.208 |
Spleen (g) | 0.71+0.101 | 0.64+0.058 | 0.62+0.084 | 0.63+0.068 |
Per body weight (%) | 0.19+0.032 | 0.17+0.015 | 0.17+0.020 | 0.17+0.013 |
Kidneys (g) | 2.15+0.185 | 2.15+0.216 | 2.09+0.232 | 1.98+0.207 |
Per body weight (%) | 0.56+0.050 | 0.56+0.048 | 0.57+0.045 | 0.53+0.042 |
Thymus (g) | 0.49+0.063 | 0.51+0.081 | 0.44+0.107 | 0.36+0.101* |
Per body weight (%) | 0.13+0.021 | 0.13+0.021 | 0.12+0.022 | 0.10+0.022* |
Heart (g) | 1.11+0.105 | 1.10+0.081 | 1.15+0.151 | 1.08+0.119 |
Per body weight (%) | 0.29+0.022 | 0.28+0.021 | 0.31+0.035 | 0.29+0.024 |
Ovary (g) | 0.15+0.021 | 0.15+0.015 | 0.15+0.033 | 0.13+0.013 |
Per body weight (%) | 0.04+0.006 | 0.04+0.005 | 0.04+0.010 | 0.03+0.006 |
aValues are presented as mean+SD.
*Significant difference at P < 0.05 level when compared with the control group.
Table 4: Antioxidant Enzymes, Glutathione and Lipid Peroxidation Levels in the Livers of Pregnant Rats Treated With Multi-Wall Carbon Nanotubes During Gestational Days 6–19
|
Multi-wall carbon nanotubes (mg/kg/day)
| |||
Parameters | 0 | 40 | 200 | 1000 |
No. of dams | 11 | 10 | 12 | 11 |
Catalase (unit/mg protein) | 26.5 ± 3.87a | 25.5 ± 4.49 | 27.6 ± 5.11 | 22.8 ± 6.34 |
Glutathione reductase (unit/mg protein) | 199.3 ± 10.43 | 231.3 ± 16.89 | 251.5 ± 15.90 | 228.9 ± 44.63 |
Glutathione-S-transferase (mmol/mg protein) | 6.8 ± 0.63 | 6.0 ± 0.68 | 6.3 ± 0.24 | 5.7 ± 0.41 |
Glutathione peroxidase (nmol/mg protein) | 2.6 ± 0.48 | 2.6 ± 0.35 | 2.4 ± 0.31 | 2.6 ± 0.51 |
Glutathione (nmol/mg protein) | 264.2 ± 28.74 | 315.8 ± 63.2 | 230.8 ± 68.03 | 375.1 ± 29.78 |
Malondialdehyde (mmol/mg protein) | 64.6 ± 11.12 | 71.4 ± 26.66 | 72.7 ± 12.25 | 72.4 ± 10.24 |
aValues are presented as mean+SD.
Note: For the endpoints in table 4 different values are reported in the second reference.
Table 5: Cesarean Section Data in Pregnant Rats Treated With Multi-Wall Carbon Nanotubes During Gestational Days 6–19
|
Multi-wall carbon nanotubes (mg/kg/day)
| |||
Parameters | 0 | 40 | 200 | 1000 |
No. of dams | 11 | 10 | 12 | 11 |
No. of corpora lutea | 14.7+3.26a | 14.6+1.84 | 13.8+2.12 | 14.8+1.40 |
No. of implantation sites | 11.6+3.70 | 11.9+4.18 | 11.5+3.63 | 14.0+1.61 |
Pre-implantation loss (%)b | 20.0+20.49 | 18.7+25.95 | 19.1+24.97 | 5.5+7.02 |
Fetal deaths | 0.5+0.82 | 0.5+0.53 | 0.4+0.67 | 0.5+0.52 |
Resorption: Early | 0.5+0.82 | 0.4+0.52 | 0.4+0.67 | 0.5+0.52 |
Late | 0 | 0.1+0.32 | 0 | 0 |
Dead fetuses | 0 | 0 | 0 | 0 |
Post-implantation loss (%)c | 3.1+5.65 | 3.6+3.81 | 4.7+6.30 | 3.2+3.67 |
Litter size | 11.2+3.34 | 11.4+3.92 | 11.1+3.70 | 13.5+1.51 |
Male/female | 70/53 | 59/55 | 73/60 | 78/71 |
Gender ratio | 1.32 | 1.07 | 1.22 | 1.10 |
Fetal weight (g): Male | 3.62+0.194 | 3.65+0.219 | 3.42+0.150 | 3.61+0.181 |
Female | 3.39+0.233 | 3.50+0.287 | 3.28+0.150 | 3.41+0.204 |
Placental weight (g) | 0.53+0.050 | 0.58+0.081 | 0.53+0.057 | 0.51+0.047 |
aValues are presented as mean+SD.
bPre-implantation loss (%) = ([No. of corpora lutea-No. of implantation sites]/No. of corpora lutea) x 100.
cPost-implantation loss (%) = ([No. of implantation sites-No. of live embryos]/No. of implantation sites) x 100.
Effect on developmental toxicity: via oral route
- Endpoint conclusion:
- adverse effect observed
- Dose descriptor:
- NOAEL
- 1 000 mg/kg bw/day
- Study duration:
- subacute
- Experimental exposure time per week (hours/week):
- 168
- Species:
- rat
- Quality of whole database:
- High quality study comparable to guideline study with acceptable restrictions
Additional information
A study assessing developmental toxicity of MWCNT was conducted similar to OECD TG 414 in specific pathogen free Sprague-Dawley rats.
The test material (MWCNT Hanwha CM-95) was administered in doses of 0, 40, 200 and 1000 mg/kg bw/day orally per gavage. Control animals received the same volume of pure vehicle (CMC solution). 12 female rats were assigned to each dosing group. The number of pregnant females in control, low dose, mid dose or high dose group was 11, 10, 12 or 11, respectively. Clinical signs, mortality, body weights, food consumption, serum biochemistry, kidney oxidation damage, gross findings, organ weights, and Caesarean section findings (Gravid uterus weight, number of corpora lutea, number of implantations, early resorptions, late resorptions, live and dead fetuses, external examinations, soft tissue examinations, skeletal examinations, fetal sex ratio, fetal and placental weights) were examined.
In the high dose group, dams showed decreased thymus weights (absolute and body weight relative) when compared to control dams. Therefore, the maternal NOAEL was set to 200 mg/kg bw/day.
There were no effects on fetal development obsereved. Thus, the according NOAEL was set to 1000 mg/kg bw/day.
Justification for classification or non-classification
The criteria for classification were not met.
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