2-Methoxy-4-methylphenyl methyl carbonate

Endpoint summary

Description of key information

Oral: NOAEL (rat): 650 mg/kg bw/day ; male/female, OECD TG 407, 2012

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

09-02-2012 to 02-10-2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study performed under GLP. All relevant validity criteria were met.

Justification for type of information:

Information as to the availability of the in vivo study is provided in 'attached justification'.

Qualifier:

according to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.7 (Repeated Dose (28 Days) Toxicity (Oral))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

inspected: July 2011 ; signature: August 2011

Limit test:

no

Species:

rat

Strain:

other: Wistar Han RccHan: WIST

Details on species / strain selection:

The species and strain was selected in accordance with the OECD TG 407 and the other relevant guidelines.

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Recognised supplier (reported in the full study report)
- Females (if applicable) nulliparous and non-pregnant: Yes.
- Age at study initiation: approximately 6 to 8 weeks
- Weight at study initiation: males 209 - 233 g and females 158 – 184 g; individuals were randomly allocated to treatment groups using a stratified body weight randomization procedure and the group mean body weights were then determined to ensure similarity between the treatment groups.
- Fasting period before study: None
- Housing: Polypropylene body with a stainless steel mesh lid with softwood flake bedding, changed at appropriate intervals; group housed (5 per group) by sex. Environmental enrichment was provided in the form of wooden chew blocks and cardboard fun tunnels. Cage distribution within the holding rack was randomized.
- Diet (e.g. ad libitum): Rodent 2014C, Global Certified Diet, ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 5 days.

DETAILS OF FOOD AND WATER QUALITY: Feed: Rodent 2014C, Global Certified Diet – batch numbers and certificates of analysis provided in the full study report. The diet, drinking water, bedding and environmental enrichment were considered not to contain any contaminant at a level that might have affected the purpose or integrity of the study.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 55 ± 15 (or 40 to 70)
- Air changes (per hr): 15 per hour
- Photoperiod (hrs dark / hrs light): 12 h light / 12 h dark

IN-LIFE DATES: From: 2012-03-08 To: 2012-04-05

Route of administration:

oral: gavage

Vehicle:

arachis oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
The test item was prepared at the appropriate concentrations as a suspension in Arachis oil BP. The stability and homogeneity of the test item formulations were determined. Results show the formulations to be stable for at least twenty one days. Formulations were prepared five times during the treatment period and stored at approximately 4ºC in the dark.

DIET PREPARATION
- Rate of preparation of diet (frequency): Not applicable.
- Mixing appropriate amounts with (Type of food): Not applicable.
- Storage temperature of food: Not applicable.

VEHICLE
- Justification for use and choice of vehicle (if other than water): Applicant assessment indicates: Aqueous vehicle was not applicable due to limited solubility. Arachis oil BP was considered as appropriate based on test item solubility. The stability and homogeneity of the test item formulations were determined during the study. Results show the formulations to be homogeneous and stable for at least twenty one days. Formulations were prepared five times during the treatment period and stored at approximately 4ºC in the dark.
- Concentration in vehicle: Samples of the test item formulations were taken on two occasions and analyzed for concentration of test item (method of analysis provided in full study report). The results indicate that the prepared formulations were within ± 10% of the nominal concentration. Arachis oil formulations was assessed and confirmed at nominal concentrations of 3.75 mg/mL and 250 mg/mL, during refrigerated storage. The test item concentrations for each group are indicated in table 1.
- Amount of vehicle (if gavage): Treatment volume was 4 mL/kg for control (negative, untreated group) and all treatment groups with applicable test item concentrations per group.
- Other: Dose-formulations were analysed during the study and were reported as with ± 10% applied limits.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

- The homogeneity and stability was confirmed in Arachis oil BP formulations at nominal concentrations of 3.75 mg/mL and 250 mg/mL , during refrigerated storage in the dark for at least twenty one (21) days.
- Refrigerated formulations were also analysed within two days of preparation: the formulation was removed from storage and equilibrated to ambient temperature. The formulations were mixed according to mixing procedure (as used in the definitive test) shaking between sampling and single samples were removed for analysis from the top, middle and bottom of the mixed formulation.
- The analysis consisted of GC FID analysis with external calibration (within a dedicated formulation analysis report attached to the full study report). Samples of Arachis oil BP were accurately fortified with known amounts of test item equivalent to the lowest and highest anticipated dose concentrations. These were then subjected to analysis by GC FID and using external calibration, with linear regression to calibration standard. The analytical method was validated (details available within the full study report).
- Mean concentrations of dose-formulations analysed during the study were within ± 10% applied limits confirming accurate test item/vehicle formulation.

Duration of treatment / exposure:

28 days

Frequency of treatment:

daily

Dose / conc.:

0 mg/kg bw/day (nominal)

Remarks:

Control

Dose / conc.:

30 mg/kg bw/day (nominal)

Remarks:

Low – Group

Dose / conc.:

300 mg/kg bw/day (nominal)

Remarks:

Intermediate – Group

Dose / conc.:

650 mg/kg bw/day (nominal)

Remarks:

High – Group

No. of animals per sex per dose:

5 per sex per dose (5 male / 5 female)

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Dose levels were based on the results of a previously conducted 7-day sighting study (Report number attached to and cited in the full study report). Dose levels were selected following 7-day sighting test as: Group 1: 0 mg/kg/day (Arachis oil BP) Group 2: 30 mg/kg/day, Group 3: 300 mg/kg/day Group 4: 650 mg/kg/day (Treatment Group - High). In the 7-day range finder (administered consecutively, for 7-days) the following effects were determined was using a range finding dose range of 250, 500 and 1000 mg/kg bw/day: High dose females demonstrated ataxia and lethargy on days 1 to 3. Decreased respiration in one female and prostration. Following reduction, no clinical observable signs between days 4 to 6. Prostration was recorded in one high dose female at day 7. High dose females showed a reduction in body weight gain. Other dose levels showed an overall reduction body weight gain for males. High dose females showed reduction in food consumption and food efficiency. Males showed reduction on day 3 only. Increased water consumption was shown in high dose males/females and females at 500 and 250 mg/kg bw/day. No abnormalities were revealed in necropsy. Basis: other: nominal in vehicle (Arachis Oil BP).
- Rationale for animal assignment (if not random): Randomly assigned
- Post-exposure recovery period in satellite groups: None.
- Section schedule rationale: Random

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: All individuals were examined for overt signs of toxicity, ill-health or behavioural change immediately before dosing, up to thirty minutes post dosing and one hour after dosing. During week-days observations before, and one and five hours after dosing specifically completed. All observations were recorded. Additional functional observations were made as ‘special evaluations’. This was prior to the start of treatment and on Days 5, 12, 19 and 26, all animals were observed for signs of functional/behavioural toxicity. Functional performance tests were also performed on all animals during Week 4, together with an assessment of sensory reactivity to different stimuli. Observations were conducted at least two hours after dosing.

BODY WEIGHT: Yes
- Time schedule for examinations: Individual body weights were recorded prior to dosing on Day 1 and at weekly intervals thereafter. Body weights were also performed prior to termination.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Not applicable.
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Not applicable.
- Other: Food consumption was recorded for each cage group at weekly intervals throughout the study. Food conversion efficiency was calculated retrospectively.

FOOD EFFICIENCY: Yes.
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: Yes. Food conversion efficiency was calculated retrospectively.

WATER CONSUMPTION: Yes
- Time schedule for examinations: Daily. Water intake was observed daily, for each cage group, by visual inspection of the water bottles for any overt changes except during Week 3 where water intake was measured gravimetrically. A possible intergroup difference was detected during Week 3, therefore water consumption was continued to be measured and recorded for each cage group until the termination.

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: Prior to the start of treatment and on Days 7, 14, 21 and 28, all animals were observed (e.g. for exophthalmia and similar parameters). Additional histopathology was conducted on eyes after termination.
- Dose groups that were examined: All test animals.

HAEMATOLOGY: Yes
- Time schedule for collection of blood: End of treatment period (day 28) for all test and control group individuals.
- Anaesthetic used for blood collection: Not reported.
- Animals fasted: No.
- How many animals: All animals
- Parameters checked: Hemoglobin (Hb), Erythrocyte count (RBC), Hematocrit (Hct), Erythrocyte indices – including: mean corpuscular hemoglobin (MCH), mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), Total leukocyte count (WBC), Differential leukocyte count – including: neutrophils (Neut), lymphocytes (Lymph), monocytes (Mono), eosinophils (Eos), basophils (Bas), Platelet count (PLT), Reticulocyte count (Retic). Additionally: Prothrombin time (CT) was assessed by ‘Innovin’ and Activated partial thromboplastin time (APTT) was assessed by ‘Actin FS’ using samples collected into sodium citrate solution (0.11 mol/L)

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: End of treatment period (day 28) for all test and control group individuals.
- Animals fasted: No.
- How many animals: All animals
- Parameters checked: Urea, Aspartate aminotransferase (ASAT), Glucose, Alanine aminotransferase (ALAT), Total protein (Tot.Prot.), Alkaline phosphatase (AP), Albumin, Creatinine (Creat), Albumin/Globulin (A/G) ratio (by calculation), Total cholesterol (Chol), Sodium (Na+), Total bilirubin (Bili), Potassium (K+), Triglycerides (Tri), Chloride (Cl-), Bile acids, Calcium (Ca++), Inorganic phosphorus (P)

URINALYSIS: No.

NEUROBEHAVIOURAL EXAMINATION: Yes. Was conducted as part of ‘special evaluations’
- Time schedule for examinations: Additional functional observations were made as ‘special evaluations’. This was prior to the start of treatment and on Days 5, 12, 19 and 26, all animals were observed for signs of functional/behavioural toxicity. Functional performance tests were also performed on all animals during Week 4, together with an assessment of sensory reactivity to different stimuli. Observations were conducted at least two hours after dosing.
- Dose groups that were examined: All.
- Battery of functions tested: sensory activity / grip strength / motor activity

IMMUNOLOGY: No

OTHER: Additional post-termination observations were made at necropsy.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
- organs weighed: Adrenals, Liver, Brain, Ovaries, Epididymides, Spleen, Heart, Testes, Kidneys, Thymus, Pituitary (post-fixation), Thyroid/Parathyroid (post fixation), Prostate and Seminal Vesicles, Uterus with Cervix (with coagulating glands and fluids)

HISTOPATHOLOGY: Yes
- Organs and tissues preserved in neutral buffered 10% formalin: Adrenals, Ovaries, Aorta (thoracic), Pancreas, Bone & bone marrow (femur including stifle joint), Pituitary, Bone & bone marrow (sternum), Prostate, Brain (including cerebrum, cerebellum and Rectum pons), Salivary glands (submaxillary), Caecum, Sciatic nerve, Colon, Seminal vesicles (with coagulating glands and fluids), Duodenum, Epididymides (Preserved in modified Davidson’s fluid), Skin, Esophagus, Spinal cord (cervical, mid thoracic and lumbar), Eyes (fixed in Davidson’s fluid), Gross lesions, Spleen, Heart, Stomach, Ileum ,Testes (Preserved in modified Davidson’s fluid), Jejunum, Thymus, Kidneys, Thyroid/Parathyroid, Liver,Trachea, Lungs (with bronchi) - inflated to approximately normal inspiratory volume with buffered 10% formalin before immersion in fixative, Urinary bladder, Lymph nodes (mandibular and mesenteric), Uterus & Cervix, Mammary gland, Vagina, Muscle (skeletal).
Microscopic analysis was conducted thereof. Any macroscopically observed lesions were also processed. In addition, sections of testes and epididymides from all Control and 650 mg/kg bw/day males were stained with Periodic Acid-Schiff (PAS) stain and examined.
- Other: Specific tissues shown above, for all control and 650 mg/kg bw/day dose group animals were prepared. Any macroscopically observed lesions were also processed together with the liver and spleen from all 30 and 300 mg/kg bw/day dose group animals. Further information in attached tables.

Other examinations:

- Thyroid Hormone Assessment: blood samples were taken at exsanguination and the serum was stored frozen at approximately -20 °C. No treatment-related effects on the pituitary-thyroid axis were identified, therefore these samples were discarded.

Statistics:

Where considered appropriate, quantitative data was subjected to statistical analysis to detect the significance of intergroup differences from control; statistical significance was achieved at a level of p<0.05. Statistical analysis was performed on the following parameters:
Grip Strength, Motor Activity, Body Weight Change, Hematology, Blood Chemistry, Micronucleus results, Absolute Organ Weights, Body Weight-Relative Organ Weights.
Where appropriate, data transformations were performed using the most suitable method. Data were analysed using the decision tree from proprietary tables and statistics modules incorporating, homogeneity of variance from mean values was analysed using Bartlett’s test. Intergroup variances were assessed using suitable ANOVA, or if required, ANCOVA with appropriate covariates. Transformed data were analysed to find the lowest treatment level that showed a significant effect using the Williams Test for parametric data or the Shirley Test for non-parametric data. If no dose response was found but the data shows non-homogeneity of means, the data were analysed by a stepwise Dunnett’s (parametric) or Steel (non-parametric) test to determine significant difference from the control group. Where the data were unsuitable for these analyses, pair-wise tests was performed using the Student t-test (parametric) or the Mann-Whitney U test (non-parametric).

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

At 650 mg/kg bw/day dose level: Increased respiratory rate was recorded for one male on day 19 only. Another male showed ataxia and lethargy on day 23. Ataxia was also recorded for two males one female on day 27. Incidents of increased salivation were evident in males/females. Although was not considered in isolation as an indication of toxicity. One female treated with 650 mg/kg bw/day had a damaged tail between days 26 to 29. This was considered as accidental damage and non treatment related.
At 300 mg/kg bw/day dose level: Incidents of increased salivation were evident in males/females.
At 30 mg/kg bw/day dose level: No significant clinical signs were observed.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

One control group male (No.2) exhibited mortality during the bleeding procedure on Day 28 of the study. This death was considered procedure related therefore is of no toxicological significance. There were no further unscheduled mortalities.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

No treatment related effects on body weight development in test animals, which was similar to that of controls.

Food efficiency:

no effects observed

Description (incidence and severity):

No adverse effect on food consumption during the study. Food efficiency (the ratio of body weight change to dietary intake) in test animals was similar to that of controls.

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

no effects observed

Description (incidence and severity):

Daily visual inspection of water bottles during the first two weeks of the treatment and following gravimetrical measurement of water consumption did not reveal any obvious intergroup differences.

Ophthalmological findings:

no effects observed

Description (incidence and severity):

There were no reported effects to the eyes (in life or post termination) in the parameters examined.

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

There were no toxicologically significant effects detected in the hematological parameters examined at the end of the treatment period.

At 650 and 300 mg/kg bw/day dose level: Females showed a statistically significant reductions in mean corpuscular haemoglobin count and/or concentration (p<0.05) when compared to controls. However, majority of the individual values were within the normal ranges for the strain and age of the rat used and were also attributed to higher than expected control values. These reductions were considered unrelated to treatment.
At 650 mg/kg bw/day dose level: showed a statistically significant increase in neutrophil count when compared with controls. The significance achieved was minimal (p<0.05) and majority of the individual values were within the normal expected range.
At 30 mg/kg bw/day dose level: Females showed a statistically significant reduction in reticulocyte count (p<0.05) when compared with control values. In the absence of similar effects detected in females treated with 650 or 300 mg/kg bw/day this finding was considered to be of no toxicological significance.

No effects were observed in males.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

There were no toxicologically significant effects detected in the blood chemical parameters examined at the end of the treatment period, in females at 650 mg/kg bw/day and/or males and females at 300 or 30 mg/kg bw/day.

At 650 mg/kg bw/day dose level: males showed a statistically significant increase in total cholesterol and bile acids concentration (p<0.05). Additionally, the males showed a statistically significant reduction in glucose concentration (p<0.05). The majority of individual values and mean group value were within the normally expected range. The reduction was therefore considered to be attributable to higher than expected control mean value. As such, this reduction was considered not to represent systemic toxicity. Males showed a statistically significant increase in potassium concentration (p<0.05) and males from all treatment groups showed
statistically significant increase in calcium concentration (p<0.05 and p<0.01). The majority of individual values and mean group value were within the normally expected range. Control values for calcium concentration were lower than in all dosed groups. This finding was considered of no toxicological importance.

At 650 mg/kg bw/day dose level: females showed a statistically significant reduction in urea concentration (p<0.05). All individual values were within the normal ranges for the strain and age of the rats used and were also attributed to higher than expected control values. As such, this reduction was considered not to be related to treatment.

At 650 or 300 mg/kg bw/day dose level: females howed a statistically significant increase in inorganic phosphorus concentration (p<0.05). The majority of individual values and mean group value were within the normally expected range. As such, this reduction was considered not to represent systemic toxicity.

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Description (incidence and severity):

There were no treatment-related changes in the behavioural parameters or in sensory reactivity. There was no toxicologically relevant changes in functional performance.

At 650 mg/kg bw/day dose level: males showed a statistically significant increase (p<0.05) in test 1 forelimb grip strength measurement when compared to controls. No such change was detected during the following two repetitions of this test and in the absence of any similar effects detected for females treated with this dose level and also in the absence of any supporting clinical observations to suggest an effect of neurotoxicity was not considered a relevant finding.

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

At 650 mg/kg bw/day dose level: males showed statistically significant increase in liver (p<0.01) and thyroid (p<0.05) weights, both absolute and relative to terminal body weights. No effects were observed in females.

At 300 and 30 mg/kg bw/day dose levels: no effects were observed.

Gross pathological findings:

no effects observed

Description (incidence and severity):

Macroscopic examination revealed no test item related lesions or abnormalities.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

At 650 mg/kg bw/day dose level: males demonstrated liver effects: centrilobular hepatocellular hypertrophy and increased hepatocellular glycogen content. In the thyroid gland there was increased incidence and severity of follicular hypertrophy. No effects were observed in females. For the liver, organ weight data supported this finding with increased absolute and relative liver weights observed in males. In the absence of any degenerative or inflammatory changes, this condition is considered to be adaptive in nature. The thyroid and liver changes are characteristic of a consequence of hepatocellular induction as a result of enhanced hepatic metabolism. The effects were considered adaptive changes.

At 300 and 30 mg/kg bw/day dose levels: no toxicologically significant effects were observed. Specifically, microscopic findings were within the range of normal background lesions for the strain of rat and age.

Histopathological findings: neoplastic:

no effects observed

Description (incidence and severity):

There were no treatment-related macroscopic abnormalities detected. There were no microscopic findings that were considered to be related to treatment with the test item.

Other effects:

no effects observed

Description (incidence and severity):

1. Thyroid Hormone Assessment: blood samples were taken at exsanguination and the serum was stored frozen. No treatment-related effects on the pituitary-thyroid axis were identified and therefore further analysis was not conducted.

Key result

Dose descriptor:

NOAEL

Effect level:

>= 650 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Remarks on result:

not determinable due to adverse toxic effects at highest dose / concentration tested

Critical effects observed:

no

Conclusions:

Under the conditions of this study, the no-observed-adverse-effect level (NOAEL) for males and females is considered to be 650 mg/kg body weight per day.

Executive summary:

The study was performed according the requirements of OECD TG 407 and EU method B.7 guidelines under GLP conditions. Following a previously conducted 7-day sighting study, the systemic toxic potential of the test item was assessed orally in a 28 day gavage study in Wistar Han : RccHan : WIST rats. Three groups, each comprising five male and five female rats, received test item at doses of 30, 300 or 650 mg/kg/day. A control group of five males and five females was dosed with vehicle alone (Arachis oil BP). Clinical signs, functional and behavioural observations, body weight change, food and water consumption were monitored during the study. Hematology and blood chemistry were evaluated for all non-recovery group animals at the end of the treatment period. All individuals were subjected to gross necropsy examination and at termination. Histopathological examination of selected tissues was performed. There was an unscheduled mortality in one control group male on day 2. There was no other unscheduled mortality. Males and females treated at 650 and 300 mg/kg bw/day showed increased salivation during the study. At 650 mg/kg bw/day increased respiratory rate was recorded for one male on Day 19 only, ataxia and lethargy were evident for one male on Day 23 and ataxia was also recorded for two males and one female on Day 27. One female treated with 650 mg/kg bw/day had a damaged tail recorded between Days 26 and 29. No clinically observable signs of toxicity were detected in animals of either sex treated with 30 mg/kg bw/day. There were no treatment-related changes in the behavioural parameters or in sensory reactivity. There was no toxicologically relevant changes in functional performance. There were no treatment related effects detected on body weight development. There were no adverse effects related to treatment on food consumption or food conversion efficiency. There was no adverse difference recorded for water consumption. No toxicologically significant effects were detected in the hematological parameters at the end of the treatment period. In blood chemical parameters males treated with 650 mg/kg bw/day showed an increase in total cholesterol and bile acids concentration. There were no toxicologically significant effects were detected in females treated at 650 mg/kg bw/day or in males or females below this dose level. There were no treatment-related macroscopic abnormalities detected. Males treated with 650 mg/kg bw/day showed an increase in liver and thyroid weights, both absolute and relative to terminal body weight. No such effects were observed in females and no effects were observed in males or females at 30 or 300 mg/kg bw/day. In the histopathology assessment no effects were observed at 30 or 300 mg/kg bw/day. At the high dose of 650 mg/kg bw/day in males: in the Liver there was centrilobular hepatocellular hypertrophy and increased hepatocellular glycogen content and in the Thyroid there was increased incidence and severity of follicular hypertrophy. The oral (gavage) administration of the test item to males/females at dose levels of 30, 300 or 650 mg/kg bw/day resulted in treatment related effects in males at 650 mg/kg bw/day including centrilobular hepatocellular hypertrophy of the liver and increased incidence and severity of follicular hypertrophy of the thyroid which was considered adaptive in nature. No adverse effects were evident at 300 or 30 mg/kg bw/day. Under the conditions of this study, the No-Observed-Adverse-Effect-Level (NOAEL) was regarded to be 650 mg/kg/day for males/females.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

650 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

The key study is GLP compliant and of a high quality (Klimisch 1); The available information as a whole meets the tonnage driven information requirements of REACH.

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Repeated dose - Oral:

OECD TG 407, 2012 : The study was performed according the requirements of OECD TG 407 and EU method B.7 guidelines under GLP conditions. Following a previously conducted 7-day sighting study, the systemic toxic potential of the test item was assessed orally in a 28 day gavage study in Wistar Han : RccHan : WIST rats. Three groups, each comprising five male and five female rats, received test item at doses of 30, 300 or 650 mg/kg/day. A control group of five males and five females was dosed with vehicle alone (Arachis oil BP). There was an unscheduled mortality in one control group male on day 2. There was no other unscheduled mortality. Males and females treated at 650 and 300 mg/kg bw/day showed increased salivation during the study. At 650 mg/kg bw/day increased respiratory rate was recorded for one male on Day 19 only, ataxia and lethargy were evident for one male on Day 23 and ataxia was also recorded for two males and one female on Day 27. One female treated with 650 mg/kg bw/day had a damaged tail recorded between Days 26 and 29. No clinically observable signs of toxicity were detected in animals of either sex treated with 30 mg/kg bw/day. There were no treatment-related changes in the behavioural parameters or in sensory reactivity. There was no toxicologically relevant changes in functional performance. There were no treatment related effects detected on body weight development. There were no adverse effects related to treatment on food consumption or food conversion efficiency. There was no adverse difference recorded for water consumption. No toxicologically significant effects were detected in the hematological parameters at the end of the treatment period. In blood chemical parameters males treated with 650 mg/kg bw/day showed an increase in total cholesterol and bile acids concentration. There were no toxicologically significant effects were detected in females treated at 650 mg/kg bw/day or in males or females below this dose level. There were no treatment-related macroscopic abnormalities detected. Males treated with 650 mg/kg bw/day showed an increase in liver and thyroid weights, both absolute and relative to terminal body weight. No such effects were observed in females and no effects were observed in males or females at 30 or 300 mg/kg bw/day. In the histopathology assessment no effects were observed at 30 or 300 mg/kg bw/day. At the high dose of 650 mg/kg bw/day in males: in the Liver there was centrilobular hepatocellular hypertrophy and increased hepatocellular glycogen content and in the Thyroid there was increased incidence and severity of follicular hypertrophy. The oral (gavage) administration of the test item to males/females at dose levels of 30, 300 or 650 mg/kg bw/day resulted in treatment related effects in males at 650 mg/kg bw/day including centrilobular hepatocellular hypertrophy of the liver and increased incidence and severity of follicular hypertrophy of the thyroid which was considered adaptive in nature. No adverse effects were evident at 300 or 30 mg/kg bw/day. Under the conditions of this study, the No-Observed-Adverse-Effect-Level (NOAEL) was regarded to be 650 mg/kg/day for males/females.

Justification for classification or non-classification

The substance does not meet classification criteria under Regulation (EC) No 1272/2008 for specific organ toxicity repeated exposure (STOT-RE).

Since there was no reported significant effects relevant to humans reported at guidance related levels (ORAL ≤ 300 mg/kg bw/day) then there is no requirement to classify STOT-RE.

References:

1. ECHA Guidance on Application on the CLP Criteria, (v5.0, July 2017), Section 3.9.2 : Table 3.16 - Equivalent guidance values for 28-day and 90-day studies