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Repeated dose toxicity: oral

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Administrative data

Endpoint:
sub-chronic toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2019-20
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
Per ECHA decision on Compliance Check (Decision number: CCH-D-2114381478-36-01/F). See attachemnet.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2020

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)
Version / remarks:
“Repeated Dose 90-Day Oral Toxicity Study in Rodents” adopted on June 25, 2018.

Deviations:
no
GLP compliance:
yes (incl. QA statement)
Limit test:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
2,2-dimethylpropan-1-ol, tribromo derivative
EC Number:
253-057-0
EC Name:
2,2-dimethylpropan-1-ol, tribromo derivative
Cas Number:
36483-57-5
Molecular formula:
C5H9Br3O
IUPAC Name:
3-bromo-2,2-bis(bromomethyl)propan-1-ol
Constituent 2
Reference substance name:
Tribromoneopentyl alcohol
IUPAC Name:
Tribromoneopentyl alcohol
Test material form:
solid: flakes
Details on test material:
Test substance FR-513.
Test substance identity (including alternative names) FR-513, Trinol or Tribromoneopentyl alcohol.
Chemical name Tribromoneopentyl alcohol.
Intended use Flame retardant.
Appearance White/off-white flakes.
Storage conditions Ambient temperature.
Supplier Sponsor.
Batch number (Sample ID) 2119-72-01 (from Certificate of Analysis).
Expiry date 10 January 2017 (from Certificate of Analysis).
Purity 97%
Specific details on test material used for the study:
See COA attachment

Test animals

Species:
rat
Strain:
Sprague-Dawley
Details on species / strain selection:
Justification for the selection of species: Rat is the standard laboratory rodent species used for toxicity assessment and also recommended by various regulatory authorities.

Source: Vivo Bio Tech Ltd.
Sy. #349/A, Pregnapur-502311,
Gajwel Mandal, Medak District, Telangana
India
Sex:
male/female
Details on test animals or test system and environmental conditions:
Age at the start of treatment : 5-6 weeks
Body weight range at the start of treatment: Males: 155.54 to 204.99g
Females: 126.13 to 169.98g
At the commencement of the treatment, the weight variation of rats used did not exceed ± 20% of the mean body weight in each sex and group.

After detailed clinical examination for good health and the suitability for the study, the rats were acclimatized for five days before start of the treatment.
During acclimatization period, all rats were observed once daily for clinical signs, morbidity and mortality. Only nulliparous and non-pregnant females were used
in the study.

Environmental Conditions
The rats were housed under standard laboratory conditions, air conditioned with adequate fresh air supply (12.6–12.8 air changes/hour). Environment: Temperature 19–25°C, relative humidity 49–68 %, with 12 hours light and 12 hours dark cycle.
The maximum and minimum temperature in the experimental room was recorded once daily. The relative humidity in the experimental room was calculated daily from dry and wet bulb temperature recordings.

Housing
Two rats per sex per cage were housed in solid floor standard polysulfone cages (Size: L 425 x B 266 x H 185 mm), with stainless steel top grill having facilities for providing pelleted food and drinking water in polycarbonate bottle with stainless steel sipper tubes. The last animal in the recovery groups was housed individually.
Polycarbonate rat huts were provided to the animals from first day of acclimatization as environmental enrichment objects in the cages that either provide shelter or exercising opportunities to minimize animal stress and promote overall well-being.

Bedding
Steam sterilized clean corn cob was used as bedding and changed along with the cage twice a week.

Diet and Water
Altromin Rat/Mice Maintenance diets manufactured by Altromin Spezialfutter GmbH & Co. KG, Im Seelenkamp 20, 32791 Lage, Germany, was provided ad libitum to the rats.

Deep bore-well water passed through activated charcoal filter and exposed to UV rays in Aquaguard® on-line water filter-cum-purifier manufactured by Eureka Forbes Ltd., Mumbai - 400 001, India, was provided ad libitum to rats in polycarbonate bottles with stainless steel sipper tubes.

Administration / exposure

Route of administration:
oral: gavage
Details on route of administration:
Route of test item administration was through oral gavage. The oral route was chosen because it will provide an exaggerated model of possible exposure in humans. The oral route is also an acceptable and standard method for administering test substances in toxicology studies, and is a standard method as per the Guidelines (OECD 408).
Vehicle:
corn oil
Remarks:
The corn oil was used as the vehicle to prepare the dose formulations in the previously conducted toxicity studies with the test item by the Sponsor (Envigo Study Number: AFH0038). Hence, the same was selected as vehicle to prepare the dose formulations.
Details on oral exposure:
The dose formulations were administered orally by gavage to a specific group of rats once daily at approximately the same time (± 3 hours) each day for a period of 90 consecutive days. Similarly, the vehicle was administered to rats in the vehicle control and vehicle control recovery group once orally for 90 consecutive days.
The vehicle and the dose formulations were not administered to the rats in the recovery groups for four weeks (i.e. 28 Days) following the 90 day treatment period.
The dose formulation and the vehicle were administered at an equivolume of 5 mL/kg body weight. The dose volume was calculated for individual animal on the first day of the treatment period and was adjusted according to the most recent body weights recorded during the treatment period.

A table summarizing the Experimental Design, Group Allocation and Number of Rats is shown in the appropriate section.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
The stability and homogeneity of the test item in the vehicle was established at 1 and 250 mg/mL under Eurofins Advinus Study No. G18488 (attached). Based on the results, the test item was found to be resuspendable and
stable in the vehicle up to 15 days when stored at room temperature.
For homogeneity and test item concentration analysis, prepared formulation samples were sampled on Day 1, during month 2 (Day 33) and month 3 (Day 74) of the treatment period and analysed in-house.
Two replicates were drawn from the top, middle and bottom layers of each preparation and in case of the control, a single replication sample was drawn from the middle layer.
The analysis was done as per the method validated under Eurofins Advinus Study No.: G18448.
Dose formulations were considered acceptable as the overall mean (calculated using all the 6 replicate values) of all the layers and mean of each layer was within ± 20% of the claimed concentration and the relative standard deviation (% RSD, calculated using all the 6 replicate values) of assay of top, middle and bottom layers were less than 20%.
Duration of treatment / exposure:
Tribromoneopentyl Alcohol was administered orally by gavage for 90 consecutive days and to assess the reversibility of any effects following 28 days recovery period.
Frequency of treatment:
once daily
Doses / concentrationsopen allclose all
Dose / conc.:
50 mg/kg bw/day (actual dose received)
Remarks:
Low dose (G2)
Dose / conc.:
150 mg/kg bw/day (actual dose received)
Remarks:
mid dose (G3)
Dose / conc.:
450 mg/kg bw/day (actual dose received)
Remarks:
High dose (G4)
Dose / conc.:
450 mg/kg bw/day (actual dose received)
Remarks:
Recovery group (G4R)
Dose / conc.:
0 mg/kg bw/day (actual dose received)
Remarks:
Vehicle control (G1)
Dose / conc.:
0 mg/kg bw/day (actual dose received)
Remarks:
Recovery Vehicle control (G1R)
No. of animals per sex per dose:
Main groups: 10 males + 10 females
Recovery groups: 5 males + 5 females

Total number of rats: 100 (50 males + 50 females)



Control animals:
yes, concurrent vehicle
Details on study design:
The test item was suspended in vehicle (Corn Oil) and administered to rats at the graduated dose levels of 50, 150, and 450 mg/kg bwt/day for low dose (G2), mid dose (G3) and high dose (G4)/high dose recovery (G4R) group rats, respectively. The rats in the vehicle control group (G1)/vehicle control recovery (G1R) groups received vehicle alone. The dose volume administered was 5 mL/kg body weight. Each main group in the experiment comprised of 10 males and 10 female rats and recovery groups comprised of 5 males and 5 female rats.

Each rat in the experiment was observed for clinical signs, mortality and morbidity. Ophthalmological examination was carried out for all the rats prior to start of treatment, at the end of treatment for main groups and at the end of recovery period for recovery groups. The body weights and food consumption were measured during in-life phase of the experiment. Neurological examinations were conducted towards the end of treatment for main groups and towards the end of recovery period for recovery groups. The clinical laboratory investigations such as haematology, coagulation, clinical chemistry, hormone analysis and urine analysis were performed at termination.
All rats in the experiment were subjected to detailed necropsy and the organ weights and their ratio were derived as percentage of fasting body weights and brain weights. Histopathological examination was carried out on all the preserved organs and tissues of vehicle control (G1) and high dose (G4) group rats and on all gross lesions. Kidneys, urinary bladder and stomach were examined from the lower dose (G2 and G3) and recovery (G1R and G4R) groups.

Examinations

Observations and examinations performed and frequency:
Each rat in the experiment was observed for clinical signs, mortality and morbidity. Ophthalmological examination was carried out for all the rats prior to start of
treatment, at the end of treatment for main groups and at the end of recovery period for recovery groups. The body weights and food consumption were measured during in-life phase of the experiment. Neurological examinations were conducted towards the end of treatment for main groups and towards the end of recovery period for recovery groups. The clinical laboratory investigations such as haematology, coagulation, clinical chemistry, hormone analysis and urine analysis were performed at termination.
Sacrifice and pathology:
All rats in the experiment were subjected to detailed necropsy and the organ weights and their ratio were derived as percentage of fasting body weights and brain weights. Histopathological examination was carried out on all the preserved organs and tissues of vehicle control (G1) and high dose (G4) group rats and on all gross lesions. Kidneys, urinary bladder and stomach were examined from the lower dose (G2 and G3) and recovery (G1R and G4R) groups.
Other examinations:
Sperm parameters
Terminal fasting body weight
T3, T4,TSH
Statistics:
STATISTICAL ANALYSIS
Data captured using Provantis™ for the parameters body weight, organ weights, haematology, coagulation, clinical chemistry and terminal fasting body weight were analyzed using Provantis™ built-in statistical tests.
Derived data like net body weight change, food consumption and organ weight ratios were also analyzed using built-in statistical tests.
The data from the treatment groups (G2, G3 & G4) were compared with the vehicle control group (G1).
In case of recovery groups, data was also analysed using the methods stated above. Comparison of means between treatment recovery group and control recovery groups were performed.
The statistical analysis of the experimental data which were not collected using ProvantisTM, was carried out using the validated package in Excel and also using licensed copies of SYSTAT Statistical package ver.12.0.
All quantitative variables like neurological observations (neuromuscular observation/body temperature/body weights) and T3, T4, TSH data were tested for normality (Shapiro-Wilk test) and homogeneity of variances (Levene’s test) within the group before performing a one-factor ANOVA modeling by treatment groups. Non-optimal (non-normal or heteroschedastic) data was transformed, before performing ANOVA. Comparison of means between treatment groups and control group was done using Dunnett’s test when the overall treatment, ‘F’ test found to be significant.
The data pertaining to males and female rats were evaluated separately.
All analyses and comparisons were evaluated at the p<0.05. Statistically significant differences (p<0.05), indicated by the aforementioned tests were designated by the following symbols throughout the report:
*: Significantly different from the control group at p<0.05 level.

Results and discussion

Results of examinations

Clinical signs:
effects observed, treatment-related
Description (incidence and severity):
No clinical signs of toxicity were observed at 50 mg/ kg bwt/day in either sex.
The treatment related clinical sign of perinium wet with urine was observed in both males and females at 450 mg/kg bwt/day from treatment Day 57. By the end of the treatment period, this clinical sign was observed in 9/10 males and 7/10 female rats of main group and 4/5 male and 3/5 female rats of recovery group. This sign was persisted in few high dose recovery animals during first week of the recovery period and all the recovery group animals became normal during subsequent week (week 2) of the recovery period.
The clinical sign of perinum wet with urine was also observed in one male and female rat on Day 91 at 150 mg/kg bwt/day.
Mortality:
no mortality observed
Body weight and weight changes:
effects observed, non-treatment-related
Description (incidence and severity):
A significantly higher body weight gain was observed during Days 15-22 and 36-43 and Total % weight gain in main group males tested at 50 mg/kg bwt/day and significantly lower body weight gain was observed during Days 15-22 and 78-85 in recovery group males tested at 450 mg/kg bwt/day.
These significant differences were considered incidental and toxicologically not relevant as the mean body weights at these respective periods were comparable to vehicle the control group. Thus, the treatment had no effects on body weights at all the doses tested in males and females.
Food consumption and compound intake (if feeding study):
effects observed, non-treatment-related
Description (incidence and severity):
Males:
A significantly lower food consumption was observed during Days 36-43 at 50 mg/kg bwt/day, during Days 36-43 and 43-50 in recovery group tested at 450 mg/kg bwt/day.
A significantly higher food consumption was observed during Days 50-57, 71-78 at 450 mg/kg bwt/day and during Days 85-90 in the main groups tested at all the doses.
Females:
A significantly lower food consumption was observed during Days 15-22 and 36-43 at 50 mg/kg bwt/day, during Days 50-57 at 450 mg/kg bwt/day and overall mean food consumption during Days 1-90 at 450 mg/kg bwt/day recovery group.
The above significant increase/decrease in the food consumption observed at different intervals during treatment period were considered to be toxicologically not relevant because of isolated occurrence, lack of dose correlation and/or body weights were unaffected.
Thus, the treatment did not affect the body weights or food consumption in males and females either during treatment or recovery periods at the doses tested.
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
no effects observed
Description (incidence and severity):
Ophthalmological examination carried out prior to start of treatment, at the end of the treatment and recovery periods did not reveal any abnormalities in the eyes of the experimental rats.
Haematological findings:
no effects observed
Description (incidence and severity):
Haematology, Coagulation and Clinical Chemistry
There were no test item related changes in Haematology, PT and APTT in males and females.
An increase in Blood Urea Nitrogen at 450 mg/kg bwt/day and creatinine at ≥150 mg/kg/day in males was considered as test item related. This increase was associated with microscopic findings of increased eosinophilic droplets in the tubular epithelium consisting tubular casts in kidneys. These findings reversed at the end of recovery period.
All the other variations were considered as incidental findings as either the values were within the normal biological range or there was no dose relation.
Clinical biochemistry findings:
no effects observed
Description (incidence and severity):
See description above.
Urinalysis findings:
no effects observed
Description (incidence and severity):
The urinalysis parameters were not affected by test item administration.
Behaviour (functional findings):
no effects observed
Description (incidence and severity):
Home cage and Handling observations:
None of the evaluated parameters shows any abnormal findings except a treatment-related sign of perinium wet with urine in 6/10 males and 7/10 females at 450 mg/ kg bwt/day during handling observations.

Open field observations:
No treatment-related abnormalities were observed in any of the doses tested in both sexes.
Sensory observations: No treatment-related abnormalities were observed in any of the groups in both sexes.

Motor Activity: No treatment-related abnormalities were observed in any of the doses tested in both sexes except for few incidences as mentioned below:
Higher:
• Ambulatory time at interval 3 and total Ambulatory time in the main group males tested at 150 and 450 mg/kg bwt/day.
• Ambulatory Time at all intervals, Total Ambulatory time, Horizontal Counts at all intervals, Total Horizontal Counts, Ambulatory Count at interval 2 and interval 3 and Total Ambulatory Counts in the recovery group males tested at 450 mg/kg bwt/day.
• Ambulatory Time at interval 1 in the recovery group females tested at 450 mg/kg bwt/day.
Lower:
• Ambulatory time at interval 1 and Total Ambulatory time in the main group females tested at 450 mg/kg bwt/day.
The above observed statistical variations in the motor activity measurements are considered to be incidental as there were no changes observed in the home cage or open field observations. Further there were no clinical signs observed during daily clinical observations.
Neuromuscular observation:

Landing hind limb footsplay:
No treatment-related changes were observed at all the tested doses in both sexes except an incidental finding of reduced hindlimb footsplay in 450 mg/kg bwt/day recovery dose group males. This change was considered incidental as there were no associated changes in the muscle tone, gait, posture and hind limb grip strength.

Grip strength:
No treatment-related changes were observed at all the tested doses in both sexes except an incidence of higher forelimb grip strength in females treated at 450 mg/kg bwt/day, which was considered incidental and not related to the treatment. (Mean of G4 Females: 1087.30, Historical Control Data Low: 924.0 and High: 1139.0)

Physiological observation:
Body temperature: No significant changes were observed at all the tested doses in both sexes.

Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Description (incidence and severity):
There were no test item related changes in the organ weights and their ratios to body weights and brain weights.
Gross pathological findings:
no effects observed
Description (incidence and severity):
There were no test item related gross lesions at all the doses tested.
Neuropathological findings:
no effects observed
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Description (incidence and severity):
Test item related microscopic changes were noted in kidneys and urinary bladder in males.
In kidneys, increased eosinophilic droplets were noted in the tubular epithelium in the cortex of 6 males treated at 150 mg/kg bwt/day and all males treated at 450 mg/kg bwt/day but not in females. A single incidence of papillary necrosis was also observed at 450 mg/kg bwt/day males and considered as test item related. Diffuse epithelial hyperplasia was noted in urinary bladder of 6 males at 150 mg/kg bwt/day and all males and one female at 450 mg/kg bwt/day.
Both these changes reversed at the end of recovery period.

All the other microscopic changes noted were considered as spontaneous/back ground findings common for this age group rats.
Histopathological findings: neoplastic:
no effects observed
Other effects:
no effects observed
Details on results:
• Oestrous cycle evaluation : The stage of oestrous cycle was recorded prior to necropsy in the treated groups only to facilitate interpretation of ovary and uterus organ weight and histopathology. No intergroup difference were observed in either parameter.

• Hormone Analysis : There were no test item related changes in T3, T4 and TSH.

• Sperm Parareters: There were no significant intergroup differences in any of the sperm parameters evaluated

• Terminal Fasting Body Weight Organ Weight: The terminal fasting body weights were not affected by test item administration.

Effect levels

open allclose all
Key result
Dose descriptor:
NOAEL
Effect level:
50 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male
Basis for effect level:
gross pathology
Key result
Dose descriptor:
NOAEL
Effect level:
150 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
female
Basis for effect level:
gross pathology

Target system / organ toxicity

Key result
Critical effects observed:
yes
Lowest effective dose / conc.:
50 mg/kg bw/day (actual dose received)
System:
urinary
Organ:
bladder
kidney
Treatment related:
yes
Dose response relationship:
yes
Relevant for humans:
no

Applicant's summary and conclusion

Conclusions:
The daily oral gavage administration of Tribromoneopentyl alcohol for 90 days to Sprague Dawley rats at 50, 150 and 450 mg/kg bwt/day resulted in no mortalities up to the highest dose over the 90-day dosing period. The body weights, body weight gains and food consumption were not altered by the treatment at any of the doses tested in either sex. Neurobehavioural observations of all the tested groups were comparable to the vehicle control group. There were no treatment-related changes observed in haematology, coagulation parameters, thyroid hormone levels, urine parameters, sperm analysis and there were no gross pathological changes observed in at any of the doses tested.
The clinical signs of perineum wet with urine was observed in both males and females at 150 and 450 mg/kg bwt/day. At 150 mg/kg bwt/day in males, a increase in creatinine correlated with increased eosinophilic droplets in tubular epithelium in kidneys and urinary bladder epithelial hyperplasia were considered as test item related changes. At 450 mg/kg bwt/day in males, a minimal increase in blood urea nitrogen and creatinine with morphological correlates in kidneys and urinary bladder was observed. In kidneys, increased eosinophilic droplets in tubular epithelium and one animal with papillary necrosis were noted. In all males and only one female, diffuse epithelial hyperplasia was present in urinary bladder. All these changes reversed at the end of 28 day recovery period.

No Observed Adverse Effect Level (NOAEL): Based on the above findings, treatment did not cause any adverse effects at 50 mg/kg bwt/day in males and at 150 mg/kg bwt/day in females during the 90 days treatment period. Hence, 50 mg/kg bwt/day in males and 150 mg/kg bwt/day in females are considered to be No Observed Adverse Effect Level (NOAEL) for the test item Tribromoneopentyl Alcohol, under the test conditions and doses employed.
Executive summary:

The purpose of this repeat dose (90-day) oral toxicity study was to assess the systemic toxicity potential of the test item, Tribromoneopentyl Alcoholin Sprague-Dawley rats when administered orally by gavage for 90 consecutive daysand to assess the reversibilityof any effects following 28days recovery period. This study was also intended to provide the information on major toxic effects, target organs and an estimation of a No Observed Adverse Effect Level (NOAEL).

The test item was suspended in vehicle (Corn Oil) and administered to rats at the graduated dose levels of 50, 150, and 450 mg/kg bwt/day for low dose (G2), mid dose (G3) and high dose (G4)/high dose recovery (G4R) group rats, respectively. The rats in the vehicle control group (G1)/vehicle control recovery (G1R) groups received vehicle alone. The dose volume administered was 5 mL/kg body weight. Each main group in the experiment comprised of 10 males and 10 female rats and recovery groups comprised of 5 males and 5 female rats.

The identity of Tribromoneopentyl Alcohol was provided by the study Sponsor by a Certificate of Analysis. The stability and homogeneity of the test item in the vehicle was established at 1 and 250 mg/mL under Eurofins Advinus Study No. G18488. Based on the results, the test item was found to be resuspendable and stable in the vehicle up to 15 days when stored at room temperature. The dose formulations were analysed for homogeneity and test item concentration on Day 1 and during month 2 (Day 33) and month 3 (Day 74) of the treatment period. The results indicated that the dose formulations were considered acceptable as the overall mean (calculated using all the 6 replicate values) of all the layers and mean of each layer was ≤8% of the claimed concentration and the relative standard deviation (% RSD, calculated using all the 6 replicate values) of assay of top, middle and bottom layers was ≤ 2.037%, against the target limit of ±20%.

Each rat in the experiment was observed for clinical signs, mortality and morbidity. Ophthalmological examination was carried out for all the rats prior to start of treatment, at the end of treatment for main groups and at the end of recovery period for recovery groups. The body weights and food consumption were measured during in-life phase of the experiment. Neurological examinations were conducted towards the end of treatment for main groups and towards the end of recovery period for recovery groups. The clinical laboratory investigations such as haematology, coagulation, clinical chemistry, hormone analysis and urine analysis were performed at termination.

All rats in the experiment were subjected to detailed necropsy and the organ weights and their ratio were derived as percentage of fasting body weights and brain weights. Histopathological examination was carried out on all the preserved organs and tissues of vehicle control (G1) and high dose (G4) group rats and on all gross lesions. Kidneys, urinary bladder and stomach were examined from the lower dose (G2 and G3) and recovery (G1R and G4R) groups.

Under the experimental conditions employed, the following results were obtained:

·        Clinical Signs, Mortalities and Ophthalmological Examination:There were no clinical signs or mortality observed at 50 and 150 mg/kg bwt/day dose levels tested in both sexes except an incidence of perineum wet with urine in a male and female on Day 91. Treatment related clinical signs of perineum wet with urine was observed in both males and females at 450 mg/kg bwt/day and it could be due to the changes in epithelial cells in the urinary bladder.

·        Ophthalmological examination did not reveal any ocular abnormalities.

·        Neurological Findings:No treatment-related neurological abnormalities were observed at any of the doses tested

·        Body Weights, Body Weight Gains and Food Consumption:The body weights and food consumption were unaffected by the treatment at all the tested doses in both the sexes.The percentage difference of mean body weights in the treatment groups was within -6.1 to +11.8 from the respective control group during the treatment period.The percentage difference of average food consumption in the treatment groups was within -3.2 to +3.2 from the respective control group during treatment period.

·        Haematology, Coagulation, Clinical Chemistry, Hormone Analysis and Urine Parameters:There were no test item related changes in Haematology, PT and APTT in males and females.An increase in Blood Urea Nitrogen at 450 mg/kg bwt/day and creatinine at ≥150 mg/kg/day in males was considered as test item related. These increases were associated with microscopic findings of increased eosinophilic droplets in the tubular epithelium in kidneys. These findings reversed at the end of recovery period.

·        There were no test item related changes in T3, T4 and TSH.

·        The urinalysis parameters were not affected by test item administration.

·        Sperm Parameters: There were no significant intergroup differences in sperm motility, sperm morphology and sperm counts evaluated.

·        Terminal Fasting Body Weight, Organ Weights and Organ Weight Ratios:The terminal fasting body weights were not affected by test item administration. There were no test item related changes in the organ weights and their ratios to body weights and brain weights.

·        Gross and Histopathology:There were no test item related gross lesions at all the doses tested.An isolated incidence of dilated uterus one each in 50 and 450 mg /kg bwt/day dose group female was observed and considered as incidental finding and not related to test item administration.At 450 mg/kg bwt/day dosed males, increased eosinophilic droplets in tubular epithelium, tubular basophilia and papillary necrosis were noted in kidneys. In both males and females, diffuse epithelial hyperplasia was present in urinary bladder.At 150 mg/kg bwt/day, increased eosinophilic droplets in tubular epithelium in kidneys and urinary bladder epithelial hyperplasia were considered as test item related in males.

          All these changes reversed at the end of 28 day recovery period.

Based on the above findings, treatment did not cause any adverse effects at 50 mg/kg bwt/day in males and at 150 mg/kg bwt/day in females during the 90 days treatment period. Hence, 50 mg/kg bwt/day in males and 150 mg/kg bwt/day in females are considered to be No Observed Adverse Effect Level (NOAEL) for the test item Tribromoneopentyl Alcohol, under the test conditions and doses employed.