(+)-neomenthol

Endpoint summary

Description of key information

Repeated dose oral:

NOAEL was considered to be 600 mg/kg bw when treated with test material orally. Thus, comparing this value with the criteria of CLP regulation (+)-neomenthol is likely to be not classify as repeated dose oral toxicity.

Repeated dose inhalation toxicity:

According to Annex IX of the REACH regulation, testing by the inhalation route is appropriate only if exposure of humans via inhalation is likely. Taking into account the low vapour pressure of the substance Reaction mass of (+)-neomenthol (CAS no 2216-52-6), which is reported as 7.67E-03 mm Hg at 25 C. Thus, exposure to inhalable dust, mist and vapour of the chemical Reaction mass of (+)-neomenthol is highly unlikely. Therefore this study is considered for waiver.  

Repeated dose dermal toxicity:

In accordance with coloumn 2 of Annex IX, this end point was considered for waiver since the acute toxicity by the dermal route has already been provided in section 7.2.3 (as part of the Annex VIII information requirements)

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: oral

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Remarks:

Experimental data of read across substances

Justification for type of information:

Weight of evidence approach based on structurally similar chemicals

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

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

Principles of method if other than guideline:

WoE- based on two repeated dose oral toxicity study1 Repeated dose oral toxicity study was performed to determine the toxic nature of the test chemical2. To assess toxicological profile of test chemical to determine target organ of toxicity, its reversibility and No Observed Adverse Effect Level (NOAEL) in the rat after 28 consecutive days of oral administration.

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

other: 1. I.I.Sc., 2, Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

1. TEST ANIMALS- Source: No data- Age at study initiation: 3-4 months old- Weight at study initiation: 160-180 g- Fasting period before study: No data- Housing: Rats were housed in groups of 6 animals per cage- Diet (e.g. ad libitum): Ad libitum- Water (e.g. ad libitum): No data- Acclimation period: No dataENVIRONMENTAL CONDITIONS- Temperature (°C): No data- Humidity (%):No data- Air changes (per hr): No data- Photoperiod (hrs dark / hrs light): No data2. TEST ANIMALS- Source:National Institute of Biosciences, Pune- Females (if applicable) nulliparous and non-pregnant:[yes- Age at study initiation:6 to 8 weeks- Weight at study initiation: Male - 173.58 g (= 100 %), Female - 153.64 g (= 100 %)- Fasting period before study:- Housing: The rats were housed in polycarbonate cages with paddy as bedding.After allocation to respective dose groups rats were housed 2/sex/cage.- Temperature (°C): 22 ± 3°C- Humidity (%): 30% to 70%- Air changes (per hr): The animal room was independently provided with at least ten air changes per hour of 100% fresh air that has been passed through the HEPA filters- Photoperiod (hrs dark / hrs light): An artificial light and dark cycle of 12 hours each was provided to theroomIN-LIFE DATES:From: 12-12-2017To: 19-03-2018- Diet (e.g. ad libitum): Rodent feed, ad libitum- Water (e.g. ad libitum): Water was provided ad libitum from individual bottles attached to the cages.Water was from a local source and passed through the reverse osmosis membrane before use- Acclimation period: 5 daysDETAILS OF FOOD AND WATER QUALITY: There were no known contaminants, which were reasonably expected to be in the dietary materials and water capable of interfering with the conduct of this study.ENVIRONMENTAL CONDITIONS

Route of administration:

oral: gavage

Vehicle:

other: 1. methylcellulose, 2. corn oil

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

1. 3 days2. 28 days

Frequency of treatment:

Daily

Remarks:

1.0 or 600 mg/Kg/day

Remarks:

2. 0, 250, 500 and 1000 mg/kg bw

No. of animals per sex per dose:

2.Total: 720 mg/kg bw: 6 male, 6 female250 mg/kg bw: 6 male, 6 female500 mg/kg bw: 6 male, 6 female1000 mg/kg bw: 6 male, 6 femaleReversal group500 mg/kg bw: 6 male, 6 female1000 mg/kg bw: 6 male, 6 female

Control animals:

yes, concurrent vehicle

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes- Time schedule:twice daily- Cage side observations checked in table [No.?] were included.: Viability observed.DETAILED CLINICAL OBSERVATIONS: Yes- Time schedule:once dailyBODY WEIGHT: Yes- Time schedule for examinations: Body weights were recorded on the day of randomization, day of first dosing, weekly thereafter and a fasting body weight at scheduled sacrifice on day 29 and day 43.FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kgbody weight/day: Yes- Compound intake calculated as time-weighted averages from the consumption and body weight gaindata: YesFOOD EFFICIENCY:- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weightedaverages from the consumption and body weight gain data: Not specifiedWATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes / No / Not specified- Time schedule for examinations:OPHTHALMOSCOPIC EXAMINATION: Yes- Time schedule for examinations:The eyes of all the animals were examined prior to the initiation of the dosing and at scheduled sacrifice. Eye examination was carried out by using a HEINE mini 2000 ophthalmoscope were employed for evaluation after the induction of mydriasis with 1% solution of tro picamide sulfate.- Dose groups that were examined: All 72 animalsHAEMATOLOGY: Yes- Time schedule for collection of blood: At the end of dosing period on day 29 and at termination of recovery period on day 43.- Anaesthetic used for blood collection: No- Animals fasted: Yes- How many animals: All 72 animals- Parameters checked in table [No.?] were examined.: Hb (Hemoglobin (g/dL)), RBC (Red Blood Corpuscles (x 106 /μL)), HCT (Hematocrit (%)), MCV (Mean Corpuscular Volume (fL)), MCH (Mean Corpuscular Hemoglobin (pg)), MCHC (Mean Corpuscular Hemoglobin Concentration (g/dL)), Platelets (x 103 /μL), WBC (White Blood Corpuscles (x 103 /μL)), Rt.(Reticulocytes (%)), N (Neutrophils (%)), L (Lymphocytes (%)), E (Eosinophils (%)), M (Monocytes (%)), B (Basophil (%)) and Pt. (Prothrombin time (sec.)) were examined.CLINICAL CHEMISTRY: Yes- Time schedule for collection of blood: At the end of dosing period on day 29 and at termination of recovery period on day 43.- Animals fasted: Yes- How many animals:All 72 animals- Parameters checked in table [No.?] were examined.: Total Protein (g/dL), Blood Urea Nitrogen (mg/ dL), Urea Nitrogen (mg/dL) Calculated, ALT : Alanine Aminotransferase (U/L), AST, Aspartate Aminotransferase (U/L), ALP : Alkaline Phosphatase (U/L), GGT : Gamma Glutamyl Transferase (U/L), Glucose (mg/dL), Calcium (mmol/L), Phosphorous (mg/dL), Albumin (g/dL), Total Bilirubin (mg/dL), Creatinine (mmol/L), Total Cholesterol (mg/dL), Triglycerides (mg/dL), Globulin (g/dL) Calculated, Sodium (mmol/L), Potassium (mmol/L), Chloride (mmol/L) andBile acid (μmol/L) were examined.URINALYSIS: Yes- Time schedule for collection of urine: During the last week of dosing period and on reversal group rats attermination of recovery period on day 43.- Metabolism cages used for collection of urine: Yes- Animals fasted: Not specified- Parameters checked in table [No.?] were examined.: Volume , Appearance, Colour, pH , Specific Gravity, Proteins, Glucose, Ketones,Bilirubin, Urobililogen, Occult Blood and Nitrite were examined.NEUROBEHAVIOURAL EXAMINATION: Yes- Time schedule for examinations: Towards the end of the exposure period of 28 days and towards the end of the recovery period on day 42, sensory reactivity to stimuli of different types (e.g. auditory, visual and proprioceptive stimuli) assessment of grip strength and motor activity assessment were conducted for all the animals- Dose groups that were examined: All 72 animals- Battery of functions tested: sensory activity / grip strength / motor activity / other:Arousal level, Sensory Activity, Visual Placing Response, Air righting response, Grip Strength, Motor Activity,IMMUNOLOGY: Not specified- Time schedule for examinations:Not specified- How many animals:Not specified- Dose groups that were examined:Not specified- Parameters checked in table [No.?] were examined.Not specifiedOTHER: Organ Weights were examined.

Sacrifice and pathology:

2. GROSS PATHOLOGY: Yes, All the rats surviving at the end of the treatment were sacrificed and gross l esions were noted.HISTOPATHOLOGY: Yes, From each rat, samples or the whole of the tissues listed below were preserved. All tissues were fixed in 10% neutral buffered formalin except, eyes and testes of all animals were preserved in Davidson’s solution for 24 hours and transferred to 10% neutral buffered formalin. Procedure for preparation of slides of tissues of various organs from the rats of various dose groups were performed as per the standard operating procedures of Indian Institute of Toxicology, Pune. Following tissue samples of organs from control and animals treated at different dose groups were preser ved and those from control and treated at the highest dose level of 1000 mg/kg were subjected to histopathological examination.Adrenals, Aorta, Brain (cerebrum, cerebellum and pons), Caecum, Cervix, Colon, Duodenum, Epididymides, Eyes, Heart, Ileum, Jejunum, Kidneys, Liver, Lungs, Mesenteric Lymphnodes, Muscles - Skeletalmuscle, Oesophagus, Ovaries, Pancreas, Pharyngeal Lymphnodes, Pituitary, Prostate, Rectum, Sciatic Nerve, Seminal Vesicles with coagulation gland, Skin with Mammary Gland, Spleen, Spinal Cord (Cervical, mid thoracic and lumbar), Sternum with bone marrow, Stomach, Testes, Thymus, Trachea, Thyroid / Parathyroid, Urinary Bladder, Uterus, Vagina.

Other examinations:

1. Enzyme assay: Microsomes were prepared from liver and kidneys by a differential centrifugation method. Cytochromes P-450 and b5, NAD(P)H-cytochrome c reductase activities, heme content {estimated at 557 nm as the pyridine ferrochromogen), protein, SGPT, glucose-6-phosphatase and aminopyrine Ndemethylase were determined

Statistics:

1. All statistical analyses were performed using Student's t-test and levels of significance determined at P < 0.052. Raw data was processed and analyzed for reporting group means and standard deviations with significance between the controls and treated groups, using SYSTAT 13 validated statistical software supplied by Starcom Information Technology Limited, Bangalore developed by Systat Software, Inc. USA. All the parameters characterized by continuous data such as body weight, feed consumption (calculated as gram per animal), organ weight, relative organ weight, haematological and clinical chemistry data were subjected to Bartlett’s test to meet the homogeneity of variance before conducting Analysis of Variance(ANOVA) and Dunnett’s t-test. Where the data does not meet the homogeneity of variance, Student’s ttest were performed to calculate significance.Significance was calculated at 5% level and indicated in the summary tables as follows:* = Significant than control at 95% level of confidence (p<0.05).

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

2. Male -Group I (Control, 0 mg/kg): No clinical signs of toxicity were observed in the animals throughout the dosing period of 28 days (animal nos.1 to 6).Group II (Control, 0 mg/kg, Reversal): No clinical signs of toxicity were observed in the animals throughout the dosing period of 28 days and during the post-dosing recovery period (animal nos.13 to 18).Group III (250 mg/kg): No clinical signs of toxicity were observed in the animals throughout the dosing period of 28 days (animal nos.25 to 30).Group IV (500 mg/kg): No clinical signs of toxicity were observed in the animals throughout the dosing period of 28 days (animal nos.37 to 42).Group V (1000 mg/kg): Polyurea was observed in animals (animal nos. 49, 51 to 54, with onset from day 23) during the dosing period of 28 days.Group VI (1000 mg/kg, Reversal): Polyurea was observed in animals (animal nos. 61, 63 to 65, with onset from day 23) throughout the dosing period of 28 days and during the post-dosing recovery period (upto day 32).Female -Group I (Control, 0 mg/kg): No clinical signs of toxicity were observed in the animals throughout the dosing period of 28 days (animal nos.7 to 12).Group II (Control, 0 mg/kg, Reversal): No clinical signs of toxicity were observed in the animals through out the dosing period of 28 days and during the post-dosing recovery period (animal nos.19 to 24).Group III (250 mg/kg): No clinical signs of toxicity were observed in the animals throughout the dosing period of 28 days (animal nos.31 to 36).Group IV (500 mg/kg): No clinical signs of toxicity were observed in the animals throughout the dosing period of 28 days (animal nos.43 to 48).Group V (1000 mg/kg): Polyurea was observed in all animals (animal nos. 55 to 60, with onset from day 22) during the dosing period of 28 days.Group VI (1000 mg/kg, Reversal): Polyurea was observed in all animals (animal nos.67 to 72, with onset from day 22) throughout the dosing period of 28 days and during the post-dosing recovery period (upto day 32).

Mortality:

no mortality observed

Description (incidence):

2. All animals from control and different dose groups survived throughout the dosing period of 28 days and the post-dosing recovery period of 14 days.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

2. Male -Reduced body weight gain of 14.94% was observed in male animals from 1000 mg/kg dose group.All male animals from control, 250 mg/kg, 500 mg/kg and 1000 mg/kg reversal dose groups exhibited normal body weight gain throughout the dosing period of 28 days and the recovery period of 14 days.Female -Female animals from control, 250 mg/kg, 500 mg/kg and 1000 mg/kg dose groups exhibited normal body weight gain throughout the dosing period of 28 days.Reduced body weight gain of 11.36% was observed in female animals from 1000 mg/kg reversal group.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

2. Male and Female -Animals from control and different dose groups exhibited normal feed consumption at the end of the dosing period of 28 days.Animals from control reversal and high reversal dose groups exhibited normal feed consumption at the end of the recovery period of 14 days.

Food efficiency:

not specified

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

not specified

Ophthalmological findings:

no effects observed

Description (incidence and severity):

No ocular abnormalities were observed on ophthalmological examination in the animals during pre-exposure and at the end of the respective termination.

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

2. Male :Total RBC and HCT: Decreased levels were observed in animals from 1000 mg/kg reversal dose group, sacrificed on day 43 (p<0.05).Female :Hb and HCT: Decreased values were obtained for animals from 500 mg/kg dose group, sacrificed on day 29 (p<0.05) and Total RBC: Decreased values were obtained for animals from 250 mg/kg and 500 mg/kg dose groups, sacrificed on day 29 (p<0.05).

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

2. Male :Globulin: Elevated levels were observed in animals from 250 mg/kg dose group, sacrificed on day 29 (p< 0.05),BUN and Urea Nitrogen: Decreased levels were observed in animals from 250 mg/kg dose group, sacrificed on day 29 (p<0.05) and Calcium : Decreased levels were observed in animals from 1000 mg/kg reversal dose group, sacrificed on day 43 (p<0.05).Female :BUN and Urea Nitrogen: Decreased levels were observed in animals from 500 mg/kg dose group, sacrificed on day 29 (p<0.05),Alanine Aminotransferase : Decreased levels were observed in animals from 250 mg/kg and 500 mg/kg dose groups, sacrificed on day 29 (p<0.05),Alkaline Phosphatase: Decreased levels were observed in animals from 250 mg/kg dose group, sacrificed on day 29 (p<0.05) and Bile Acid : Elevated levels were observed in animals from 1000 mg/kg reversal dose group, sacrificed on day 43 (p<0.05).

Urinalysis findings:

effects observed, non-treatment-related

Description (incidence and severity):

2. Urine analysis conducted on male animals during 4th and 6th week of study period (on day 23, 24 and 43), revealed no abnormality attributable to the treatment.Urine analysis conducted on female animals during 4th week of study period (on day 24 and 26), revealed higher volume of urine from 1000 mg/kg dose group (p<0.05). Urine analysis conducted on female animals during 6th week of study period (on day 43) revealed no abnormality attributable to the treatment.

Behaviour (functional findings):

no effects observed

Description (incidence and severity):

2. Sensory Reactivity Observations:All animals from control and different dose groups showed normal arousal level, visual response, touch response, auditory response, tail pinch response and visual placing response. Normal air righting reflex was observed in all animals from control and different dose groups in week 4. Grip Strength:Grip strength values observed in male and female animals for control and different dose groups were comparable.Motor Activity:Motor activity values observed in male and female animals for control and different dose groups were comparable.

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

effects observed, non-treatment-related

Description (incidence and severity):

Male -In comparison with controls at the end of dosing on day 29, organ weight data of animals from 1000 mg/kg dose group revealed increased relative weights of brain (p<0.05). Increased relative weights of liver and kidneys (p<0.05) were observed in animals from 500 mg/kg and 1000 mg/kg dose groups. Increased relative weights of spleen (p<0.05) was observed in animals from 250 mg/kg and 1000 mg/kg dose groups. Increased relative weights of thymus (p<0.05) was observed in animals from 250 mg/kg dose group.In comparison with controls at the end of post-dosing recovery period on day 43, organ weight data of animals from 1000 mg/kg reversal group was found to be comparable.Female -In comparison with controls at the end of dosing on day 29, organ weight data of animals from 1000 mg/ kg dose group revealed increased relative weights of liver (p<0.05). Increased relative weights of kidneys (p<0.05) was observed in animals from 500 mg/kg and 1000 mg/kg dose groups. In addition, decreased r elative weights of heart (p<0.05) was observed in animals from 500 mg/kg dose group. In comparison with controls at the end of post-dosing recovery period on day 43, organ weight data of animals from 1000 mg/kg reversal group revealed increased relative weights of brain, liver, kidneys, spleenand uterus (p<0.05).Although significant changes in the values of organ weight were observed in male and female animals from 250 mg/kg and 500 mg/kg dose groups, no related gross pathological and histopathological findings were seen, hence these findings were considered to be of no toxicological importance.

Gross pathological findings:

no effects observed

Description (incidence and severity):

Gross pathological examination on male and female animals from control and different dose groups did not reveal any abnormality.

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

2. Histopathological examination revealed focal to diffuse, minimal to moderate tubular dilatation in kidneys in male (1/6) and female (6/6) animals from 1000 mg/kg dose group, in male (1/6) and female (6/6) ani mals from 500 mg/kg dose group and in male (0/6) and female (5/6) animals from 250 mg/kg dose groupand in female (1/6) from 1000 mg/kg reversal dose group.Focal to multifocal, minimal mononuclear cells infiltration was observed in kidneys in male (1/6) and female (3/6) animals from 1000 mg/kg dose group and in female animals from 250 mg/kg (2/6) and 500 mg/kg (2/6) dose groups.

Histopathological findings: neoplastic:

not specified

Other effects:

effects observed, non-treatment-related

Description (incidence and severity):

Oral administration of menthone (600 mg/kg per day), for 3 days resulted in a marginal increase (≈13%) in hepatic cytochrome P-450 without affecting cytochrome b5 levels.

Dose descriptor:

NOAEL

Effect level:

600 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male

Basis for effect level:

body weight and weight gain

clinical biochemistry

clinical signs

food consumption and compound intake

gross pathology

haematology

histopathology: non-neoplastic

mortality

ophthalmological examination

organ weights and organ / body weight ratios

urinalysis

other: hepatic cytochrome P-450

Remarks on result:

other: No effect observed

Critical effects observed:

not specified

System:

other: not specified

Organ:

not specified

Treatment related:

not specified

Dose response relationship:

not specified

Relevant for humans:

not specified

Conclusions:

NOAEL was considered to be 600 mg/kg bw when treated with test material orally.

Executive summary:

Data available for the test chemicals was reviewed to determine the toxic nature of (+)-Neomenthol (CAS no 2216-52-6). The studies are as mentioned below: 

Study 1:

Repeated dose oral toxicity study was performed to determine the toxic nature of the test chemical. The study was performed using male rats. The test chemical was dissolved in 1% methyl cellulose and use at dose level of 0 or 600 mg/kg/day. Microsomes were prepared from liver and kidneys by a differential centrifugation method. Cytochromes P-450 and b5, NAD (P)H-cytochrome c reductase activities, heme content {estimated at 557 nm as the pyridine ferrochromogen), protein, SGPT, glucose-6-phosphatase and aminopyrine N-demethylase were determined. Oral administration at 600 mg/kg per day, for 3 days resulted in a marginal increase (≈13%) in hepatic cytochrome P-450 without affecting cytochrome b5 levels. However, the hepatic cytochrome P-450 system was not affected due to test chemical treatment. Based on the observations made, the No observed adverse effect level (NOAEL) for the test chemical is considered to be 600 mg/Kg/day.

Study 2:

In a repeated dose oral toxicity study, Sprague-Dawley male and female rats were treated with test chemical in the concentration of 0, 250, 500 and 1000 mg/kg bw orally by gavage for 28 days. All the male and female animals from control and different dose groups up to 1000 mg/kg survived throughout the dosing period of 28 days and the recovery period of 14 days. At the end of the dosing period reduced body weight gain of 14.94% was observed in male animals from 1000 mg/kg dose group. All the male animals from control, 250, 500 and 1000 mg/kg reversal dose groups exhibited normal body weight gain throughout the dosing period of 28 days and the recovery period of 14 days. Female animals from control, 250, 500 and 1000 mg/kg dose groups exhibited normal body weight gain throughout the dosing period of 28 days. Reduced body weight gain of 11.36% was observed in female animals from 1000 mg/kg reversal group. Feed intake of animals from control and different dose groups was found to be comparable throughout the dosing period of 28 days and the recovery period of 14 days. Ophthalmoscopic examination, conducted prior to and at the end of dosing period on animals from control and different dose groups did not reveal any abnormality. No signs of toxicity were observed in male and female animals from 250 and 500 mg/kg dose groups during the dosing period of 28 days. Polyurea was observed in male and female animals from 1000 mg/kg and 1000 mg/kg reversal dose groups during the dosing period of 28 days and the recovery period of 14 days. Similarly, Detailed clinical observations conducted at weekly interval (upto 6thweek) did not reveal any abnormality in all male and female animals from control and different dose groups during the dosing period of 28 days and the recovery period of 14 days. Towards the end of the exposure period in week 4, functional observation battery such as sensory reactivity to stimuli of different types (e.g. auditory, visual and proprioceptive stimuli), Grip strength and Motor activity values revealed no abnormalities attributable to the treatment. No statistically significant changes in the values of various Haematological parameters were at the end of the dosing period on day 29. At the end of the recovery period on day 43, statistically significant decrease in the values of Total RBC and HCT at 1000 mg/kg in male. Statistically significant decrease in the values of Hb and HCT at 500 mg/kg and Total RBC at 250 and 500 mg/kg were observed in female rat. At the end of the recovery period on day 43, no statistically significant changes in the values of various parameters in female rats. The decrease in the values of various parameters was marginal and within the normal biological and laboratory limits. Clinical biochemistry analysis at the end of the dosing period on day 29, revealed statistically significant increase in the values of Globulin at 250 mg/kg in male rat. In addition statistically significant decrease was observed in the values of BUN and Urea Nitrogen at 250 mg/kg in male, BUN and Urea Nitrogen at 500 mg/kg in female rat, Alanine Aminotransferase at 250 and 500 mg/kg in female and Alkaline Phosphatase at 250 mg/kg in female rat. At the end of the recovery period on day 43 (Reversal groups) statistically significant increase was observed in the values of Bile Acid at 1000 mg/kg in female and statistically significant decrease was observed in the values of Calcium at 1000 mg/kg in male. The increase/decrease in the values of various parameters was marginal and within the normal biological and laboratory limits. Urine analysis conducted on male animals during 4thand 6thweek of study period (on day 23, 24 and 43), revealed no abnormality attributable to the treatment. Urine analysis conducted on female animals during 4thweek of study period (on day 24 and 26), higher volume of urine was observed in female at 1000 mg/kg dose group. During 6th week of study period (on day 43) revealed no abnormality attributable to the treatment. At termination of dosing on day 29, male animals from 1000 mg/kg dose group revealed increased relative weights of brain. In addition, increased relative weights of liver and kidneys were observed in male at 500 and 1000 mg/kg dose groups when compared with that of controls. Increased relative weights of spleen were observed in male at 250 and 1000 mg/kg as compared to controls. Increased relative weights of thymus were observed in male at 250 mg/kg as compared to controls. No effect on male organ weight sacrificed on day 43 from 1000 mg/kg as comparable to controls. At termination of dosing on day 29, at 1000 mg/kg increased relative weights of liver were observed in female as compared to controls. In addition, increased relative weights of kidneys were observed in female at 500 and 1000 mg/kg as compared to controls. At 500 mg/kg dose decreased relative weights of heart in female rats as compared to controls. Organ weight data of female animals sacrificed on day 43 at 1000 mg/kg increased relative weights of brain, liver, kidneys, spleen and uterus were observed in female as compared to controls. Although significant changes in the values of organ weight of brain, liver, spleen, thymus, heart and uterus were observed in male and female animals at 250 mg/kg and 500 mg/kg dose groups, no related gross pathological and histopathological findings were seen, hence these findings were considered to be of no toxicological importance. Gross pathological examination did not reveal any abnormality attributable to the treatment. Histopathological examination revealed focal to diffuse, minimal to moderate tubular dilatation in kidneys in male (1/6) and female (6/6) animals from 1000 mg/kg dose group, in male (1/6) and female (6/6) animals from 500 mg/kg dose group and in male (0/6) and female (5/6) animals from 250 mg/kg dose group and in female (1/6) from 1000 mg/kg reversal dose group. Focal to multifocal, minimal mononuclear cells infiltration was observed in kidneys in male (1/6) and female (3/6) animals from 1000 mg/kg dose group and in female animals from 250 mg/kg (2/6) and 500 mg/kg (2/6) dose groups. All histopathological the changes observed in male animals were reversible during the recovery period of 14 days. The histopathological changes observed in female animals were evident in reversal group one animal, during the recovery period of 14 days. Therefore, No Observed Adverse Effect Level (NOAEL) of test chemical in the Sprague Dawley rat via oral route, over a period of 28 days was found to be 250 mg/kg body weight in male animals and less than 250 mg/kg body weight in female animals.

Data available for the read across chemicals was reviewed to determine the repeated dose oral toxicity of (+)-neomenthol. NOAEL was considered to be 600 mg/kg bw when treated with test material orally. Thus, comparing this value with the criteria of CLP regulation (+)-neomenthol is likely to be not classify as repeated dose oral toxicity.

Endpoint conclusion

Endpoint conclusion:

no study available

Dose descriptor:

NOAEL

600 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

Data is Klimisch 2 and from publication

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Endpoint:

repeated dose toxicity: inhalation, other

Data waiving:

other justification

Justification for data waiving:

other:

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

Link to relevant study records

Reference

Endpoint:

repeated dose toxicity: dermal, other

Data waiving:

other justification

Justification for data waiving:

other:

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:

Data available for the test chemicals was reviewed to determine the toxic nature of (+)-Neomenthol (CAS no 2216-52-6). The studies are as mentioned below: 

Study 1:

Repeated dose oral toxicity study was performed to determine the toxic nature of the test chemical. The study was performed using male rats. The test chemical was dissolved in 1% methyl cellulose and use at dose level of 0 or 600 mg/kg/day. Microsomes were prepared from liver and kidneys by a differential centrifugation method. Cytochromes P-450 and b5, NAD (P)H-cytochrome c reductase activities, heme content {estimated at 557 nm as the pyridine ferrochromogen), protein, SGPT, glucose-6-phosphatase and aminopyrine N-demethylase were determined. Oral administration at 600 mg/kg per day, for 3 days resulted in a marginal increase (≈13%) in hepatic cytochrome P-450 without affecting cytochrome b5 levels. However, the hepatic cytochrome P-450 system was not affected due to test chemical treatment. Based on the observations made, the No observed adverse effect level (NOAEL) for the test chemical is considered to be 600 mg/Kg/day.

Study 2:

In a repeated dose oral toxicity study, Sprague-Dawley male and female rats were treated with test chemical in the concentration of 0, 250, 500 and 1000 mg/kg bw orally by gavage for 28 days. All the male and female animals from control and different dose groups up to 1000 mg/kg survived throughout the dosing period of 28 days and the recovery period of 14 days. At the end of the dosing period reduced body weight gain of 14.94% was observed in male animals from 1000 mg/kg dose group. All the male animals from control, 250, 500 and 1000 mg/kg reversal dose groups exhibited normal body weight gain throughout the dosing period of 28 days and the recovery period of 14 days. Female animals from control, 250, 500 and 1000 mg/kg dose groups exhibited normal body weight gain throughout the dosing period of 28 days. Reduced body weight gain of 11.36% was observed in female animals from 1000 mg/kg reversal group. Feed intake of animals from control and different dose groups was found to be comparable throughout the dosing period of 28 days and the recovery period of 14 days. Ophthalmoscopic examination, conducted prior to and at the end of dosing period on animals from control and different dose groups did not reveal any abnormality. No signs of toxicity were observed in male and female animals from 250 and 500 mg/kg dose groups during the dosing period of 28 days. Polyurea was observed in male and female animals from 1000 mg/kg and 1000 mg/kg reversal dose groups during the dosing period of 28 days and the recovery period of 14 days. Similarly, Detailed clinical observations conducted at weekly interval (upto 6thweek) did not reveal any abnormality in all male and female animals from control and different dose groups during the dosing period of 28 days and the recovery period of 14 days. Towards the end of the exposure period in week 4, functional observation battery such as sensory reactivity to stimuli of different types (e.g. auditory, visual and proprioceptive stimuli), Grip strength and Motor activity values revealed no abnormalities attributable to the treatment. No statistically significant changes in the values of various Haematological parameters were at the end of the dosing period on day 29. At the end of the recovery period on day 43, statistically significant decrease in the values of Total RBC and HCT at 1000 mg/kg in male. Statistically significant decrease in the values of Hb and HCT at 500 mg/kg and Total RBC at 250 and 500 mg/kg were observed in female rat. At the end of the recovery period on day 43, no statistically significant changes in the values of various parameters in female rats. The decrease in the values of various parameters was marginal and within the normal biological and laboratory limits. Clinical biochemistry analysis at the end of the dosing period on day 29, revealed statistically significant increase in the values of Globulin at 250 mg/kg in male rat. In addition statistically significant decrease was observed in the values of BUN and Urea Nitrogen at 250 mg/kg in male, BUN and Urea Nitrogen at 500 mg/kg in female rat, Alanine Aminotransferase at 250 and 500 mg/kg in female and Alkaline Phosphatase at 250 mg/kg in female rat. At the end of the recovery period on day 43 (Reversal groups) statistically significant increase was observed in the values of Bile Acid at 1000 mg/kg in female and statistically significant decrease was observed in the values of Calcium at 1000 mg/kg in male. The increase/decrease in the values of various parameters was marginal and within the normal biological and laboratory limits. Urine analysis conducted on male animals during 4thand 6thweek of study period (on day 23, 24 and 43), revealed no abnormality attributable to the treatment. Urine analysis conducted on female animals during 4thweek of study period (on day 24 and 26), higher volume of urine was observed in female at 1000 mg/kg dose group. During 6th week of study period (on day 43) revealed no abnormality attributable to the treatment. At termination of dosing on day 29, male animals from 1000 mg/kg dose group revealed increased relative weights of brain. In addition, increased relative weights of liver and kidneys were observed in male at 500 and 1000 mg/kg dose groups when compared with that of controls. Increased relative weights of spleen were observed in male at 250 and 1000 mg/kg as compared to controls. Increased relative weights of thymus were observed in male at 250 mg/kg as compared to controls. No effect on male organ weight sacrificed on day 43 from 1000 mg/kg as comparable to controls. At termination of dosing on day 29, at 1000 mg/kg increased relative weights of liver were observed in female as compared to controls. In addition, increased relative weights of kidneys were observed in female at 500 and 1000 mg/kg as compared to controls. At 500 mg/kg dose decreased relative weights of heart in female rats as compared to controls. Organ weight data of female animals sacrificed on day 43 at 1000 mg/kg increased relative weights of brain, liver, kidneys, spleen and uterus were observed in female as compared to controls. Although significant changes in the values of organ weight of brain, liver, spleen, thymus, heart and uterus were observed in male and female animals at 250 mg/kg and 500 mg/kg dose groups, no related gross pathological and histopathological findings were seen, hence these findings were considered to be of no toxicological importance. Gross pathological examination did not reveal any abnormality attributable to the treatment. Histopathological examination revealed focal to diffuse, minimal to moderate tubular dilatation in kidneys in male (1/6) and female (6/6) animals from 1000 mg/kg dose group, in male (1/6) and female (6/6) animals from 500 mg/kg dose group and in male (0/6) and female (5/6) animals from 250 mg/kg dose group and in female (1/6) from 1000 mg/kg reversal dose group. Focal to multifocal, minimal mononuclear cells infiltration was observed in kidneys in male (1/6) and female (3/6) animals from 1000 mg/kg dose group and in female animals from 250 mg/kg (2/6) and 500 mg/kg (2/6) dose groups. All histopathological the changes observed in male animals were reversible during the recovery period of 14 days. The histopathological changes observed in female animals were evident in reversal group one animal, during the recovery period of 14 days. Therefore, No Observed Adverse Effect Level (NOAEL) of test chemical in the Sprague Dawley rat via oral route, over a period of 28 days was found to be 250 mg/kg body weight in male animals and less than 250 mg/kg body weight in female animals.

Data available for the read across chemicals was reviewed to determine the repeated dose oral toxicity of (+)-neomenthol. NOAEL was considered to be 600 mg/kg bw when treated with test material orally. Thus, comparing this value with the criteria of CLP regulation (+)-neomenthol is likely to be not classify as repeated dose oral toxicity.

Repeated dose inhalation toxicity:

According to Annex IX of the REACH regulation, testing by the inhalation route is appropriate only if exposure of humans via inhalation is likely. Taking into account the low vapour pressure of the substance Reaction mass of (+)-neomenthol (CAS no 2216-52-6), which is reported as 7.67E-03 mm Hg at 25 C. Thus, exposure to inhalable dust, mist and vapour of the chemical Reaction mass of (+)-neomenthol is highly unlikely. Therefore this study is considered for waiver.  

Repeated dose dermal toxicity:

In accordance with coloumn 2 of Annex IX, this end point was considered for waiver since the acute toxicity by the dermal route has already been provided in section 7.2.3 (as part of the Annex VIII information requirements)

Justification for classification or non-classification

Based on the data available for the read across chemicals was reviewed to determine the repeated dose oral toxicity of (+)-neomenthol. Thus, comparing this with the criteria of CLP regulation (+)-neomenthol is likely to be not classify as repeated dose oral, dermal and inhalation toxicity.