N,N-dimethyl-p-toluidine

Endpoint summary

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

repeated dose toxicity: oral

Remarks:

combined repeated dose and carcinogenicity

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Qualifier:

according to guideline

Guideline:

other:

Principles of method if other than guideline:

Combined repeated dose & carcinogenicity studies of N, N-Dimethyl-p-Toluidine in F344/N rats by oral route.

GLP compliance:

not specified

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Taconic Farms, Inc. (Germantown, NY)

- Age at study initiation: 6 to 7 weeks

- Weight at study initiation: No data available

- Fasting period before study: No data available

- Housing:
Animal were housed in Polycarbonate (Lab Products, Inc., Seaford, DE), changed weekly (male rat) or twice weekly, bedded on irradiated Sani-Chips (P.J. Murphy Forest Products Corp., Montville, NY), changed weekly (male rat) or twice weekly. Spun-bonded polyester. Cage Filters (Snow Filtration Co., Cincinnati, OH) were changed every 2 weeks and Stainless steel Racks (Lab Products, Seaford, DE) changed and rotated every 2 weeks and animals were identified by tail tattoo in a controlled environment.

- Diet (e.g. ad libitum):
Irradiated NTP-2000 wafer feed (Zeigler Brothers, Inc., Gardners, PA), changed weekly, available ad libitum.

- Water (e.g. ad libitum):
Tap water (Columbus municipal supply) via automatic watering system (Edstrom Industries, Waterford, WI), available ad libitum.

- Acclimation period: 13 days for males and 14 days for females

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22.2° ± 3° C

- Humidity (%): 50% ± 15%

- Air changes (per hr): 10/hour

- Photoperiod (hrs dark / hrs light): Room fluorescent light were available for 12 hours/day


IN-LIFE DATES:
From:
Male: October 20, 2004
Female : October 21, 2004
To:
Male: October 17, 2006
Female: October 19, 2006

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

Details on oral exposure
PREPARATION OF DOSING SOLUTIONS: Dose preperation were prepared by adding the appropriate amount of N, N-dimethyl-p-toluidine to 2.5 ml of corn oil to achieve the desired concentration of 0, 6, 20 and 60 mg/kg.

DIET PREPARATION
- Rate of preparation of diet (frequency): No data available

- Mixing appropriate amounts with (Type of food): No data available

- Storage temperature of food: No data available

VEHICLE
- Justification for use and choice of vehicle (if other than water): No data available

- Concentration in vehicle: 0, 6, 20 and 60 mg/kg

- Amount of vehicle (if gavage): 2.5 ml of corn oil.

- Lot/batch no. (if required): 050404,
Obtained in multiple lots from Spectrum Chemicals and Laboratory Products (Gardena, CA).

- Purity: No data available

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Periodic analyses of the dose preparation and 1.0 mg/ml formulation in corn oil were done by the study laboratory using GC/FID. Dose preparation were also analyzed at every 3 months, animal room samples were also analyzed. Stability was confirmed for up to 44 days for preparations. Preparations were stored in amber glass containers sealed with Teflon®-lined lids, protected from light, at up to room temperature and for at least 3 hours under simulated animal room conditions.

Duration of treatment / exposure:

104 weeks for male and 105 weeks for female (2 years)

Frequency of treatment:

5 days/week

Remarks:

Doses / Concentrations:
0, 6, 20 and 60 mg/kg
Basis:

No. of animals per sex per dose:

Total: 420
Control: 50 male,50 female
6 mg/kg: 50 male,50 female
20 mg/kg: 50 male,50 female
60 mg/kg: 50 male,50 female
Clinical pathology study: 10 male and 10 female rats

Control animals:

yes, concurrent vehicle

Details on study design:

Details on study design
- Dose selection rationale:
Based on mortality in the 1,000 mg/kg groups, decreased (more than 10%) final mean body weights in the 125, 250, and 500 mg/kg male groups and treatment related nonneoplastic lesions in the liver, nose, spleen, kidney and bone marrow with increased severity at 125 mg/kg or greater.on the basis of above rationales a high dose of 60 mg/kg N,N-dimethyl-p-toluidine was selected. The low dose of 6 mg/kg was selected because this dose was reported to cause toxicity in humans. The doses selected for study in rats were 0, 6, 20, and 60 mg/kg , with a threefold dose spacing.

- Rationale for animal assignment (if not random): Animals were distributed randomly into groups of approximately equal initial mean body weights.

- Rationale for selecting satellite groups: No data available

- Post-exposure recovery period in satellite groups: No data available

- Section schedule rationale (if not random): No data available

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: No data available

- Time schedule: No data available

- Cage side observations checked in table [No.?] were included.: No data available

DETAILED CLINICAL OBSERVATIONS: Yes

- Time schedule: Clinical findings were recorded every 4 weeks beginning with week 5 and at the end of the study termination.

BODY WEIGHT: Yes

- Time schedule for examinations: Body weights were recorded on day 1, weekly for the first 13 weeks, every 4 weeks thereafter and at terminal sacrifice.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): No data available

- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No data available

- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No data available

FOOD EFFICIENCY:
- 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: No data available

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data available

- Time schedule for examinations: No data available

OPHTHALMOSCOPIC EXAMINATION: No data available

- Time schedule for examinations: No data available

- Dose groups that were examined: No data available

HAEMATOLOGY: Yes

- Time schedule for collection of blood:
On 86, 88 day (hemoglobin and methemoglobin) and at the end of study termination.

- Anaesthetic used for blood collection: Yes, anesthetization with a CO2/O2 mixture.

- Animals fasted: No data available

- How many animals:
Total: 80
0 mg/kg/bw/day: 10 male,10 female
6 mg/kg/bw/day: 10 male,10 female
20 mg/kg/bw/day: 10 male,10 female
60 mg/kg/bw/day: 10 male,10 female

- Parameters checked in table [No.?] were examined.
Hematocrit, hemoglobin and methemoglobin concentrations, erythrocyte, reticulocyte, platelet and Heinz body counts, mean cell volume, mean cell hemoglobin, mean cell hemoglobin concentration and leukocyte count and differentials were examined.

CLINICAL CHEMISTRY: No data available

- Time schedule for collection of blood: No data available

- Animals fasted: No data available

- How many animals: No data available

- Parameters checked in table [No.?] were examined.: No data available

URINALYSIS: No data available

- Time schedule for collection of urine: No data available

- Metabolism cages used for collection of urine: No data available

- Animals fasted: No data available

- Parameters checked in table [No.?] were examined.: No data available

NEUROBEHAVIOURAL EXAMINATION: No data available

- Time schedule for examinations: No data available

- Dose groups that were examined: No data available

- Battery of functions tested: sensory activity / grip strength / motor activity / other: No data available

OTHER:
Survival: Yes,
Survival of rats of control, 6, 20 and 60 mg/kg dose group were observed

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
Gross lesions and tissue masses were observed in control. 6, 20 and 60 mg/kg dose group.

Organ examined:
Adrenal gland, bone (including marrow), brain, clitoral gland, esophagus, eye, gallbladder, harderian gland, heart (including aorta), large intestine (cecum, colon, and rectum), small intestine (duodenum, jejunum, and ileum), kidney, liver, lung (and mainstem bronchi), lymph nodes (mandibular and mesenteric), mammary gland, nose, ovary, pancreas, parathyroid gland, pituitary gland, preputial gland, prostate gland, salivary gland, skin, spleen, stomach (forestomach and glandular), testis (with epididymis and seminal vesicle), thymus, thyroid gland, trachea, urinary bladder, uterus, and Zymbal’s gland (male rats) were examined .

HISTOPATHOLOGY: Yes,
Incidences of mononuclear cell leukemia and neoplasms and nonneoplastic lesions were observed in control, 6,20 and 60 mg/kg/bw/day dose group.

Organ examined:
Adrenal gland, bone (including marrow), brain, clitoral gland, esophagus, eye, gallbladder, Harderian gland, heart (including aorta), large intestine (cecum, colon, and rectum), small intestine (duodenum, jejunum, and ileum), kidney, liver, lung (and mainstem bronchi), lymph nodes (mandibular and mesenteric), mammary gland, nose, ovary, pancreas, parathyroid gland, pituitary gland, preputial gland, prostate gland, salivary gland, skin, spleen, stomach (forestomach and glandular), testis (with epididymis and seminal vesicle), thymus, thyroid gland, trachea, urinary bladder, uterus, and Zymbal’s gland (male rats) were examined .

Other examinations:

Survival Analyses: Analysis of survival was estimated by the product-limit procedure of Kaplan and Meier . Statistical analyses for possible dose related effects on survival were analyzed by useing Cox’s method for testing two groups for equality and Tarone’s life table test to identify dose related trends. All reported P values for the survival analyses are two sided.

Statistics:

Analysis of Neoplasm and Nonneoplastic Lesion Incidences: The Poly-k test was used to analyzed neoplasm and nonneoplastic lesion. A value of k=3 was usedin the analysis of site-specific lesions. Continuity corrected Poly-3 tests were used in the analysis of lesion incidence and reported P values are one sided. Thesignificance of lower incidences or decreasing trends in lesions is represented as 1–P with the letter N added (e.g., P=0.99 is presented as P=0.01N). Body weight were analyszed by multiple comparison procedures of Dunnett and Williams.
Hematology, clinical chemistry, spermatid and epididymal spermatozoal were analyzed by using the nonparametric multiple comparison methods of Shirley and Dunn. Jonckheere’s test was used to analyszed by the significance of the dose related trends and to determine whether a trend sensitive test (Williams’ or Shirley’s test) was more appropriate for pairwise comparisons than a test that does not assume a monotonic dose related trend (Dunnett’s or Dunn’s test).
Females in each dosed group were compared to the control group using the Fisher exact test. Tests for extended periods of estrus, diestrus, metestrus and proestrus as well as skipped estrus and skipped diestrus were constructed based on a Markov chain model proposed by Girard and Sager. For each dose group, a transition probability matrix was estimated for transitions among the proestrus, estrus, metestrus and diestrus stages with provision for extended stays within each stage as well as for skipping estrus or diestrus within a cycle. Equality of transition matrices among dose groups and between the control group and each dosed group was tested by using chi-square statistics.

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

effects observed, treatment-related

Details on results:

Clinical signs and mortality: Mortality: Survival of male rat was significantly less than the vehicle controls in 60 mg/kg dose group.
Clinical signs: Pallor in 60 mg/kg in females and hyperactivity and boxing behavior in 20 mg/kg females and 60 mg/kg males and females rat were observed.
Boxing behavior, characterized by “kangaroo boxing” between cage mate pairs was observed in 20 mg/kg females and 60 mg/kg males and females rats.

Body weight and weight gain: Mean body weights of male rat (after 61 weeks) were 10% less than vehicle controls and mean body weights of females rat (after 33 weeks) were less than vehicle controls when treated with 60 mg/kg .

Haematology: Decreased in hematocrit and erthrocytes in male rat and hemoglobin and MCHC in male and female rat were observed and Increases in reticulocytes, methemoglobin, methamoglobin hemoglobin in male rat and Heinz bodies in male and female rat were obsarved in 60 mg/kg/bw/day dose group.
Decrased in hematocrit, hemoglobin, erythrocytes and MCHC and inceased in reticulocytes, MCV, methemoglobin, methamoglobin hemoglobin and Heize bobies were observed in 20 mg/kg male and female rat.
Increased in reticulocytes, methemoglobin, methamoglobin hemoglobin and decrased in hemoglob in male and female rat and MCV,MCHC and Heinz bodies were observed in 6 mg/kg in female rat.

Gross pathology: Liver: Enlarged hepatocytes were observed in 60 mg/kg. Eosinophilic hepatocytes, multilocular cystic structures that often contained flocculent eosinophilic material were observed in 20 and 60 mg/kg.
Nose:
Small exophytic masses that arose from the transitional epithelium lining the nasotur binates or the lateral wall between the maxilloturbinate, lightly granular eosinophilic cytoplasm and basophilic to amphophilic nucleoli were observed in 6 and 60 mg/kg dose group.
Nests of cells surrounded and separated by a delicate fibrovascular stroma were observed in 60 mg/kg.
Increased numbers of transitional epithelium cells lining the lateral wall and less frequently the nasoturbinate, decreased cellularity and disorganization of the transitional epithelium, hyperplasia , increased number of submucosal glands in the lateral wall region, disorganization of the olfactory epithelium with increased intercellular spaces and vacuolization or apoptosis of individual cells , presence of increased numbers of glands, glands in the olfactory region lined by ciliated cuboidal to columnar epithelium were observed in 60 mg/kg
Increased numbers of respiratory epithelial cells, hyaline droplet accumulation consisted of brightly eosinophilic droplets or globules within the cytoplasm of the epithelial cells were observed in 20 and 60 mg/kg/day.

Thyroid Gland:
Follicular cell neoplasms, well circumscribed expansile mass that caused compression of the adjacent parenchyma and contained papillary infoldings of epithelial cells were observed in 20 and 60 mg/kg.

Hematopoietic System (Spleen, Bone Marrow and Mes-enteric Lymph Node):
Spleen :Erythrocytes distending the sinusoids of the red pulp, hematopoietic cell proliferation consisted of minimal to moderate increases in the number of erythroid and myeloid precursors, megakaryotes, scattered throughout the red pulp, pigmentation consisted of dark brown granules,hemosiderin, within macrophages, atrophy of the lymphoid follicle,thickening of the capsule by fibrous connective tissue and small numbers of mononuclear cells were observed In 6 and 60 mg/kg.
Bone Marrow: Expansion due to increased numbers of hematopoietic cells with a concomitant decrease in marrow adipose tissue were observed in 20 and 60 mg/kg.
Mesenteric lymph node: Increased number of histiocytes (macrophages) within the lymph node, usually within the medullary sinuses were observed in 20 and 60 mg/kg.

Kidney: Presence of regenerative cortical tubules with occasionally thickened basement membranes, variable amounts of interstitial connective tissue, and mononuclear cellular infiltrates, accumulation of dark brown granular pigment was observed within cortical epithelial cells. Hyperplasia of the transitional epithelium consisted of proliferations of transitional epithelial cells in papillary or frond like proliferations along renal pelvis were observed in 20 and 60 mg/kg.

Forestomach: Mixed inflammatory infiltrates in the mucosa and submucosa and focal areas of increased layers of squamous epithelium were observed in 20 and 60 mg/kg

Histopathology:Liver : In 60 mg/kg males and females, there were significantly increased in hepatocellular carcinoma and hepatocellular adenoma or hepatocellular carcinoma (combined). Significant increased in eosinophilic focus in all dosed male groups and 20 and 60 mg/kg females, clear cell focus in all dosed female groups and mixed cell focus in 60 mg/kg males and females. Incidences of basophilic focus in all dosed groups of males and 20 and 60 mg/kg females were significantly less than vehicle controls. Incidences of cystic degeneration were significantly increased in 60 mg/kg males and females. In the bile ducts of the liver, fibrosis in 20 and 60 mg/kg/bw/day males and females and hyperplasia in 20 mg/kg males and 6, 20 and 60 mg/kg dosed groups of females were significantly increased.In 20 and 60 mg/kg males and females, significant increased in hepatocellular hypertrophy were observed.In 60 mg/kg females, significant increased in hepatocellular necrosis was observed.

Nose:
Significant increased in transitional epithelium adenoma and transitional epithelium adenoma or carcinoma (combined) in 6, 20 and 60 mg/kg male and in 6 and 60 mg/kg females. Transitional epithelium carcinoma was observed in two 60 mg/kg males. An adenoma of the glands underlying the olfactory epithelium (Bowman’s glands) was observed in 60 mg/kg male. In the transitional epithelium of the nose, the incidences of hyperplasia in 20 and 60 mg/kg males and females were significantly greater than vehicle controls. Degeneration of the transitional epithelium was observed in one 60 mg/kg female rat. In the glands underlying the transitional epithelium, increased hyperplasia was observed in 20 and 60 mg/kg males and females and dilatation in 20 mg/kg males and 60 mg/kg females rat.
In the olfactory epithelium of the nose, significant increased in degeneration, basal cell hyperplasia and respiratory metaplasia in 60 mg/kg males and females rat.
In the glands underlying the olfactory epithelium, hyperplasia, dilatation, metaplasia, and necrosis was observed in 60 mg/kg males and females were oserved and significantly greater than vehicle controls. Two 60 mg/kg/bw/day females found with squamous metaplasia of the olfactory epithelium.
In the respiratory epithelium of the nose, the incidences of hyperplasia were significantly increased in 6, 20 and 60mg/kg dosed groups male and 60 mg/kg females.
In the glands underlying the respiratory epithelium, significant increased in hyperplasia in 6, 20 and 60mg/kg dosed groups male and 20 and 60 mg/kgfemales were observed, dilatation were observed in 20 mg/kg females and 60 mg/kgmales and females and respiratory metaplasia in 6, 20 and 60mg/kg dosed groups of males and females were observed. Significant increased in inflammation of the nose and atrophy of the nerves underlying the olfactory epithelium of 60 mg/kg males and females were observed.

Thyroid Gland:
Increased in follicular cell adenoma or carcinoma (combined) 6, 20 and 60mg/kg dosed groups of males were observed. In 20 mg/kg females, increased in follicular cell adenoma were observed but it is not statistically significant. Highest follicular cell neoplasms were observed in females of 20 mg/kg dose group as compare to control group.

Hematopoietic System (Spleen, Bone Marrow and Mesenteric Lymph Node):
In spleen, significant increased in congestion in 60 mg/kg/bw/day males and in 6, 20 and 60 mg/kg dosed female groups, hematopoietic cell proliferation in 6, 20 and 60mg/kg male and female dosed groups and pigmentation in 6, 20 and 60 mg/kg dosed groups male and 60 mg/kg females were observed. The incidences of lymphoid follicle atrophy were observed in 6 mg/kg males and 60 mg/kg males and females, capsule fibrosis in 60 mg/kg males and females and mesothelial hypertrophy of the capsule in 60 mg/kg males and 6, 20 and 60 mg/kg dosed groups female were significantly greater as compare to vehicle controls. In 60 mg/kg males, significant increased in red pulp atrophy were observed.In bone marrow, significant increased in incidences of hyperplasia were observed in 20 and 60 mg/kg/bw/day males and 60 mg/kg/ females.In the mesenteric lymph node, the incidences of histiocytic cellular infiltrates were observed in 20 and 60 mg/kg male rat.

Kidney:
Significant increased in nephropathy in 6, 20 and 60 mg/kg/bw/day dosed groups female and increases in the severity of the lesion in 6, 20 and 60 mg/kg dosed groups male rat were observed. Pigmentation in 6, 20 and 60 mg/kg/bw/day dosed groups male and 60 mg/kg females were significantly greater than vehicle control groups. In addition, the incidences of hyperplasia of the transitional epithelium of the renal pelvis were significantly increased in 20 mg/kg males and females rat.

Forestomach:
Significant increased in ulcer and hyperplasia was observed in 20 and 60 mg/kg males and inflammation in 60 mg/kg male rat.

Other Organs:
In female rats, uterine stromal polyp and uterine stromal polyp or stromal sarcoma (combined) were increased in 6 and 60 mg/kg dose group. One vaginal polyp in a 6 mg/kg/bw/day female rat was also observed.
In tongue, the incidences of squamous cell papilloma or squamous cell carcinoma (combined) were increased in 6 and 60 mg/kg in males and 60 mg/kg/bw/day in female rat were observed.
In mammary gland in 60 mg/kg/ females, significant decreased in fibro adenoma were observed.

Dose descriptor:

LOAEL

Effect level:

6 other: mg/kg

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Effects observed in Body weight, Survival rates, hematology and histopathology

Critical effects observed:

not specified

Conclusions:

The Low Observd adverse effect level (LOAEL) of N, N-Dimethyl-p-Toluidine in male and female rats was considered to be 6 mg/kg

Executive summary:

In a repeated dose toxicity study, male and femaleF344/Nrats were exposed toN,N-Dimethyl-p-Toluidineby oral gavage in the concentrations of 0, 6, 20 and 60 mg/kg.The results showed a toxic effect observed in several and body weight in 60 mg/kg. In addition, significant histopathological changes were observed in liver, nose, thyroid gland,spleen, bone marrow and mesenteric lymph node, kidney, forestomach,tongue, mammary gland, urinary bladder and uterusand effects inhaematologywas observed in6, 20 and 60 mg/kg dose group males and females when treated withN,N-Dimethyl-p-Toluidine.Therefore, LOAEL is considered to be 6 mg/kg when male and female rats are exposed toN,N-Dimethyl-p-Toluidineby oral gavage on a daily basis.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LOAEL

6 mg/kg bw/day

Study duration:

chronic

Species:

rat

Quality of whole database:

K2 level data from NTP study report

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Endpoint:

repeated dose toxicity: inhalation

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Critical effects observed:

not specified

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

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Critical effects observed:

not specified

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Repeated Dose Toxicity Oral:

Based on studies of target substance CAS NO 99-97-8 reviewed for repeated dose oral toxicity from reliable sources having Klimisch rating 2and considering the WoE approcach.

 The summary of the results are presented below

Sr. No	End point	Value	Species	Route	Effects	Remarks
1	LOAEL	6 mg/kg	rat	Oral	Effects observed in Body weight, Survival rates, hematology and histopathology	Data from study report on target chemical
2	LOAEL	62.5 mg/Kg	Rat	Oral	Effects observed in Body weight, Survival rates, hematology and histopathology	Data from study report on target chemical
3	LOAEL	60 mg/kg	mouse	Oral	Effects observed in Body weight, Clinical signs, organ weight, hematology and histopathology.	Data from study report on target chemical

 

Based on the studies summarized in the above table it can be observed that LOAEL values was found to be in the range of is 6 to 62.5 mg/Kg.. The effects observed on these doses was listed as follows

·        toxic effect observed in several and body weight,significant histopathological changes were observed in liver, nose, thyroid gland,spleen, bone marrow and mesenteric lymph node, kidney, forestomach,tongue, mammary gland, urinary bladder and uterusand effects in haematology

·        toxic changes were observed in liver, kidney, spleen, nose and bone marrow. Effects on organ weight and hematology of male and female were observed. Effect on reproductive performance in estrous cycle was also observed

·        

Thus based on above values and effects it can be concluded that substance CAS NO 99-97-8 is expected to show the toxicological effect. Since low effective dose value (LOAEL) is 6 mg/Kg thus based on this value it can be concluded that substance CAS NO 99-97-8 is considered to be toxic to repeated dose via oral route for the above mentioned dose. based on this value it can be concluded that CAS: 99 -97 -8 is classified as STOT RE 2 category which is the harmized classification of the substance.

Repeated Dose toxicity Inhalation:

In accordance with column 1 of Annex IX, this end point was considered for waiver since the details for acute toxicity by the inhalation route have already been provided as part of the Annex VII requirements of the REACH regulation in section 7.2.3 of this dossier.

Repeated dose toxicity Dermal:

In accordance with column 1 of Annex IX, this end point was considered for waiver since the details for acute toxicity by the dermal route have already been provided as part of the Annex VII requirements of the REACH regulation in section 7.2.3 of this dossier

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
In a repeated dose toxicity study, male and femaleF344/Nrats were exposed toN,N-Dimethyl-p-Toluidineby oral gavage in the concentrations of 0, 6, 20 and 60 mg/kg.The results showed a toxic effect observed in several and body weight in 60 mg/kg. In addition, significant histopathological changes were observed in liver, nose, thyroid gland,spleen, bone marrow and mesenteric lymph node, kidney, forestomach,tongue, mammary gland, urinary bladder and uterusand effects inhaematologywas observed in6, 20 and 60 mg/kg dose group males and females when treated withN,N-Dimethyl-p-Toluidine.Therefore, LOAEL is considered to be 6 mg/kg when male and female rats are exposed toN,N-Dimethyl-p-Toluidineby oral gavage on a daily basis.

Justification for selection of repeated dose toxicity inhalation - systemic effects endpoint:
In accordance with column 1 of Annex IX, this end point was considered for waiver since the details for acute toxicity by the inhalation route have already been provided as part of the Annex VII requirements of the REACH regulation in section 7.2.3 of this dossier

Justification for selection of repeated dose toxicity dermal - systemic effects endpoint:
In accordance with column 1 of Annex IX, this end point was considered for waiver since the details for acute toxicity by the dermal route have already been provided as part of the Annex VII requirements of the REACH regulation in section 7.2.3 of this dossier

Justification for classification or non-classification

According to CLP regulation classification criteria and repeated exposure studies discussed, it is observed that repeated exposure of the test substance showed effects on organs via oral route, it is concluded that the substance N,N-dimethyl-p-toluidine is classified asSTOT RE (repeated exposure) 2.