2-chlorotoluene

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: well documented and scientifically acceptable

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1974

Reference 2

Reference Type:

secondary source

Title:

Unnamed

Year:

1974

Materials and methods

Principles of method if other than guideline:

Four dogs/group were given daily oral doses of 5, 20, or 80 mg/kg bw of o-chlorotoluene (OCT). The control group was given 5% aqueous acacia solution, 0.5 ml/kg. Daily doses were administered for 3 month by capsule. A general observation, body weight changes, hematology, clinical biochemistry, and urinalysis were performed. Organ weights, bone marrrow and hepatic microsomal activity was examined and pathological findings were evaluated.

GLP compliance:

no

Test material

Test material information

1

Reference substance name:

2-chlorotoluene

EC Number:

202-424-3

EC Name:

2-chlorotoluene

Cas Number:

95-49-8

Molecular formula:

C7H7Cl

IUPAC Name:

1-chloro-2-methylbenzene

Test animals

Species:

dog

Strain:

Beagle

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Purebred yound adults:
- Age at study initiation: 10 - 14 months
- Weight at study initiation: 7.1 - 12.7 kg
- Fasting period before study: no, capsules were administered in the morning shortly aftzzer dogs were fed
- Diet: Wayne dog food 300 g/d (Allied Mills Inc., CHicago, Illinois, USA)
- Water: ad libitum

Administration / exposure

Route of administration:

oral: capsule

Vehicle:

other: 5 % aqueous accacia solution

Details on oral exposure:

Due to the very high volatility of the test substance difficulty was experienced in measuring the material gravimetrically. This problem was avoided by using emulsions which were freshly prepared each day with a 5% aqueous acacia solution. Based on the specific gravity of thew test substance and the oncentration of the solvent desired in a stock emulsion, the neceasary amounts of OCT and the acacia solution were measured volumetrically and placed in a Sorvall container, and then blended with a mixer a for 30 aeconds. Dilutions of the stock emulsion were prepared in a similer mannor, i.e., by blending a sufficient quantity of the stock emulsion with the needed amount of acacia olution for 30 seconds.
The concentration of the test substance was adjuated so that dogs at each treatment level reveived 0.5 ml/kg. The daily dose for each deg (approximately 5 ml) was conveniently adminiatered in 2 gelatin capsules. The dose was given in the morning, shortly after the dole were fad.

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

3 months

Frequency of treatment:

daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

80 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

20 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

5 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

0 mg/kg bw/day (nominal)

No. of animals per sex per dose:

4 males and 4 females/dose

Control animals:

yes, concurrent vehicle

Details on study design:

Post-exposure period: no

Positive control:

No

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: before study initiation, at 1, 2, 4 weeks and monthly thereafter, and before sacrifice
- Dose groups that were examined: all

HAEMATOLOGY: Yes
- Time schedule for collection of blood: before study initiation, at 1, 2, 4 weeks and monthly thereafter, and before sacrifice
- Anaesthetic used for blood collection: Not specified
- Animals fasted: Not specified
- How many animals: all

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: before study initiation, at 1, 2, 4 weeks and monthly thereafter, and before sacrifice
- Animals fasted: Not specified
- How many animals: all

URINALYSIS: Yes
- Time schedule for collection of urine: before study initiation, at 1, 2, 4 weeks and monthly thereafter, and before sacrifice
- Metabolism cages used for collection of urine: Not specified
- Animals fasted: Not specified

NEUROBEHAVIOURAL EXAMINATION: No

IMMUNOLOGY: No

Sacrifice and pathology:

Organe weights of , liver, kidney, heart, spleen, thyroid, adrenal, and testen or ovaries were recorded.
Sections of these tissues and of colon, duodenum, ileum, jejunun, Jungs, lymph node, mammary, pancrean, parathyroid, prostate, salivary gland, skin, stomach, striated muscle, thymus, urinary bladder, and uterus were submitted for histopathological examination.

Other examinations:

Bone marrow, obtained from the costa, was counted to determine myeloid/erythroid
cell ratio. A section of this tissue was submitted for microscopic examination.

A liver sample from each dog was used to determine microsomal processing enzyme activity.

Statistics:

Statistical ex aminations were made of the following data:
hematocrit, hemoglobin, red blood cell count, white blood cell count, prothrombin time, platelets, mean corpuscular volume, calcium, serum glucose, blood urea nitrogen, total bilirubin, alkaline phosphatase, and serum glutamic oxalacetic tranoaminase.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Excepting for one holiday when no treatment was given, the male dogs were treated for 97 and the fermales for 96 consecutive days, thus the dogs received a total of 96 and 95 doses respectively.

A female, in the high exposure group vomited 3 times between test days 10 and 17, and during the 3rd treatment week; red blood was observed in this animal's feces. During test week 2 the dog lost approximately 1 kg body weight, but regained this weight during test weeks 3 and 4. One male in the high exposure group lost approximately 1 kg during test weeks 1 and 2, but recovered
this weight during week 3.

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

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:

no effects observed

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

A statistically significant increase in platelets in female was noted in the highest dose in the second, third, and fourth bleedings. In the final bleeding the platelets
returned to their pretreatment level.

Clinical biochemistry findings:

no effects observed

Endocrine findings:

not examined

Urinalysis findings:

effects observed, non-treatment-related

Behaviour (functional findings):

no effects observed

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

The gross examination of the organs and the histological study of the slides of the dogs showed no pathological alteration induced by the drug.
The parasitosis, branchial rest, pericholangitis, nephrocalcinosis, and dystrophic calcification found are common findings in the strain of dog used.

Histopathological findings: neoplastic:

no effects observed

Other effects:

no effects observed

Description (incidence and severity):

Normal variations without treatment related changes were observed in the ratios of the myelocytic vs. erythrocytic cell series.

Effect levels

Dose descriptor:

NOEL

Effect level:

20 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

clinical signs

Remarks on result:

other: Dogs which received daily oral doses of 5, 20, or 80 mg o-chlorotoluene were similar in all respects to the controls. The save level was 20 mg/kg.

Target system / organ toxicity

Critical effects observed:

no

Any other information on results incl. tables

All dose groups: no effects on behaviour, survival, eyes, haematology, clinical chemistry, bone marrow; no findings in the histopathological examinations attributable to treatment.
80 mg/kg bw/d: 1/4 females vomited 3 times between test day 10 and 17 and during the 3rd treatment week, red blood was observed in this animal feces (no further information).

For details on body weight, clinical and haematological values see illustration below.

Applicant's summary and conclusion

Conclusions:

Under the conditions of this oral sub-chronic toxicity study in male and femals Beagle dogs, a NOEL of 20 mg/kg bw/d based on clinical findings in the highest dose group was identified. This was the only signficant effect observed in this study.

Executive summary:

Four dogs per dose group were given daily oral doses of 5, 20, or 80 mg/kg bw of the test substance. The control group was given 5% aqueous acacia solution, 0.5 ml/kg bw. Daily doses were administered for 3 month by capsule. A general observation was performed, body weight changes recorded, hematology analysis, clinical biochemistry, urinalysis and a histopathological evaluation of several organs were performed. Organ weights, bone marrrow and hepatic microsomal activity was examined and pathological findings were evaluated.

NOEL = 20 mg/kg bw/d based on clinical signs at 80 mg/kg bw/d in one animal.