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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
chronic toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: study performed by regulatory organisation, but no guideline followed

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1978

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
other: OECD 451
Deviations:
yes
Remarks:
only two dose groups
Principles of method if other than guideline:
Groups of animals are administerd to the test substance for 78 weeks and observed for 26 weeks additionally.
Two dose groups and a control group are chosen per sex.
Body weights and clinical signs are collected and killed animals are pathologicaly examined
GLP compliance:
not specified
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
not specified
Details on test material:
- Name of test material (as cited in study report): 1H-Benzotriazole
- Distributor: Aldrich Chemical Company, Milwaukee, Wisconsin
- Analytical purity: >99 %
- Purity test date:
- Lot/batch No.: 122917 and 030737
- Storage condition of test material: 4 °C

Test animals

Species:
rat
Strain:
Fischer 344
Sex:
male/female
Details on test animals and environmental conditions:
second test animals:
Species : mice
Strain: B6C3F1
Sex: male/ female


TEST ANIMALS
- Source: Charles River Breeding Laboratorie, Inc., Wilmington, Massachusetts
- Age at study initiation: 42 days (rat), 44 days (mice)
- Weight at study initiation: ca. 90 g (rat), ca. 20 - 25 g (mice)
- Fasting period before study: no
- Housing: steel wire-mesh cages, solid polycarbonate cages
- Diet: ground Wayne Lab Blox animal feed, ad libitum
- Water: Tap water (0.75 - 1 ppm chlorine), ad libitum
- Acclimation period: two weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23-24 °C
- Humidity (%): no data
- Air changes (per hr): 6
- Photoperiod (hrs dark / hrs light): 12

Administration / exposure

Route of administration:
oral: feed
Vehicle:
unchanged (no vehicle)
Details on oral exposure:
PREPARATION OF DOSING SOLUTIONS:
Mixing a weighed amount of chmical with an aliquot of food in a mortar.
When the premix is homogeneous, it is blended with the remainign feed and
mixed for 20 min.


DIET PREPARATION
- Rate of preparation of diet (frequency): once a week
- Mixing appropriate amounts with (Type of food): Ground Wane Lab Blox animal feed
- Storage temperature of food: 4 °C
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Analyzation by ultraviolet spectroscopy at intervals of 2 - 6 weeks after mixing.
Concentrations were within 25 % of the theoretical value
Duration of treatment / exposure:
78 weeks
Frequency of treatment:
daily
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
6700 ppm
Basis:
other: rats, nominal in diet, low-dose group; time-weighted average dose
Remarks:
Doses / Concentrations:
12100 ppm
Basis:
other: rats, nominal in diet, high-dose group; time-weighted average dose
Remarks:
Doses / Concentrations:
11700 ppm
Basis:
other: mice, nominal in diet, low-dose group; time-weighted average dose
Remarks:
Doses / Concentrations:
23500 ppm
Basis:
other: mice, nominal in diet, high-dose group; time-weighted average dose
No. of animals per sex per dose:
50
Control animals:
yes
Details on study design:
- Dose selection rationale: based on subchronic study
Positive control:
no

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

BODY WEIGHT: Yes
- Time schedule for examinations: every 2 weeks in the first 12 weeks, then every month

Sacrifice and pathology:
GROSS PATHOLOGY: Yes (see table)
HISTOPATHOLOGY: Yes (see table)
Statistics:
Probabilities of survival are estimated by the product-limit procedure of Kaplan and Meier (1958).
Statistical analyses for a possible dose-related effect on survial use the method of Cos (1972) and Tarone's (1975) extensions.
One-tailed P values have been reported for all tests except the departure from linearity test, which is only reported when its two-tailed P value is less than 0.05. The one-tailed Fisher exact test (Cox 1970) is used to compare the tumor incidence of a control group with that of a group of dosed animals at each dose level.
The Cochran-Armitage test for linear trend in proportions, with continuity correction (Armitage 1971) is also used

Results and discussion

Results of examinations

Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
lowered mean body weights
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:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
not specified
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
no effects observed
Details on results:
CLINICAL SIGNS AND MORTALITY
Rats:
Eye discoloration or inflammation up to two animals per group (also control).
Inflammation of the posterior ventral surface in one high-dose male.
Alopecia in one control male.
Survival ranged from 64 to 86 %, with the lower values observed in the control groups (For details see table 1)

Mice:
Alopecia in 1 low-dose female, 2 high-dose females, 27 control males, 30 control females
distentrion of the stomach in 1 control male and female
swelling and inflammation in the anal region in 1 low-dose male
abscess in the anal region in 1 high-dose male
poor balance at the end of study in 1 high-dose female
Survival ranged from 60 to94 %, with the lower values observed in the control groups (For details see table 2)

BODY WEIGHT AND WEIGHT GAIN
Rats:
Mean body weights of the dosed male and female rats were lower than those of the corresponding controls throughout most of the bioassay. A dose-related effect was generally indicated by the data for each sex, except for the last 24weeks in the females when the mean body weights of both the low- and high-dose groups gradually rose toward those of the controls.

Mice:
Mean body weights of the dosed male and female mice were lower than those of the corresponding controls throughout most of the bioassay, and a dose-related effect was indicated by the data for each sex.

PATHOLOGY (gross pathology, histopathology, for details, please rever to attachment)
Rats:
Hepatic lesions observed in male and female rats consisted of neoplastic nodules of the liver in five males and two females from the high-dose groups. No animals in the control or low-dose groups had neoplastic nodules. Morphologic features of the neoplastic nodules were similar to those described in the literature. Neoplastic nodules were spherical lesions up to several liver lobules in size composed of plates of hepatocytes which were sharply demarcated and compressed the adjacent normal parenchyma. Hepatocytes within these nodules showed varying degrees of cytoplasmic change, including clear cell, eosinophilic, and basophilic alterations. Mitotic figures and varying degrees of nuclear atypia including multinucleation and hyperchromasia were noted. Brain lesions observed in rats as early as week 21 consisted of an oligodendroglioma in one low-dose male and gliomas in two low-dose males and one high-dose female. These tumors were not present in the control animals. In female rats a non-dose-related increase in the incidence of C-cell adenomas and carcinomas of the thyroid was noted. The incidence in the controls was 0/43, the low-dose group 5/43, and
the high-dose group 3/50. Most of the remaining neoplasms occurred randomly in control and dosed groups, and their incidences and types, with few exceptions, were similar to those observed historically in Fischer 344 rats. With the possible exception of the liver in male rats and the brain in male and female rats, no particular organ or system seemed to be the target of this chemical. One high-dose female had a rare and unusual neoplasm which appeared to be a primary nonchromaffin paraganglioma of the heart. The mass was visible microscopically in the wall of the left ventricle and was composed of sheets of cells arranged in small organoid-like packets. The cells had large oval and round vesicular nuclei, high nuclear cytoplasmic ratios, and a light gray-blue cytoplasm. The endocrine-like appearance of the mass suggested it might be a chemodectoma, since all efforts to
demonstrate chromaffin granules were negative. A variety of degenerative, proliferative, and inflammatory lesions were observed in the control and dosed rats, but none were believed to be related to administration of 1H-benzotriazole.

Mice:
In female mice, a non-dose-related increase in the incidence of alveolar/bronchiolar adenomas and carcinomas was noted. The incidence in the controls was 0/49, the low-dose group 10/49, and the high-dose group 4/49. The remaining neoplasms occurred randomly in control and dosed groups, and their incidence and type, with few exceptions, were similar to those observed historically in B6C3F1 mice. No particular organ or system seemed to be the target of this chemical. A variety of degenerative, proliferative, and inflammatory lesions were seen in the control and dosed mice.


Effect levels

open allclose all
Key result
Dose descriptor:
LOAEL
Effect level:
ca. 6 700 ppm
Based on:
test mat.
Remarks:
nominal in diet, time weighted average in rats
Sex:
male/female
Basis for effect level:
body weight and weight gain
Remarks on result:
other: species rats
Key result
Dose descriptor:
LOAEL
Effect level:
ca. 11 700 ppm
Based on:
test mat.
Remarks:
nominal in diet, time weighted average in mice
Sex:
male/female
Basis for effect level:
body weight and weight gain
Remarks on result:
other: species mice

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

Table 1: Survival of rats

Group absolute numbers  Survival 
 high-dose males 36/50  72 % 
 low-dose males 34/50  68 % 
 control males 32/50  64 % 
 high-dose females 43/50  86 % 
 low-dose females 40/50  80 % 
 control females 36/50  72 % 

Table 2: Survival of mice

 Group absolute numbers  Survival 
 high-dose males 42/50  84 % 
 low-dose males 36/50  72 % 
 control males 33/50  66 % 
 high-dose females 47/50  94 % 
 low-dose females 39/50  78 % 
 control females 30/50  60 % 

Applicant's summary and conclusion

Conclusions:
Concerning the body weight gain, a LOAEL of 6700 ppm in rats and 11700 ppm in mice was observed. Organo-toxicological effects related to the substance were not observed. The LOAEL of 6700 ppm is equivalent to 335 mg/kg bw/day, 11700 ppm to 1755 mg/kg bw/day.

Although administration of this chemical to rats may be associated with neoplastic nodules of the liver in male Fischer 344 rats, there was no convincing evidence, based on the histopathologic examination, that administration of 1H-benzotriazole was carcinogenic under the conditions of this bioassay.
In the B6C3F1 mouse, based on the histopathologic examination, there was no evidence for the carcinogenicity of IH-benzotriazole under the conditions of this bioassay.