2-phenyl-1H-benzimidazole-5-sulphonic acid

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

September - December 1977

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1978

Report date:

1978

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Deviations:

not specified

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2-phenyl-1H-benzimidazole-5-sulphonic acid

EC Number:

248-502-0

EC Name:

2-phenyl-1H-benzimidazole-5-sulphonic acid

Cas Number:

27503-81-7

Molecular formula:

C13H10N2O3S

IUPAC Name:

2-phenyl-1H-benzimidazole-5-sulphonic acid

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Experimental Animals and Housing Conditions
SPF rats (strain Wistar W, 74, bred by Winkelmann, Borchen) were used for this study.
At the start of study rats were about 42 to 49 days old. The mean initial weight of males was 93- 94 g, that of females 94 g.
The animals were housed individually, under conventional conditions, in Makrolon type II cages (SPIEGEL and GONNERT, 1961) on dustfree wood granules at a room temperature of 23 ±2 °C. During the study period the animals received fresh Altromin R- powder feed (manufactured by Altromin GmbH, Lage) and tap water ad libitum.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: aqueous thylose suspension

Details on oral exposure:

Groups of 15 male and 15 female rats each received the test substance by gavage 7 times a week.

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

for 3 months

Frequency of treatment:

daily (7 times a week)

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

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

Doses / concentrations 2

Dose / conc.:

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

Doses / concentrations 3

Dose / conc.:

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

Doses / concentrations 4

Dose / conc.:

1 000 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Details on study design:

The following doses were administered, 0 (control), 100, 330 and 1000 mg/kg bw/day.
The substance was applied in a 5% aqueous tylose suspension at a constant volume of 10 ml/kg. Control animals received the corresponding volume of tylose suspension.
At the start of study the rats were separated, by sex and three weight groups (light, medium, heavy) were established for each sex group. The animals were allocated to dose groups using a randomization list. Subsequently the animals were numbered chronologically.

Positive control:

none

Examinations

Observations and examinations performed and frequency:

1,General Examinations
a.Inspection of Experimental Animals
The animals were inspected daily and occurring changes and signs were recorded.
b Determination of Body Weights and Feed Intake
Body weights were determined weekly. Male rats could not be weighed in the 9th week of study due to a defect of the scales. Weekly feed intake was determined by comparing the final weight of feed at the end of the week to the initial weight.
2, Clinical Laboratory Investigations
Clinical laboratory investigations were performed on 5 male and 5 female rats each per dose 6 weeks and 3 months after the start of feeding. Blood samples for the determination of blood sugar were taken from the caudal vein, for the other determinations from the retro-orbital venous plexus of animals under ether anesthesia (according to NOLLER, 1955).
a.Haematology
Erythrocyte count and leucocyte count using the Coulter-Counter, type ZF.
Thrombocyte count using the Coulter-Counter, type FN Reticulocyte count after staining with brilliant cresyl blue Haemoglobin content using the Coulter-Counter haemoglobinometer Haematocrit using the Heraeus-Christ micro-haematocrit centrifuge
Differential blood count using smears (staining according to Wright) at 630-fold magnification MCH and MCV calculation
Thromboplastin time at the end of study according to QUICK, 1951 using Metrolab clottimer
b. Clinical Chemistry
Enzymes
Alkaline phosphatase (ALP), Glutamic-oxalacetic-transaminase (GOT), Glutamic-pyruvic-transaminase (GPT)
Substrates
Creatinine, Blood sugar, Cholesterol ,Bilirubin, ,Total protein in serum
c.Urinalysis semiquantitative
Glucose, blood, protein and pH value, Ketone bodies, Bilirubin, Macroscopic examinations of sediment

Sacrifice and pathology:

Gross Pathology
a, Necropsy of Rats Dvincr Intercurrently
Rats dying intercurrently were necropsied and macroscopically evaluated; organs and tissues deemed evaluable were fixed in 10% formaldehyde solution.
b. Necropsy of Rats Sacrificed at the End of Study
After a feeding period of 3 months all surviving animals were anesthetized with ether and exsanguinated. The animals were subsequently necropsied and macroscopically examined. The weights of the following organs were determined: thyroid gland, thymus, heart, lung, liver, spleen, kidneys, adrenals, testes or ovaries.
The following organ material from 5 male and 5 female rats each killed regularly at the end of study was fixed in Bouinian fluid (after about 30 hours decanted into 70% alcohol), adrenals, aorta brain, epididymides, esophagus, eyes, femur, heart. intestine (duodenum, jejunum, ileum, colon), kidneys, liver, lung, lymph nodes, ovaries, pancreas, pituitary, prostate, salivary gland, sciatic nerve, seminal vesicle, skeletal musculature, spleen, sternum, stomach, testes, thymus, thyroid gland, trachea, urinary bladder, uterus as well as all organs showing macroscopic lesions The organ material from the other animals was fixed in 10% formaldehyde solution and, in addition, parts of the liver from all animals were fixed in formol-calcium.

Statistics:

The following parameters were calculated, arithmetic group means, standard deviation s, upper and lower confidence limits at the confidence level of l-a = 95 % and l-a= 99 %.
The values of the treated groups were compared to those of the control groups using the significance test (U-test) as described by Mann, Whitney and Wilcoxon at the significance level of a = 5 % and a = 1 %. An IBM-370/145 computer was used.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

mortality observed, non-treatment-related

Description (incidence):

During the entire study period one male of the control group and female each of the dose groups 330 and 1000 mg/kg bw/day died. Mortalities were not considered treatment related.

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:

not examined

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

The protein content in serum, which, at the end of study, was significantly increased (P < 0.01) in females of the dose group 1000 mg/kg bw/day is not considered to be an indication of damage because all values were within the biological range (2s range 5.37 - 6.89 g/100 mL, measured in 100 female rats of that age).

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

no effects observed

Behaviour (functional findings):

not examined

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:

no effects observed

Histopathological findings: neoplastic:

not examined

Other effects:

not examined

Details on results:

During the entire study period one male of the control group and female each of the dose groups 330 and 1000 mg/kg bw/day died.
During the entire study period treated animals showed no treatment-related signs in any dose group. Growth, feed intake, water intake and mortality were not affected.
Haematological investigations performed during as well as at the end of study gave no indication of damage in any dose group,
Clinico-chemical analyses, gross pathology and histopathological investigations established no damage to the liver in the dose group of up to 1000 mg/kg bw/day.
The protein content in serum, which, at the end of study, was significantly increased (P < 0.01) in females of the dose group 1000 mg/kg bw/day is not considered to be an indication of damage because all values were within the biological range (2s range 5.37 - 6.89 g/100 mL, measured in 100 female rats of that age).
Urinalysis, urea and creatinine concentrations in serum as well as gross pathological, gravimetric and histopathological organ findings gave no indication of an effect on the kidneys.
No treatment-related organ changes were observed in any rat at necropsy.
Histopathological investigations of the other organs gave no indication of a damaging effect by test article.

Effect levels

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Target system / organ toxicity

Key result

Critical effects observed:

no

Applicant's summary and conclusion

Conclusions:

In conclusion, the no-observed-adverse-effect-level (NOAEL) of the test article is considered to be 1000 mg/kg bw/day.

Executive summary:

This study was performed following OECD guideline 408 with test article exposed in a 3-month toxicity test in female and male rats. The following dose levels of 0 (control), 100, 330 and 1000 mg/kg bw/day were used with application of gavage daily (7 times a week). During the entire study period one male of the control group and female each of the dose groups 330 and 1000 mg/kg bw/day died. There was no significant differences in Clinical chemistry, Blood sugar and cholesterol concentrations of rats, blood ,urinalysis, clinico-chemical analyses, necropsies and histopathological investigations, gross pathology and histopathology compared with controls in the parameters investigated of the dose groups of 100 to 1000 mg/kg bw/day. All vaules were within normal range. Therefore, it is concluded that test article showed no treatment-related adverse effects in all test doses up to 1000 mg/kg bw/day.