5-[(2,3-dihydro-6-methyl-2-oxo-1H-benzimidazol-5-yl)azo]barbituric acid

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

The study contains experimental data of a read-across analogue.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1982

Report date:

1982

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD Guideline 413 (90-Day (Subchronic) Inhalation Toxicity Study (migrated information)

Principles of method if other than guideline:

The present study is a 90-day subchronic allyl chloride inhalation study which was conducted in male and female Fischer 344 rats to determine inhalation toxicity of allyl chloride.

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

3-chloropropene

EC Number:

203-457-6

EC Name:

3-chloropropene

Cas Number:

107-05-1

Molecular formula:

C3H5Cl

IUPAC Name:

3-chloro-1-propene

Test material form:

liquid

Details on test material:

Substance Name: Allyl chloride
Molecular Formula: C3-H5-Cl
Molecular Weight: 76.5255
InChI: InChI=1S/C3H5Cl/c1-2-3-4/h2H,1,3H2
Smiles: ClCC=C

Specific details on test material used for the study:

Chramatogrpahi c Analysi s (Wt. %) lot No. TB06037-1 lot No. TB06167-1
Allyl Chloride 98.9 98.7
2-Chloropropene 0.02 0.01
Isopropyl Chloride 0.42 0.47
1-5 Hexadiene 0.37 0.48
Nonnal propyl chloride 0.26 0.25
Acetonitrlle 0.05 0.01

Test animals

Species:

rat

Strain:

Fischer 344

Details on species / strain selection:

Not specified.

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Wilmington, Massachusetts, U.S.A.
- Age at study initiation: approximately 6 weeks of age at acclimatization and 8 weeks at exposure
- Weight at study initiation: males 204 - 205 g (average), females: 143 - 145 g (average) at 10 d prior to exposure
- Fasting period before study: no
- Housing: 3 or 4/cage,
- Diet (e.g. ad libitum): not specified, ad libitum
- Water (e.g. ad libitum): not specified, ad libitum
- Acclimation period: 2 wks


ENVIRONMENTAL CONDITIONS
not specified

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Remarks on MMAD:

MMAD / GSD: not applicable, exposure by vapors of a volatile chlorinated short-chain hydrocarbon

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: 14.5 m³, chambers with steel ceilings in the shape of a regular quadrangular pyramid and an epoxy resin coating on the walls and floors
- Method of holding animals in test chamber: exposed in home cages
- Source and rate of air: not reported
- Method of conditioning air: controlled for temperature and humidity
- System of generating vapor: metering a calculated amount of 3-chloropropene liquid into a heated (approximately 80 ° C) vaporization flask with a precision syringe pump and sweeping the vapor with filtered air (controlled for temperature and humidity) into the main chamber
- Temperature, humidity, pressure in air chamber: temp: 20.3 - 24 °C (averages), hum: 40.5 - 60.6 % (averages, pres: not reported
- Air flow rate: 2200-2900 liters per minute
- Air change rate: 9-12 air changes per hour
- Treatment of exhaust air: not reported


TEST ATMOSPHERE
- Brief description of analytical method used: The analytical concentration of allyl chloride vapor in each chamber was determined 5 or 6 times per day using a Miran IA-CVF infrared spectrophotometer.
- Samples taken from breathing zone: not reported

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

TThe analytical concentration of ally' chloride vapor in each chamber was determined 5 or 6 times per day using a Miran IA-CVF infrared spectrophotometer. A strip chart recorder monitored IR output. Instrument settings were as follows:
Wavelength: 10.8 µ
Pathlength: 18.75 m
Slit width: 1 mm
Standards were prepared by injecting a calculated amount of allyl chloride liquid into a 100 liter Saran bag. All standard curves were drawn using linear regression analysis (Texas Instruments SR-51A linear regression function). Analytical values for chamber concentrations of allyl chloride were extrapolated from the standard curves. A 100 ppm standard was run each exposure day during the 90-day study.

Duration of treatment / exposure:

6 hours/day,5 days/week.

Frequency of treatment:

5 days/week.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 ppm

Doses / concentrations 2

Dose / conc.:

50 ppm

Doses / concentrations 3

Dose / conc.:

100 ppm

Doses / concentrations 4

Dose / conc.:

250 ppm

No. of animals per sex per dose:

25 animals/sex/dose

Control animals:

yes, sham-exposed

Details on study design:

In the 4-day probe study 10 animals/sex/species per control and 250 ppm exposure group were used to derive data for establishing exposure levels used in the subsequent 90-day subchronic study.There were 10 animals/sex/species in one group exp performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- list of conducted observations not presented in detail


DETAILED CLINICAL OBSERVATIONS: No


BODY WEIGHT: Yes
- Time schedule for examinations: before the initiation of exposure, twice weekly for the first 30 days of the study, and once weekly for the duration of the study


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


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
osed to 250 ppm aliyl chloride vapor, while the other group was exposed to filtered chamber air (controls). Exposures were conducted 6 hours/day for 4 consecutive days and the rats and mice were necropsied on day 5 of the study.

Positive control:

No positive controls were included.

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: No


BODY WEIGHT: Yes
- Time schedule for examinations: before the initiation of exposure, twice weekly for the first 30 days of the study, and once weekly for the duration of the study


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


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


WATER CONSUMPTION: No


OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: at final sacrifice
- Dose groups that were examined: all dose groups

HAEMATOLOGY: Yes
- Time schedule for collection of blood: approximately one week prior to the designated interim and terminal necropsies
- Anaesthetic used for blood collection: not reported
- Animals fasted: No
- How many animals: 10 rats/group at interim sacrifice + 10 rats/group at terminal sacrifice, collected from the tail veins of the rats
- Parameters checked in table 1 were examined.


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at terminal and interim sacrifice
- Animals fasted: Yes
- How many animals: 10 rats/group at interim sacrifice + 10 rats/group at terminal sacrifice, from the severed cervical vessels
- Parameters checked in table 1 were examined.


URINALYSIS: Yes
- Time schedule for collection of urine: approximately one week prior to the designated interim and terminal necropsies
- Metabolism cages used for collection of urine: Not reported
- Animals fasted: No
- Parameters checked in table 1 were examined.


NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

Statistics:

Hematology, clinical chemistry, urinary specific gravity, organ weight, and body weight data were evaluated using an analysis of variance and Dunnett's test (Steel, R. G. D. and Torrie, H. H., Principles and Procedures of Statistics, McGraw-Hill, New York (1960), pp. 101-105; 111-112.). The level of significance chosen for all cases was p<0.05.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Description (incidence and severity):

- initially in the 90-day study, male and female rats at all exposure levels and controls showed conjunctival redness and palpebral closure suggestive of irritation. This observation was due to an outbreak of infectious sialodacryoadenitis noted in these rats during the first 2 weeks of the study. In the 250 ppm exposed rats there was an occasional in-life observation suggesting that the feces were less well formed.
- However, no consistent observations were noted either in rats or mice which were considered of toxicologic significance due to allyl chloride exposure

Mortality:

mortality observed, non-treatment-related

Description (incidence):

Two animals died during the course of the study. One male control rat was sacrificed in a moribund condition 8 days prior to the interim necropsy. One female mouse from the 100 ppm exposure group was found dead after three days of exposure. Neither of these observations were considered a result of exposure to the test material.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

no statistically significant differences in body weights were detected

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

Description (incidence and severity):

In the 90-day study, male and female rats at all exposure levels and controls showed conjunctival redness and palpebral closure suggestive of irritation. This observation was due
to an outbreak of infectious sialodacryoadenitis noted in these rats during the first 2 weeks of the study.

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

All of the hematology parameters evaluated in the rats were within the range of normal in 90 days subchronic study, however, occasional values were statistically significantly increased or decreased. The red blood cell parameters in the 250 ppm groups of animals were noted to be slightly decreased, suggesting a slight physiological change at this level of exposure. No biologically significant differences were noted for these parameters when one compares the results from the interim and terminal necropsies.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

All of the biochemical values were within the range of normal for controls; however, occasional statistically significant observations were noted. None of the statistically significant observations were interpreted to be reflecting an exposure-related indication of target organ toxicity.
In subchronic study, the decrease in AP values noted in rats from the 250 ppm group was considered to be a reflection of decreased intestinal origin of this enzyme. Decreases in this enzyme are markedly affected by the slight alterations in the nutritional state of the animal and may reflect a slight physiological change in allyl chloride exposed animals. In any event, this decrease in AP was not an indication of a hepatotoxic effect, since an elevation in AP is seen in those conditions. As was readily noted for the rats, the BUN and SGPT enzyme levels, indicators of renal or hepatotoxicity, were not elevated at any time.

Urinalysis findings:

no effects observed

Description (incidence and severity):

No biologically significant change was noted in the urinalyses parameters for male or female rats from the interim or terminal kill which indicated an exposure-related effect of toxicologic significance.

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Multiple instances of statistically significant deviations from control mean were observed for the various determinations. The statistically significant differences noted in the absolute and/or relative weights of brain, heart, spleen and testes lacked an exposure concentration related effect and were also not associated with any light microscopic findings indicative of toxicity due to allyl chloride exposure.For the liver and/or kidney weights there were statistically significant differences frequently observed at all exposure levels in rats; however, they usually did not follow the expected exposure concentration response.
Therefore, to better evaluate the presence of any possible adverse treatment related effects, histopathologic findings in these organs were found to be more definitive, and demonstrated an exposure concentration-related effect in the kidney.

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

Review of the gross observations in rats noted at these two time intervals (interim and terminal necropsies) would suggest changes were present in the lungs, liver, kidneys and thymus. These observations did not show a consistent pattern at the interim and terminal necropsy as would be expected for an exposure-related effect.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

In the 100 and 250 ppm exposed male and female rats there were microscopic changes in the kidneys identical to those described in the 4-day probe study. These changes consisted of increased cytoplasmic granularity and eosinophilic staining of the cortical epithelial cells. In addition, a greater number of the male and female rats in the 250 ppm group contained
slightly more tubules in their kidneys with focal collapse and atrophy. These changes in the kidneys of 250·ppm rats represent a slight accentuation of those which occur normally and were considered exposure-related. Although increased granularity and eosinophilic staining of the cortical epithelial cells was noted in the 100 ppm group more frequently than in the control group, there did not appear to be an increased incidence or severity of tubules showing focal collapse and atrophy. Therefore, these changes in the kidneys of 100 ppm male anc female rats were interpreted to be a physiological adaptation due to allyl chloride exposure.
In the lungs of nearly all male and female rats in the 250 ppm group there were microscopic changes characterized as focal granulomatous inflammation. Most of these focal inflammatory lesions contained a foreign plant or hair like material within their center.The microscopic change present in the lungs of these rats was not characteristic of a chemically induced pneumonitis, and therefore was not considered a direct result of allyl chloride exposure.
The gross observations in the male and female rat livers noted at the interim and terminal necropsies did not indicate a significant hepatotoxic effect. Occasional animals showed variation in liver color; however, evidence of gross degenerative changes were not noted.

Histopathological findings: neoplastic:

no effects observed

Effect levels

1

Dose descriptor:

NOAEC

Effect level:

50 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

clinical biochemistry

clinical signs

gross pathology

haematology

histopathology: neoplastic

histopathology: non-neoplastic

mortality

ophthalmological examination

organ weights and organ / body weight ratios

urinalysis

2

Dose descriptor:

LOAEC

Effect level:

100 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

histopathology: non-neoplastic

organ weights and organ / body weight ratios

Target system / organ toxicity

Critical effects observed:

no

Applicant's summary and conclusion

Conclusions:

Based on the above observation, when Fischer 344 rats of both sexes were exposed to allyl chloride for 6 hours/day,5 days/week in doses 0, 50, 100, or 250 ppm for 90-day subchronic study the NOAEC (No observed adverse effect lconcentration) was found to be 50 ppm air and LOAEC (Lowest observed adverse effect concentration) was found to be 100 ppm.

Executive summary:

To characterize the potential adverse effects of allyl chloride inhalation exposure, a 90-day Subchronic study was conducted in Fischer 344 rats of both sexes. Exposure concentrations were 0, 50, 100, or 250 ppm for 6 hours/day,5 days/week in the 90-day subchronic study. The 90-day subchronic study contained additional animals for an interim necropsy at approximately 30 days, as well as a terminal necropsy at the end of exposure. A variety of parameters were evaluated during the in-life portion of the study as well as at necropsy to assess any adverse effect of exposure. Review of all the data including in-life observations, body weight, hematology, clinical chemistry, urinalyses, organ weights, gross pathology and histopathology indicated that the kidneys were adversely affected following allyl chloride exposure. Light microscopic changes in rats at the 100-ppm level revealed a slight increase in the cytoplasmic granularity and eosinophilic staining of the cortical epithelial cells when compared to the control rats. In the rats exposed to 250 ppm allyl chloride there were comparable light microscopic changes present in the kidneys as were noted in the 100-ppm group. However, at this exposure level the kidneys also contained an increase in the number of tubules showing collapse and atrophy of a focal nature. This change was comparable to those which occurs in control rats but was slightly accentuated in the 250-ppm exposed group. The changes noted in the kidneys of the 100-ppm group of rats were interpreted as reflecting a physiologic adaptation. At the 250-ppm exposure level the capability for adaptations appeared to be exceeded and minimal pathologic changes resulted.

In conclusion, allyl chloride inhalation exposure studies in rats revealed minimal adverse effects in the kidneys of 250 ppm exposed rats. This was considered the most sensitive organ and species exhibiting an exposure related toxicologically significant effect. Various statistically significant observations were noted in rats in the 50, 100, or 250 ppm exposure groups. These were generally considered to represent normal biological variability or physiological adaptation to the allyl chloride exposures. Changes indicative of an adverse effect and considered toxicologically significant were not observed at levels of allyl chloride exposure below 250 ppm.

Based on the above observation, when Fischer 344 rats of both sexes were exposed to allyl chloride for 6 hours/day,5 days/week in doses 0, 50, 100, or 250 ppm for 90-day subchronic study the NOAEL (No observed adverse effect level) was found to be 100 mg/L air and LOAEL (Lowest observed adverse effect level) was found to be 250 mg/L based on the histopathological findings in kidney.