1,2-benzisothiazol-3(2H)-one 1,1-dioxide, sodium salt

Endpoint summary

Description of key information

Repeated dose toxicity: Oral

The purpose of this study was to evaluate the toxicity of the test chemical in Sprague-Dawley Rats. Sprague-Dawley Rats were given the test chemical in diet at dose of 20000 ppm (1000 mg/Kg). Body weight, food consumption, Haematology, Clinical chemistry, Urinalysis, gross and histopathology were examined in the treated animals. No Statistically significant difference were observed in body weight, Organ weight, food consumption, Haematology, Clinical chemistry, Urinalysis in treated as compared to control. No test material related lesions were observed during gross and microscopic studies. Based on the observations made, the No Observed Adverse Effect Level (NOAEL) of the test chemical on Sprague-Dawley Rats in 13 weeks study was considered to be at a dose concentration of 20000 ppm (1000 mg/kg bw/day).

Repeated dose toxicity: Inhalation

The particle size distribution of the test substance was found to vary in the size of 53-500 µm, so the potential for the generation of inhalable forms is low. Moreover the normal conditions of use of this substance will not result in aerosols, particles or droplets of an inhalable size, so exposure to humans via the inhalatory route will be unlikely to occur, and therefore repeated dose toxicity by inhalation route was considered to be waived.

Repeated dose toxicity: Dermal

Since the substance is used in solid form there is very low probability of the substance penerating the skin. Further the results are negative for skin sensatization and skin irritation. Therefore this end point for repeated dose toxicity by dermal route of exposure was considered for waiver.

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from peer reviewed publication

Qualifier:

according to guideline

Guideline:

other: Refer below principle

Principles of method if other than guideline:

Effect of the test chemical was assessed in CD-COBS rats in a 25- to 54-day study.

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

other: CD-COBS

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Calco, Italy
- Weight at study initiation: 150 ± 10 g
- Diet (e.g. ad libitum): standard open formula diet
- Water (e.g. ad libitum): ad libitum

Route of administration:

oral: feed

Vehicle:

other: standard open formula diet

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS: A standard open formula diet containing the test chemical was prepared by Dottori Piccioni, Brescia, Italy, and consisted of 28.7% corn, 10% wheat, 13% barley, 7.3% corn germ, 4% fish meal, 5.5% meat meal, 10% soya flour extract, 11% carob pulp, 2% dry yeast, 2% hydrogenated coconut oil, 1% calcium carbonate, 1% salt mixture, 1% bone phosphate, plus vitamin mixture.

DIET PREPARATION
- Rate of preparation of diet (frequency): No data
- Mixing appropriate amounts with (Type of food): No data
- Storage temperature of food: No data

VEHICLE
- Justification for use and choice of vehicle (if other than water): standard open formula diet
- Concentration in vehicle: 0, 1, 2.5 and 5% (0, 1666.66, 4166.66, 8333.33 mg/kg bw/day)
- Amount of vehicle (if gavage): No data
- Lot/batch no. (if required): No data
- Purity: No data

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

25 to 54 days

Frequency of treatment:

Daily

Remarks:

Doses / Concentrations:
0, 1, 2.5 and 5% (0, 1666.66, 4166.66, 8333.33 mg/kg bw/day)
Basis:
nominal in diet

No. of animals per sex per dose:

EFFECT ON PRIMARY HUMORAL ANTIBODY PRODUCTION
3-6 animals per experimental group (3 in total) for 25, 30 or 54 days of exposure.

EFFECT ON PHA RESPONSIVENESS
3-6 animals per experimental group (3 in total) for 30 or 54 days of exposure

Control animals:

yes, concurrent vehicle

Details on study design:

No data

Positive control:

No data

Observations and examinations performed and frequency:

BODY WEIGHT
Animals were weighed in the beginning of the experiment and then on day 30 and 54.

HAEMATOLOGY
The number of spleen plaque-forming (PFC) cells and phytohemagglutinin (PHA) responsiveness were evaluated.

Plaque forming cells:
The rats were immunized in the morning by i.p. injection of 4.108 SRBC. 4 days later they were killed between 9 and 11 a.m. and the number of spleen PFC was evaluated by localized hemolysis in gel

PHA (phytohemagglutinin) responsiveness
Spleens were minced with scissors in BME. The cells were washed with 50 ml of BME and resuspended in RPM1 1640 medium supplemented with 10% fetal bovine serum and 50 ug/ml gentamycin. One vial of PHA was dissolved in 5 ml BME and used as 100% PHA solution. Lymphocytes (4 x 105/0.2 ml) were cultured for 72 h in the round-bottomed wells of micro titer plates, 20 h before the end of the experiment cultures were pulsed with 0.5 uCi [methy13H]thymidine The cultures were harvested on filters Harvester. Radioactivity was measured using a Nuclear Chicago liquid scintillation spectrometer.

Sacrifice and pathology:

GROSS PATHOLOGY: No data

HISTOPATHOLOGY: Yes

PHA (phytohemagglutinin) responsiveness
Spleens were minced with scissors in BME. The cells were washed with 50 ml of BME and resuspended in RPM1 1640 medium supplemented with 10% fetal bovine serum and 50 ug/ml gentamycin. One vial of PHA was dissolved in 5 ml BME and used as 100% PHA solution. Lymphocytes (4 x 105/0.2 ml) were cultured for 72 h in the round-bottomed wells of micro titer plates, 20 h before the end of the experiment cultures were pulsed with 0.5 uCi [methy13H]thymidine The cultures were harvested on filters Harvester. Radioactivity was measured using a Nuclear Chicago liquid scintillation spectrometer.

Other examinations:

No data

Statistics:

Results are mean +S.D. and significance was assessed by Duncan’s new multiple range test. PFC values were evaluated after logarithmic transformation of the data

Clinical signs:

not examined

Mortality:

not examined

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Increase in body weight 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, treatment-related

Description (incidence and severity):

dose dependent suppression of primary humoral antibody production was observed

Clinical biochemistry findings:

not examined

Urinalysis findings:

not specified

Behaviour (functional findings):

not examined

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

not examined

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Other effects:

not specified

Details on results:

Body weight and weight gain
Increase in body weight after day 30 of treatment (346±11, 348±16, 346±23 and 341±65 g) was observed for rats fed diets containing 0, 1, 2.5 and 5% saccharin per day, respectively. After 54 days of treatment body weights were 415±16, 407±19, 396±24 and 408±9 for controls and rats given 1, 2.5 and 5% saccharin per day.

Hematology
Rats fed for 54 days with diets containing 1 to 5% saccharin per day showed marked, dose dependent suppression of primary humoral antibody production against SRBC. At a 5% saccharin per day concentration, inhibition of direct PFC/spleen ranged from 80 to 98%.

There is borderline inhibition of PHA responsiveness observed only at one mitogen concentration (0.1% per day) was not detectable after 54 days of exposure to saccharin in the same experiment or after 30 or 25 days of treatment in subsequent experiments.

Dose descriptor:

LOAEL

Effect level:

1 666.66 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Body weight, hematology

Critical effects observed:

not specified

Conclusions:

The Low Observed Adverse Effect Level (LOAEL) of the test chemical in CD-COBS rats for the period of 25 to 54 days was considered at dose concentration of 1666.66 mg/kg bw/day

Executive summary:

The purpose of this study to evaluate the immune competence of rats fed diets containing high concentrations of the test chemical. The test chemical was administered in feed to male CD-COBS rats for the period of 25 to 54 days at dose concentration of 0, 1, 2.5 or 5% (0, 1666.66, 4166.66, 8333.33 mg/kg bw/day) saccharin per day. The test chemical showed marked, dose-dependent suppression of primary humoral antibody production against SRBC. In contrast to this PFC response, PHA blastogenesis was relatively unaffected, borderline suppression being observed only in one experiment at one PHA concentration. Increase in body weight was also observed in treated group as compared to control group. Therefore, Low Observed Adverse Effect Level (LOAEL) of the test chemical in CD-COBS rats for the period of 25 to 54 days was considered at dose concentration of 1666.66 mg/kg bw/day

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Experimental exposure time per week (hours/week):

1

Species:

rat

Quality of whole database:

The data is K2 peer reviewed publication

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

Quality of whole database:

Waiver

Repeated dose toxicity: inhalation - local 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: 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

Quality of whole database:

Waiver

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Data available for the target chemical was reviewed to determine the mutagenic nature of the test chemical. The studies are as mentioned below:

Repeated dose toxicity: Oral

The purpose of this study was to evaluate the toxicity of the test chemical in Sprague-Dawley Rats. Sprague-Dawley Rats were given the test chemical in diet at dose of 20000 ppm (1000 mg/Kg). Body weight, food consumption, Haematology, Clinical chemistry, Urinalysis, gross and histopathology were examined in the treated animals. No Statistically significant difference were observed in body weight, Organ weight, food consumption, Haematology, Clinical chemistry, Urinalysis in treated as compared to control. No test material related lesions were observed during gross and microscopic studies. Based on the observations made, the No Observed Adverse Effect Level (NOAEL) of the test chemical on Sprague-Dawley Rats in 13 weeks study was considered to be at a dose concentration of 20000 ppm (1000 mg/kg bw/day).

Another study was performed to evaluate the repeated dose oral toxicity of the test chemical in Beagle dogs. Beagle dogs were given the test chemical alone at dose of 20000 ppm alone 20000 ppm (500 mg/Kg/day) for 16 weeks. Body weight, food consumption, Haematology, Clinical chemistry, Urinalysis, gross and histopathology were examined. No Statistically significant difference were observed in body weight, Organ weignt, food consumption, Haematology, Clinical chemistry, Urinalysis in treated as compared to control. No test material related lesions were observed during gross and microscopic studies. Based on the observations made, the no Observed Adverse Effect Level (NOAEL) of the test chemical on Beagle dogs  in 16 weeks study was observed at dose concentration of 20000 ppm (500 mg/kg bw/day).

Yet another study was performed to evaluate the immune competence of rats fed diets containing high concentrations of the test chemical. The test chemical was administered in feed to male CD-COBS rats for the period of 25 to 54 days at dose concentration of 0, 1, 2.5 or 5% (0, 1666.66, 4166.66, 8333.33 mg/kg bw/day) saccharin per day. The test chemical showed marked, dose-dependent suppression of primary humoral antibody production against SRBC. In contrast to this PFC response, PHA blastogenesis was relatively unaffected, borderline suppression being observed only in one experiment at one PHA concentration. Increase in body weight was also observed in treated group as compared to control group. Therefore, Low Observed Adverse Effect Level (LOAEL) of the test chemical in CD-COBS rats for the period of 25 to 54 days was considered at dose concentration of 1666.66 mg/kg bw/day

In another study, combined repeated dose & carcinogenicity was performed to determine the toxic nature of the test chemical upon repeated exposure by oral route. Spargue dawley rats were fed the test chemical in the diet at dose level of 0 or 5% (0 or 2500 mg/Kg/day) for 80 weeks. During the study period, the test animals were observed for general condition, mortality, body weight changes, food consumption and the animals were subjected to gross and histopathology. The general condition of rats was not altered and no mortality was observed during the study. There was no difference in the weight gain in treated and control rats. The consumption of feed was higher in SD rats during the initial 8 wk, but was slightly lower in the following period. At the beginning of the study, relative urinary volume was also significantly higher in SD rats given the test chemical in comparison with rats fed the control diet. Urinary excretion of sodium was approximately twice as high in the test chemical treated groups, but urinary pH was not affected by rat strain or treatment. All of the bladders appeared to be normal with no evidence of bladder stones, enlargement, or detectable lesions. Histological examination revealed simple hyperplasia in two rats amongst the treated animals, but no carcinomas or precancerous lesions were observed. Based on the observations made, the low observed adverse effect level (LOAEL) for the test chemical is considered to be 2500 mg/Kg/day when male rats were exposed to the test chemical for 80 weeks.

 

Repeated dose toxicity: Inhalation

The particle size distribution of the test substance was found to vary in the size of 53-500 µm, so the potential for the generation of inhalable forms is low. Moreover the normal conditions of use of this substance will not result in aerosols, particles or droplets of an inhalable size, so exposure to humans via the inhalatory route will be unlikely to occur, and therefore repeated dose toxicity by inhalation route was considered to be waived.

Repeated dose toxicity: Dermal

Since the substance is used in solid form there is very low probability of the substance penerating the skin. Further the results are negative for skin sensatization and skin irritation. Therefore this end point for repeated dose toxicity by dermal route of exposure was considered for waiver.

Based on the data available for the target chemical, the test chemical is not likely to be toxic upon repeated exposure by oral route. Hence the test chemical is likely to be "not classified" for repeated exposure by oral, inhalation and dermal route as per the criteria mentioned in CLP regulation.

Justification for classification or non-classification

Based on the data available for the target chemical, the test chemical is not likely to be toxic upon repeated exposure by oral route. Hence the test chemical is likely to be "not classified" for repeated exposure by oral, inhalation and dermal route as per the criteria mentioned in CLP regulation.