1,2-benzisothiazol-3(2H)-one

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Link to relevant study records

Reference

Endpoint:

two-generation reproductive toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.3800 (Reproduction and Fertility Effects)

GLP compliance:

yes

Specific details on test material used for the study:

Proxel Press Paste
Batch Numbers 103 and 344.

Purity

Batch No. 103: 93.1%
Batch No. 344: 92.7 ± 1.1%

Species:

rat

Strain:

other: WI(Glx/BRL/Han)BR

Sex:

female

Route of administration:

oral: feed

Duration of treatment / exposure:

Exposure period: P generation: Max of 18 weeks, F1 generation: Max of 19 weeks
Premating exposure period (females): 10 weeks
Duration of test: Total Duration: 38 weeks

Frequency of treatment:

daily

Details on study schedule:

IUCLID4 Number of generation studies: 1

Remarks:

Doses / Concentrations:
P generation: 250, 500 and 1000 ppm with calculated intake of 27.0, 54.2 and 112.0 mg/kg bw/day
F1 generation: 250, 500 and 1000 ppm with calculated intake of 28.2, 56.6 and 114.8 mg/kg bw/day

Control animals:

other: Yes, fed diet only

Clinical signs:

no effects observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Other effects:

no effects observed

Reproductive function: oestrous cycle:

no effects observed

Reproductive performance:

no effects observed

In females, there were treatment-related incidences of macroscopic abnormalities of the stomach including raised foci, reddening and thickening. In the stomach of the intermediate and high dose group animals, limiting ridge hyperplasia was noted in 8/24 intermediate dose females and 16/24 high dose females. The finding was characterised by a minor increase in the thickness of the epithelium at the limiting ridge between the forestomach and fundus, with variable rete peg formation and folding of the epithelium. In one intermediate and three high dose females there was also squamous cell hyperplasia of the forestomach and in one high dose female, forestomach gastritis.

Key result

Dose descriptor:

NOAEL

Effect level:

112 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

clinical signs

body weight and weight gain

Key result

Dose descriptor:

NOAEL

Effect level:

112 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reproductive function (oestrous cycle)

reproductive function (sperm measures)

reproductive performance

Clinical signs:

no effects observed

Mortality / viability:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Sexual maturation:

no effects observed

Gross pathological findings:

effects observed, treatment-related

Histopathological findings:

effects observed, treatment-related

At necropsy examination, there were increased incidences of raised foci in, and thickening of, the stomachs of the high dose animals, particularly the females. In the intermediate and high dose groups, limiting ridge hyperplasia of the stomach was noted in 4/24 intermediate dose females and 17/24 high dose females. In the high dose females there was also squamous cell hyperplasia (14/24), forestomach gastritis (2/24), hyperkeratosis (7/24) and erosion/ulcer (1/24).

Key result

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

56.6 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

Key result

Dose descriptor:

NOAEL

Generation:

F2a

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

viability

body weight and weight gain

Key result

Reproductive effects observed:

no

Conclusions:

Materials and methods
The objective of the study was to investigate the effects of the test article, PROXEL Press Paste (1,2-Benzisothiazolin-3-one, aka BIT), on the integrity and performance of the male and female reproductive systems including gonadal function, the oestrous cycle, mating behaviour, conception, pregnancy, parturition, lactation, weaning and the growth and development of the offspring when administered orally, by diet, to two successive generations. The study was designed to meet the known requirements of the EPA Health Effects Test Guidelines OPPTS 870.3800 (1998).
Groups of 24 male and 24 female parental rats (P generation) were given PROXEL Press Paste by admixture with the diet at dose levels of 250, 500 or 1000 ppm. A similar group received the control diet only. The animals received the test diet for 10 weeks before pairing for two weeks. The dosing continued during this pairing period and throughout the resulting pregnancies. The P generation females were allowed to litter and rear their offspring (F1a) to weaning. Administration of the test article continued throughout the weaning of the F1 offspring until necropsy.
Twenty-four animals of each sex were randomly selected from each group to form the filial (F1) generation. Direct treatment of the F1 generation continued during their maturation period (10 weeks), the mating period (up to two weeks) and throughout the resulting pregnancies and weaning of the F2 offspring up until necropsy. All F1 females were allowed to litter and rear their offspring (F2a) to weaning.




Results and discussion
P Generation
Clinical observations, body weights and food intakes were unaffected by treatment.
Mating data, duration of gestation, numbers of implantations, numbers of pups born and pup survival were similar in all groups.
Mean pup weight gain of the high dose pups was slightly lower than control over the first week post partum. However, over the whole lactation period, mean pup weight gain was similar in all groups.
There were no adverse effects of treatment on the seminology data.
In the high dose group, mean liver weight of the males was slightly higher than, and mean testes weight slightly lower than, control. Neither of these findings was considered to represent adverse effects of treatment.
Minor limiting ridge hyperplasia in the stomach was noted in some intermediate and many high dose animals. Squamous cell hyperplasia and forestomach gastritis were also seen in a few animals.
F1 Generation
Males in the high dose group gained slightly less weight than the controls during the study and the high dose females gained slightly less weight during the pre-pairing period, only.
Clinical observations and food intakes were unaffected by treatment.
Physical development of the F1 generation, mating data, duration of gestation and F2a pup sex ratio were unaffected by treatment. Pup survival to Day 4 post partum and mean pup weight gain were slightly lower in the high dose group compared to control.
Seminology investigations, organ weights and ovarian follicle counts were unaffected by treatment.
In the intermediate and high dose groups, limiting ridge hyperplasia in the stomach was noted. This was most prominent in the high dose females where there was also squamous cell hyperplasia, forestomach gastritis, hyperkeratosis and erosion/ulcer.

Conclusion
Dietary administration of 1000 ppm PROXEL Press Paste to rats for two generations produced slight adult toxicity in the F1 generation in terms of lower body weight gain, and in both generations, limiting ridge hyperplasia of the stomach together with incidences of squamous cell hyperplasia, forestomach gastritis, keratosis and erosion/ulcer. At this concentration, the growth of the offspring was slightly impaired and in the F2a offspring, there was a slight reduction in pup survival.
At the 500 ppm dose level there were incidences of limiting ridge hyperplasia in the stomach.
There were no adverse effects of treatment at 250 ppm, equivalent to an approximate overall mean intake of 24 mg/kg/day.

LO(A)EL
Parent males LO(A)EL: 500 ppm (mean dose of 37.2 mg/kg/day) based on hyperplasia of the limiting ridge of the stomach
Parent females LO(A)EL: 500 ppm (mean dose of 54.2 mg/kg/day) based on hyperplasia of the limiting ridge of the stomach
F1 males LO(A)EL: 1000 ppm (mean dose of 97.8 mg/kg/day) based on impaired growth and survival of pups
F1 females LO(A)EL: 1000 ppm (mean dose rate of 114.8 mg/kg/day) based on impaired growth and survival of pups


NO(A)EL
Parent males 250 ppm (mean dose rate of 18.5 mg/kg/day)
Parent females 250 ppm (mean dose rate of 27.0 mg/kg/day)
F1 males 500 ppm (mean dose rate of 48.0 mg/kg/day)
F1 females 500 ppm (mean dose rate of 56.6 mg/kg/day)

Executive summary:

A study was conducted to determine the reproductive toxicity of the substance in rats according to US EPA Guideline OPPTS 870.3800. Groups of 24 male and 24 female rats (P generation) were administered the test substance by diet at dose levels of 250, 500 or 1000 ppm (equivalent to 27.0, 54.2  and 112.0 mg/kg bw/day). A similar group received the control diet only. The animals received the test diet for 10 weeks before pairing for two weeks. The dosing continued during this pairing period and throughout the resulting pregnancies. The P generation females were allowed to litter and rear their offspring (F1a) to weaning. Administration of the test substance continued throughout the weaning of the F1 offspring until necropsy. 24 animals of each sex were randomly selected from each group to form the F1 generation. Treatment of the F1 generation at dose levels of 250, 500 and 1000 ppm (equivalent to 28.2, 56.6 and 114.8 mg/kg/day) through diet continued during their maturation period (10 weeks), the mating period (up to two weeks) and throughout the resulting pregnancies and weaning of the F2 offspring up until necropsy. All F1 females were allowed to litter and rear their offspring (F2a) to weaning. Clinical observations, body weights and food intake of the P generation were unaffected by treatment. Mating data, duration of gestation, numbers of implantations, numbers of pups born and pup survival were similar in all groups. In F1, the mean pup weight gain of the high dose pups was slightly lower than control over the first week post-partum.  However, over the whole lactation period, mean pup weight gain was similar in all groups. There were no adverse effects of treatment on the seminology data. Minor limiting ridge hyperplasia in the stomach was noted in some intermediate and many high dose F1 animals. Squamous cell hyperplasia and forestomach gastritis were also seen in few animals. F1 males in the high dose group gained slightly less body weight than the controls during the study and the high dose females gained slightly less body weight during the pre-pairing period only. Clinical observations and food intake of F1 were unaffected by treatment. Physical development of the F1 generation, mating data, duration of gestation and F2a pup sex ratio were unaffected by treatment. Pup survival till Day 4 post-partum and mean pup weight gain were slightly lower in the high dose group compared to control. Seminology investigations, organ weights and ovarian follicle counts were unaffected by treatment. In the intermediate and high dose F1 animals, limiting ridge hyperplasia in the stomach was noted. This was most prominent in the high dose females where there was also squamous cell hyperplasia, forestomach gastritis, hyperkeratosis and erosion/ulcer. Based on the study results, it was concluded that, dietary administration of the test substance at 1000 ppm to rats for two generations produced toxicity in the F1 generation in terms of lower body weight gain, and in both generations, limiting ridge hyperplasia of the stomach together with incidences of squamous cell hyperplasia, forestomach gastritis, keratosis and erosion/ulcer. At this dose, the growth of the offspring was slightly impaired and in the F2a generation, there was a slight reduction in pup survival probably as a consequence of maternal toxicity. Under the study conditions, the systemic NOAEL of the substance in rats was considered to be 112 mg/kg/day in P generation, 56.6 mg/kg/day in F1 generation and 56.6 mg/kg/day in the F2 generation considering the local nature of the gastric irritation produced by the test substance administration. The NOAEL for reproductive toxicity of the substance in rats was considered to be 112 mg/kg/day (Clode, 2002).

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

112 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

A study was conducted to determine the reproductive toxicity of the substance in rats according to US EPA Guideline OPPTS 870.3800. Groups of 24 male and 24 female rats (P generation) were administered the test substance by diet at dose levels of 250, 500 or 1000 ppm (equivalent to 27.0, 54.2  and 112.0 mg/kg bw/day). A similar group received the control diet only. The animals received the test diet for 10 weeks before pairing for two weeks. The dosing continued during this pairing period and throughout the resulting pregnancies. The P generation females were allowed to litter and rear their offspring (F1a) to weaning. Administration of the test substance continued throughout the weaning of the F1 offspring until necropsy. 24 animals of each sex were randomly selected from each group to form the F1 generation. Treatment of the F1 generation at dose levels of 250, 500 and 1000 ppm (equivalent to 28.2, 56.6 and 114.8 mg/kg/day) through diet continued during their maturation period (10 weeks), the mating period (up to two weeks) and throughout the resulting pregnancies and weaning of the F2 offspring up until necropsy. All F1 females were allowed to litter and rear their offspring (F2a) to weaning. Clinical observations, body weights and food intake of the P generation were unaffected by treatment. Mating data, duration of gestation, numbers of implantations, numbers of pups born and pup survival were similar in all groups. In F1, the mean pup weight gain of the high dose pups was slightly lower than control over the first week post-partum.  However, over the whole lactation period, mean pup weight gain was similar in all groups. There were no adverse effects of treatment on the seminology data. Minor limiting ridge hyperplasia in the stomach was noted in some intermediate and many high dose F1 animals. Squamous cell hyperplasia and forestomach gastritis were also seen in few animals. F1 males in the high dose group gained slightly less body weight than the controls during the study and the high dose females gained slightly less body weight during the pre-pairing period only. Clinical observations and food intake of F1 were unaffected by treatment. Physical development of the F1 generation, mating data, duration of gestation and F2a pup sex ratio were unaffected by treatment. Pup survival till Day 4 post-partum and mean pup weight gain were slightly lower in the high dose group compared to control. Seminology investigations, organ weights and ovarian follicle counts were unaffected by treatment. In the intermediate and high dose F1 animals, limiting ridge hyperplasia in the stomach was noted. This was most prominent in the high dose females where there was also squamous cell hyperplasia, forestomach gastritis, hyperkeratosis and erosion/ulcer. Based on the study results, it was concluded that, dietary administration of the test substance at 1000 ppm to rats for two generations produced toxicity in the F1 generation in terms of lower body weight gain, and in both generations, limiting ridge hyperplasia of the stomach together with incidences of squamous cell hyperplasia, forestomach gastritis, keratosis and erosion/ulcer. At this dose, the growth of the offspring was slightly impaired and in the F2a generation, there was a slight reduction in pup survival probably as a consequence of maternal toxicity. Under the study conditions, the systemic NOAEL of the substance in rats was considered to be 112 mg/kg/day in P generation, 56.6 mg/kg/day in F1 generation and 56.6 mg/kg/day in the F2 generation considering the local nature of the gastric irritation produced by the test substance administration. The NOAEL for reproductive toxicity of the substance in rats was considered to be 112 mg/kg/day (Clode, 2002).

Effects on developmental toxicity

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Toxicity to reproduction: other studies

Additional information

A study was conducted to determine the prenatal developmental toxicity of the substance in rats according to a method comparable to EU Method B.31. Groups of 24 pregnant female rats (Wistar-derived Alpk:APfSD) were orally gavaged with 0, 10, 40 or 100 mg/kg/day of the test substance from Days 7 to 16 of gestation. A control group of animals received the vehicle alone. Clinical observations were made daily throughout the study. Food consumption was also monitored throughout the study and the bodyweight of each animal was recorded on Days 1 and 4; daily from Days 7 -16 and on Days 19 and 22 of gestation. On Day 22 of gestation the females were sacrificed and macroscopic examination of all tissues was performed. Uterine content was examined, the number of live fetuses and intra-uterine deaths were recorded and the foetuses were weighed, examined for external and visceral abnormalities. The sex ratio was calculated and the abnormalities were classified as major, minor or variant. At high dose of 100 mg/kg/day, there was reduced bodyweight gain during the dosing period, reduced food consumption and an increase in stomach lesions at post mortem examination. Similar but less marked effects (except stomach lesions) were seen at 40 mg/kg/day. There were no treatment-related effects at 10 mg/kg/day. There were no adverse effects on gravid uterus weight, litter weight, numbers of corpora lutea or numbers of intra-uterine deaths at any dose level. At 100 mg/kg/day, there was a small but statistically significant reduction in mean foetal weight. The overall incidence of skeletal defects was not significantly different from control in the treated groups. However, some individual defects, non-ossified cervical centra and partially ossified parietals showed statistically significant changes in incidence at 40 or 100 mg/kg/day. In addition, there were some individual skeletal variants which showed a change in incidence at 40 or 100 mg/kg/day. Taken in conjunction with the slight reduction in foetal weight at 100 mg/kg/day, these results indicate a marginal effect on ossification (and hence foetotoxicity) at this dose level. At 40 mg/kg/day, the changes are considered to be too minor and too inconsistent to be of toxicological significance. This is substantiated by the absence of any effect on manus and pes scores, which are generally sensitive indicators of effects on ossification. There were no indications of any effect at 10 mg/kg/day. Under the study conditions, the systemic NOAEL of the substance was considered to be 10 mg/kg/day and the NOAEL for fetotoxicity was considered to be 40 mg/kg/day (Pigott, 1988).

Justification for classification or non-classification

Based on a reproductive toxicity study with the substance, no classification for this endpoint is warranted according to EU CLP (1272/2008) criteria.