Registration Dossier

Administrative data

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

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2002

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EPA OPPTS 870.3800 (Reproduction and Fertility Effects)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid
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%

Test animals

Species:
rat
Strain:
other: WI(Glx/BRL/Han)BR
Sex:
female

Administration / exposure

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
Doses / concentrations
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

Results and discussion

Results: P0 (first parental animals)

General toxicity (P0)

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
Gross pathological findings:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Other effects:
no effects observed

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:
no effects observed
Reproductive performance:
no effects observed

Details on results (P0)

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.

Effect levels (P0)

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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

Results: F1 generation

General toxicity (F1)

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

Details on results (F1)

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).

Effect levels (F1)

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

Results: F2 generation

Effect levels (F2)

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

Overall reproductive toxicity

Key result
Reproductive effects observed:
no

Applicant's summary and conclusion

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).