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REACH

N-tert-butylbenzothiazole-2-sulphenamide

EC number: 202-409-1 | CAS number: 95-31-8

Life Cycle description
Uses advised against

Toxicological information

Endpoint summary

Administrative data

Key value for chemical safety assessment

Effects on fertility

Description of key information

NOAEL (fertility) = 4500 ppm (ca. 291 mg/kg bw/day) – equiv. OECD 416 by read across to substance DCBS – Ema (2008)

NOAEL (fertility) = greater than 1000 mg/kg bw/day – equiv. OECD 422 – MHWJ (1997)

Link to relevant study records

Reference 1

Endpoint:

two-generation reproductive toxicity

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Justification for type of information:

Refer to Section 13 for category & read across justification.

Sex:

male/female

Clinical signs:

no effects observed

Description (incidence and severity):

There were no compound-related clinical signs of toxicity in either male or female rats during the pre-mating, mating, gestation, or lactation periods.

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Description (incidence):

No compound-related mortality was noted.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

P0 males: 80, 600 ppm: no effects, 4500 ppm significant decrease throughout the dosing period.
P0 females: 80, 600 ppm: no effects, 4500 ppm significant decrease during first week of dosing and throughout pregnancy and lactation.
P0: body weight at the scheduled terminal sacrifice was significant lower at 4500 ppm.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

P0 males: 80, 600 ppm no effects, 4500 ppm significant decrease during weeks 1 -8 and 13 -14
P0 females: 80, 600 ppm no effects, 4500 ppm significant decrease during week 1 of dosing and days 14 -21 of lactation

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

P0 males at 4500 ppm: significant higher percent of lymphocytes
P0 females: no effects

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

There were no significant changes in biochemistry parameters such as total protein, albumin and globulin in male and female P0 and P1 adult rats.
No significant changes in any serum hormone levels of male and female P0 adults were noted between the control and DCBS treated groups.

Endocrine findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

No compoundrelated gross lesions or remarkable microscopic alterations of tissues and organs, including the reproductive organs, were noted in males and females in the highest dose group and dead animals before the scheduled terminal sacrifice.

Histopathological findings: neoplastic:

not examined

Other effects:

no effects observed

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Description (incidence and severity):

No significant changes in sperm counts, percentage of motile sperm and progressively motile sperm, swimming speed and pattern, or percentage of morphologically abnormal sperm in DCBS treated animals.

Reproductive performance:

no effects observed

Description (incidence and severity):

No significant differences in: copulation index, fertility index, gestation index, pre-coital interval, gestation length, number of implantations, delivery index, number of P1/F1 pups delivered, sex ratio of P1/F1 pups, or viability of P1/F1 pups during lactation between control and DCBS-treated groups; no malformed P1/F1 pups were found in any groups.

Key result

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

female

Basis for effect level:

other: no adverse effects

Remarks on result:

other: Generation: maternal

Key result

Critical effects observed:

Clinical signs:

no effects observed

Description (incidence and severity):

There were no compound-related clinical signs of toxicity in either male or female rats during the pre-mating, mating, gestation, or lactation periods.

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Description (incidence):

No compound-related mortality was noted.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

No effects.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

P1 males: 80 ppm significant decrease in food consumption during weeks 4 and 7, 600 ppm during week 6, and 4500 ppm during week 4.
P1 females: 80, 600, 4500 ppm: no effects.

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

P1 males: no effects.
P1 females at 600 ppm: significant higher percent of lymphocytes.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

P1 males: no effects
P1 females at 600 ppm: significant higher percent of lymphocytes.
There were no significant changes in biochemistry parameters such as total protein, albumin and globulin in male and female adult rats.

Endocrine findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

P1 males: at 4500 ppm: significant decrease in absolute weights of brain, thymus, liver, kidney, adrenal gland, epididymis, ventral prostate, decrease in both relative and absolute weights: of spleen, increase in relative weights of the brain, liver and testis, decrease in rel. and absolute seminal vesicle, increased relative weight of kidney, increase of relative and absolute liver weights.
P1 females: significant decrease at 4500 ppm at scheduled sacrifice; at 4500 ppm: significant decrease absolute weights: brain, thymus, liver, kidney, spleen, adrenal, ovary and uterus and relative weight spleen, brain, liver, kidney.

Gross pathological findings:

no effects observed

Description (incidence and severity):

No compound-related gross lesions or remarkable microscopic alterations of tissues and organs, including the reproductive organs were noted in males and females of the highest dose group. Histopathological examinations of the ovary in P1 females, did not significant differ in the number of primordial follicles between control and 4500 ppm groups.

Neuropathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

No compound-related gross lesions or remarkable microscopic alterations of tissues and organs, including the reproductive organs were noted in males and females of the highest dose group. Histopathological examinations of the ovary in F1 females, did not significant differ in the number of primordial follicles between control and 4500 ppm groups.

Histopathological findings: neoplastic:

not examined

Other effects:

effects observed, treatment-related

Description (incidence and severity):

Delayed preputial separation at 4500 ppm as well as delayed vaginal opening and higher body weight at the age of vaginal opening at 600 and 4500 ppm were found in the F1 generation.

Reproductive function: oestrous cycle:

no effects observed

Description (incidence and severity):

Although one F1 female each in the control and 600 ppm groups displayed extended diestrous vaginal smears, no significant changes in the incidence of females having normal estrous cycles or length of the estrous cycles were observed.

Reproductive function: sperm measures:

effects observed, treatment-related

Description (incidence and severity):

A significant decrease in the mean lateral head displacement was found at 4500 ppm in F1 males.

Reproductive performance:

no effects observed

Description (incidence and severity):

P1 parents/F2 offspring: No significant changes in the copulation index, fertility index, gestation index, pre-coital index, gestation lengh, number of implantations, delivery index, number of F2 pups delivered, sex ratio of F2 pups, or viability of F2 pups during lactation were observed.
(Two P1 males in the 600 ppm group did not copulate. One female of the control group and two females in the 80 and 600 ppm groups did not become pregnant. One female in the 600 ppm group did not deliver. One dam experienced a total litter loss by PND 3 at 4500 ppm),
(malformation: oligodactyly in one female of control group, one microphthalmia in one male at 80 ppm)

Key result

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no adverse effects

Remarks on result:

other: Generation: foetal

Clinical signs:

no effects observed

Description (incidence and severity):

There were no compound-related clinical signs of toxicity in either male or female rats during the pre-mating, mating, gestation, or lactation periods.

Dermal irritation (if dermal study):

not examined

Mortality / viability:

no mortality observed

Description (incidence and severity):

No compound-related mortality was noted.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

No effects.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

F1 males: 80 ppm significant decrease in food consumption during weeks 4 and 7, 600 ppm during week 6, and 4500 ppm during week 4
F1 females: 80, 600, 4500 ppm: no effects

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

F1 males: no effects.
F1 females at 600 ppm: significant higher percent of lymphocytes.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

F1 males: no effects
F1 females at 600 ppm: significant higher percent of lymphocytes.
There were no significant changes in biochemistry parameters such as total protein, albumin and globulin in male and female adult rats.

Urinalysis findings:

not examined

Sexual maturation:

no effects observed

Anogenital distance (AGD):

no effects observed

Nipple retention in male pups:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

F1 males: at 4500 ppm: significant decrease in absolute weights of brain, thymus, liver, kidney, adrenal gland, epididymis, ventral prostate, decrease in both relative and absolute weights: of spleen, increase in relative weights of the brain, liver and testis, decrease in rel. and absolute seminal vesicle, increased relative weight of kidney, increase of relative and absolute liver weights.
F1 females: significant decrease at 4500 ppm at scheduled sacrifice; at 4500 ppm: significant decrease absolute weights: brain, thymus, liver, kidney, spleen, adrenal, ovary and uterus and relative weight spleen, brain, liver, kidney.

Gross pathological findings:

no effects observed

Description (incidence and severity):

No compound-related gross lesions or remarkable microscopic alterations of tissues and organs, including the reproductive organs were noted in males and females of the highest dose group. Histopathological examinations of the ovary in F1 females, did not significant differ in the number of primordial follicles between control and 4500 ppm groups.

Histopathological findings:

no effects observed

Description (incidence and severity):

No compound-related gross lesions or remarkable microscopic alterations of tissues and organs, including the reproductive organs were noted in males and females of the highest dose group. Histopathological examinations of the ovary in F1 females, did not significant differ in the number of primordial follicles between control and 4500 ppm groups.

Other effects:

effects observed, treatment-related

Description (incidence and severity):

Delayed preputial separation at 4500 ppm as well as delayed vaginal opening and higher body weight at the age of vaginal opening at 600 and 4500 ppm were found in the F1 generation.

Behaviour (functional findings):

no effects observed

Developmental immunotoxicity:

not examined

Key result

Dose descriptor:

NOAEL

Generation:

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no adverse effects

Remarks on result:

other: Generation: foetal

Clinical signs:

no effects observed

Dermal irritation (if dermal study):

not examined

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Body weights of F2 pups at 4500 ppm were significantly lowered on PNDs 7,14 and 21 in males and PNDs 14 and 21 in females.

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:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Sexual maturation:

not examined

Anogenital distance (AGD):

no effects observed

Nipple retention in male pups:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Males: A decrease in the absolute and relative weight of the spleen was observed at 80 ppm. The relative weights of the liver and kidney were higher at 600 ppm. At 4500 ppm,a decreased absolute weight of the adrenal gland, decreased absolute and relative weights of the thymus and spleen, and increased relative weights of the brain, liver, and kidney were noted in males.
Females: A significant decrease in the body weight at sacrifice was found at 4500 ppm. The relative weight of the thymuswas lower at 80 ppm. An increased relative weights of the liver and kidney, and reduced absolute and relative weights of the uterus were found at 600 ppm. At 4500 ppm, decreased absolute weights of the brain and spleen, and absolute and relative weights of the thymus and uterus, and increased relative weights of the brain, liver and kidney were noted in females.

Gross pathological findings:

no effects observed

Description (incidence and severity):

There were no compound-related gross lesions or microscopic alterations in male and female F1 and F2 pups, including pups that died before weaning.

Histopathological findings:

no effects observed

Description (incidence and severity):

There were no compound-related gross lesions or microscopic alterations in male and female F1 and F2 pups, including pups that died before weaning.

Other effects:

not specified

Behaviour (functional findings):

no effects observed

Developmental immunotoxicity:

not examined

There were no compound-related gross lesions or microscopic alterations in male and female P1/F1 and F2 pups, including pups that died before weaning.

Key result

Dose descriptor:

NOAEL

Generation:

Effect level:

291 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no adverse effects

Key result

Critical effects observed:

Key result

Reproductive effects observed:

Adults/weanlings

Mortality:

P0: no compound-related mortality was noted in any of the animals of the F0 generation during the pre-mating, mating, gestation or lactation period

P1/F1: no compound-related mortality was noted in any of the animals of the F1 generation during the pre-mating, mating, gestation or lactation period

Clinical observations:

P0 and P1/F1: no compound-related clinical signs of toxicity in neither male or female P0 and P1/F1 rats during the pre-mating, mating, gestation, or lactation period

Body weight and body weight gain:

P0 males: 80, 600 ppm: no effects, 4500 ppm significant decrease throughout the dosing period

P0 females: 80, 600 ppm: no effects, 4500 ppm significant decrease during first week of dosing and throughout pregnancy and lactation

P1/F1 males and females: no effects

Food consumption:

P0 males: 80, 600 ppm no effects, 4500 ppm significant decrease during weeks 1 -8 and 13 -14

P0 females: 80, 600 ppm no effects, 4500 ppm significant decrease during week 1 of dosing and days 14 -21 of lactation

P1/F1 males: 80 ppm significant decrease in food consumption during weeks 4 and 7, 600 ppm during week 6, and 4500 ppm during week 4

P1/F1 females: 80, 600, 4500 ppm: no effects

Mean daily intake (corresponding to 80, 600, 4500 ppm in diet)

P0 males: 5.2, 39, 291 mg/kg bw

P0 females: 7.2, 54, 416 mg/kg bw

P1/F1 males: 5.9, 44, 331 mg/kg bw

P1/F1 females: 7.4, 55, 417 mg/kg bw

Necropsy and histopathology:

P0: no compound-related gross lesions or remarkable microscopic alterations of tissues and organs, including the reproductive organs were noted in males and females of the highest dose group

P1/F1: no compound-related gross lesions or remarkable microscopic alterations of tissues and organs, including the reproductive organs were noted in males and females of the highest dose group. Histopathological examinations of the ovary in P1/F1 females, did not significant differ in the number of primordial follicles between control and 4500 ppm groups.

Estrous cyclicity:

P0 females: no effects.

P1/F1females: no significant changes in the incidence of females having normal estrous cycles or length of the estrous cycles

(two P1/F1 females showing abnormal estrous cycles remained in diestrus for 10 -11 days).

Reproductive effects:

P0 parents/P1/F1 offspring: no significant differences in: copulation index, fertility index, gestation index, pre-coital interval, gestation length, number of implantations, delivery index, number of P1/F1 pups delivered, sex ratio of P1/F1 pups, or viability of P1/F1 pups during lactation between control and DCBS-treated groups; no malformed P1/F1 pups were found in any groups, a significant lower body weight was observed in male and female P1/F1 pups at 4500 ppm on PND 4, 7 and 21.

(P0 parent animals, all pairs in all groups copulated, although two females in the control group did not become pregnant, and all pregnant females in all groups delivered live pups)

P1/F1 parents/F2 offspring: No significant changes in the copulation index, fertility index, gestation index, pre-coital index, gestation lengh, number of implantations, delivery index, number of F2 pups delivered, sex ratio of F2 pups, or viability of F2 pups during lactation were observed.

(Two P1/F1 males in the 600 ppm group did not copulate. One female of the control group and two females in the 80 and 600 ppm groups did not become pregnant. One female in the 600 ppm group did not deliver. One dam experienced a total litter loss by PND 3 at 4500 ppm),

(malformation: oligodactyly in one female of control group, one microphthalmia in one male at 80 ppm).

Body weights of F2 pups at 4500 ppm were significant lowered on PND 7, 14, and 21 in males and PNDs 14 to 21 in females.

Organ weights:

P0: body weight at the scheduled terminal sacrifice was significant lower at 4500 ppm

P0males: 4500 ppm significant lower absolute organ weights: spleen, adrenal gland; increase in relative weight of: brain, thyroid, liver, kidney and testis

P0 females: significant increase in absolute weights of: brain (80 ppm, 600 ppm), pituitary (80 ppm); decrease in relative weights: spleen (80 ppm and 600 ppm),

significant decrease absolute weight of: spleen and increase relative weights of brain, kidney, adrenal gland at 4500 ppm

P1/F1 (weanlings and adults)

P1/F1 males: at 4500 ppm: significant decrease in absolute weights of brain, thymus, liver, kidney, adrenal gland, epididymis, ventral prostate, decrease in both relative and absolute weights: of spleen, increase in relative weights of the brain, liver and testis, decrease in rel. and absoluteseminal vesicle, increased relative weight of kidney, increase of relativeand abolute liver weights.

P1/F1 females: significant decrease at 4500 ppm at scheduled sacrifice;

at 4500 ppm: significant decrease absolute weights: brain, thymus, liver, kidney, spleen, adrenal, ovary and uterus and relative weight spleen, brain, liver, kidney.

F2 (weanlings)

F2 males/females: at 4500 ppm body weight significant reduced

F2 males at 4500 ppm: signifcant decrease in absolute weights: adrenal gland, decrease in absolute and relative weights of: thymus, spleen; increase in rel. weights in brain, liver, kidney

F2 females: at 600 ppm: significantly increase in rel weights: liver, kidney, reduced absolute and rel. weights: uterus

at 4500 ppm: significant decrease in absolute weights: brain, spleen, and absolute and rel. weights of thymus, uterus, and increased rel. weights of brain, liver and kidney

Hematological and blood biochemical parameters

P0 males at 4500 ppm: significant higher percent of lymphocytes

P0 females: no effects

P1/F1 males: no effects

P1/F1 females at 600 ppm: significant higher percent of lymphocytes

F0/P1,F1: no significant changes in biochemistry parameters such as total protein, albumin and globulin

Serum hormone levels (P0 and P1/F1 adults)

P0 male/female: no significant changes

P1/F1 male: significant higher levels of testosterone at 80 and 600 ppm, no significant changes at 4500 ppm

P1/F1 female: no significant changes in any serum hormone levels

Sperm parameter (P0 and P1/F1 adults)

P0 males: no significant changes in sperm counts, percentage of motile sperm and progressively motile sperm, swimming speed and pattern, or percentage of morphologically abnormal sperm in DCBS treated animals

P1/F1: at 4500 ppm a significant decrease in the mean lateral displacement (20.5 µm ± 1.0 vs. control 21.3 ± 0.9 µm).

Conclusions:

Although a few P0 and P1/F1 adults showed reproductive difficulties, necropsy and the histopathology of reproductive organs revealed no evidence of reproductive failure in these rats. In conclusion, no significant changes in reproductive indices were noted in any generation even at the highest dose 4500 ppm (ca. 291 mg/kg bw and day).

Executive summary:

Study design

Results

The deaths and clinical signs observed in the present study are not related to the administration of DCBS. Decreased food consumption was noted in P0 males and females at 4500 ppm and was accompanied by reduced body weight, body weight gain and food consumption. However, no consistent lowered food consumption accompanied by lower body weights were noted in P1/F1 adults. No significant changes in sperm counts, percentage of motile sperm and progressively motile sperm, swimming speed and pattern, or percentage of morphologically abnormal sperm were noted in F0 and P1/F1 adults between control and DCBS-treated groups. However, a slight but significant decrease in mean lateral head displacement was noted in P1/F1 males of the highest group (20.5 µm ± 1.0 vs. control 21.3 ± 0.9 µm). All P0 females showed normal oestrous cycles in all groups, and the length of the oestrous cycles was not different between the control and DCBS-treated groups. Although one P1/F1 female each in the control and 600 ppm groups displayed extended diestrus vaginal smears, no significant changes in the incidence of females having normal oestrous cycles or length of the oestrous cycles were observed. There were no significant differences in the copulation index, fertility index, gestation index, pre-coital interval, gestation length, number of implantations, delivery index, number of P1/F1 pups delivered, sex ratio of P1/F1 pups, or viability of P1/F1 pups during lactation between control and DCBS-treated groups. No malformed P1/F1 pups were found in any groups. Two P1/F1 males in the 600 ppm group did not copulate. One female in the control group and two females each in the 80 and 600 ppm groups did not become pregnant. One pregnant female in the 600 ppm group did not deliver. One dam in the control group died on day 5 of lactation, and her pups were euthanized. One dam experienced a total litter loss by PND 3 at 4500 ppm. No significant changes in the copulation index, fertility index, gestation index, pre-coital interval, gestation length, number of implantations, delivery index, number of F2 pups delivered, sex ratio of F2 pups, or viability of F2 pups during lactation were observed. Oliodactyly in one female of the control group and microphthalmia in one male at 80 ppm were observed. Although a few P0 and P1/F1 adults showed reproductive difficulties, necropsy and the histopathology of reproductive organs revealed no evidence of reproductive failure in these rats.

Conclusion

In conclusion, no significant changes in reproductive indices were noted in any generation even at the highest dose 4500 ppm (ca. 291 mg/kg bw/day).

Reference 2

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Remarks:

Guideline GLP study with limited reporting in English (abstract, data tables etc)

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Principles of method if other than guideline:

N-tert-butyl-2-benzothiazolesulfenamide was studied for oral toxicity in rats in an OECD combined repeat dose and reproductive/developmental screening test at doses of 0, 40, 200, or 1000 mg/kg/day.

Note: The study does not report information on the following tissues/organs as required according to the guidelines: brain, spinal cord, large and small intestine, stomach, thyroid, trachea and lungs, uterus urinary bladder, lymph nodes, peripheral nerve, and bone marrow.

GLP compliance:

yes

Limit test:

Species:

rat

Strain:

Sprague-Dawley

Remarks:

Crj:CD SPF

Details on species / strain selection:

Rats of this strain were chosen because they are the most commonly used in reproductive and developmental toxicity studies and historical control data are available.

Sex:

male/female

Route of administration:

oral: gavage

Vehicle:

other: 5% gum arabic

Details on mating procedure:

No data.

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

Males 42 days, females 38 days (from 14 days prior to mating to day 3 of lactation).

Frequency of treatment:

Daily.

Dose / conc.:

0 mg/kg bw/day (nominal)

Remarks:

Control

Dose / conc.:

40 mg/kg bw/day (nominal)

Dose / conc.:

200 mg/kg bw/day (nominal)

Dose / conc.:

1 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

13 animals per dose and sex.

Control animals:

yes

Positive control:

None.

Parental animals: Observations and examinations:

Number of mated pairs, number of copulated pairs, copulation index, number of pregnant animals, fertility index, pairing days until copulation.

Oestrous cyclicity (parental animals):

Frquency of vaginal estrus.

Litter observations:

Number of pregnant females, number of pregnant females with pups alive, gestation index, number of corpora lutea, number of implantation sites, implantation index, number of pups born, delivery index, number of pups alive, birth index, live birth index, pup weights in grams.

Postmortem examinations (parental animals):

Gross pathology and histopathology. See also IUCLID section 7.5.1 MHJW, 1997.

Reproductive indices:

Gestation index, implantation index, delivery index, birth index, live birth index, sex ration, viability index.

Offspring viability indices:

Day 4 of lactation: number of pups alive, viability index, pup weights in grams.

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

In males and females temporary salivation after each administration at 1000 mg/kg/day.

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

In males suppresion of food consumption and body weight gain at 1000 mg/kg/day.
In females food consumption was decreased prior mating and along with slight suppression of body weight gain during pregnancy at 1000 mg/kg/bw.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

In males hemoglobin and hemocrit values were slightly decreased and hemolytic anemia was induced at 1000 mg/kg bw.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

In males slight increase in the total bilirubin concentration and dose-dependent increase in the deposition of hemosiderin in the spleen at 200 and 1000 mg/kg bw.

Urinalysis findings:

not specified

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

In males increase in eosinophilic bodies in the kidney, however the incidences was increased but not the severity compared to control. hypertrophy of hepatocytes in the central zone. Decrease in fatty change of hepatocytes in the periportal zone.
In females at autopsy on postpartum day 4, slight vacuolar degeneration in the proximal tubules of kidney was observed, slight hypertrophy of hepatocytes in the central zone and depostion of brown pigment in the spleen (tended to increase but in many cases comparable to control group).

Histopathological findings: neoplastic:

not examined

Key result

Dose descriptor:

NOAEL

Remarks:

Systemic

Effect level:

40 mg/kg bw/day

Based on:

test mat.

Sex:

female

Basis for effect level:

other: no effects

Key result

Dose descriptor:

LOAEL

Remarks:

Systemic

Effect level:

40 mg/kg bw/day

Based on:

test mat.

Sex:

male

Basis for effect level:

other: increase in eosinophilic bodies in the kidney

Key result

Dose descriptor:

LOAEL

Remarks:

systemic

Effect level:

200 mg/kg bw/day

Based on:

test mat.

Sex:

female

Basis for effect level:

other: slight histopathological changes in kidney and in the liver

Key result

Dose descriptor:

NOAEL

Remarks:

fertility

Effect level:

200 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no effects

Critical effects observed:

yes

Lowest effective dose / conc.:

200 mg/kg bw/day (nominal)

System:

urinary

Organ:

kidney

liver

Treatment related:

yes

Dose response relationship:

yes

Clinical signs:

not examined

Dermal irritation (if dermal study):

not examined

Mortality / viability:

no mortality observed

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:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Description (incidence and severity):

N-tert-butyl-2-benzothiazolesulfenamide at the dose levels applied did not demonstrate teratogenicity.

Histopathological findings:

no effects observed

Description (incidence and severity):

N-tert-butyl-2-benzothiazolesulfenamide at the dose levels applied did not demonstrate teratogenicity.

Other effects:

no effects observed

Behaviour (functional findings):

not examined

Developmental immunotoxicity:

no effects observed

N-tert-butyl-2-benzothiazolesulfenamide at the dose levels aplied did not exert adverse effects on copulation and ovulation. Fertility indices in the 40 and 1000 mg/kg groups were lower than the control level. However the low index observed in the 40 mg/kg group seemed to be an artificial finding because all the females in the 200 mg/kg group were found to be fertile. No relation between the low index observed in the 1000 mg/kg group and the adminisatrion of N-tert-butyl-2-benzothiazolesulfenamide was found. Thus, the no effect level for fertility was 200 mg/kg.
No dose related abnormalities were observed with regard to parturition and lactation. There were no adverse effects on viability, the sex ratio and body weights of pups in any N-tert-butyl-2-benzothiazolesulfenamide treated group.
N-tert-butyl-2-benzothiazolesulfenamide at the dose levels applied did not demonstrate teratogenicity.
The no effect level (NOEL) of N-tert-butyl-2-benzothiazolesulfenamide for reproductive and developmental toxicity was 200 mg/kg/day in males and females.

Key result

Dose descriptor:

NOAEL

Generation:

Effect level:

> 1 000 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No adverse effects on viability, the sex ratio and body weights of pups in any of the treated animals. TBBS at the dose levels applied did not demonstrate teratogenicity.

Remarks on result:

other: 1000 mg/kg bw was the highest applied dose.

Key result

Critical effects observed:

Key result

Reproductive effects observed:

Males:

40 mg/kg bw/day

increase in eosinophilic bodies in the kidney, however the incidences was increased but not the severity compared to control (see table 1)

200 mg/kg bw/day

temporary salivation after each administration of test substance

increase in eosinophilic bodies in the kidney, however the incidences was increased but not the severity compared to control (see table 1)

slight hypertrophy of hepatocytes in the central zone

slight increase in the total bilirubin concentration and dose-dependent increase in the deposition of hemosiderin in the spleen

1000 mg/kg bw/day

suppresion of food consumption and body weight gain

temporary salivation after each administration of test substance

increase in eosinophilic bodies in the kidney, however the incidences was increased but not the severity compared to control (see table 1)

increase in absolute and relative kidney weights

hypertrophy of hepatocytes in the central zone

increase in relative liver weights

decrease in fatty change of hepatocytes in the periportal zone

slight increase in the total bilirubin concentration and dose-dependent increase in the deposition of hemosiderin in the spleen

hemoglobin and hemocrit values were slightly decreased and hemolytic anemia was induced

slight increase in total cholesterol concentration

Females:

40 mg/kg bw/day

no effects

200 mg/kg bw/day

temporary salivation after each administration

at autopsy on postpartum day 4, slight vacuolar degeneration in the proximal tubules of kidney was observed (see table 1)

slight increase in the relative kidney weights (not dose dependent)

slight hypertrophy of hepatocytes in the central zone

1000 mg/kg bw/day

temporary salivation after each administration

food consumption was decreased prior mating and along with slight suppression of body weight gain during pregnancy

at autopsy on postpartum day 4, slight vacuolar degeneration in the proximal tubules of kidney was observed

slight increase in the relative kidney weights

slight hypertrophy of hepatocytes in the central zone

increase in absolute and relative liver weights

depostion of brown pigment in the spleen (tended to increase but in many cases comparable to control group)

Table 1: Body weights of male rats treated orally with N-tert-butyl-2-benzothiazolesulfenamide in the combined repeat dose and reproductive/developmental toxicity screening test

Days of administration	Dose
Days of administration	0	40	200	1000
1 (initial weight)	281.4 ± 8.6	281.8 ± 9.4	281.9 ± 9.9	281.9 ± 9.0
8	327.1 ± 8.6	333.7 ± 16.4	336.2 ± 17.2	317.3 ± 17.8
15	327.2 ± 18.2	376.4 ± 22.0	385.1 ± 21.1	357.0 ± 24.2
22	401.3 ± 23.7	410.3 ± 27.7	414.9 ± 22.0	385.6 ± 30.2
29	430.6 ± 27.5	440.8 ± 33.0	442.5 ± 24.5	411.5 ± 36.1
36	458.6 ± 32.8	469.2 ± 36.0	471.1 ± 27.3	431.9 ± 40.6
42	479.4 ± 37.7	488.2 ± 37.7	487.2 ± 31.3	445.8 ± 44.5

Values are expressed as Mean ± S.D. in grams – 13 animals used in each group throughout the study

Table 2: Body weights of female rats treated orally with N-tert-butyl-2-benzothiazolesulfenamide in the combined repeat dose and reproductive/developmental toxicity screening test

Days of		Dose (mg/kg)
administration (pre-mating period)	0	40	200	1000
1 (Init. wt.)	190.2 ± 7.2 (13)	189.5 ± 6.4 (13)	189.7 ± 6.8 (13)	190.0 ± 5.8 (13)
8	211.2 ± 8.2 (13)	208.2 ± 10.0 (13)	211.4 ± 8.1 (13)	207.3 ± 7.6 (13)
15	229.8 ± 11.8 (13)	225.9 ± 11.7 (13)	229.5 ± 10.9 (13)	222.5 ± 8.6 (13)
Days of pregnancy 0	234.2 ± 13.5 (10)	236.9 ± 21.0 (7)	239.0 ± 11.5 (13)	233.5 ± 16.4 (9)
7	272.2 ± 17.1 (10)	273.8 ± 29.3 (7)	276.0 ± 16.2 (13)	258.9 ± 19.0 (9)
14	308.1 ± 18.1 (10)	311.3 ± 34.9 (7)	312.5 ± 17.7 (13)	290.4 ± 22.6 (9)
20	374.1 ± 23.4 (10)	380.4 ± 41.4 (7)	385.1 ± 26.1 (13)	343.0 ± 40.4 (9)
Days of lactation 0	284.2 ± 23.2 (10)	276.6 ± 37.3 (6)	283.6 ± 26.2 (13)	262.2 ± 27.4 (8)
4	302.5 ± 14.1 (10)	308.1 ± 29.3 (6)	301.5 ± 20.3 (13)	284.9 ± 34.6 (8)

Values are expressed as Mean ± S.D. in grams.

Parenthesis indicates number of animals

Table 3: Food consumption of male rats treated orally with N-tert-butyl-2-benzothiazolesulfenamide in the combined repeat dose and reproductive/developmental toxicity screening test

Days of		Dose (mg/kg)
administration	0	40	200	1000
1 – 8	202.8 ± 22.7	205.7 ± 10.9	211.1 ± 13.3	181.9 ± 15.5**
8 – 15	202.9 ± 19.4	200.1 ± 11.1	215.4 ± 13.5	191.1 ± 21.3
29 – 36	197.4 ± 20.4	205.2 ± 21.8	211.4 ± 18.5	192.7 ± 25.4
36 – 42	174.9 ± 18.6	177.9 ± 19.6	179.6 ± 14.3	165.8 ± 20.3

Values are expressed as Mean ± S.D. in grams – 13 animals used in each group throughout the study

**: significant difference from control, p<0.01

Table 4: Food consumption of female rats treated orally with N-tert-butyl-2-benzothiazolesulfenamide in the combined repeat dose and reproductive/developmental toxicity screening test

Days of Dose (mg/kg) administration 0 40 200 1000

(pre-mating period)

1 – 8 132.5 ± 7.3 (13) 130.8 ± 8.9 (13) 133.2 ± 9.3 (13) 116.7 ± 8.0** (13)

8 – 15 137.3 ± 10.8 (13) 134.1 ± 12.9 (13) 136.8 ± 11.7 (13) 124.7 ± 12.5* (13)

Days of pregnancy

0 – 7 166.8 ± 16.9 (10) 165.3 ± 29.1 (7) 164.2 ± 16.5 (13) 133.4 ± 25.8* (9)

7 – 14 177.9 ± 15.2 (10) 180.9 ± 29.4 (7) 177.9 ± 15.2 (13) 161.2 ± 16.3 (9)

14 – 20 140.9 ± 8.8 (10) 138.3 ± 9.8 (7) 143.3 ± 11.7 (13) 122.4 ± 16.3* (9)

Days of lactation

0 – 4 122.3 ± 21.9 (10) 117.6 ± 15.0 (6) 108.8 ± 25.8 (13) 121.2 ± 25.3 (8)

Values are expressed as Mean ± S.D. in grams

Parenthesis indicates number of animals

*: significant difference from control, p<0.05

**: significant difference from control, p<0.01

Table 5: Hematological findings of male rats treated orally with N-tert-butyl-2-benzothiazolesulfenamide in the combined repeat dose and reproductive/developmental toxicity screening test

	0	40	200	1000
		Red Blood Cells
Count (X10⁴/mm³)	805 ± 35	814 ± 40	807 ± 31	774 ± 40
Hemoglobin (g/dl)	15.4 ± 0.6	15.5 ± 0.7	15.3 ± 0.5	14.5 ± 0.4**
Hematocrit (%)	44.4 ± 1.6	44.7 ± 1.9	43.7 ± 1.7	41.6 ± 1.6**
MCV (µm ³)	55.2 ± 1.7	55.0 ± 2.1	54.2 ± 1.1	53.7 ± 1.1
MCH (pg)	19.1 ± 0.7	19.0 ± 0.8	18.9 ± 0.4	18.7 ± 0.5
MCHC (%)	34.6 ± 0.6	34.6 ± 0.4 White Blood Cells	35.0 ± 0.5	34.8 ± 0.5
Count (X10²/mm³)	116 ± 20	111 ± 23	101 ± 19	86 ± 28**
Band neutrophil (%)	0 ± 0	0 ± 0	0 ± 0	0 ± 0
Segmented neutrophil (%)	10 ± 4	10 ± 5	15 ± 10	16 ± 11
Eosinophil (%)	0 ± 1	1 ± 1	1 ± 1	1 ± 1
Basophil (%)	0 ± 0	0 ± 0	0 ± 0	0 ± 0
Monocyte (%)	2 ± 2	2 ± 2	1 ± 1	2 ± 2
Lymphocyte (%)	87 ± 5	87 ± 6 Platelet	83 ± 10	81 ± 11
Count (X10⁴/mm³)	114.1 ± 8.2	112.5 ± 10.1	111.9 ± 8.9	115.8 ± 8.1

Values are expressed as Mean ± S.D. – 13 animals used in each group throughout the study

**: significant difference from control, p<0.01

Table 6: Blood chemical findings of male rats treated orally with N-tert-butyl-2-benzothiazolesulfenamide in the combined repeat dose and reproductive/developmental toxicity screening test

	Dose (mg/kg) 0	40	200	1000
Total protein (g/dl)	5.5 ± 0.3	5.6 ± 0.3	5.8 ± 0.2	5.7 ± 0.4
Albumin (g/dl)	2.8 ± 0.2	2.9 ± 0.3	3.0 ± 0.1	3.0 ± 0.1
A/C	1.05 ± 0.08	1.06 ± 0.15	1.08 ± 0.12	1.10 ± 0.15
BUN (mg/dl)	17 ± 2	17 ± 2	17 ± 2	18 ± 2
Creatinine (mg/dl)	0.7 ± 0.1	0.7 ± 0.1	0.7 ± 0.0	0.7 ± 0.1
Glucose (mg/dl)	137 ± 13	157 ± 14**	141 ± 12	120 ± 15**
Total cholesterol (mg/dl)	59 ± 13	58 ± 11	59 ± 8	70 ± 12*
Total bilirubin (mg/dl)	0.07 ± 0.02	0.09 ± 0.02	0.09 ± 0.02**	0.09 ± 0.02**
Na (mEq/l)	144.5 ± 1.1	144.4 ± 0.9	144.6 ± 0.9	145.6 ± 0.7*
K (mEq/l)	3.77 ± 0.23	3.76 ± 0.13	3.83 ± 0.22	3.91 ± 0.2
Cl (mEq/l)	106.6 ± 1.4	105.8 ± 0.9	105.9 ± 1.0	106.0 ± 1.2
Ca (mg/dl)	8.6 ± 0.4	8.6 ± 0.5	8.7 ± 0.2	8.9 ± 0.2
Inorg. phos. (mg/dl)	6.2 ± 0.6	6.2 ± 0.5	5.7 ± 0.4	5.8 ± 0.5
ALP (U/l)	199 ± 41	218 ± 54	220 ± 38	205 ± 65
GOT (U/l)	58 ± 7	59 ± 7	60 ± 6	59 ± 10
γ. GTP (U/l)	0 ± 0	0 ± 0	0 ± 0	0 ± 0

Values are expressed as Mean ± S.D. – 13 animals used in each group throughout the study

*: significant difference from control, p<0.05

**: significant difference from control, p<0.01

Table 7: Absolute and relative organ weights of rats treated orally with N-tert-butyl-2-benzothiazolesulfenamide in the combined repeat dose and reproductive/developmental toxicity screening test

Sex

Dose (mg/kg bw/day)

200

1000

Male

Final body weight (g)

447.2 ± 35.0

(13)

458.4 ± 36.1

(13)

455.9 ± 29.2

(13)

416.5 ± 42.4

(13)

Liver (g)

12.57 ± 1.73^a

(13)

14.21 ± 1.78

(13)

13.65 ± 0.98

(13)

13.41 ± 1.53

(13)

2.80 ± 0.21^b

3.09 ± 0.22**

3.00 ± 0.15*

3.22 ± 0.22**

Kidneys (g)

2.94 ± 0.32

(13)

3.03 ± 0.26

(13)

3.16 ± 0.27

(13)

3.27 ± 0.25*

(13)

0.66 ± 0.06

0.66 ± 0.05

0.69 ± 0.05

0.79 ± 0.06**

Spleen (g)

0.77 ± 0.11

(13)

0.76 ± 0.07

(13)

0.76 ± 0.09

(13)

0.73 ± 0.10

(13)

0.17 ± 0.02

0.18 ± 0.02

Thymus (mg)

389.8 ± 122.5

86.8 ± 25.7

(13)

370.1 ± 55.2

80.8 ± 10.8

(13)

375.7 ± 67.3

82.5 ± 14.9

(13)

313.5 ± 97.5

74.3 ± 18.3

(13)

Testes (g)

3.04 ± 0.29

(13)

3.01 ± 0.21

(13)

3.02 ± 0.38

(13)

3.14 ± 0.21

(13)

0.68 ± 0.06

0.66 ± 0.07

0.76 ± 0.09*

Epididymides (g)

1.10 ± 0.12

(13)

1.04 ± 0.10

(13)

1.07 ± 0.13

(13)

1.06 ± 0.10

(13)

0.24 ± 0.03

0.23 ± 0.03

0.26 ± 0.04

Final body weight (g)

302.5 ± 14.1

(10)

308.1 ± 29.3

(6)

301.5 ± 20.3

(13)

284.9 ± 34.6

(8)

Liver (g)

12.87 ± 1.01

(10)

13.16 ± 1.49

(6)

14.15 ± 2.26

(13)

14.59 ± 3.05

(8)

4.26 ± 0.38

4.27 ± 0.29

4.70 ± 0.67

5.10 ± 0.68*

Kidneys (g)

2.09 ± 0.24

(10)

2.00 ± 0.28

(6)

2.14 ± 0.24

(13)

2.09 ± 0.11

(8)

Female

0.69 ± 0.08

0.65 ± 0.07

0.71 ± 0.07

0.74 ± 0.06

Spleen (g)

0.66 ± 0.09

(10)

0.60 ± 0.10

(6)

0.56 ± 0.07

(13)

0.57 ± 0.11

(8)

0.22 ± 0.03

0.19 ± 0.01

0.19 ± 0.02

0.20 ± 0.03

Thymus (mg)

190.5 ± 49.5

(10)

168.7 ± 39.2

(6)

177.5 ± 76.6

(13)

154.7 ± 68.4

(8)

62.8 ± 15.0

55.1 ± 13.4

58.5 ± 24.5

52.6 ± 19.5

Values are expressed as Mean ± S.D.

Parenthesis indicates number of animals

a: absolute weight

b: relative weight (g or mg per 100 g body weight)

*: significant difference from control, p<0.05

**: significant difference from control, p<0.01

Table 8: Histopathological findings of rats treated with TBBS in the combined repeat dose and reproductive/developmental toxicity screening test

Organ findings, grade and number of animals	Sex	male				female
	Dose (mg/kg bw/d)	0	40	200	1000	0	40	200	1000
Kidney
	Number of animals evaluated	13	13	13	13	13	13	13	13
Eosinophilic body	total	6	13**	13**	13**	0	0	0	0
	+/-	2	5	6	1
	+	1	7	5	2
	++	3	1	1	10
	+++	0	0	1	0

Basophilic tubule cortex	total	9	9	7	8	4	3	6	1
	±	7	9	5	8	3	3	6	1
	+	2	0	1	0	1	0	0	0
	++	0	0	1	0

Degeneration, vacuolar, proximal tubule	total	0	0	0	0	0	0	3	3
	±					0	0	3	1
	+					0	0	0	2

**significant difference from control, p<0.01 (Mann-Whitney U test)

Table 9: Summary of reproductive performance in parental rats treated orally with TBBS in the combined repeat dose and reproductive/development toxicity screening test

	Dose (mg/kg)
	0	40	200	1000
Number of mated pairs	13	13	13	13
Number of copulated pairs	12	12	13	13
Copulation index ^A	92.3	92.3	100	100
Number of pregnant animals	10	7	13	9
Fertility index ^B	83.3	58.3	100	69.2
Pairing days until copulation Mean ± S.D.	3.2 ±2.1	2.3 ± 1.1	3.7 ± 1.7	3.0 ± 2.8
Frequency of vaginal estrus Mean ± S.D.	1.1 ± 0.3	1.0 ± 0.0	1.2 ± 0.4	1.0 ± 0.0
Copulation index = (Number of copulated pairs/Number of mated pairs) X 100: % Fertility index = (Number of pregnant animals/Number of copulated pairs) X 100: %

Table 10: Summary of development of pups from dams treated orally with TBBS in the combined repeat dose and reproductive/developmental toxicity screening test

	Dose (mg/kg)
	0	40	200	1000
Number of pregnant females	10	7	13	9
Number of pregnant females with pups alive	10	6	13	8
Gestation index ^A	100	85.7	100	88.9
Gestation length in days	22.3±0.5 (10)	22.5±0.5 (6)	22.4±0.5 (13)	22.5±0.5 (8)
Number of corpora lutea	16.5±2.0 (10)	15.9±2.3 (7)	17.2±2.2 (13)	15.7±2.6 (9)
Number of implantation sites	14.0±4.0 (10)	14.0±5.5 (7)	14.5±5.3 (13)	12.8±5.8 (9)
Implantation index ^B	84.3±19.6 (10)	85.7±31.1 (7)	83.0±26.6 (13)	78.5±30.2 (9)
Day 0 of lactation
Number of pups born	13.0±4.1 (10)	13.3±6.0 (7)	13.8±5.2 (13)	11.0±5.8 (9)
Delivery index ^C	92.7±9.0 (10)	83.0±36.7 (7)	94.9±5.6 (13)	75.8±31.5 (9)
Number of pups alive	12.9±4.0 (10)	13.1±5.9 (7)	13.5±4.9 (13)	10.9±5.8 (9)
Birth index ^D	92.1±8.6 (10)	82.2±36.4 (7)	93.2±4.8 (13)	75.1±31.8 (9)
Live birth index ^E	99.4±1.9 (10)	99.1±2.3 (6)	98.3±2.7 (13)	98.9±3.2 (8)
Pup weight in grams
Male	6.8±0.9 (10)	6.5±0.3 (6)	6.7±1.0 (13)	6.5±0.9 (8)
Female	6.5±1.0 (10)	6.2±0.4 (5)	6.5±0.9 (13)	6.2±0.7 (8)
Sex ratio ^F	52.7±14.7 (10)	49.2±9.3 (6)	48.9±7.8 (13)	44.3±10.1 (8)
Day 4 of lactation
Number of pups alive	12.7±4.1 (10)	13.0±5.9 (7)	13.3±4.8 (13)	10.6±5.5 (9)
Viability index ^G	97.8±5.4 (10)	98.8±2.9 (6)	99.1±2.2 (13)	97.8±6.2 (8)
Pup weight in grams
Male	11.0±1.8 (10)	9.6±0.8 (6)	10.3±2.6 (13)	9.9±2.0 (8)
Female	10.5±1.8 (10)	9.5±0.7 (6)	9.8±2.3 (13)	9.5±1.6 (8)
Values are expressed as Mean ± S.D. Parenthesis indicates the number of litters evaluated Gestation index = (Number of pregnant females with pups alive/Number of pregnant females) X 100: % Implantation index = ( Number of implantation sites/Number of corpora lutea) X 100: % Delivery index = (Number of pups born/Number of implantation sites) X 100: % Birth index = (Number of pups alive on day 0/Nmber of implantation sites) X 100: % Live birth index = (Number of pups alive on day 0/Number of pups born) X 100: % Sex ratio = (Number of male pups alive on day 0/Number of pups alive on day 0) X 100: % Viability index = (Number of male pups alive on day 4/Number of male pups alive on day 0) X 100: %

Conclusions:

NOEL(fertility): 200 mg/kg.
NOAEL(fertility) at least 1000 mg/kg bw/day
NOAEL(developmental): at least 1000 mg/kg bw/day

Executive summary:

Study design

In a combined oral repeat dose reproductive/developmental toxicity screening test [OECD TG 422] rats were dosed by gavage at 40, 200 and 1000 mg/kg bw/day for 42 days in males and from 14 days before pregnancy to day 3 of lactation in females.

Results

No dose related abnormalities were observed with regard to parturition and lactation. There were no adverse effects on viability, the sex ratio and body weights of pups in any N-tert-butyl-2-benzothiazolesulfenamide treated group.

N-tert-butyl-2-benzothiazolesulfenamide at the dose levels applied did not demonstrate teratogenicity.

Conclusion

The no observed adverse effect level (NOAEL) of N-tert-butyl-2-benzothiazolesulfenamide for reproductive and developmental toxicity was 1000 mg/kg/day in males and females.

Effect on fertility: via oral route

Endpoint conclusion:: no adverse effect observed
Dose descriptor:: NOAEL
: 291 mg/kg bw/day
Study duration:: subchronic
Species:: rat
Quality of whole database:: The endpoint is currently concluded based on a study assigned a Klimisch rating of 1: reliable without restriction. This has been undertaken according to GLP and an accepted OECD TG for this endpoint (TG 416). It is supported by a K2 rated study, also conducted to GLP and an accepted OECD TG (OECD 422).

Effect on fertility: via inhalation route

Endpoint conclusion:: no study available

Effect on fertility: via dermal route

Endpoint conclusion:: no study available

Additional information

Two relevant studies are available: 1 on TBBS and one on category member DCBS via read-across.

1. MHWJ, 1997: Combined repeat dose and reproductive/ developmental toxicity screening test

The toxicity to fertility of the test substance TBBS was further evaluated in a GLP and OECD Guideline study (OECD 422, combined repeat dose and reproductive/ developmental toxicity screening test) (MHWJ 1997). Male and female Sprague Dawley rats were treated in this gavage study with 0, 40, 200 and 1000 mg/kg bw/day test substance in 5% gum arabic vehicle. Male rats were treated for 42 days and females for 38 days (from 14 days prior pregnancy to day 3 of lactation).

Maternal toxicity of the test substance was observed at ≥ 200 mg/kg bw/day, indicated by slight histopathological changes in the kidney and in the liver of treated females and a decrease of food consumption and body weight gain at the highest dose group (for further details see endpoint repeated dose toxicity).

TBBS at the dose levels applied did not exert adverse effects on copulation and ovulation. Fertility indices in the 40 and 1000 mg/kg groups were lower than the control level. However, the low index observed in the 40 mg/kg group seemed to be an artificial finding because all the females in the 200 mg/kg group were found to be fertile. No relation between the low index observed in the 1000 mg/kg bw group and the administration of TBBS was found.

There were no effects on viability, the sex ratio and body weights of pups in any TBBS treated group. TBBS at the dose levels applied did not demonstrate teratogenicity. Thus, a NOAEL fertility of 1000 mg/kg bw/day was suggested.

2. Ema, 2008: 2 generation reproductive toxicity test (by read-across to catgegory member DCBS)

A two-generation reproductive toxicity study was performed to evaluate the potential effects of DCBS on reproduction and development in rats (Ema 2008). Based on the category justification for CBS (CAS 95-33-0), DCBS (CAS 4979-32-2), TBBS (CAS 95-31-8) and MBS (CAS 102-77-2) a read-across with the 2-generation study with DCBS is justified and conducted.

A two-generation reproductive toxicity study was performed to further evaluate the potential effects of DCBS on reproduction and development in rats (Ema 2008). Male and female Crl: CD (SD) rats (24 per group and sex) was administered through the oral dietary route at 0, 80, 600 or 4500 ppm, beginning at the onset of a 10-week pre-mating period and continuing through mating, gestation, and lactation periods for two generations. The test substance intake corresponded to ca. 0, 5.2, 39, 291 mg/kg bw/day in F0 males, 0, 7.2, 54, 416 mg/kg bw/day in F0 females, 0, 5.9, 44, 331 mg/kg bw/day in F1 males and 0, 7.4, 55, 417 mg/kg bw/day in F1 females. The dose levels were selected based on results of the previous reproduction and developmental toxicity study (Ema, 2007). Within this study there were reduced body weight gain at ≥3000 ppm, reduced number of implantations at ≥6000ppm, decreased absolute and relative weight of the spleen in females at ≥6000 ppm, reduced number of pups born at 10000 ppm, lower pup weights at ≥6000 ppm and decreased in the absolute and relative weight of the spleen in male weanlings at ≥1500 ppm and female weanlings at ≥3000 ppm. The author concluded that the dose level of 6000 ppm was potent enough to adversely affect the survival of the F1 pups. On review, it is considered that the dose level of 6000 ppm was therefore not selected as the high dose level as the study authors were concerned it was too high to ensure a sufficient number of pregnancies in the F0 and F1 generation and number of F1 pups surviving the lactation period to meet the objectives of a Two-Generation Study. As such, it is thought the high dose 4500 ppm was select as it is halfway between 6000 ppm (where toxicity was considered to be too high) and 3000 ppm (where there was little toxicity in the Dose Range Finding Study), as the highest level that could be used whilst ensuring there was a sufficient number of pregnancies and F1 weanlings to meet the objectives of a Two-Generation Study.

The deaths and clinical signs observed in the study were considered not to be related to the administration of DCBS. Decreased food consumption was noted in F0 males in Study Week 1-14 and females in Study Week 1 and Lactation Day 14-21 at 4500 ppm. At this dose level, body weight and body weight gain was also lower in the F0 males throughout the dosing period, in the females during in Study Week 1 and through gestation and lactation. A parallel lower food consumption was recorded in Study Week 4 in F1 males at 4500 ppm; no changes observed in the F0 females. There were no changes in body weights or body weight gains in the F1 males or females.

In the F1 males there was a slight but significant decrease in mean lateral head displacement was noted in F1 males of the highest group (20.5 µm ± 1.0 vs. control 21.3 ± 0.9 µm). No other significant changes in sperm counts, percentage of motile sperm and progressively motile sperm swimming speed and pattern, or percentage of morphologically abnormal sperm were noted in F0 and F1 adults between control and DCBS-treated groups. All F0 females showed normal oestrous cycles in all groups, and the length of the oestrous cycles was not different between the control and DCBS-treated groups. Although one F1 female each in the control and 600 ppm groups displayed extended diestrus vaginal smears, no significant changes in the incidence of F1 females having normal oestrous cycles or length of the oestrous cycles were observed. In the F0 and F1 generation although a few females had reproductive difficult within all groups there was considered to be no significant changes in the copulation index, fertility index, gestation index, pre-coital interval, gestation length, number of implantations, delivery index, number of F2 pups delivered, sex ratio of F2 pups, or viability of F2 pups during lactation were observed. In the F2 pups 0liodactyly in one female of the control group and microphthalmia in one male at 80 ppm were observed, no malformations were observed in the F1 generation therefore it was considered that there were no DCBS-related effects. In both the F1 and F2 pups there was a lower body weight between PND 7-21. In conclusion, no significant changes in reproductive indices were noted in any generation even at the highest dose 4500 ppm (ca. F0 males - 291 mg/kg bw/ day, F0 females – 416 mg/kg bw/day, F1 males – 331 mg/kg bw/day and F1 females – 417 mg/kg bw/day).

Concluding remarks

A recent scientific evaluation of the Sulfenamides category data set was undertaken to identify testing requirements to ensure suitable coverage of required endpoints for all member substances. Although a 2-generation reproductive toxicity study is available on the category member DCBS, in order to further improve data coverage amongst category members, this category member was identified as having a data gap for Extended One Generation Reproductive Toxicity Testing (EOGRTS; OECD 443), required in accordance with Annex X of Regulation (EC) No 1907/2006. A testing proposal has been submitted for an OECD 443 on TBBS via the oral dietary route (January 2023). The results of this study will be used to complete the dossier for TBBS, as well as form part of the overall category data set as a source study for read across.

Effects on developmental toxicity

Description of key information

NOAEL(maternal/foetal) = 500 mg/kg bw/day – OECD 414 rat - Monsanto (1981)

NOAEL (maternal/foetal) = at least 1000 mg/kg bw/day - OECD 414 rabbit by read across to substance DCBS – Charles River (2016)

Link to relevant study records

Referenceopen all close all

Reference 1

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study, comparable to guideline study with acceptable restrictions (purity of test substance not indicated).

Reason / purpose for cross-reference:

reference to other study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Principles of method if other than guideline:

Pregnant Charles River COBS CD rats were used to determine the teratogenic potential of Santocure NS (N-tert-butyl-2-benzothiazolesulfenamide). Dosage levels of 0, 50, 150 or 500 mg/kg/day were administered orally by gavage as a single daily dose on days 6 through 15 of gestation. Cesarean sections were performed on all surviving dams on gestation day 20.

GLP compliance:

yes

Limit test:

Species:

rat

Strain:

other: Charles River COBS CD rats

Details on test animals or test system and environmental conditions:

All animals were individually housed, except during mating, in suspended wire-mesh cages and maintained in a temperature-, humidity-, and light-controlled environment.

Route of administration:

oral: gavage

Vehicle:

corn oil

Analytical verification of doses or concentrations:

not specified

Details on mating procedure:

- M/F ratio per cage: 1: 1

Duration of treatment / exposure:

Days 6-15 of gestation.

Frequency of treatment:

Daily.

Duration of test:

Days 6 to 20 of gestation.

Dose / conc.:

0 mg/kg bw/day

Dose / conc.:

50 mg/kg bw/day

Dose / conc.:

150 mg/kg bw/day

Dose / conc.:

500 mg/kg bw/day

No. of animals per sex per dose:

25 animals per dose

Control animals:

yes

Details on study design:

Dose selection rationale: Doses were selected based on the results of a pilot study (1979).
Within the primer study, animals were exposed to dose levels of 0 / 10 / 50 / 300 / 1000 / 3000 mg/kg bw/d TBBS on gestation days (GD) 6-15 inclusive.

≥ 1000 mg/kg bw/d: increases in early resorptions & reductions in viable fetuses were observed; 3 of 4 maternal animals had anogenital staining, and mean b.w. decreased throughout treatment.

At 3000 mg/kg bw/d: 3 of 4 maternal animals died by GD12, with preceding clinical signs concomitant with severe toxicity in all 4 animals.

Based on principles applied at the time of study conduct, authors concluded based on the above that a dose level of 1000 mg/kg bw/d is excessive for a teratology study, and as such a high dose between 300 and 1000 was selected (500 mg/kg bw/day).

Maternal examinations:

Clinical signs, body weights, Cesarean section observations.

Ovaries and uterine content:

Uterus was excised and weighed prior to removal of the fetuses, the number and location of viable and nonviable fetuses, early and late resoptions and the number of total implantations and corpora lutea were recorded
Abdominal and thoracic cavities and organs of the dams were examined for grossly evident morphological changes
Uteri from females that appeared nongravid were opened and placed in a 10% ammonium-sulfid solution for confirmation of pregnancy status

Fetal examinations:

fetuses weights were recorded
fetuses were individually examined for external malformations and variations, including the palate and eyes
each fetus was externally sexed
Ca. one-half of the fetuses were placed in Bouin's fixative for subsequent visceral examination
Ca. one-half were fixed for subsequent skeletal examination

Historical control data:

Historical control data were available.

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

No biologically meaningful differences in appearance or behavior in rats when compared to the control group Matting of the ventral or anogenital haircoat was noted in all four dosage groups with the greatest incidence occuring in rats in the 500 mg/kg bw/d dose group (4, 1, 2 and 10 respectively).A post-dose response of reduced activity was noted in two of these 10 rats of the highest dose group on gestation day 6 and 7. Incidental findings of hair loss and/or red matter on the nasal region were noted on several rats in the treated groups as well as the control group at various times during gestation.

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Description (incidence and severity):

50 and 150 mg/kg bw/d: no biologically relevant differences compared to control. 500 mg/kg bw/d: very slight decrease in mean maternal body weight gain (ca. 1 -2 %) during the treatment period. However, no differences were noted in comparing the corrected gestation day 20 body weights (gestation day 20 body weight minus uterus weight) of the treated groups to the control group.

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Behaviour (functional findings):

not examined

Immunological findings:

not specified

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

not specified

Description (incidence and severity):

Slight decrease were noted in the mean numbers of corpora lutea (4 %, 1%, 4 % at 50, 150 and 500 mg/kg bw/d, respectively) and total implantations in all three treatment groups (7 %, 6% and 8 % at 50, 150 and 500 mg/kg bw/d). These decreases were attributed to random occurence as ovulation and implantation occur prior to treatment. A corresponding decrease in the mean numbers of viable fetuses in these groups was not considered biologically meaningful as the values were comparable to the historical control value.

Dose descriptor:

NOAEL

Effect level:

500 mg/kg bw/day

Basis for effect level:

other: maternal toxicity

Fetal body weight changes:

no effects observed

Description (incidence and severity):

There were nobiologically meaninful or statistically significant differences in the mean numbers of postimplantation loss, early resorptions, mean fetal body weight or the fetal sex distribution in the 50, 150 or 500 mg/kg/day dosage groups when compared to the control group.

Reduction in number of live offspring:

no effects observed

Description (incidence and severity):

Changes in sex ratio:

no effects observed

Description (incidence and severity):

Changes in litter size and weights:

no effects observed

Description (incidence and severity):

Changes in postnatal survival:

not specified

External malformations:

no effects observed

Description (incidence and severity):

There were no biologically meaningful differences in the total numbers of fetuses or litters with malformations in the 50, 150, or 500 mg/kg/day dosage groups when compared with the control group.

Skeletal malformations:

no effects observed

Description (incidence and severity):

There were no biologically meaningful differences in the total numbers of fetuses or litters with malformations in the 50, 150, or 500 mg/kg/day dosage groups when compared with the control group.

Visceral malformations:

no effects observed

Description (incidence and severity):

There were no biologically meaningful differences in the total numbers of fetuses or litters with malformations in the 50, 150, or 500 mg/kg/day dosage groups when compared with the control group.

Key result

Dose descriptor:

NOAEL

Effect level:

500 mg/kg bw/day

Basis for effect level:

other: teratogenicity

Key result

Abnormalities:

no effects observed

Key result

Developmental effects observed:

Materal observations:

Clinical signs and mortality:

No mortality occured in any of the treated animals 50 and 150 mg/kg bw/d: no biologically meaningful differences in appearance or behavior in rats when compared to the control group Matting of the ventral or anogenital haircoat was noted in all four dosage groups with the greatest incidence occuring in rats in the 500 mg/kg bw/d dose group (4, 1, 2 and 10 respectively).A post-dose response of reduced activity was noted in two of these 10 rats of the highest dose group on gestation day 6 and 7. Incidental findings of hair loss and/or red matter on the nasal region were noted on several rats in the treated groups as well as the control group at various times during gestation.

Necropsy observations at Cesarean section:

Control: 1/25 hydrometra

Clinical 50 mg/kg bw/d: 1/25 ovarian cyst 500 mg/kg bw/d: 1/25 fibrinous pleuritis and congested lungs, 1/25 hydrometra, 1/25 ovarian cyst.

Body weights:

Cesarean section observations:

50, 150, 500 mg/kg bw/d: no biologically meaningful or statistically significant differences in the mean numbers of postimplantation loss, early resorptions, mean fetal body weight or fetal sex distribution compared to control

Slight decrease were noted in the mean numbers of corpora lutea (4 %, 1%, 4 % at 50, 150 and 500 mg/kg bw/d, respectively) and total implantations in all three treatment groups (7 %, 6% amd 8 % at 50, 150 and 500 mg/kg bw/d). These decreases were attributed to random occurence as ovulation and implantation occur prior to treatment. A corresponding decrease in the mean numbers of viable fetuses in these groups was not considered biologically meaningful as the values were comparable to the historical control value.

Fetal morphological observations:

50, 150 and 500 mg/kg bw/d: no biologically meaningful differences in the total numbers of fetuses or litters with malformations compared to control.

A slight increase in the number of litters and fetuses with undeveloped renal papillae and/or distended ureters was noted in the three treated groups but was not considered biologically meaninful since this increase was within the range estabished in the historical control data. Renal papillae not developed and/or distended ureters: control: fetuses: 3(1.7%), litters: 2( 8.3 %).

50 mg/kg bw/d: fetuses: 7(4.6 %), litters: 5( 22.7 %)

150 mg/kg bw/d: fetuses: 8(5.1 %), litters: 5( 21.7 %)

500 mg/kg bw/d: fetuses: 7(4.8 %), litters: 6( 27.3 %)

Conclusions:

Treatment with Santocure NS (N-tert-butyl-2-benzothiazolesulfenamide) did not produce a teratogenic response when administered orally to pregnant Charles River COBS CD rats at a dosage level of 500 mg/kg/day (highest applied dose) or less.

Executive summary:

Reference 2

Endpoint:

developmental toxicity

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Justification for type of information:

Refer to Section 13 for category read-across justification.

Species:

rabbit

Ovaries and uterine content:

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

In 16/22, 19/22, 17/22 and 19/22 females treated at 0, 100, 300 and 1000 mg/kg/day, respectively, faeces production was reduced, varying in duration and severity. Additionally, incidental diarrhea, faeces containing mucus or pale faeces was noted in the control, mid and/or high dose groups. As the majority of these findings were noted in all groups, this is not related to treatment with the test item.
Three female (no. 28, 53 and 83 in Groups 2, 3 and 4, respectively) had red staining of the vagina and/or red fluid on the manure tray at the end of the treatment period. All three females had normal litters and therefore these finding were not considered adverse effects of treatment.
The lean appearance of female 83 (1000 mg/kg), corresponds with a body weight loss of approximately 7% (20.5 % when corrected for weight of the uterus). This female was the most sensitive animal in this group.
The incidence of all other observed clinical signs remained within the range of background findings to be expected for rabbits of this strain and age.

Mortality:

no mortality observed

Description (incidence):

No mortality occurred in this study.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

From Day 16 post-coitum onwards, body weight gain was slightly reduced in females treated at 1000 mg/kg/day, compared to the control animals. As this effect was very slight, not reaching statistical significance and body weight corrected for weight of the uterus was unaffected, it was considered not toxicologically relevant.
At 100 and 300 mg/kg/day, body weight remained within the same range as the control group.

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

no effects observed

Description (incidence and severity):

No treatment related macroscopic findings were observed up to 1000 mg/kg/day.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Other effects:

no effects observed

Details on results:

No maternal toxicity was observed in the 100, 300 and 1000 mg/kg/day groups.

Number of abortions:

no effects observed

Pre- and post-implantation loss:

no effects observed

Total litter losses by resorption:

no effects observed

Early or late resorptions:

no effects observed

Dead fetuses:

no effects observed

Changes in pregnancy duration:

no effects observed

Changes in number of pregnant:

no effects observed

Other effects:

no effects observed

Details on maternal toxic effects:

No maternal toxicity was observed in the 100, 300 and 1000 mg/kg/day groups.

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day

Based on:

act. ingr.

Remarks on result:

other: Purity/composition correction factor: Correction factor is 1.065 according to purity

Fetal body weight changes:

no effects observed

Description (incidence and severity):

There was no treatment related effect on mean fetal body weights.

Reduction in number of live offspring:

no effects observed

Description (incidence and severity):

There were no treatment related effects on litter size for any group.
The mean litter size in the high dose group was slightly lower compared to the control group (8.4 compared to 9.8 for the 1000 mg/kg/day and control groups, respectively). The lower litter size in the high dose group could be explained by the litters of females 75 and 76, which both had only two viable fetuses. For female no. 76, this was caused by a relatively high pre-implantation loss, which cannot be contributed to treatment, as this starts after implantation. The relatively high number of early resorptions and consequently high post-implantation loss, resulting in the low number of viable fetuses for female no. 75, was considered a chance finding. Taken together, the lower litter size at 1000 mg/kg/day was of no toxicological relevance. Mean litter sizes were 9.9 and 9.3 for the 100 and 300 mg/kg/day groups, respectively.

Changes in sex ratio:

no effects observed

Description (incidence and severity):

The male:female ratio was unaffected by treatment up to 1000 mg/kg/day.

Changes in litter size and weights:

no effects observed

Description (incidence and severity):

Changes in postnatal survival:

not examined

External malformations:

no effects observed

Description (incidence and severity):

There were no treatment related effects on external morphology following treatment up to 1000 mg/kg/day.
Three malformations were observed in this study. One 1000 mg/kg/day fetus A082-02 had an omphalocele and fetus A063-08 in the 300 mg/kg/day group was totally malformed externally, which was substantiated viscerally and skeletally. The third affected fetus was the dead fetus in the 100 mg/kg/day group (A040-07) which had a distended abdomen; at visceral examination this appeared to be ascites accompanied with a large heart. All these cases occurred singly at different dose levels and therefore were considered to be chance findings and not related to treatment.
There were no external variations seen for any fetus in any group.

Skeletal malformations:

no effects observed

Description (incidence and severity):

There were no treatment related effects on skeletal morphology following treatment up to 1000 mg/kg/day.
Malformations occurred in 0 (0), 2 (2), 9 (7) and 7 (4) fetuses (litters) in the control, 100, 300 and 1000 mg/kg/day groups, respectively.
In total, seven different types of malformations were noted of which three were seen in the 1000 mg/kg/day group only. These were a rib anomaly in fetus A072-04 and A086-02, a caudal vertebral anomaly in fetus A072-01 and fused skull bones in fetus A072-02.
It is remarkable that these were not observed in the other groups, but all three malformations occurred previously in historical controls. Moreover, it is noteworthy that three of the aforementioned fetuses are from litter A072 and that in this litter, fetus 09 was skeletally affected as well. This fetus had a vertebral anomaly with associated rib anomaly and was found to have multiple cardiovascular malformations viscerally. Also it should be noted that the mean fetal body weights of litter A072 are the lowest of the group and far below the group mean value (30.1 versus 38.2 grams, respectively), despite normal litter size (9 viable fetuses and 1 early resorption). Taken these aspects into account, it is considered that all skeletal malformations in litter A072 were a result of general defective fetal development and were not related to treatment.
The fetus in the 300 mg/kg/day that was totally malformed externally and viscerally (A063-08) was also totally malformed skeletally. At the single incidence, it was considered a chance finding.
Remaining skeletal malformations of this study were a vertebral anomaly with or without associated rib anomaly (A028-09, A051-02, A057-06 and A074-10), fused sternebrae (A035-01, A050-06, A59-09, A085-03), split skull bones (A060-04, A064-02) and bent limb bones (A064 fetus 06 and 07). These occurred once or twice in one or more dose groups and all were noted previously in historical controls; thus, these were considered not to be treatment related.
Skeletal variations that were noted in this study occurred at low incidences, in the absence of a dose-related incidence and/or at frequencies that were within the range of available historical control data.

Visceral malformations:

no effects observed

Description (incidence and severity):

There were no treatment related effects on visceral morphology following treatment up to 1000 mg/kg/day.
In the 1000 mg/kg/day group, four fetuses had a visceral malformation. Multiple cardiovascular malformations (interrupted aortic arch, ventricular septum defect, retroesophageal ductus arteriosus and right sided descending aorta) were noted in fetus
A072-09, Tetralogy of Fallot was found in fetus A067-09 and absence of an accessory lung lobe in litter mates A072-06 and -08. The latter two malformations also occurred in other dose groups, namely Tetralogy of Fallot at 300 mg/kg/day (A045-04) and a missing accessory lung lobe in the control group (A001-06 and A016-01) and at 100 mg/kg/day (A030-02 and A040-08). The very low incidence and group distribution of these malformations does not indicate a treatment relationship. Moreover, all but two (retroesophageal ductus arteriosus and right sided aorta descending) were noted previously in historical controls.
The fetus in the 300 mg/kg/day that was totally malformed externally (A063-08) was also totally malformed viscerally. At the single incidence, it was considered a chance finding.
All variations noted, were considered not treatment related as they occurred infrequently, occurred at frequencies that were within the range of available historical control data, were observed in the absence of a dose-incidence trend or were limited to control fetuses only.

Other effects:

no effects observed

Details on embryotoxic / teratogenic effects:

No developmental toxicity was observed in the 100, 300 and 1000 mg/kg/day groups.

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day

Based on:

act. ingr.

Sex:

male/female

Remarks on result:

other: Purity/composition correction factor: Correction factor is 1.065 according to purity

Key result

Abnormalities:

no effects observed

Key result

Developmental effects observed:

SUMMARY OF MATERNAL SURVIVAL AND PREGNANCY STATUS

Dose Group:	1		2		3		4
	No.	%	No.	%	No.	%	No.	%
Females on study	22		22		22		22
Females that oborted or delievered	0	0.0	0	0.0	0	0.0	0	0.0
Females that died	0	0.0	0	0.0	0	0.0	0	0.0
Females that aborted	0	0.0	0	0.0	0	0.0	0	0.0
Nongravid	0	0.0	0	0.0	0	0.0	0	0.0
Gravid	0	0.0	0	0.0	0	0.0	0	0.0

Females that were euthanized	0	0.0	0	0.0	0	0.0	0	0.0
Nongravid	0	0.0	0	0.0	0	0.0	0	0.0
Gravid	0	0.0	0	0.0	0	0.0	0	0.0

Females examined at
Scheduled necropsy	22	100.0	22	100.0	22	100.0	22	100.0
Nongravid	2	9.1	1	4.5	1	4.5	2	9.1
Gravid	20	90.9	21	95.5	21	95.5	20	90.9
With resorptions only	2	0.0	0	0.0	0	0.0	0	0.0
with viable fetuses	20	100.0	21	100.0	21	100.0	20	100.0

Total females gravid	20	90.9	21	95.5	21	95.5	20	90.9

1- 0 mg/kg/day 2- 100 mg/kg/day 3- 300 mg/kg/day 4- 1000 mg/kg/day

SUMMARY OF FETAL DATA AT SCHEDULED NECROPSY

Group		Sex M	Sex F	Viable Fetuses	Dead Fetuses	Resorptions Early	Resporptions Late	Post Implantation Loss	Implantation Sites	Corpora Lutea	Pre implantation Loss	Fetal Weights in grams	No. of gravid females
1	Total	98	98	196	0	6	0	6	202	216	14	NA	20
1	Mean	4.9	4.9	9.8	0 .0	0.3	0.0	0.3	10.1	10.8	0.7	38.2
1	S.D.	2.31	1.80	1.99	0.00	0.57	0.00	0.57	1.80	1.77	0.73	4.55
2	Total	100	107	207	1	3	5	9	216	221	5	Na	21
2	Mean	4.8	5.1	9.9	0.0	0.1	0.2	0.4	10.3	10.5	0.2	37.6
2	S.D.	1.55	1.37	1.49	0.22	0.36	0.54	0.81	1.35	1.44	0.44	4.63
3	Total	96	100	196	0	3	3	6	202	211	9	NA	21
3	Mean	4.6	4.8	9.3	0.0	0.1	0.1	0.3	9.6	10.0	0.4	37.3
3	S.D.	1.75	1.30	2.22	0.00	0.48	0.48	0.78	2.48	2.44	0.81	4.76
4	Total	82	86	168	0	12^	1^	13^	173^	189^	16^	NA	20
4	Mean	4.1	4.3	8.4	0.0	0.6^	0.1^	0.7^	9.1^	9.9^	0.8^	38.2
4	S.D.	2.10	1.89	2.91	0.00	1.42^	0.23^	1.42^	2.62^	2.01^	1.57^	5.67

-----------------------------

------------------------------------------------------------------------------------------------------

None significantly different from control group

NA = NOT APPLICABLE MEAN NUMBER OF VIABLE FETUSES,

MEAN NUMBER OF IMPLANTATION SITES, MEAN NUMBER OF CORPORA LUTEA, FETAL WEIGHTS COMPARED USING DUNNETT'S TEST

^ Calculated based on n=19 litters, due to missing data for dam# A085 -----------------------------------------------------------------------------------------------------------------------------------

1- 0 MG/KG/DAY 2- 100 MG/KG/DAY 3- 300 MG/KG/DAY 4- 1000 MG/KG/DAY

SUMMARY OF FETAL DATA AT SCHEDULED NECROPSY [% PER LITTER]

Group	0 mg/kg/day	100 mg/kg/day	300 mg/kg/day	1000 mg/kg/day
Corproa Lutea
Mean	10.8	10.5	10.0	9.9
S.D.	1.77	1.44	2.44	2.01
N	20	21	21	19
Implantation sites
Mean	10.1	10.3	9.6	9.1
S.D.	1.80	1.35	2.48	2.62
N	20	21	21	19
Viable fetuses (%)
Mean	96.8	95.9	97.7	92.3
S.D.	5.97	7.83	6.08	17.46
N	20	21	21	19
Early resprptions
Mean	3.2	1.5	1.2	7.3
S.D.	5.97	3.72	4.16	17.55
N	20	21	21	19
Late resorptions
Mean	0.0	2.2	1.2	0.4
S.D.	0.00	4.81	3.69	1.77
N	20	21	21	19
Total resorptions
Mean	3.2	3.6	2.3	7.7
S.D.	5.97	6.35	6.08	17.46
N	20	21	21	19
Pre-implantation loss (%)
Mean	6.4	3.6	2.3	7.7
S.D.	6.97	6.35	6.08	17.46
N	20	21	21	19
Post-implantation loss (%)
Mean	3.2	4.1	2.3	8.9
S.D.	5.97	3.90	6.08	17.54
N	20	21	21	19
Males (%)
Mean	48.9	48.0	47.9	46.9
S.D.	19.53	13.62	11.52	18.47
N	20	21	21	20
Females (%)
Mean	51.1	52.0	52.1	53.1
S.D.	19.53	13.62	11.52	18.47
N	20	21	21	20
Male fetal weights (g)
Mean	39.0	38.7	38.0	38.0
S.D.	5.35	4.39	4.88	5.34
N	20	21	21	19
Female fetal weights (g)
Mean	37.6	36.6	36.6	37.8
S.D.	4.96	5.34	4.96	5.67
N	20	21	21	20
Combined fetal weights (g)
Mean	38.2	37.6	37.3	38.2
S.D.	4.55	4.63	4.76	5.67
N	20	21	21	20

PROPORTIONAL (%) DATA COMPARED USING THE MANN-WHITNEY TEST

FETAL WEIGHTS COMPARED USING DUNNETT'S TEST

None significantly different from control group

SUMMARY OF FETUSES AND LITTERS WITH MALFORMATIONS [ABSOLUTE NO.]

		Fetuses				Litters
	Dose group:	1	2	3	4	1	2	3	4
Number examined externally		196	207	196	168	20	21	21	20
Fetus totally malformed		0	0	1	0	0	0	1	0
Trunk omphalocele		0	0	0	1	0	0	0	1

Number examined viscerally		196	207	196	168	20	21	21	20
Teratology of fallot		0	0	1	1	0	0	1	1
Lung - absent lobe(s)		2	2	0	2	2	2	0	1
Aortic arch - interrupted		0	0	0	1	0	0	0	1
Ventricular septum defect		0	0	0	1	0	0	0	1
Ductus arteriosus retroesophagal		0	0	0	1	0	0	0	1
Aorta descending - right sides		0	0	0	1	0	0	0	1
Fetus totally malformed		0	0	1	0	0	0	1	0

Number examined skeletally		196	207	196	168	20	21	21	20
Vertebral anomaly with or without associated rib anomaly		0	1	2	2	0	1	2	2
Rib anomaly		0	0	0	2	0	0	0	2
Caudal vertebral anomaly		0	0	0	1	0	0	0	1
Skull bones - fused		0	0	0	1	0	0	0	1
Sternebrae fused		0	1	2	1	0	1	2	1
Skull bone(s) - split		0	0	2	0	0	0	2	0
Bent limb bones		0	0	2	0	0	0	1	0
Fetus totally malformed		0	0	1	0	0	0	1	0

Total number with malformations
External		0	0	1	1	0	0	1	1
Soft tissue		2	2	2	4	2	2	2	2
Skeletal		0	2	9	7	0	2	7	4
Combined		2	4	10	11	2	4	8	6

1- 0 MG/KG/DAY 2- 100 MG/KG/DAY 3- 300 MG/KG/DAY 4- 1000 MG/KG/DAY

SUMMARY OF LITTER PROPORTIONS OF MALFORMATIONS % PER LITTER

	Dose group		1	2	3	4
Number of litters examined
Total malformations
Percent per litter with external malformations		Mean S.D.	0.0 0.00	0.0 0.00	0.3 1.56	1.0 4.47
Percent per litter with soft tissuel malformations		Mean S.D.	1.0 2.94	1.3 4.04	0.8 2.62	2.2 7.67
Percent per litter with skeletal malformations		Mean S.D.	0.0 0.00	1.0 3.01	5.5 10 .97	4.0 10.50
Total percent per litter with malformations		Mean S.D.	1.0 2.94	2.2 4.78	6.3 10.85	6.6 15.41

1- 0 MG/KG/DAY 2- 100 MG/KG/DAY 3- 300 MG/KG/DAY 4- 1000 MG/KG/DAY

None significantly different from control group

SUMMARY OF LITTER PROPORTIONS OF VARIATIONS % PER LITTER

	Dose group		1	2	3	4
Number of litters examined			20	21	21	20
Total variations
Percent per litter with external variations		Mean S.D.	0.0 0.00	0.0 0.00	00 0.00	0.0 0.00
Percent per litter with soft tissuel variations		Mean S.D.	6.4 9.24	3.5 6.20	5.0 6.23	7.1 8.18
Percent per litter with skeletal variations		Mean S.D.	72.6 26.43	74.8 19.14	76.1 24.04	83.7 21.04
Total percent per litter with variations		Mean S.D.	73.9 25.31	75.7 18.79	77.3 23.95	85.2 19.54

1- 0 MG/KG/DAY 2- 100 MG/KG/DAY 3- 300 MG/KG/DAY 4- 1000 MG/KG/DAY

None significantly different from control group

Conclusions:

In conclusion, based on the results in this prenatal developmental toxicity study the maternal and developmental No Observed Adverse Effect Level (NOAEL) for N,N-dicyclohexylbenzothiazole-2-sulphenamide was established as being at least 1000 mg/kg/day.

Executive summary:

Title

Prenatal developmental toxicity study of N,N-dicyclohexylbenzothiazole-2-sulphenamide in rabbits by oral gavage.

Guidelines

The study procedures described in this report were based on the following guidelines:

•Organization of Economic Co-operation and Development Guidelines (OECD) for testing of Chemicals Guideline 414, Prenatal Developmental Toxicity Study, January 2001.

•Commission regulation (EC) No 440/2008 Part B: Methods for the Determination of Toxicity and other Health Effects; B.31: "Prenatal Developmental Toxicity Study". Official Journal of the European Union No. L142, May 2008.

•The United States Environmental Protection Agency (EPA) Health Effects Test Guidelines OPPTS 870.3700, Prenatal Developmental Toxicity Study, August 1998.

Study outline

Eighty-eight mated female New Zealand White rabbits were assigned to four groups of 22 animals each. The test item, N,N-dicyclohexylbenzothiazole-2-sulphenamide, was administered once daily by oral gavage from Days 6 to 28 post-coitum at doses of 100, 300 and 1000 mg/kg/day (Groups 2, 3 and 4, respectively). Rabbits of the control group received the vehicle, 1% aqueous carboxymethyl cellulose with 0.1% Tween-80, alone. Females were checked daily for the presence of clinical signs. Food consumption and body weight were determined at periodic intervals. Formulations prepared on one day during treatment were analyzed for accuracy and homogeneity.

On Day 29 post-coitum, all animals were subjected to an examination post-mortem and external, thoracic and abdominal macroscopic findings were recorded. A laparohysterectomy was performed on each female. The uteri, placentae and ovaries were examined, and the numbers of fetuses, early and late resorptions, total implantations and corpora lutea were recorded. Gravid uterine weights were recorded, and net body weights and net body weight changes were calculated. The fetuses were weighed, sexed and examined for external, visceral and skeletal malformations and developmental variations. All live fetuses were euthanized. Approximately, one half of the fetuses were decapitated and the heads were fixed in Bouin’s fixative. All fetuses were dissected and examined for visceral anomalies and subsequently fixed in 96% aqueous ethanol. Following staining with Alizarin Red S, skeletons of all fetuses of all groups were examined.

Results

Accuracy and homogeneity of formulations were demonstrated by analyses.

Maternal findings:

No maternal toxicity was observed in the 100, 300 and 1000 mg/kg/day groups.

Developmental findings:

No developmental toxicity was observed in the 100, 300 and 1000 mg/kg/day groups.

Conclusion

Based on the results in this prenatal developmental toxicity study the maternal and developmental No Observed Adverse Effect Level (NOAEL) for N,N-dicyclohexylbenzothiazole-2-sulphenamide was established as being at least 1000 mg/kg/day.

Effect on developmental toxicity: via oral route

Endpoint conclusion:: no adverse effect observed
Dose descriptor:: NOAEL
: 500 mg/kg bw/day
Study duration:: subacute
Species:: rat
Quality of whole database:: The endpoint is currently concluded based on a studies of high quality (assigned a Klimisch rating of 1: reliable without restriction, or 2: reliable with restrictions). The key/supporting studies have been undertaken according to GLP and an accepted OECD TG for this endpoint (TG 414).

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:: no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:: no study available

Additional information

Two relevant studies are available:

1. Monsanto, 1981: developmental toxicity in 1^st species (rat)

One study is available on TBBS. The developmental toxicity of the test substance TBBS was evaluated in a developmental toxicity study (OECD TG 414) in rats (Monsanto, 1981). Pregnant Sprague-Dawley rats were used to determine the teratogenic potential of the test substance TBBS. Following a pilot dose setting study (Monsanto, 1979) dosage levels of 0, 50, 150 and 500 mg/kg bw/day were administered orally by gavage as a single daily dose on day 6 through 15 of gestation. Cesarean sections were performed on all surviving dams on gestation day 20. Increased matting of the ventral or anogenital haircoat and a very slight decrease in mean maternal body weight gain (ca. 1 to 2 %) was noted in the 500 mg/kg bw and day dosage group. Survival was 100 % in all groups. There were no other biologically meaningful differences in appearance or behaviour, maternal or foetal body weight, mean number of viable fetuses or post-implantation losses in any of the treatment groups when compared to the control group. In addition, there were no biologically relevant differences in the total numbers of foetuses or litters with malformation in any of the treatment groups when compared to the control group.

A slight increase in the number of litters and foetuses with undeveloped renal papillae and/or distended ureters was noted in all three treatment groups but was not considered biologically relevant since this increase was within the range established in the historical control data. Based on the findings of this study a NOAEL maternal/foetal of 500 mg/kg bw/day (highest dose tested) was suggested.

2. Charles River Laboratories, 2016: prenatal developmental toxicity in 2^nd species (rabbit)

An additional a prenatal developmental toxicity study according to OECD 414 of N,N-dicyclohexylbenzothiazole-2-sulphenamide in rabbits by oral gavage is available. Based on the category justification for CBS (CAS 95-33-0), DCBS (CAS 4979-32-2), TBBS (CAS 95-31-8) and MBS (CAS 102-77-2) a read-across with the developmental study with DCBS is justified and conducted.

An OECD Guideline 414 (Prenatal Developmental Toxicity Study) was conducted in rabbits (Charles River Laboratories, 2016). Eighty-eight mated female New Zealand White rabbits were assigned to four groups of 22 animals each. The test item was administered once daily by oral gavage from Days 6 to 28 post-coitum at doses of 100, 300 and 1000 mg/kg bw/day (Groups 2, 3 and 4, respectively). Rabbits of the control group received the vehicle, 1% aqueous carboxymethyl cellulose with 0.1% Tween-80, alone. No maternal toxicity was observed in the 100, 300 and 1000 mg/kg bw/day groups. No developmental toxicity was observed in the 100, 300 and 1000 mg/kg bw/day groups. In conclusion, based on the results in this prenatal developmental toxicity study the maternal and developmental No Observed Adverse Effect Level (NOAEL) for DCBS was established as being at least 1000 mg/kg bw/day.

Concluding remarks

Based on the available information, the lower NOAEL of 500 mg/kg bw/day was selected as the most conservative dose descriptor for this endpoint.

A recent scientific evaluation of the Sulfenamides category data set was undertaken to identify testing requirements to ensure suitable coverage of required endpoints for all member substances. To further improve data coverage amongst category members, this category member was identified as having a data gap for prenatal developmental toxicity in a 2^nd species (rabbit) (OECD 414), required in accordance with Annex X of Regulation (EC) No 1907/2006. A testing proposal has been submitted for an OECD 414 on TBBS (January 2023). The results of this study will be used to complete the dossier for TBBS, as well as form part of the overall category data set as a source study for read across. In particular, it will allow assessment of the impact of the structural differences between the category substances, and interpolation to support the proposed category hypothesis.

Toxicity to reproduction: other studies

Link to relevant study records

Reference

Endpoint:

toxicity to reproduction: other studies

Remarks:

subchronic gavage study with histology of the preproduction organs

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: subchronic gavage study with histology of reproduction organs, GLP study, comparable to guideline study.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

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

Principles of method if other than guideline:

Twenty male and twenty female Sprague-Dawley rates received 0, 100, 300 or 1000 mg N-tert-butylbenzothiazole-2-sulphenamide/kg bw by gavage. the animals were examined for mortality, overt signs of toxicity, body weight and food consumption. Clinical chemistry, haematological and urinalysis determinations were proformed. At sacrifice animnals were subjected to a complete gross necropsy and a microscopic examination (incl. testis, epidiymides, ovaries, uterus) for the control and high dose group performed.

GLP compliance:

yes

Type of method:

in vivo

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

Subchronic toxicity study.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples were analysed weekly using a liquid chromatographic procedure.

Duration of treatment / exposure:

90 day.

Frequency of treatment:

Daily.

Duration of test:

90 day.

Dose / conc.:

0 mg/kg bw/day

Dose / conc.:

100 mg/kg bw/day

Dose / conc.:

300 mg/kg bw/day

Dose / conc.:

1 000 mg/kg bw/day

No. of animals per sex per dose:

20 per dose and sex.

Control animals:

yes, concurrent vehicle

Details on study design:

See IUCLID section 7.5.1 Monsanto 1985.

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No histological alteration of reproduction organs.

Mortality:

All animals survived three months of exposure to the test substance

Body Weight:

Reduced body weights were noted for males at the middle and highest dose groups (300 and 1,000 mg/kg/day, respectively). Most affected were the high dose group males with 13 weeks reduction at 99% statistical confidence. Middle group males were affected the final 11 out of 13 weeks, primarily at 95% statistical confidence.

Body weights were unaffected for the low dose males (100 mg/kg/day) and all three female treatment groups as compared to controls.

Food Consumption:

Similar amounts of food were consumed by both sexes from all three treatment groups when compared to their control groups. Two exceptions were mid dose group males (300 mg/kg/day) at week 9 and high dose males (1,000 mg/kg/day) at week 1, however, these exceptions appear random and are probably not related to SANTOCURE NS exposure.

Clinical Observations:

Animals in all treatment groups salivated after dosing and mid and high dose animals salivated prior to dosing or sometimes resisted dosing. High dose females exhibited urine stained abdomens. Other than the above, no clinical signs or abnormal behavior related to treatment were observed. Due to the lack of gross or microscopic findings of gastrointestinal effects, the behavioral reactions were considered to be related to poor palatability of the test material rather than a toxic response.

Hematology and chemical data:

There were several statistically significant changes in mean values for hematologic or serum chemistry parameters. Statistically significant increases in reticulocyte counts occurred in Group 2 males (300 mg/kg bw/d) and Group 3 (1000 mg/kg bw/d) females. These values remained well within normal limits and were of no toxicological significance.

Depressions of SGOT and SGPT at 100 and 1000 mg/kg bw in females were probably artifactual due to high group mean values for these enzymes in control females. When clearly abnormal values for NFOO4 and NFO15 are deleted, a minimal (p 0.05) depression was found affecting only Group 1 females (100 mg/kg bw/d). These changes were not considered to be relevant. Minimal depressions in sodium affected all dose level of females and Group 2 (300 mg/kg bw/d) males. These were within normal range and were not considered to be toxicologically relevant.

The only change which may have been biologically relevant was a mild increase in the mean cholesterol value for females from Group 3 (1000 mg/kg bw /d). Urine specific gravity was increased in males from Group 3 (1000 mg/kg bw) and females from Groups 2 and 3 (300 and 1000 mg/kg bw/d). The increased values for males and females from Group 3 were statistically significant There were increases in the occurrence of mild ketonuria in male Groups 1, 2 and 3.

Gross Pathology:

There were no gross lesions associated with chemical administration. There was a linear decrease in terminal body weights of males from Groups 1, 2 and 3. There were, however, essentially no changes in weights of females from treated groups as compared to controls. The only significant changes in absolute organ weights were decreased mean brain weight in females from Group 3 (1000 mg/kg bw/d)and increased mean hepatic weight in females from Group 3(1000 mg/kg bw/d). Organ to body weight ratios were increased in a dose related manner for all male organs for which weights were obtained (statistically significant in most instances) for Groups 2 and 3. Kidneys to body weight ratios were increased in females from Group 3 (statistically significant) as were liver to body weight ratios in females from Groups 2 and 3 (300 and 1000 mg/kg bw/d).

Microscopic Pathology:

There were no microscopic lesions with an apparent association with chemical administration.

No test substance-related adverse effects on the reproductive organs were indicated (testis, epidiymides, ovaries, uterus) up to the highest dose evaluated

Conclusions:

No histological alteration of reproduction organs were found.

Executive summary:

No histological alteration of reproduction organs were found..

Additional information

One study within the wider dataset contains relevant appraisal to this endpoint.

1. Monsanto, 1985: subchronic repeated dose toxicity

In a subchronic study similar to OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity in Rodents) 20 male and 20 female Sprague Dawley rats received 0, 100, 300, and 1000 m/kg bw/day in corn oil vehicle (Monsanto, 1985). The study did not reveal any test substance-related adverse effects on the reproductive organs.

Justification for classification or non-classification

Harmonised classification:

The substance has no harmonised classification according to the Regulation (EC) No. 1272/2008 (CLP).

Self-classification:

Within the current dataset, no relevant adverse effects were observed in the fertility studies in rats and developmental toxicity studies in rats and rabbits. Therefore, no classification is required according to the classification criteria of Regulation (EC) No. 1272/2008 (CLP). None of the category members is classified for reproductive or developmental toxicity.

January 2023: An OECD 414 study in rat is planned on category member DCBS. An OECD 414 study in rabbit is planned on category member TBBS. An OECD 443 study (Cohort 1A + 1B) is planned on category member TBBS. The dossier will be updated as soon as the new studies become available.

Additional information

Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.

Registration Dossier

Registration Dossier

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Diss Factsheets

N-tert-butylbenzothiazole-2-sulphenamide

Endpoint summary

Administrative data

Key value for chemical safety assessment

Effects on fertility

Description of key information

Link to relevant study records

Referenceopen allclose all

Reference 1

Reference 2

Effect on fertility: via oral route

Effect on fertility: via inhalation route

Effect on fertility: via dermal route

Additional information

Effects on developmental toxicity

Description of key information

Link to relevant study records

Referenceopen allclose all

Reference 1

Reference 2

Effect on developmental toxicity: via oral route

Effect on developmental toxicity: via inhalation route

Effect on developmental toxicity: via dermal route

Additional information

Toxicity to reproduction: other studies

Link to relevant study records

Reference

Additional information

Justification for classification or non-classification

Additional information

Referenceopen all close all

Referenceopen all close all