Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Link to relevant study records

Reference

Endpoint:

two-generation reproductive toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to OECD guideline with GLP, acceptable with restrictions (male reproductive parameters, oestrous cycle, and developmental milestones of pups and fertility index/gestation index were not examined)

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)

Deviations:

yes

Remarks:

male reproductive parameters, oestrous cycle, and developmental milestones of pups and fertility index/gestation index were not examined

GLP compliance:

yes

Remarks:

Huntingdon Research Centre Ltd., England

Limit test:

yes

Species:

rat

Strain:

other: Crl:COBS CD (SD) BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River UK Ltd., Manston Road, Margate, Kent
- Age at study initiation: (P) x 6 wks; (F1) x 4 wks (±4 days)
- Diet (e.g. ad libitum): Spratt's Laboratory Diet No. 2 (low fat)
- Water (e.g. ad libitum): drinking water
- Acclimation period: 8 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±3
- Humidity (%): 50±20
- Air changes (per hr): 13
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: feed

Details on exposure:

DIET PREPARATION
- Rate of preparation of diet (frequency): Fresh batches of each concentration of diet were prepared weekly throughout the study. Diet remaining in the food hoppers at the end of each week was discarded.
- Mixing appropriate amounts with (Type of food): An appropriate quantity of material as supplied was weighed and ground directly into a weighed amount of sieved Spratt's Laboratory Diet No. 2 and stirred by hand to give a premix of suitable strength. The dietary concentrations required were obtained from this premix by direct dilution with further quantities of diet, homogeneity being achieved by mixing for 7 minutes in a rotary double-cone blender.
- Storage temperature of food: The diets were then stored until use in heat-sealed opaque polythene bags.

Details on mating procedure:

- M/F ratio per cage: 1:1
- Length of cohabitation: 20 days
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

- Premating Exposure Period: 10 weeks
- Treatment of the F0 males and females by dietary inclusion began when they were 6 weeks of age, and continued until all F1 litters had been weaned. Direct treatment of the F1 males and females was considered to commence when they were four weeks (± 4 days) of age, and continued until all F2 litters had been weaned.

Frequency of treatment:

continuously

Details on study schedule:

- F1 parental animals not mated until 4 weeks after selected from the F1 litters.
- Selection of parents from F1 generation when pups were 21 days of age.

Remarks:

Doses / Concentrations:
500, 1500 and 5000 ppm
Basis:
nominal in diet

Remarks:

Doses / Concentrations:
32.09, 96.48 and 315.12 mg/kg bw/d in males and 39.00, 111.26 and 373.04 mg/kg bw/d in females
Basis:
actual ingested

No. of animals per sex per dose:

F0 generation: 28
F1 generation: 24

Control animals:

yes, concurrent no treatment

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Cage side observations: signs and mortalities

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes

WATER CONSUMPTION: Yes
- Time schedule for examinations: daily

BODY WEIGHT: Yes
- Time schedule for examinations: The weight of each animal of the F0 generation was determined initially (i.e. week -1) and subsequently at weekly intervals. All pups from the main mating phase of each generation (Fl and F2) were weighed at birth, and on Days 4, 8, 12 and 21 post partum. Pups derived at re-mating were weighed at birth and on Days 4 and 8. Animals retained for the Fl generation were weighed weekly from selection. During the mating period, all females were additionally weighed on alternate days throughout. The occurrence of a positive indication of mating (i.e. sperm or plug) was considered as Day 0 of pregnancy and thereafter females were also weighed on presumed Days 0, 7, 14, 17 and 20 of gestation. Weights of pregnant animals without positive indication of mating were obtained by retrospective calculation from birth (assuming a 22- day gestation period. Dams that littered were weighed as soon as possible after parturition and on Days 7, 14 and 21 post partum.

OTHER:
- Pregnancy rate was determined as the percentage of paired females that became pregnant.
- Vaginal smears were taken during the mating period to enable the number of animals that mated on specific days to be determined, this information was used:
(i) to detect whether pregnancy was interrupted after mating
(ii) to detect marked anomalies of the oestrous cycle
(iii) to determine the median pre-coital time for the group
- The duration of gestation was taken as the time between the day of successful mating and parturition.

Litter observations:

STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: no, as soon as possible after parturition

PARAMETERS EXAMINED
The following parameters were examined in [F1 / F2] offspring:
number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain (main mate pups were also weighed on Days 4, 8, 12 and 21 post partum; pups from the re-mated females were weighed on Days 4 and 8), physical or behavioural abnormalities

GROSS EXAMINATION OF DEAD PUPS:
yes, for external and internal abnormalities

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals [after the majority of litters had been weaned]
- Maternal animals: All surviving animals [3 weeks after weaning of their litter]

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations

HISTOPATHOLOGY / ORGAN WEIGHTS
- The tissues indicated below were prepared for microscopic examination: adrenals, aorta, bone (femur), bone marrow (sternum), brain, cranial vault (for lachrymal glands, teeth, nasal turbinates, inner ear), caecum, colon, duodenum, eyes, heart, ileum, jejunum, kidneys, liver, lungs, lymph nodes (cervical/ mesenteric), mammary gland, oesophagus, ovaries, pancreas, pituitary, prostate with seminal vesicle (adults only), salivary gland, sciatic nerve, Skeletal muscle, skin, spinal column (vertebral column), spleen, stomach, testes with epididymides, thymus (if present), thyroids, tongue, trachea (with larynx, pharynx), urinary bladder, uterus with vagina.
- Selected organs were weighed prior to preservation, where appropriate, organs were weighed as a pair. When one of a pair of organs was abnormal,
both organs were weighed individually.

Postmortem examinations (offspring):

SACRIFICE
- The F1 offspring not selected as parental animals and all F2 offspring were sacrificed at 23 days of age.
- These animals were subjected to postmortem examinations (macroscopic and microscopic examination).

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations

HISTOPATHOLOGY / ORGAN WEIGTHS
- The tissues indicated below were prepared for microscopic examination: adrenals, aorta, bone (femur), bone marrow (sternum), brain, cranial vault (for lachrymal glands, teeth, nasal turbinates, inner ear), caecum, colon, duodenum, eyes, heart, ileum, jejunum, kidneys, liver, lungs, lymph nodes (cervical/ mesenteric), mammary gland, oesophagus, ovaries, pancreas, pituitary, prostate with seminal vesicle (adults only), salivary gland, sciatic nerve, Skeletal muscle, skin, spinal column (vertebral column), spleen, stomach, testes with epididymides, thymus (if present), thyroids, tongue, trachea (with larynx, pharynx), urinary bladder, uterus with vagina.
- Selected organs were weighed prior to preservation, where appropriate, organs were weighed as a pair. When one of a pair of organs was abnormal,
both organs were weighed individually.

Clinical signs:

no effects observed

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Other effects:

effects observed, treatment-related

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

no effects observed

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS):
There were no obvious signs of reaction to treatment. Five adult mortalities occurred, one at 1500 ppm and four at 5000 ppm. There was no clear indication of a direct effect of treatment.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS):
At 5000 ppm mean weekly bodyweight gain of males and females in both generations tended to be slightly lower than among control animals during the first part of the treatment period. Subsequently, towards the end of each generation there was a tendency among males for parity with control animals to be regained. Occasional statistically significant differences from control animals were recorded (p<0.001 during 0 to 3 weeks in males and females; p<0.01 during 0 to 10 weeks in females). Weight gain of females at 5000 ppm during gestation tended to be slightly lower than among control animals, in both generations. At 500 and 1500 ppm there were no consistent or obvious dosage-related differences among mean weekly bodyweights. At both concentrations, mean weight gain of F0 females during gestation was slightly lower than among control animals in the F1 generation, weight gain during gestation was similar to that of control animals. At 5000 ppm there appeared to be a slight general reduction in mean food consumption (-6.4% in males and -7.3 % in females of F0; -2.8% in males and -6% in females of F1). There was no clear effect on mean food consumption at 500 or 1500 ppm; marginally lower values did occur but not consistently and there were no statistically significant differences. There was no difference in the mean food conversion ratios in the treatment and control groups of both F0 and F1 generations.

TEST SUBSTANCE INTAKE (PARENTAL ANIMALS)
F0 generation: 32.09, 96.48 and 315.12 mg/kg bw/d in males and 39.00, 111.26 and 373.04 mg/kg bw/d in females of the 0, 500, 1500 and 5000 ppm dose levels, respectively.
F1 generation: 41.92, 127.60 and 435.21 mg/kg bw/d in males and 46.37, 141.14 and 469.39 mg/kg bw/d in females of the 0, 500, 1500 and 5000 ppm dose levels, respectively.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS):
Mating performance, as judged by the median pre-coital time and vaginal smear records, and pregnancy rate, as indicated by the proportion of females that became pregnant, were similar for all groups in both generations. The duration of gestation was similar for all groups in both generations.

ORGAN WEIGHTS (PARENTAL ANIMALS)
5000 ppm: Statistically significant (p<0.01) increases in liver weight (+10% in males and +12% in females of F0; +9% in males and +10% in females of F1) and reductions in spleen weight (-12% in males and no effect in females of F0; -17% in males and females of F1). Although significantly lower brain weight was recorded among F1 adults, the reduction in adjusted mean weights was slight (approximately 3.5%) and F0 adults were unaffected.
1500 ppm: Organ weight analyses of F0 and F1 adults showed statistically significant (p<0.05) reductions in spleen weight (-7% in males and -1% in females of F0; -6% in males and -11% in females of F1). Liver weight was not adversely affected.
500 ppm: there was no effect on adults other than for statistically significant (p<0.05) reductions in spleen weight among F0 males (-10%) and F1 females (-10%).

GROSS PATHOLOGY (PARENTAL ANIMALS):
Among F0 generation males at 5000 ppm there was a slight increase in the incidence of animals showing macroscopically enlarged livers (5/28 compared with 0/28 among control animals). No other macroscopic changes attributable to treatment were observed at terminal autopsy of F0 or F1 generation adults.

HISTOPATHOLOGY (PARENTAL ANIMALS):
Minimal centrilobular hepatocyte enlargement was observed in 7/24 male and 11/19 female rats in the 5000 ppm treatment group of F1 generation compared to the controls. This change was considered to be treatment related. Similar changes were not observed in any rat examined from the 1500 ppm treatment group. Histology examination of spleens and brain sections from F1 adult animals showed no treatment-related abnormality.

OTHER FINDINGS (PARENTAL ANIMALS): There was no clear or consistent effect on mean water consumption.

Dose descriptor:

NOAEL

Remarks:

Fertility

Effect level:

>= 5 000 ppm (nominal)

Sex:

female

Basis for effect level:

other: highest dose tested (5000 ppm is equivalent to ca. 373.04 mg/kg bw/day in F0 generation)

Dose descriptor:

NOEL

Remarks:

Systemic toxicity

Effect level:

1 500 ppm (nominal)

Sex:

male/female

Basis for effect level:

other: histological changes and organ weight (1500 ppm is equivalent to ca. 96.48 mg/kg bw/d in males and 111.26 mg/kg bw/d in females of F0 generation)

Dose descriptor:

NOEL

Effect level:

< 500 ppm (nominal)

Sex:

male/female

Basis for effect level:

other: organ weight

Remarks on result:

other: Generation: F1 and F2 (migrated information)

Clinical signs:

not specified

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Sexual maturation:

no effects observed

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

no effects observed

Histopathological findings:

no effects observed

VIABILITY (OFFSPRING):
At 5000 ppm mean total litter size at birth in the F0 generation was significantly lower than among control animals (P<0.05), and in the F1 generation although not significantly affected (P>0.05) was both below the concurrent control value and slightly below the recent laboratory control range. Post partum pup mortality at 5000 ppm in the F0 generation appeared slightly but significantly higher than among control animals even with the exclusion of dams showing total litter loss (P<0.05). In the F1 generation there was no obvious effect on pup mortality. At 500 and 1500 ppm, mean total litter sizes at birth in the F0 generation were lower than the control value to a similar extent as at 5000 ppm. In the F1 generation mean litter size at birth at 1500 ppm was similar to the control value and at 500 ppm slightly lower. In the absence of a consistent pattern of differences across the two generations and taking into account the extent of variation in litter size among control groups in recent studies, there was no clear indication of a treatment-related effect on initial litter size at these two dietary inclusions in either generation.

BODY WEIGHT (OFFSPRING):
At all three dietary concentrations there was no obvious effect on mean pup weight at birth in either generation. Subsequently during lactation at 5000 ppm in the F0 generation there was a tendency for lower pup weight gain with significantly (p<0.05 to p<0.001) lower values occurring at Days 12 and 21 post partum (-9 and -14%, respectively). In the F1 generation at 5000 ppm there was no significant effect on pup weight although marginally lower values were recorded despite the lower litter size and hence reduced intra-litter competition. The mean litter weight during lactation at 5000 ppm was significantly reduced in both generations (P<0.05 to P<0.001). During lactation at 500 and 1500 ppm, there was no clear effect on mean pup weight in either generation. Significantly lower values for litter weight at both concentrations in the F0 generation (P<0.05 to P<0.01) mainly reflected initial differences in total litter size at birth rather than an effect on mean pup weight.

ORGAN WEIGHTS (OFFSPRING)
Brain: At 5000 ppm slightly lower mean brain weights in comparison with corresponding control values were observed among F1 weanling males [-5.1%] and females [-2.8%] with differences attaining statistical significance (P<0.05 to P<0.01). Among F2 weanlings however, mean values appeared unaffected by treatment. At 1500 ppm slightly but significantly lower (P<0.05) brain weights were recorded for F1 weanling males [-2.4%] and females [-3.2%]. There was no apparent effect on values for F2 weanlings. At 500 ppm F1 weanling males showed slightly [-3.0%] but significantly lower brain weights; there were no other significant differences (P>0.05).
Liver: At 5000 ppm male and female adults and weanlings of both generations showed significantly higher liver weights [+15 to +27%] in comparison with control values (P<0.01). At 500 and 1500 ppm significantly higher liver weights [+9 to +15%] occurred among weanlings of both generations (P<0.05 to P<0.01).
Spleen: At 5000 and 1500 ppm, weanlings of both generations showed significantly lower spleen weights [-10 to -23%] in comparison with control animals (P<0.05 to P<0.01). At 500 ppm F2 weanling females showed significantly lower spleen weights [-3 to 10%] (P<0.05); occasional other mean values were slightly lower than among control animals but were not statistically significant (P>0.05).

GROSS PATHOLOGY (OFFSPRING):
Macroscopic examination of offspring showed no obvious increase in the incidence of deformities.

HISTOPATHOLOGY (OFFSPRING):
No microscopic abnormality was detected in any brain, liver or spleen examined of F2 generation weanlings.

Reproductive effects observed:

not specified

Conclusions:

In this investigation at 5000 ppm, the highest dose level, reaction to treatment was indicated by differences among adult observations during the study, litter data and, at termination, organ weight differences among adults and weanlings. Histological examinations showed centrilobular hepatocyte enlargement in the livers of Fl adults. At 500 and 1500 ppm reaction to treatment among adults and offspring was confined to statistically significant organ weight differences. These differences however occurred in the apparent absence of histological change. Mating performance, pregnancy rate and the duration of gestation at all three dietary concentrations were unaffected by treatment. Based on the results, the NOAEL for fertility in the parental generation was considered to be 5000 ppm (highest dose tested). The histological changes in the highest dose or organ weight difference can be due to the adaptive response to the treatment, however no such information is provided. Therefore the NOEL was identified for systemic toxicity in the parental generation, which was considered to be 1500 ppm. Similarly, the NOEL for F1 and F2 generations was considered to be <500 ppm.

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

315 mg/kg bw/day

Species:

rat

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

Discussion

In a 2-generation study (CIBA-GEIGY 1986), rats were fed with 500, 1500 and 5000 ppm of the test substance in diet (equivalent to 32.09, 96.48 and 315.12 mg/kg bw/d in males and 39.00, 111.26 and 373.04 mg/kg bw/d in females). In the highest dose level, effects on in-life parameters, litter data and organ weight of adults and weanlings were observed. The histological examinations showed centrilobular hepatocyte enlargement in the livers of Fl adults. At 500 and 1500 ppm reaction to treatment among adults and offspring was confined to organ weight differences. These differences occurred in the apparent absence of histological change. Mating performance, pregnancy rate and duration of gestation at all three dietary concentrations were unaffected by treatment.

Observation of littermates revealed higher pup mortality in F0 generation at 5000 ppm and lower initial litter size in both generations. Litter size during lactation at 5000 ppm was reduced in the F0 generation and to a lesser extent in Fl generation. The pup mortality at 500 and 1500 ppm was not affected in either generation.

The lower values for viable litter size at birth and during lactation in the F0 generation was due to differences in the initial total litter size and not due to pup mortality. Subsequently, during lactation in the 5000 ppm group, there was a tendency for lower pup weight gain with significantly lower values occurring at Days 12 and 21 post partum of the F0 generation. In the Fl generation at 5000 ppm there was no effect on pup weight although marginally lower values were recorded despite the lower litter size and hence reduced intra-litter competition. Reflecting these differences and differences in litter size, mean litter weight during lactation at 5000 ppm was significantly reduced in both generations.

During lactation at 500 and 1500 ppm there was no effect on mean pup weight in either generation. Significantly lower values for litter weight at both concentrations in the F0 generation mainly reflected initial differences in total litter size at birth rather than an effect on mean pup weight.

Additional information

The results from the 2-years chronic repeated dose study (CIBA-GEIGY 1974) showed no effects on reproductive organs (testes weights as well as information on gross and microscopic pathology for testes, prostate, ovaries and uteri) at the highest dose level (218 mg/kg bw in males and 275 mg/kg bw in females).

No effects on the mating ratio, on the numbers of implantations and embryonic deaths were observed in the dominant lethal assay in mice (CIBA-GEIGY 1975) where compound was administered orally in single doses of 1000 and 3000 mg/kg bw to male albino mice (NMRI-derived) which were then mated to untreated females over a period of six weeks.

Conclusion

Based on these results, the NOAEL for fertility in the parental generation was considered to be 5000 ppm (315.12 mg/kg bw/d in males and 373.04 mg/kg bw/d in females). The NOAEL for F1 and F2 generation is considered to be 5000 ppm (315.12 mg/kg bw/d in males and 373.04 mg/kg bw/d in females).

Short description of key information:
The substance is not toxic to reproduction as assessed in a valid two-generation study at doses of up to 5000 ppm (315 - 378 mg/kg bw/day) (Ciba-Geigy 1986).

Justification for selection of Effect on fertility via oral route:
Comparable to OECD guideline with GLP

Effects on developmental toxicity

Description of key information

The substance showed no teratogenicity in two teratogenicity studies (OECD 414) at gavage doses of up to 1000 mg/kg bw in mice and rats (Ciba-Geigy 1975b and c). No indication of developmental toxicity was observed in the two generation study in rats at feed applications of up to 5000 ppm (Ciba-Geigy 1986).

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1975

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable with guideline, acceptable with restrictions (gravid uterus weight, number of corpora lutea and fetal sex were not examined)

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

gravid uterus weight, number of corpora lutea and fetal sex were not examined

GLP compliance:

no

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: ca. 240 g
- Housing: 5/cage
- Diet (e.g. ad libitum): standard diet, Nafag No.890
- Water (e.g. ad libitum): tap water

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±0.5
- Humidity (%): 56±5
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

CMC (carboxymethyl cellulose)

Details on exposure:

VEHICLE
- Concentration in vehicle: 2%
- Amount of vehicle (if gavage): 1 ml/100 g bw

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1:3
- Length of cohabitation: overnight
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy

Frequency of treatment:

single

Duration of test:

GD 6-15

Remarks:

Doses / Concentrations:
150, 500, 1000 mg/kg bw
Basis:
actual ingested

No. of animals per sex per dose:

25 for all test groups, 30 for control group

Control animals:

yes, concurrent vehicle

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- Cage side observations: general condition, symptoms, mortality

BODY WEIGHT: Yes
- Time schedule for examinations: daily

FOOD CONSUMPTION: Yes

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 21
- Organs examined: ovaries and uterus (mucosa and contents, including amniotic fluid and placentae), the foetuses were subjected to careful external inspection and the condition of their body orifices was checked.

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: 1/3 per litter (using slicing technique)
- Skeletal examinations: Yes: 2/3 per litter

Statistics:

t-test was used for comparison between treated and control groups.

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
Body-weight gain was slightly (non-specific) depressed following the 500 mg/kg bw and 1000 mg/kg bw doses. At the three dose levels, particularly in the intermediate and high-dose group, feed consumption was reduced during the period of treatment. No further signs of intolerability of the compound were noted. The data on the rates of implantation and embryolethality (resorptions) were comparable for all groups.

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
The average weight of the foetuses was significantly (p<0.01) diminished in the 500 mg/kg bw (-1.7%) and 1000 mg/kg bw (-2.5%) dose group when compared with the control. The mean weight of live fetuses in the control, 150, 500 and 1000 mg/kg bw dose groups were 5.18, 5.16, 5.09 and 5.05 g, respectively. By applying the slicing technique in a few foetuses of the experimental groups minor anomalies were detected which have also occurred in a cumulative of "untreated" controls. Concerning skeletal assessment the only clear-cut deviation from the control group was increase in the number of not yet ossified phalangeal nuclei of the hindlimb following the administration of 1000 mg/kg bw. However, this deviation was not dose-related (Table 1).

Dose descriptor:

NOAEL

Effect level:

> 1 000 mg/kg bw/day (actual dose received)

Basis for effect level:

other: teratogenicity

Abnormalities:

not specified

Developmental effects observed:

not specified

Table 1. Skeletal examinations

Dose groups (mg/kg bw/day)	No. of skeletons examined	Phalangeal Nuclei
		Fore-limb	Hind-limb
150	193	4 (2.1 %)	52 (26.9%)
500	197	6 (3.0%)	33 (16.8%)
1000	192	2 (1.0%)	74 (38.5%)
control	238	0	36 (15.1%)

Conclusions:

Based on the results, no teratogenic effects were observed. The NOAEL for teratogenic effects was considered to be >1000 mg/kg bw.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Species:

rat

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

In a developmental toxicity study performed similar to the current OECD guideline 414 (CIBA-GEIGY 1975b), 25 rats/group were gavaged with dose levels of 150, 500 and 1000 mg/kg/d bw on days 6-15 of gestation. Maternal body-weight gain was slightly (non-specific) depressed following the 500 mg/kg bw and 1000 mg/kg bw doses. At the three dose levels, particularly in the intermediate and high-dose group, feed consumption was reduced during the period of treatment. No further signs of intolerability of the compound were noted. The data on the rates of implantation and embryolethality (resorptions) were comparable for all groups. The average weight of the foetuses was significantly (p<0.01) diminished in the 500 mg/kg bw (-1.7%) and 1000 mg/kg bw (-2.5%) dose group when compared with the control. The mean weight of live fetuses in the control, 150, 500 and 1000 mg/kg bw dose groups were 5.18, 5.16, 5.09 and 5.05 g, respectively. By applying the slicing technique in a few foetuses of the experimental groups minor anomalies were detected which have also occurred in a cumulative of "untreated" controls. Concerning skeletal assessment the only clear-cut deviation from the control group was increase in the number of not yet ossified phalangeal nuclei of the hindlimb following the administration of 1000 mg/kg bw. However, this deviation was not dose-related and therefore not considered to be treatment related. Thus, the NOAEL for teratogenic effects was considered to be >1000 mg/kg bw. The results were supported by similar study in mice (CIBA-GEIGY 1975c) at same dose levels. No teratogenic effects were observed and the NOAEL for teratogenic effects in mice was also considered to be >1000 mg/kg bw.

Justification for selection of Effect on developmental toxicity: via oral route:
Comparable with guideline

Justification for classification or non-classification

Dangerous Substance Directive (67/548/EEC)

The available studies are considered reliable and suitable for classification purposes under 67/548/EEC. As a result the substance is not considered to be classified for reproductive toxicity under Directive 67/548/EEC, as amended for the 28th time in Directive 2001/59/EC.

Classification, Labelling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance is not considered to be classified for reproductive toxicity under Regulation (EC) No. 1272/2