Cyclohexane-1,2-dicarboxylic anhydride

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2010-02-17 to 2010-04-19

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD 421

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Cyclohexane-1,2-dicarboxylic anhydride

EC Number:

201-604-9

EC Name:

Cyclohexane-1,2-dicarboxylic anhydride

Cas Number:

85-42-7

Molecular formula:

C8H10O3

IUPAC Name:

octahydro-2-benzofuran-1,3-dione

Test material form:

solid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Polynt Lot No. T208210033
- Manufacturing date: 11 Feb 2010
- Expiration date of the lot/batch: 11 Feb 2011

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Keep container tightly closed. Keep in a dry, cool and well ventilated place.
- Storage at testing facility 5 years

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source:Charles River (UK) Ltd.
- Choice:The rat was chosen as the test species because of the requirement for a rodent species by regulatory agencies. The Crl:CD (SD) strain was used because of the background data available in the laboratory.
- Age at study initiation: approximately 56 to 63 days of age
- Weight at study initiation: 290 to 330 g for males and 200 to 224 g for females
- Housing:barriered rodent facility (Building 30, Room 3021). The facility was designed and operated to minimise the entry of external biological and chemical agents and to minimise the transference of such agents between rooms. Before the study commenced the room was cleaned and disinfected. the rats are housed in P2000 or 2154 solid bottomed cages, or RB3 modified cages which were polypropylene cages with stainless steel grid flo oring. Wood based bedding was used when animals were housed in solid-bottomed cages, which was sterilised by autoclaving and changed at least twice a week.
- Diet : ad libitum , free access to a standard rodent diet (SDS VRF 1 Certified)
- Water : ad libitum, Potable water taken from the public supply was freely available via polycarbonate bottles fitted with sipper tubes.
- Acclimation period:15 days
- Health check: twice daily during the acclimitisation period

ENVIRONMENTAL CONDITIONS
- Temperature (°C):19 - 23 °C
- Humidity (%): 40 - 70 %
- Photoperiod (hrs dark / hrs light): 12/12 cycle dark/light

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: HHPA, was prepared for administration as a series of graded concentrations in the vehicle.

VEHICLE
- Amount of vehicle (if gavage):5 ml/kg
- Concentration in vehicle:0, 20, 60, 200 mg/ml

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples of each formulation from the first, fourth and last preparations were analysed for achieved concentration of the test substance. Four samples were taken from all groups. Two assays from each test group and one assay from the control group were analysed.

Details on mating procedure:

After a minimum of 15 days of treatment, F0 females were paired on a one-to—one basis with males from the same treatment group for a period of up to two weeks. Each morning following pairing, the trays beneath the cages were checked for ejected copulation plugs and a vaginal smear was prepared from each female and examined for the presence of spermatozoa. Numbers of copulation plugs, an estimate of sperm density in the vaginal
smear and the quality of the spermatozoa were recorded and these records are retained with I5 the raw data for the study. The day on which mating was detected this day was designated Day 0 of gestation. Once mating had occurred, the males and females were separated and vaginal smearing discontinued. The pre-coital interval was calculated for each female as the time elapsing between initial pairing and detection of mating.

Duration of treatment / exposure:

The F0 animals were treated for 15 days before pairing, throughout pairing, gestation and lactation until the day before termination.F 0 males were terminated after approximately 48 days of treatment. F 0 females were allowed to litter and rear their offspring to Day 7 of age and were killed on Day 7 of lactation.

Frequency of treatment:

Once a day during study

Duration of test:

The F0 animals were treated for 15 days before pairing, throughout pairing, gestation and lactation until the day before termination.F 0 males were terminated after approximately 48 days of treatment. F 0 females were allowed to litter and rear their offspring to Day 7 of age and were killed on Day 7 of lactation.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

100 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

300 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

1 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

10 males / 10 females

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale:The dose levels of 0, 100, 300 and 1000 mg/kg/day were selected based on the results of a 7-day preliminary study
- Rationale for animal assignment: by numerical progression
- Negative control: the first group receive only a vehicle as negative control

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
Animals were inspected visually at least twice daily for evidence of ill-health or reaction to treatment.

DETAILED CLINICAL OBSERVATIONS: Yes
A detailed physical examination was performed on the first day of treatment and weekly thereafter for F0 males until termination, and weekly for F0 females prior to pairing and on Days 0, 7, 14 and 20 after mating and Days l and 7 of lactation to monitor general health.

BODY WEIGHT: Yes
F0 males were weighed on the first day of treatment (Week 0) and weekly throughout treatment until termination. F 0 females were weighed on the first day of treatment and weekly until mating was detected. The females were weighed subsequently on Days 0, 6, 13 and 20 after mating and on Days 1, 4 and 7 of lactation.

FOOD CONSUMPTION: Yes
Weekly from the start of treatment until the animals were paired for mating. For each F0 female, consumption was recorded for the periods Days 0-5, 6-12 and 13-19 after mating and Days 1-3 and 4-6 of lactation.

WATER CONSUMPTION: No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on lactation Day 7
- Organs examined: Examination of external appearance, appearance of the tissues and organs examined after opening of the cranial, thoracic and abdominal cavities. Abnormalities recorded with details of location, color, shape and size. Special attention was paid to the organs of the reproductive system. The number of implantation sites and of corpora lutea was recorded.
- Organ weights: Males - epididymides, spleen, testes; Females - Ovaries, spleen
- Tissues fixed and preserved: (from all animals) - Abnormalities, Adrenal glands, Brain, Caecum, Colon, Duodenum, Epididymides, Eyes, Femur, Head, Heart, Ileum, Jejunum (including Peyer’s patches), Kidneys, Liver, Lungs, Lymph nodes (mandibular, mesenteric and left axillary), Mammary area (caudal and cranial), Ovaries, Pituitary gland, Prostate gland, Rectum, Sciatic nerve, Seminal vesicles with coagulating gland, Skeletal muscle, Spinal cord, Spleen, Sternum with marrow, Stomach, Testes, Thymus, Thyroid with parathyroids, Trachea, Urinary bladder, Uterus – cervix, Vagina

HISTOPATHOLOGY: Yes
Tissues examined - Ovaries, testes and epididymides (with special emphasis on stages of spermatogenesis in the male gonads and histopathology of interstitial testicular cell structure) of the animals in the control and high dose groups..

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes

Fetal examinations:

SACRIFICE
- The F1 offspring were sacrificed at 7 days of age.
- These animals were subjected to postmortem examinations (macroscopic examination) as follows:
- External examinations: Yes: [all per litter]
- Soft tissue examinations: Yes
- Skeletal examinations: No
- Head examinations: Yes
For all F1 offspring, a full macroscopic examination of the tissues was performed. All external features and orifices were examined visually. The cranial roof was removed to allow observation of the brain, pituitary gland and cranial nerves. After ventral mid-line incision, the neck and associated tissues and the thoracic, abdominal and pelvic cavities and their viscera were exposed and examined in situ. The necropsy also included an assessment for the presence of milk in the stomach, where this was possible.

Statistics:

For bodyweight, food consumption, organ weight, litter size and survival indices data a parametric analysis was performed if Bartlett's test for variance homogeneity was not significant at the 1% level. The F1 approximate test was applied to detect significant departure from monotonicity of means when the main test for the comparison of the means is a parametric monotonic trend test, such as Williams’ test. If the F1 approximate test for monotonicity of dose-response was not significant, Williams' test for a monotonic trend was applied. If the F1 approximate test was significant, suggesting that the dose response was not monotone, Dunnett's test was performed instead. A non-parametric analysis was performed if Bartlett's test was still significant at the 1% level following both logarithmic and square-root transformations. The H1 approximate test, the non-parametric equivalent of the F1 test, was applied. If the H1 approximate test for monotonicity of dose-response was not significant at the 1% level, Shirley's test for a monotonic trend was applied. If the H1 approximate test was significant, suggesting that the dose-response was not monotone, Steel's test was performed.

For litter size and survival indices Fisher’s Exact tests were performed. Treatment groups were compared using pairwise comparisons of each dose group against the control.

For organ weight data, analysis of covariance was performed using terminal bodyweight as covariate.

Sex ratio were analysed by generalised mixed linear model with binomial errors, a logit link function and litter as a random effect. Each treated group was compared to control using a Wald chi-square test.

For gestation length an exact two-tailed Linear-by-linear test, with equally spaced scores, was applied to all groups.

For oestrous cycles an exact one-tailed (upper-tail) Linear-by-linear test was applied to all groups.

Indices:

Gestation index, pre-implantation mortality, post-implantation mortality, intra-uterine mortality, post-natal mortality, sex ratio, survival index

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Rales

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Reduced body weight gain observed during first week of treatment in animals treated at 1000 mg/kg bw/day

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

Reduced food consumption observed during first week of treatment in animals treated at 1000 mg/kg bw/day

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Slightly higher spleen weight in animals treated at 1000 mg/kg bw/day

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Maternal developmental toxicity

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

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
CLINICAL SIGNS AND MORTALITY:
There were 7 mortalities. At 1000 mg/kg/day, during the two-week pre-pairing period 2 males and 2 females were killed for welfare reasons and 1 female was found dead. One further male was found dead at the end of Week 3. All of these animals showed noisy respiration (rales) prior to death or sacrifice and 1 male and 2 females showed gasping respiration. Two males and 2 females showed bodyweight loss prior to sacrifice. At 300 mg/kg/day, 1 female was killed for welfare reasons after showing noisy and gasping respiration and reduced body tone.
Among animals surviving to scheduled termination, signs of chin rubbing, salivation and noisy respiration (rales) were apparent after dosing of males and females at 1000 mg/kg/day. At 300 mg/kg/day, there was a low incidence of chin rubbing after dosing of both sexes and a low incidence of post-dose noisy respiration and salivation among females. Transient chin rubbing and/or post—dosing salivation is commonly observed where animals are dosed by oral gavage and the reaction is generally regarded as reflecting distaste of the dosing formulations rather than a sign of toxicity.
Clinical signs observed at routine physical examination which were considered to be related to treatment were restricted to noisy respiration (rales) among some animals receiving 1000 mg/kg/day.

BODY WEIGHT:
Males receiving 1000 mg/kg/day showed markedly low mean bodyweight gain during the first week of dosing compared with controls, while females receiving 1000 mg/kg/day showed mean bodyweight stasis during this period. Thereafter, the weight gain of males and females was essentially similar to controls to termination or pairing respectively, although, as a consequence of the performance during Week 1, overall gain for males at 1000 mg/kg/day was 80% that of controls. There was no clear effect of treatment at 300 or 100 mg/kg/day on mean bodyweight gain of males or females, and the mean bodyweight gain of females during gestation and lactation was unaffected by treatment at all dose levels investigated.

FOOD CONSUMPTION:
At 1000 mg/kg/day, males showed low mean food consumption during Week 1 and to a lesser extent during Week 2 of treatment, Females in this dose group also showed statistically significantly low food consumption during Week 1, however food intake in Week 2 was similar to control. There was no effect of treatment at 300 or 100 mg/kg/day on mean food consumption for males and females during the pre-pairing period. There was no effect of treatment on food consumption for females during gestation or lactation at any dose level investigated.

ORGAN WEIGHTS:
At 1000 mg/kg/day, mean absolute spleen weights were slightly high for males and females, and adjusted spleen weights were statistically significantly high for males. Mean absolute and adjusted ovary weights were marginally high and analysis of the adjusted weights attained statistical significance. There was no evidence of an effect of treatment on the limited list of weighed organs for males and females at 100 or 300 mg/kg/day.

GROSS PATHOLOGY:
Treatment-related macroscopic findings were restricted to stomach changes, apparent as a thickened glandular region (at 1000 mg/kg/day) and discoloured/roughened/thickened non glandular region (at 1000 mg/kg/day and to a much lesser extent at 300 mg/kg/day).The incidence and distribution of all other findings were consistent with the common background incidence.

MICROSCOPIC PATHOLOGY:
There were no changes in the reproductive organs which were considered related to treatment. The seminiferous tubules were evaluated with respect to their stage in the spermatogenic cycle and the integrity of the various cell types present within the different stages. No cell or stage abnormalities were observed.

Effect levels (maternal animals)

Key result

Dose descriptor:

LOAEL

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

body weight and weight gain

clinical signs

food consumption and compound intake

organ weights and organ / body weight ratios

Results (fetuses)

Fetal body weight changes:

no effects observed

Reduction in number of live offspring:

no effects observed

Changes in sex ratio:

no effects observed

Changes in litter size and weights:

no effects observed

Changes in postnatal survival:

no effects observed

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Effect levels (fetuses)

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Lack of treatment-related effects

Fetal abnormalities

Key result

Abnormalities:

not specified

Overall developmental toxicity

Key result

Developmental effects observed:

no

Applicant's summary and conclusion

Conclusions:

In a screening study of reproductive toxicity conducted in accordance with OECD test methods, the substance caused no changes in male and female reproductive performance (gonad function, mating behaviour, conception, pregnancy, parturition) and dam’s delivery data. There were no test item related effects on offspring’s development. Based on these observations the No Observed (Adverse) Effect Level for reproductive performance of the male and female rats was regarded as 1000 mg/kg body weight/day and the NO(A)EL for F1 Offspring was 1000 mg/kg body weight/day

Executive summary:

In a screening study of reproductive toxicity conducted in accordance with OECD test methods, the substance caused no changes in male and female reproductive performance (gonad function, mating behaviour, conception, pregnancy, parturition) and dam’s delivery data. There were no test item related effects on offspring’s development. Based on these observations the No Observed (Adverse) Effect Level for reproductive performance of the male and female rats was regarded as 1000 mg/kg body weight/day and the NO(A)EL for F1 Offspring was 1000 mg/kg body weight/day