Benzophenone

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Link to relevant study records

Reference

Endpoint:

two-generation reproductive toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Japan, Inc. (Astugi breeding Center)
- Age at study initiation: (P) 5 wks; (F1) 3 wks
- Housing: Polycarbonate cages
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.0-25.0
- Humidity (%): 35-75
- Air changes (per hr): 12

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on mating procedure:

- M/F ratio per cage: 1:1
- Length of cohabitation: 2 weeks
- Proof of pregnancy: vaginal plug and /or sperm in vaginal smear referred to as day 0 of pregnancy
- Further matings after two unsuccessful attempts: no
- After successful mating each pregnant female was caged (how): no data
- Any other deviations from standard protocol: non known

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

Administration of F0 parental animals started from an age of 5 weeks and continued in males for 10 weeks. For females, administration lasted through 10 weeks or more of the pre-mating, mating, gestational, lactational and during weaning of the F1 offspring (PND 21).
Administration to F1 parental animals was started from the time of weaning (three weeks old); in F1 males it was continued until necropsy trough 10 weeks or more of the pre-mating and mating periods, and in F1 females until necropsy through 10 weeks or more of the pre-mating, mating, gestational, lactational periods, and during weaning of the F2 offspring (PND 21).

Frequency of treatment:

continously via diet

Remarks:

0, 100, 450 or 2000 ppm (nominal in diet)
F0 males: ca. 0, 6.5, 29 or 130 mg/kg bw
F0 females: ca. 0, 8.4, 38.2 or 166.5 mg/kg bw
F1 males: ca. 0, 7.8, 34.6 or 159.4 mg/kg bw
F1 females: ca. 0, 8.8, 40.5 or 179.2 mg/kg bw

No. of animals per sex per dose:

24 males and 24 females

Control animals:

yes, plain diet

Details on study design:

Dosing was based on the results of a preliminary dose-range finding study over 4 weeks with dietary concentrations of 0, 600, 2000, 6000 or 20000 ppm. The highest dose for the definite study was set at 2000 ppm.

Positive control:

no

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes (once daily)
DETAILED CLINICAL OBSERVATIONS: No data
BODY WEIGHT: Yes (time schedule: on gestation days 0, 7, 14 and 20, on lactation days 0, 4, 7, 14 and at necropsy)
FOOD CONSUMPTION AND COMPOUND INTAKE: yes

Oestrous cyclicity (parental animals):

Vaginal smears were collected from female animals everyday in the morning to examine the estrus cycle during the two weeks before mating, starting from 13 weeks of age for the F0 parents and from 11 weeks for the F1 parents.

Sperm parameters (parental animals):

Parameters examined in F0 and F1 male parental generations: In 10 animals of the control and 2000 ppm group, the number of homogenization-resistant spermatids in the testis and number of sperms in the cauda epididymal were counted.

Litter observations:

STANDARDISATION OF LITTERS: Yes (on day 4 postpartum; maximum of 8 pups/litter as nearly as possible, excess pups were killed and discarded)
PARAMETERS EXAMINED: Number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, physical or behavioural abnormalities, reflex tests
GROSS EXAMINATION OF DEAD PUPS: yes

Postmortem examinations (parental animals):

SACRIFICE: All surviving male animals as soon as possible after the last litters in each generation were produced. All surviving maternal animals after the last litter of each generation was weaned.

GROSS NECROPSY: no data

HISTOPATHOLOGY / ORGAN WEIGHTS: Organ weights in all F0 and F1 parental animals: brain, pituitary gland, thyroid including parathyroid, liver, kidneys, adrenal glands, spleen, testes, epididymes, prostate, seminal vesicle, ovaries and uterus. Histopathological examinations were conducted for the following organs from all males and females of the control and 2000 ppm groups in the F0 and F1 parents. The brain, pituitary gland, thyroid and parathyroid, liver, kidneys, adrenal glands, spleen, testes, epididymes, seminal vesicles (including coagulating glands), prostate (ventral lobe), ovaries, uterus (including the cervical region), vagina, and mammary glands. Furthermore, the liver and kidneys in the 100 and 450 ppm groups in the F0 and F1 parent animals and any macroscopically abnormal sites were also histopathologically examined. Besides, any animals that died during the course of the study or sacrificed upon becoming moribund were examined to investigate the causes.

Postmortem examinations (offspring):

SACRIFICE: Excluding the pups that died before selection on PND 4 or the pups not selected on PND 4 (when their numbers were adjusted), all the remaining pups were necropsied when they were sacrificed or were found dead.
GROSS NECROPSY: consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera. Organ weights (at weaning)
ORGAN WEIGTHS: The brain, thymus, and spleen of one F1 and F2 male and female pups each selected from each litter were weighed on PND 21.

Statistics:

Data concerning effects on the offspring until their weaning were based on values calculated per litter as the specimen unit. Using weights of bilateral organs, the sums of the left and right organs were employed for statistical analysis. Metric data were analyzed for homogeneity of variance by Bartlett’s method. When the variance was homogeneous, one-way ANOVA was carried out. When not homogeneous, on the other hand, a Kruskal-Wallis’s test was performed. When a significant inter-group difference was found, Dunnett’s method or a Dunnett type multiple-comparison method were applied. For some examination items, the Kruskal-Wallis test was applied first, and when a significant inter-group difference was found, Dunnett type multiple-comparison method was conducted. Numerical data were analyzed by the Fisher’s exact probability method. The level of statistical significance was basically set at 5%.

Reproductive indices:

No. of days until copulation (days)
Mating index (%) = (Number of males and females showing evidence of copulation / number of males and females used for mating) × 100.
Fertility index (%) = (Number of pregnant females / number of copulated females) × 100.
Gestation length (days) = Number of days from GD 0 till the delivery day.
Gestation index (%) = (Number of females with normal delivery / number of pregnant females) × 100.
Sex ratio = Total number of male pups delivered / total number of the pups delivered.

Offspring viability indices:

Birth index (%) = (Number of live pups delivered / number of implantations) × 100
Viability rate on PND 21 (weaning rate)(%) = (Number of live pups on PND 21 / number of live pups on PND 4) × 100
Viability on PND 4 (the survival rate on day 4)(%) = (Number of live pups on PND 4 / number of live pups on PND 0) × 100

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

dosing with >= 450 ppm inhibited body weight gain in both males and females

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

dosing with >= 450 ppm inhibited food consumption in both males and females

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:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

100 ppm: hypertrophy of centrilobular hepatocytes in males and females
>= 450 ppm: dilation of renal proximal tubules in both males and females. Regeneration of the proximal tubular epithelium was also apparent in all groups of males and females, including the control group. The incidence of the renal change was higher in the males receiving 450 ppm or 2000 ppm and in the females given 2000 ppm as compared with the control, and cases with moderate or marked change were included only in the former groups. Regeneration of tubular epithelium was more remarkable in males than females, and was pathologically prevalent around the dilated tubules

Histopathological findings: neoplastic:

not examined

Other effects:

effects observed, treatment-related

Description (incidence and severity):

Serum hormone levels: >= 100 ppm: testosterone levels in males showed a tendency to be elevated. No effects were found with regard to the mating index or the fertility index. Furthermore, when testosterone levels were compared between the F0 and F1 males, the dosing was found to have had no biologically significant effect. The change observed in F0 males was judged to be due to the low value in one control male. With serum levels of FSH, LH and estradiol, no change related to the treatment was found in any dose groups of F0 and F1 animals of either sex. In addition, no abnormalities were found in the hormone levels measured in three F1 control and one 100 ppm F1, all of which were non-copulating or non-pregnant.

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

see above

Dose descriptor:

NOEL

Effect level:

< 100 ppm (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

organ weights and organ / body weight ratios

histopathology: non-neoplastic

Dose descriptor:

NOEL

Remarks:

concerning reproduction and endocrine system

Effect level:

> 2 000 ppm (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no effects at any dose level

Critical effects observed:

not specified

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

dosing with >= 450 ppm inhibited body weight gain in both males and females

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

dosing with >= 450 ppm inhibited food consumption in both males and females

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:

effects observed, treatment-related

Description (incidence and severity):

450 ppm: significant increase in relative liver and kidney weights in both males and females
2000 ppm: significantly elevated values were found for both the absolute and relative weights of the liver and kidneys in males and females

Gross pathological findings:

no effects observed

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

100 ppm: hypertrophy of centrilobular hepatocytes in males and females
>= 450 ppm: dilation of renal proximal tubules in both males and females. Regeneration of the proximal tubular epithelium was also apparent in all groups of males and females, including the control group. The incidence of the renal change was higher in the males receiving 450 ppm or 2000 ppm and in the females given 2000 ppm as compared with the control, and cases with moderate or marked change were included only in the former groups. Regeneration of tubular epithelium was more remarkable in males than females, and was pathologically prevalent around the dilated tubules

Histopathological findings: neoplastic:

not examined

Other effects:

effects observed, treatment-related

Description (incidence and severity):

Serum hormone levels: >= 100 ppm: testosterone levels in males were not significantly different from the control and there were no adverse effects with regard to the mating index or the fertility index. Furthermore, when testosterone levels were compared between the F0 and F1 males, the dosing was found to have had no biologically significant effect. The change observed in F0 males was judged to be due to the low value in one control male. With serum levels of FSH, LH and estradiol, no change related to the treatment was found in any dose groups of F0 and F1 animals of either sex. In addition, no abnormalities were found in the hormone levels measured in three F1 control and one 100 ppm F1, all of which were non-copulating or non-pregnant.

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

see above

Dose descriptor:

NOEL

Effect level:

< 100 ppm (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

organ weights and organ / body weight ratios

histopathology: non-neoplastic

Dose descriptor:

NOEL

Remarks:

concerning reproduction and endocrine system

Effect level:

> 2 000 ppm (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no effects at any dose level

Critical effects observed:

not specified

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

2000 ppm: significant increase on PND 0 in males, decrease on PND 14-21 in males and females and also on PND 7-21 in males and females

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 examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Sexual maturation:

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

2000 ppm: significantly elevated relative brain weights and lower absolute spleen weights in both males and females. These changes were considered due to inhibition of the body weight gain caused by the treatment.

Gross pathological findings:

no effects observed

Histopathological findings:

not examined

Description (incidence and severity):

Not done as no macroscopic changes were observed

Behaviour (functional findings):

no effects observed

Developmental immunotoxicity:

not examined

see above

Dose descriptor:

NOEL

Generation:

F1

Effect level:

450 ppm (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

Critical effects observed:

not specified

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

450 ppm: males showed significantly elevated body weights on PND 0
2000 ppm: significant elevation for body weights on PND 0 in males and females, decreases on PND 14-21 in males and females and on PND 7-21 in females

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 examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Sexual maturation:

no effects observed

Description (incidence and severity):

2000 ppm: significantly elevated relative brain weights in both males and females. These changes were considered due to inhibition of the body weight gain induced by the treatment.

Gross pathological findings:

no effects observed

Histopathological findings:

not examined

Description (incidence and severity):

Not done as no macroscopic changes were observed

Behaviour (functional findings):

no effects observed

Developmental immunotoxicity:

not examined

see above

Key result

Dose descriptor:

NOEL

Generation:

F2

Effect level:

450 ppm (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

Critical effects observed:

not specified

Reproductive effects observed:

not specified

For details see background material section

Conclusions:

With regard to the effects of benzophenone on the F0 and F1 parental animals, inhibition of body weight gain and food consumption, significantly elevated renal weights, dilatation of the renal proximal tubules, and regeneration of the proximal tubular epithelium were seen at doses of >= 450 ppm, along with an increase in hepatic weight and centrilobular hepatocytic hypertrophy, considered as vital adaptive changes, at doses of >= 100 ppm. Obvious effects on the endocrine system and reproductive toxicological effects were not found even at the dose of 2000 ppm in the F0 or F1 parent. There were no test substance related changes in the oestrous cycle, reproductive capability, delivery and lactation, sperm parameters, serum hormone levels, or necropsy findings. As for effects on the offspring, inhibition of body weight gain was observed in both the F1 and F2 males and females of the 2000 ppm group. No effects of benzophenone were seen in the number of male and female F1 or F2 pups delivered, viability, anogenital distance (AGD), physical development, the results of reflex and response tests, or on the observation results of external abnormalities.

Executive summary:

The reproductive toxicity of benzophenone was evaluated in a two generation test according to OECD 416, in which male and female Sprague-Dawley (SD) rats, parental (F0) and first generation (F1), were exposed by feeding diets containing 0, 100, 450 or 2000 ppm. From the present study the NOEL for the parental animals is concluded to be less than 100 ppm. Concerning the effects on the endocrine system and the reproductive toxicity in the parental animals, the NOEL is 2000 ppm. In terms of the effects on the offspring, the NOEL is considered to be 450 ppm.

Effect on fertility: via oral route

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LOAEL

130 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

The reproductive toxicity of benzophenone was examined in a two-generation study in rats (Hoshino et al, 2005). Male and female Sprague-Dawley rats (parental (F0) and first generation (F1)) were dosed via diet with 0, 100, 450 and 2000 ppm (ca. 6-9, 29-40 and 130-179 mg/kg bw). In F0 and F1 parental animals, dosing with >= 450 ppm caused inhibition of body weight gain and food consumption, significantly elevated renal weights, dilatation of the renal proximal tubules, and regeneration of the proximal tubular epithelium, along with an increase in hepatic weight and centrilobular hepatocytic hypertrophy. At all doses there were no adverse effects in F0 or F1 parents concerning effects on the endocrine system and reproductive toxicological effects (no test substance related changes in the estrous cycle, reproductive capability, delivery and lactation, sperm parameters, serum hormone levels, or necropsy findings). As for effects on the offspring, inhibition of body weight gain was observed in both the F1 and F2 males and females of the 2000 ppm group, but no other treatment-related effects were observed (number of male and female F1 or F2 pups delivered, viability, anogenital distance, physical development, reflex and response tests, external abnormalities), where there was an increase in liver weight and centrilobular hypertrophy, and in kidney. Based on the dose-dependent histopathological findings in liver of adult rats a LOAEL of 6 mg/kg bw was derived.

Short description of key information:
Two-generation study according to OECD Guideline 416 in Sprague-Dawley rats with dosing of 0, 100, 450 and 2000 ppm via diet (ca. 6-9, 29-40 and 130-179 mg/kg bw).
No reproductive toxicity was found and effects on the offspring (inhibition of body weights) were observed at the highest dose only.
LOAEL: 6 mg/kg bw based on the dose-dependent histopathological findings in liver of adult rats.

Effects on developmental toxicity

Description of key information

Developmental toxicity study according to EPA OPPTS 870.3700 with Sprague-Dawley dosed via gavage with 100, 200 and 300 mg/kg bw on days 6 to 19 of gestation (Price, 2002).
Developmental toxicity study according to EPA OPPTS 870.3700 with New Zealand White rabbits dosed via gavage with 5, 25 and 45 mg/kg bw on days 6 to 29 of gestation (Price, 2002).

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.3700 (Prenatal Developmental Toxicity Study)

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Covance Research Products, Inc., Denver, PA
-Age at receipt: Females 8-10 weeks Males: 10-12 weeks
- Weight: Maternal body weights, for confirmed pregnant females used in this study, ranged from 3.124-4.473 kg on gd 0
- Fasting period before study: no
- Housing: individually housed in in stainless steel cages with mesh flooring
- Diet: Feed was rationed at ~65 g during the first 24 hours after arrival (gd 1 and 2). For the following 24 hours, females on gd 2 received ~ 125 g of feed, and feed was available ad libitum for all females from gd 3 to scheduled sacrifice.
- Water: ad libitum
- Acclimation period: 3 days

ENVIRONMENTAL CONDITIONS
The total range for temperature was 65.3-70.6 OF during Replicate I and 65.3-72.1 OF for Replicate II.
The total range for relative humidity was 45.3-64.6% for Replicate I and 36.7-59.9% for Replicate II.
- Photoperiod: 12 hrs dark / 12 hrs light

IN-LIFE DATES: Gestational day 0 dates for the first of two study replicates were April 18-
19, 1999. Evaluation of fetal heads and skeletons was completed on July 26, 1999.

Route of administration:

oral: gavage

Vehicle:

CMC (carboxymethyl cellulose)

Remarks:

0.5%

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
Benzophenone was formulated in aqueous 0.5% methyIcellulose. Dose formulations were stored in sealed, amber glass bottles at room temperature, and mixed well prior to dosing. Formulations were administered within the 30-day period of proven stability.

VEHICLE
- Justification for use and choice of vehicle (if other than water): Suspendability studies indicated that benzophenone was suspendable in 0.5% methylcellulose in water at a level of 200 mg/mL.
- Concentration in vehicle: 0, 1.67, 8.33 and 15.0 mg/mL
- Amount of vehicle (if gavage): 3 mL/kg bw

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

In connection with a previous developmental toxicity screening study in rats (NTP, 1999), the homogeneity of benzophenone in 0.5% methyIcellulose was evaluated at a concentration of 60 mg/mL. Samples from the top, middle and bottom were analyzed by high performance liquid chromatography (HPLC).The assay values were 114%, 102% and 104%, respectively. Thus, test chemical concentration and homogeneity for this chemical/vehicle mixture were verified. During the study, four sets of dose formulations were prepared (two sets per study replicate), and aliquots were submitted for verification of concentration before each period of use. In addition, the first and third mixes (Rep I, Mix 1 and Rep II, Mix 1) were analyzed after the period of use.

Details on mating procedure:

- Impregnation procedure: Females were naturally-mated by the vendor prior to shipment to RTI. For each replicate, animals arrived at RTI on gd 1 (24 females) or gd 2 (24 females).
- M/F ratio per cage: 1.1
- Proof of pregnancy: yes, successful cohabitation, referred to as day 0 of pregnancy
- Any other deviations from standard protocol: none

Duration of treatment / exposure:

Day 6 trough 29 of pregnancy

Frequency of treatment:

Once daily

Duration of test:

On gd 30, timed-mated females were sacrificed

Remarks:

0, 5, 25 or 45 mg/kg bw

No. of animals per sex per dose:

Separate shipments of 48 animals were used for each replicate of the study. Females were naturally-mated by the vendor prior to shipment to RTI. For each replicate, animals arrived at RTI on gd 1 (24 females) or gd 2 (24 females). A total of 24 naturally-mated females per group (12 per replicate per group) were assigned to this study.

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Dose selection was based on a screening study in which NZW rabbits were treated by gavage with 0, 25, 50, 75, 100, or 125 mg benzophenone/kg of body weight/day on gd 6 through 29 (NTP, 2004). In the screening study, evidence of maternal toxicity was found at all
doses, and the upper three treatment groups were terminated early due to excessive maternal toxicity or early delivery of litters. There was no statistically significant evidence of developmental toxicity at doses up to 50 mg/kg/day (NTP, 2004).

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Females were observed for clinical condition at least once/day from gd I or 2 (day of animal arrival) through gd 5 (prior to initiation of dosing). From gd 6 through 29, females were observed for clinical condition and signs of toxicity at dosing and approximately 1-2 hours after each daily dose. On gd 30, females were observed for clinical condition at weighing and at scheduled termination.

BODY WEIGHT: Yes
- Time schedule for examinations: on the mornings of gd 0 (vendor), 3, 6 through 30, and immediately following sacrifice on gd 30.

FOOD CONSUMPTION: Yes, on gd 3, 6, 9, 12, 15, 18, 21, 24, 27, 29, and 30.

WATER CONSUMPTION No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 30
- Organs examined: yes

OTHER: The body, liver, paired kidneys, and gravid uterus of each timed-mated female were weighed. Thoracic and abdominal cavities were examined. Sections of all maternal livers, maternal kidneys, as well as any maternal organs that displayed gross pathology, were saved in 10% neutral buffered formalin for optional histopathology

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Other: Dead fetuses, and live fetuses. Dead fetuses were counted, weighed, and discarded. Uteri which presented no visible implantation sites were stained with ammonium sulfide (10%) in order to visualize any implantation sites which might have undergone very early resorption.

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: All fetal carcasses were sexed and examined for visceral morphological abnormalities using a fresh tissue dissection method
- Head examinations: Heads from approximately one-half (50%) of the fetal carcasses were fixed and decalcified in Bouin' s solution and subsequently examined using a free-hand sectioning technique (Wilson, 1965).
- Skeletal examinations: All fetal carcasses were eviscerated, and the skeletons macerated and stained with alcian blue/alizarin red S stain (Marr et ai., 1988). Fetal skeletons were examined for morphological abnormalities.

Statistics:

Parametric statistical procedures were applied to quantitative continuous data (e.g., maternal body weights, fetal body weights, feed consumption, etc.). Bartlett's test for homogeneity of variance was reported using an alpha level of p=O.OOl. General Linear Models were applied to the Analyses of Variance (ANOVA) and the Tests for Linear Trend. Prior to GLM analysis, an arcsine-square root transformation was performed on all litter-derived percentage data (Snedecor and Cochran, 1967). For litterderived percentage data, the ANOV A was weighted according to litter size. When a significant (p<0.05) main effect for dose occurred, Dunnett's Multiple Comparison Test (Dunnett, 1955; 1964) was used to compare each treatment group to the control group for that measure. A one-tailed test (i.e., Dunnett's Test) was used for all pairwise comparisons to the vehicle control group, except that a twotailed test was used for maternal body and organ weight parameters, maternal feed consumption, fetal body weight, and percent males per litter. Data for any measure which showed a significant (p<0.05) dose X replicate interaction in a two-way (dose X replicate) ANOV A were presented as Mean ± SEM for each cell in the ANOV A design. Dose effects within each replicate were further evaluated using a one-way ANOVA and Test for Linear Trend. Dunnett's Test was applied for pairwise comparisons if the one-way ANOVA was significant (<0.05). Nominal scale measures were analyzed by ChiSquare Test .When Chi-Square revealed significant (p<0.05) differences among groups, then a one-tailed Fisher's Exact Probability Test, with appropriate adjustments for multiple comparisons, was used for pairwise comparisons between each treatment group and the control group. The alpha level for each statistical comparison (other than Bartlett's test above) was 0.05. The significance level for each trend test or pairwise comparison (one- or two-tailed) was reported if it reached p<0.05 or p<0.01.

Indices:

not applicable

Historical control data:

Present for comparison, if indicated

Details on maternal toxic effects:

Dose-related incidence of maternal mortality and early termination of pregnancy (i.e., abortion or early delivery), as well as reduced body weight, weight gain and feed consumption during late gestation.

Key result

Dose descriptor:

NOAEL

Effect level:

5 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: no maternal toxicity was observed

Key result

Dose descriptor:

LOAEL

Effect level:

25 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

body weight and weight gain

food consumption and compound intake

mortality

number of abortions

Abnormalities:

not specified

Details on embryotoxic / teratogenic effects:

Average fetal body weight per litter exhibited decreasing dose-response trends (males, females and both sexes combined). At the high dose, significant reductions were noted for male fetal body weight (81 % of control weight), female fetal body weight (85% of control weight) and both sexes combined (83% of control weight). There was an apparent decrease in the number of fetuses with extra rib(s) on Lumbar I with increasing doses of benzophenone. However, the apparent decrease was due to the smaller number of surviving litters at the mid and high-dose groups. Thus, there were no statistically significant differences among groups when the incidence of this finding was expressed as a percentage of rabbit fetuses (or percentage of litters) in which this finding occurred.

Key result

Dose descriptor:

NOAEL

Effect level:

25 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no toxic effects

Abnormalities:

not specified

Developmental effects observed:

not specified

For further details see attached background material

Conclusions:

The maternal toxicity LOAEL was 25 mg/kg bw and the NOAEL was 5 mg/kg bw. The developmental toxicity LOAEL was 45 mg/kg bw (based on reduced fetal body weight) and the NOAEL was 25 mg/kg bw.

Executive summary:

A developmental toxicity study in rabbits was performed according to US EPA Guideline requirements, which widely complies with OECD 414. Pregnant rabbits were treated from day 6 through 29 of pregnancy at daily dosages of 0, 5, 25 or 45 mg/kg bw. Maternal body weight and feed consumption showed decreasing trends. There were no changes in the weights of the gravid uterus, liver, or kidney of treated does. Benzophenone had no significant adverse effect on prenatal viability in litters that were carried until scheduled termination on gestational day 30. The ability of does to successfully carry their pregnancies was clearly compromised in a dose related manner (0 mg/kg, 24/24; 5 mg/kg, 24/24; 25 mg/kg, 19/22; 45 mg/kg, 12/19). Fetal body weight was significantly decreased in the 45 mg/kg group only. Developmental toxicity was noted only in the presence of well-defined maternal toxicity. There was no evidence for selective susceptibility of the conceptus relative to the pregnant dam.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

25 mg/kg bw/day

Study duration:

subacute

Species:

rabbit

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

Sprague-Dawley rats were dosed with 100, 200 and 300 mg/kg bw on days 6 to 19 of gestation. Clinical signs included lethargy, piloerection and weight loss. In dams liver and kidney weights were significantly increased in all dosed groups and body weight gain and decreased feed consumption were seen at 300 mg/kg bw. There were no adverse effects on prenatal viability or overall incidences of fetal malformations or variations, but average fetal body weight per litter was significantly lower in the highest dose group compared with controls. Incidences of unossified sternebrae were increased in all dose groupss of benzophenone, and the incidences of extra rib on Lumbar I were increased at >= 200 mg/kg bw. Therefore, no NOAEL was derived from this study.

New Zealand White rabbits were dosed with 5, 25 and 45 mg/kg bw on days 6 to 29 of gestation. There was a decreasing trend for maternal body weight and feed consumption, but there were no changes in the weights of the gravid uterus, liver, or kidney. There also was no significant adverse effect on prenatal viability in litters that were carried until scheduled termination on gestational day 30. The ability of dams to successfully carry their pregnancies was clearly dose-related compromised. At 45 mg/kg bw fetal body weight was significantly decreased.