Diphenyl carbonate

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Only females were used

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Reference

Endpoint:

sub-chronic toxicity: oral

Remarks:

one-generation study

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: OECD 416

Principles of method if other than guideline:

One-generation study following OECD TG 416 (2001) without treatment of F1 weanlings after developmental milestones had occurred (balano-preputial separation or vaginal opening at an age of about 8 weeks). The conduct of this study includes also recommendations of OECD TG 415 (adopted 1983) and OECD TG 407 (open field observation and Functional Observation Battery)

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

- Age: about 6 weeks
- Weight at study initiation: males: 111-151 g; females: 96-132 g

Route of administration:

oral: feed

Vehicle:

other: oral feeding in a diet containing 1% peanut oil

Details on oral exposure:

oral feeding in a diet containing 1% peanut oil
diets were prepared weekly

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The determination of the assay of diphenyl carbonate in the feed samples was done after extraction by gas chromatography under GLP. Formulations with 1500, 5000, and 15000 ppm diphenyl carbonate in the diet were found to be within their target values. Homogeneity requirements were met.

Duration of treatment / exposure:

about 18 weeks
Animals were exposed during the premating period of about 11 weeks, and during the mating period of up to 3 weeks. Males were sacrificed after the mating period. Females were further exposed during pregnancy and lactation, and were sacrificed when F1 offspring was weaned (after 4 weeks). At the same time most F1 animals were sacrificed, except for one F1 male and one F1 female per litter, which were sacrificed after a further treatment period of about 4 weeks, when developmental milestones had occurred (balano-preputial separation or vaginal opening).

Frequency of treatment:

continuous

Dose / conc.:

1 500 ppm

Remarks:

(nominal in diet)

Dose / conc.:

5 000 ppm

Remarks:

(nominal in diet)

Dose / conc.:

15 000 ppm

Remarks:

(nominal in diet)

No. of animals per sex per dose:

25

Control animals:

yes, concurrent no treatment

Details on study design:

Post-exposure period: no
Rationale for dose selection: based on a subchronic feeding pilot study (Eiben, 2002) Diphenylcarbonate (DPC) Subchronic study in Wistar rats (Pilot study for a one-generation study with administration in the diet), Report No. AT00045, Oct 22, 2002)
ACTUAL DOSE (mean) RECEIVED BY DOSE LEVEL BY SEX:
- low dose: 132 (m) or 219 (f) mg/kg bw/day; mid dose: 427 (m) or 710 (f)  mg/kg bw/day; high dose: 1561 (m) or 2432 (f) mg/kg bw/day 

Positive control:

none

Observations and examinations performed and frequency:

CLINICAL OBSERVATIONS AND FREQUENCY: 
- Clinical signs: at least weekly
- Mortality: twice daily
- Body weight: weekly
- Food consumption: weekly
- Water consumption: not determined
- Ophthalmoscopic examination: not determined
- Haematology: not determined
- Biochemistry: not determined
- Urinalysis: not determined

Sacrifice and pathology:

ORGANS EXAMINED AT NECROPSY:
- gross pathology: adrenals, liver, kidney, spleen, pituitary, vagina,  uterus/cervix, ovaries, oviducts, seminal vesicles with coagulation  glands, prostate, brain, trachea, larynx and esophagus, mammary glands  with skin, epididymides, thyroids/parathyroids, urethra with preputium, coagulating glands
- organ weights: brain, pituitary gland (fixed), liver, kidneys,  adrenals, spleen, thyroid (one fixed organ), uterus, seminal vesicles  with coagulation glands, prostate, epididymis (only left organ), testes  and ovaries 
- Histopathology F0 (control and 15000 ppm group): adrenals, liver,  kidney spleen, pituitary, vagina, uterus/cervix, ovaries, oviducts,  seminal vesicles with coagulation glands, prostate, brain, mammary glands  with skin, testes, epididymides, thyroids/parathyroids, 
- Histopathology F1 weanlings: ovaries

Other examinations:

- spermatology: yes (control and 15000 ppm group) spermatozoa motility  and viability, spermatozoa morphology, quantitative determination of  spermatozoa in epididymis, quantitative determination of homogenization  resistant spermatid heads in the testis)
- functional observation battery (neurotoxicity screening: sensory  reactivity to stimuli of different types): yes
- developmental milestones and investigations in post weaned F1 rats: yes

Statistics:

Dunnett-Test with variance analysis for body and organ weights;  Kruskal-Wallis-Test with a Steel-Test for food consumption data

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

No effects were observed that were test material related.

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

F0 males of 15000 ppm group showed significantly  lower (about -7%) body weights compared to controls nearly throughout the  total study; 15000 ppm females exhibited sporadically significantly lower  body weights, which reached -8% during lactation.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

No effects were observed that were test material related.

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

Behaviour (functional findings):

no effects observed

Description (incidence and severity):

no indication of neurotoxic potential

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

significantly increased relative liver weights in 5000  and 15000 ppm males (+10.1, +13.5%) and 15000 ppm females (+12%);  significantly increased absolute (+11.5, +13.5, +17.3%) and relative  (+9.5%, +14.3%, +19%) adrenal weights in females; significantly increased  ovarian weights (absolute: +22.8%, +16.3%; relative: +27.1%, +22.9%) from  5000 ppm onwards.

Gross pathological findings:

no effects observed

Description (incidence and severity):

no significant findings

Neuropathological findings:

no effects observed

Description (incidence and severity):

no indication of neurotoxic potential

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

LIVER: Hepatocellular hypertrophy was found in males of the mid and high  dose group (0, 0, 4, 6) and in females of the high dose group (0, 0, 0,  2) in low frequency and severity score. The incidence of Kupffer cell  foci was slightly increased in females of the high dose group (6, 5, 5,  10).
ADRENAL GLANDS: In mid and high dosed males the frequency of mixed-size  vacuolation of zona fasciculata and partly also glomerulosa cells was  slightly and the severity moderately increased (incidence: 18, 21, 25,  25; grade 2: 5, 6, 13, 9; grade 3: 0, 0, 5, 15). In females  microvesicular vacuolation (0, 17, 23, 24) and hypertrophy (0, 17, 23,  25) of the zona fasciculata cells were found in high incidences in all  dose groups. The severity score increased dose-dependently.
OVARIES: The  number of corpora lutea (severity score grade 2) increased slightly from  1500 ppm onwards (8, 12, 17, 16). The total number of corpora lutea per  group was also slightly elevated (365, 391, 443, 428). At 1500 ppm and  above, large corpora lutea exhibited an infiltration of predominantly  mononuclear cells (0, 21, 24, 21). In addition, many of these corpora  lutea contained granulated luteal cells (0, 20, 18, 9). Hypertrophic  ovarian interstitial cells increased (0, 16, 24, 24) with severity score  increasing in a dose dependent manner.

Histopathological findings: neoplastic:

not examined

Dose descriptor:

NOAEL

Remarks:

parental males

Effect level:

1 500 ppm

Sex:

male

Basis for effect level:

other: corresponding to about 132 mg/kg bw/day

Dose descriptor:

LOAEL

Remarks:

parental males

Effect level:

5 000 ppm

Sex:

male

Basis for effect level:

other: corresponding to about 427 mg/kg bw/day based on increased relative liver weights with hepatocellular hypertrophy

Dose descriptor:

LOAEL

Remarks:

parental females

Effect level:

1 500 ppm

Sex:

female

Basis for effect level:

other: corresponding to about 219 mg/kg bw/day based on increased relative and absolute adrenal weights with histopathological changes in the zona fasciculata, and morphological changes in the ovaries

Critical effects observed:

not specified

Conclusions:

The NOAEL in males was 1500 ppm (about 132 mg/kg bw/day). In females a NOAEL could not be determined; the LOAEL was 1500 ppm (about 219 mg/kg bw/day), based on increased relative and absolute adrenal weights with histopathological changes in the zona fasciculata, and morphological changes in the ovaries.

Executive summary:

The repeated dose toxicity of the test material was investigated in a GLP study which was conducted in accordance with the standardised guideline OECD 416 without treatment of F1 weanlings after developmental milestones had occurred. The conduct of this study also includes recommendations of the standardised guidelines OECD 415 and OECD 407 (open field observation and Functional Observation Battery).

During the study male and female Wistar rats were dosed with the test material at 1500, 5000, and 1 5000 ppm, administrated in feed containing 1 % peanut oil. Animals were exposed during the premating period (about 11 weeks) and during the mating period (up to 3 weeks). Males were sacrificed after the mating period. Females were further exposed during pregnancy and lactation, and were sacrificed when F1 offspring was weaned (after 4 weeks).

Repeated oral dosing led to changes in weight and histopathology of the liver and adrenals in males at a dietary concentration of 5000 ppm (about 427 mg/kg bw/day), and in females of 1500 ppm (about 219 mg/kg bw/day). At 1500 ppm, females also exhibited morphological changes in the ovaries.

Under the conditions of this study, the NOAEL in males was 1500 ppm (about 132 mg/kg bw/day). In females a NOAEL could not be determined; the LOAEL was 1500 ppm (about 219 mg/kg bw/day), based on increased relative and absolute adrenal weights with histopathological changes in the zona fasciculata, and morphological changes in the ovaries.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Lower diphenyl carbonate doses were given to females over the same time as in the one-generation study to establish a NOAEL for this gender. Because of instability of diphenyl carbonate below 1500 ppm in food, the substance was administered by gavage. This study was not conducted in accordance with a specific guideline.

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Diphenyl carbonate

EC Number:

203-005-8

EC Name:

Diphenyl carbonate

Cas Number:

102-09-0

Molecular formula:

C13H10O3

IUPAC Name:

diphenyl carbonate

Details on test material:

purity 99.98 %

Test animals

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

ANIMALS  
- Age: about 5-6 w
- Weight at study initiation: 140-180 g

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: Tween 20

Details on oral exposure:

- Vehicle for 0, 10, and 200 mg/kg dose: 0.5% Tween 20 in demin. water
- Vehicle for 2 and 50 mg/kg dose: < 0.5% Tween 20 in demin. water  depending on dilution factor
- Adimistration volume: 5 ml/kg bw

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analytical investigations on homogeneity, stability and content checks were done by gas chromatography. Generally the content check assured that during the study appropriate and equal mixure prodedures were followed.

Duration of treatment / exposure:

18 weeks

Frequency of treatment:

once daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

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

Doses / concentrations 2

Dose / conc.:

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

Doses / concentrations 3

Dose / conc.:

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

Doses / concentrations 4

Dose / conc.:

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

No. of animals per sex per dose:

10 females per group

Control animals:

yes, concurrent vehicle

Details on study design:

Post-exposure period: none
Study was performed to clarify results of a previous study  (one-generation reproduction feeding study, Bayer Report No. AT00196, Jan  13, 2003), where morphological changes were found in adrenals and ovaries of females of all dose groups, and to establish a NOAEL.

Positive control:

none

Examinations

Observations and examinations performed and frequency:

CLINICAL OBSERVATIONS AND FREQUENCY: 
- Clinical signs: at least weekly
- Mortality: twice daily (once on weekends and public holidays)
- Body weight: weekly
- Food consumption: weekly
- Water consumption: not determined
- clinical chemical investigations: blood parameters at sacrifice  (cholesterol, glucose, urea, creatinine, total protein, albumin, alanine  aminotransferase, aspartate aminotransferase, alkaline phosphatase, and  the electrolytes Na, K, Ca, Cl)
- Haematology: not determined
- Urinalysis: not determined

Sacrifice and pathology:

ORGANS EXAMINED AT NECROPSY:
- gross pathology: adrenals, liver, spleen, pituitary, vagina, uterus/cervix, ovaries, oviducts, brain, heart, thymus, tattooed  auricles, kidneys, lungs, and gross lesions
- organ weights: brain, liver, kidneys, adrenals, spleen, ovaries with  oviducts, and uterus
- Histopathology: liver, adrenals, ovaries, oviducts, uterus, and vagina 

Statistics:

Dunnett-Test with variance analysis for body and organ weights; adjusted  welch test

Results and discussion

Results of examinations

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

No treatment related effects were observed.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

There were no compound-related deaths (due to misapplication throughout  all groups animals died: 1 in vehicle control, 1 in 10 mg/kg bw/day  group, 2 in 50 mg/kg bw/day group, 2 in 200 mg/kg bw/day group. One rat  in the 200 mg/kg bw/day group had to be killed in moribund condition.)

Body weight and weight changes:

no effects observed

Description (incidence and severity):

No treatment-related effects were observed

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

No treatment-related effects were observed

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:

no effects observed

Description (incidence and severity):

No treatment-related effects were observed

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

No treatment-related effects were observed

Gross pathological findings:

no effects observed

Description (incidence and severity):

There were no significant findings at gross necropsy

Neuropathological findings:

not examined

Description (incidence and severity):

At 200 mg/kg bw/day ovaries of 4 animals exhibited  interstitial glands (control and lower doses 0) characterised by slight  hypertrophy and pale cytoplasm (grade 2); no test material-related effects on number of corpora lutea (both ovaries; 287, 200, 276, 234, 247); in 3 high dosed females adrenal glands showed hypertrophy of Zona fasciculata cells with  microvesicular vacuolation.

Histopathological findings: neoplastic:

no effects observed

Effect levels

1

Dose descriptor:

NOAEL

Effect level:

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

Sex:

female

Basis for effect level:

histopathology: non-neoplastic

2

Dose descriptor:

LOAEL

Effect level:

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

Sex:

female

Basis for effect level:

histopathology: non-neoplastic

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

Under the conditions of this study, the NOAEL for female rats was determined to be 50 mg/kg/day.

Executive summary:

The repeated dose toxicity of the test material to female rats was examined in a GLP study.

During the study ten rats per dose were administered 2, 10, 50 and 200 mg/kg bw/day via gavage with Tween 20 as the vehicle for 18 weeks.

No test material related mortalities occurred and no clinical signs were recorded. There were no changes in body weight relating to the test material. However, there were some histopathological observations noted at 200 mg/kg bw/day: the ovaries of four animals exhibited interstitial glands characterised by slight hypertrophy and pale cytoplasm (grade 2). There were no test material related effects on the number of corpora lutea. In 3 high dose females, the adrenal glands showed hypertrophy of Zona fasciculata cells with microvesicular vacuolation.

Under the conditions of this study, the NOAEL for female rats was determined to be 50 mg/kg/day.