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Toxicological information

Toxicity to reproduction

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Administrative data

Endpoint:
screening for reproductive / developmental toxicity
Remarks:
based on test type (migrated information)
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
1993-11-19 to 1993-12-31
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: This study is classified as reliable with restrictions because it was GLP compliant and although it didn't follow any specific guideline it was well documented and an acceptable screening study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report Date:
1994

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)
Principles of method if other than guideline:
Female rats were administered test compound beginning 7 days prior to mating and continued through mating and to gestation day 20. Dams were examined for general health and toxicity. Pups were examined for gross abnormalities at birth and body weights recorded on day 0 and 4. Pups were also sexed and observed for survival through day 4.
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
other: low viscosity hydrocarbon liquid
Details on test material:
- Name of test material (as cited in study report): F-277; CAS number 64741-82-8
- Substance type: Light coker gas oil
- Light brown to orange-coloured viscous liquid with a slightly cracked or burnt to asphaltic odour
- Flash Pt (approx °F): >150
- Specific gravity (approx): 0.89-0.95
- Purity petroleum distillates
- Stability: stable
- Volatility: slight
- Storage conditions (°F): 80 or below
- Boiling Pt range (°F): 320-1100

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: SASCO Inc., Madison, Wisconsin
- Age at study initiation: (P) x 9 to 10 weeks
- Weight at study initiation: (P) Females: 194 to 234 grams
- Housing: Individually except during mating
- Use of restrainers for preventing ingestion (if dermal): yes
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 12 to 14 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17 to 26
- Humidity (%): 40% to 70%
- Air changes (per hr): At least 10
- Photoperiod (hrs dark / hrs light): 12 hours light/12 hours dark


IN-LIFE DATES: From: 1993-11-19 To: 1993-12-31

Administration / exposure

Route of administration:
dermal
Vehicle:
unchanged (no vehicle)
Details on exposure:
TEST SITE
- Area of exposure: Backs
- % coverage: Not reported
- Type of wrap if used: None
- Time intervals for shavings or clippings: Not reported


REMOVAL OF TEST SUBSTANCE
- Washing (if done): Wiped with clean Webril pads
- Time after start of exposure: 6 hours


TEST MATERIAL
- Amount(s) applied (volume or weight with unit): Based on body weight
- Constant volume or concentration used: no


USE OF RESTRAINERS FOR PREVENTING INGESTION: yes
Details on mating procedure:
- M/F ratio per cage: one to one
- Length of cohabitation: Until at least 12 females had signs of mating
- Proof of pregnancy: copulatory plug and sperm in vaginal smear referred to as day 0
- After successful mating each pregnant female was caged (how): Individually in nesting boxes
- Any other deviations from standard protocol: Only stated that females were cohabitated with males nightly, does not specify if different males were used each night.
Analytical verification of doses or concentrations:
no
Details on analytical verification of doses or concentrations:
Not applicable
Duration of treatment / exposure:
One week prior to mating through gestational day 20
Frequency of treatment:
Daily
Details on study schedule:
F1 animals were not mated, they were sacrificed on day 4 of lactation.
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 1, 50, or 250 mg/kg/day
Basis:
nominal conc.
No. of animals per sex per dose:
Fifteen female controls and twelve females per treatment group
Control animals:
yes, sham-exposed
Details on study design:
- Dose selection rationale: Not reported, but first page of report indicates a preliminary study using 1, 250, or 500 mg/kg/day with 250 mg/kg/day considered the LOAEL.
- Rationale for animal assignment (if not random): Computer-generated randomization
Positive control:
None reported

Examinations

Parental animals: Observations and examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice daily for viability and once daily for signs of toxicity


DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Gestational days -7, -1, 0, 4, 8, 12, 16, and 20 and lactational days 0 and 4


BODY WEIGHT: Yes
- Time schedule for examinations: Gestational days -7, -1, 0, 4, 8, 12, 16, and 20 and lactational days 0 and 4


FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes


WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No

Oestrous cyclicity (parental animals):
None reported
Sperm parameters (parental animals):
Males were not treated.
Litter observations:
STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: no


PARAMETERS EXAMINED
The following parameters were examined in F1 offspring:
number and sex of pups, stillbirths, live pups postnatal mortality, presence of gross anomalies, weight gain


GROSS EXAMINATION OF DEAD PUPS:
yes, for external abnormalities
Postmortem examinations (parental animals):
SACRIFICE
- Maternal animals: All surviving animals on lactational day 4 or gestational day 25 if the female did not deliver.


GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera.


HISTOPATHOLOGY / ORGAN WEIGHTS
No tissues were prepared for microscopic examination or weighed.
Postmortem examinations (offspring):
SACRIFICE
- All F1 offspring were sacrificed at 4 days of age.
- These animals were subjected to postmortem examinations (macroscopic examination) as follows:


GROSS NECROPSY
- Gross necropsy consisted of external examinations.


Statistics:
Maternal data was analyzed with a one-way analysis of variance using t-test/Least Significant Difference or General Linear Model analyses. The reproductive and litter data used Wilcoxin Scores with Kruskal Wallis test. All proportional data were adjusted using arcsin transformation then analyzed using a one-way analysis of variance with a one-way analysis of variance using t-test/Least Significant Difference .
Reproductive indices:
Implantation sites, gestation length, and litter size.
Offspring viability indices:
Number of alive or dead pups on day 0, abnormalities, and body weight.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:
effects observed, treatment-related
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:
not examined
Histopathological findings: non-neoplastic:
not examined
Other effects:
not examined

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:
not examined
Reproductive function: sperm measures:
not examined
Reproductive performance:
no effects observed

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS): None of the dams died during the course of the study. Slight to moderate erythema, oedema and eschar were present at the treatment site in the low- and mid-dose groups (present during days 5-6 of the premating period), with more severe responses (including slight to severe erythema, ulceration in one animal) recorded in the 250 mg/kg/day group.


BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS): Mean body weight for the period gestational days 0-20 was decreased by approximately 10% (significant) in high-dose animals, with a comparable (significant) reduction in weight gain on gestational days 0-4. Maternal body weight at lactational day 4, and weight gain during the period lactational day 0-4, were also significantly decreased in postnatal dams from the 250 mg/kg/day group. Relative food consumption was significantly higher than controls in the 50 and the 250 mg/kg/day groups.


REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS): There were no differences in the reproductive performance parameters measured.



GROSS PATHOLOGY (PARENTAL ANIMALS): There were no treatment-related findings.




OTHER FINDINGS (PARENTAL ANIMALS)

Effect levels (P0)

open allclose all
Dose descriptor:
LOAEL
Effect level:
1 mg/kg bw/day (nominal)
Sex:
female
Basis for effect level:
other: dermal effects
Dose descriptor:
NOAEL
Remarks:
reproduction
Effect level:
>= 250 mg/kg bw/day
Sex:
female
Basis for effect level:
other: lack of effects

Results: F1 generation

General toxicity (F1)

Clinical signs:
no effects observed
Mortality / viability:
no mortality observed
Body weight and weight changes:
effects observed, treatment-related
Sexual maturation:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
no effects observed
Histopathological findings:
not examined

Details on results (F1)

VIABILITY (OFFSPRING): There was no treatment-related effect on viability.

CLINICAL SIGNS (OFFSPRING): There were no treatment-related effects.


BODY WEIGHT (OFFSPRING): There was a significantly decreased mean pup weight at birth (-7%) and at lactational day 4 (-14%) for the high-dose litters.



GROSS PATHOLOGY (OFFSPRING): There were no treatment-related findings.


Effect levels (F1)

Dose descriptor:
NOAEL
Generation:
F1
Effect level:
50 mg/kg bw/day (nominal)
Sex:
male/female
Basis for effect level:
other: body weight

Overall reproductive toxicity

Reproductive effects observed:
not specified

Any other information on results incl. tables

Table 1. Body weight

 

Sham Control

1 mg/kg/day

50 mg/kg/day

250 mg/kg/day

Day -7

215.4±9.5

209.7±7.4

212.8±8.3

214.4±7.4

Gestational day 0

237.3±10.7

235.4±6.2

238.8±8.7

226.3± 9.9 **

Gestational day 20

401.0±42.4

401.6±14.5

413.2±14.1

362.6±25.1 **

Lactational day 0

304.4± 22.1

302.9±13.8

308.7±14.7

273.1±21.2 **

Lactational day 4

320.9±21.2

321.0±11.1

326.8±15.0

302.4±19.6 *

Significantly different from the control * p<0.05; ** p<0.01

  

Table 2. Food consumption (g/kg/day)

 

Sham Control

1 mg/kg/day

50 mg/kg/day

250 mg/kg/day

Day -7 to -1

85.7±3.4

86.9±4.1

87.9±6.3

83.0±5.8

Gestational day 0 to 4

100.9±4.5

99.6±5.8

105.8±5.4 *

102.7±6.5

Gestational day 16 to 20

93.5±10.3

93.3±4.4

103.7±7.7 **

109.0±10.7 **

Lactational day 0 to 4

123.2±17.3

117.5±19.1

130.3±19.8

159.0±30.5 **

Significantly different from the control * p<0.05; ** p<0.01

 

Table 3. Pup body weight data

 

Sham Control

1 mg/kg/day

50 mg/kg/day

250 mg/kg/day

Lactational day 0

6.59±0.63

6.53±0.75

6.27±0.40

6.13±0.49 *

Lactational day 4

10.50±1.13

10.34±1.16

9.84±1.32

9.02±1.80 **

Significantly different from the control * p<0.05; ** p<0.01

Applicant's summary and conclusion

Conclusions:
A NOAEL of 50 mg/kg body weight/day was determined for effects of light coker gas oil on foetal/pup development (reduced body weight of live pups/ litter) after administration to pregnant rats on gestational days -7 to 20. There were no effects on reproductive parameters, but maternal animals showed signs of dermal irritation even with the lowest dose tested. The maternal NOAEL for toxicity to reproduction is greater than or equal to 250 mg/kg bw/day.
Executive summary:

Groups of female Sprague-Dawley rats received 0 (sham control), 1, 50 or 250 mg/kg body weight/day of light coker gas oil dermally. Treatment of the females commenced one week prior to mating with untreated males. Pregnant females were then assigned to the test (n = 12/dose level) and control groups (n = 15) and treatment continued until gestation day (GD) 20. The test material was applied to clipped dorsal skin (area unspecified) and the animals fitted with Elizabethan collars for 6 hours post-treatment to prevent ingestion, after which time the test site was wiped clean. It was not stated if the application site was covered or left open.

The dams were observed at intervals during gestation and up to lactation day (LD) 4 for viability, general health and toxicity, dermal irritation, body weight and food consumption followed by necropsy and a gross external and internal examination (which included the uterus and its contents). Pup parameters assessed at the time of delivery and on LD 4 included sex, body weight, presence of gross abnormalities and survival.

None of the dams died during the course of the study. Slight to moderate erythema, oedema and eschar were present at the treatment site in the low- and mid dose groups (present during days 5-6 of the premating period), with more severe responses (including slight to severe erythema, ulceration in one animal) recorded in the 250 mg/kg body weight/day group. Mean body weight for the period GD 0-20 was decreased by approx. 10% (significant) in high dose animals, with a comparable (significant) reduction in weight gain on GD 0-4. Maternal body weight at LD 4, and weight gain during the period LD 0-4, were also significantly decreased in postnatal dams from the 250 mg/kg body weight/day group.

With the exception of a significantly decreased mean pup weight at birth (-7%) and at LD 4 (‑14%) for the high dose litters, no toxicologically relevant effects were reported for the offspring.

Based on these results, the authors of the study determined a NOAEL of 50 mg/kg body weight/day for effects of light coker gas oil

on foetal/pup development (reduced body weight of live pups/ litter) after administration to pregnant rats on GD 0-20. Skin irritation was observed at the test site in all treated animals, and a confounding effect on the mothers and/or foetuses cannot be excluded. The maternal NOAEL for toxicity to reproduction is greater than or equal to 250 mg/kg bw/day. This study received a Klimisch score of 2 and is classified as reliable with restrictions because it was GLP compliant and although it didn't follow any specific guideline it was well documented and an acceptable screening study.