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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 from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1994-4-25 to 1995-7-11
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study is classified as reliable without restriction because it was performed in compliance with OECD 421 and conducted according to GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1995
Report Date:
1995

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)
Deviations:
yes
Remarks:
Only one dose level at two different concentrations was evaluated
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
liquid: viscous
Details on test material:
Read Across to Other Lubricant Base Oils
- Name of test material (as cited in study report): Chevron 100 Neutral
- Substance type: Other Lubricant Base Oil (IP 346 <3%)
- Physical state: dark brown liquid
- Lot/batch No.: LCM 6298 for both 5% and 25% concentrations
- Stability under test conditions: Stable at temperatures below 180°F (82°C) when stored at ambient temperature, protected from light
- Flash point (370 °F)
- Specific gravity (1.075 at 15 °C)
- Viscosity (11.900 cSt at 40 °C)

Test animals

Species:
rat
Strain:
other: Crl:CD BR Sprague Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles Rive Breeding Laboratories, Inc. (Portage, MI)
- Age at study initiation: 43 days old
- Weight at study initiation: (F0) Males: 283 to 284 grams; Females: 190 to 192 grams
- Fasting period before study: No
- Housing: Prior to mating, animals were housed in wire-mesh cages suspended above cage-board. After mating, males were individually housed in suspended wire-mesh cages until necropsy. Bred females were individually housed in plastic maternity cages with nesting materials.
- Diet (e.g. ad libitum): Purina Certified Rodent Chow #5002 provided ad libitum
- Water (e.g. ad libitum): Municipal water provided ad libitum
- Acclimation period: 13 days

ENVIRONMENTAL CONDITIONS
- Temperature (°F): 19 to 22
- Humidity (%): 40 to 86%
- Air changes (per hr): 10 fresh changes per hour
- Photoperiod (hrs dark / hrs light): 12-hour light/12-hour dark

IN-LIFE DATES: From: 1994-5-4 To: 1994-6-28

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
other: Chevron 100 Neutral was the vehicle in this study
Details on exposure:
VEHICLE
- Amount of vehicle (if gavage): 1.15 mg/kg/day (dose volume)
- Lot/batch no. (if required): BO 7830
Details on mating procedure:
- M/F ratio per cage: 1:1
- Length of cohabitation: If copulation was not detected after 10 days of pairing, the female was placed with another male of proven fertility from the same treatment group of an additional 5 days.
- Proof of pregnancy: vaginal plug or sperm in vaginal smear referred to as day 0 of gestation
- Further matings after two unsuccessful attempts: No; if no evidence of mating was apparent after 15 days, females were placed in a plastic cage with nesting materials
- After successful mating each pregnant female was caged (how): Individually housed in plastic cage with nesting materials
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Prior to dosing, as well as on July 5, 1994 and after the completion of dosing, three 10 millilitre samples were collected from the middle of each control, 1000 (5%), and 1000 (25%) mg/kg/day dosing formulations. Two sets of these samples were tested for homogeneity, achieved concentration, and stability by the sponsor. The remaining set was stored at WIL Research Laboratories.
Duration of treatment / exposure:
F0 males were dosed for at least 14 days prior to mating and continuing for a total dosing period of 30 days. F0 females were dose for a minimum of 14 days prior to mating and continuing until the day prior to the scheduled necropsy on lactation day 4, followed by at least 39 days of dosing.
Frequency of treatment:
F0 males were dosed for at least 14 days prior to mating and continuing for a total dosing period of 30 days. F0 females were dose for a minimum of 14 days prior to mating and continuing until the day prior to the scheduled necropsy on lactation day 4, followed by at least 39 days of dosing.
Details on study schedule:
All F0 animals were dosed for a minimum of 14 days prior to mating and through the day prior to necropsy. Dams were allowed to deliver and rear their pups to lactation day 4. The offspring were potentially exposed in utero and through lactation during lactation days 1 through 4 until euthanization on post-natal day 4. Dams were necropsied on lactation day 4, following at least 39 days of dosing. Parental males were necropsied after mating, following 30 days of dosing.
Doses / concentrations
Remarks:
Doses / Concentrations:
1000 (25%) and 1000 (5%) mg/kg/day
Basis:
nominal conc.
Dose volumes of 1.10 (1000, 25%) and 1.15 (1000, 5%) mg/kg/day
No. of animals per sex per dose:
12 males and 12 females per dose
Control animals:
yes
Positive control:
A positive control was not used.

Examinations

Parental animals: Observations and examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Weekly throughout the study period for males and females

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Animals were observed twice daily for appearance, behaviour, morbundity, and mortality. Males and females were observed at the time of dosing and one hour following dose administration.

BODY WEIGHT: Yes
- Time schedule for examinations: F0 male and female body weights were measured weekly. Dam body weights were measured on gestation days 0, 7, 14, and 20, and on lactation days 1 and 4.

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; F0 male and female food consumption was measured weekly until the mating period. Food consumption was not measured during the mating period due to cohabitation. Individual female food consumption was measured on gestation days 0, 7, 14, and 20 and lactation days 1 and 4 in pregnant females.
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data
Oestrous cyclicity (parental animals):
Estrous cyclicity was not measured.
Sperm parameters (parental animals):
Sperm parameters were not evaluated.
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 births, physical or behavioural abnormalities, weights (lactation days 1 and 4), and presence of gross anomalies

GROSS EXAMINATION OF DEAD PUPS: Yes; Intact offspring dying from lactation days 0 to 4 were necropsied using a modified Stuckhardt and Poppe fresh dissection technique. Gross lesions were preserved in 10% neutral buffered formalin. Carcasses were eviscerated and fixed in 100% ethyl alcohol for suspected skeletal anomalies. After fixation, foetuses were macerated in potassium hydroxide, stained with Alizarin Red S.
Postmortem examinations (parental animals):
SACRIFICE
- Male animals: All surviving animals were necropsied on June 10, 1994. Animals were euthanized by carbon dioxide inhalation.
- Maternal animals: All surviving animals were necropsied on lactation day 4. Animals were euthanized by carbon dioxide inhalation

GROSS NECROPSY
- For dams, the number of corpora lutea and former implantations sites were recorded. Gross necropsy for dams were performed to determine pregnancy status with specific emphasis placed on anatomical or pathological findings which may have interfered with pregnancy. Uteri without macroscopic evidence of implantation, if present, were opened and placed in 10% ammonium sulphide solution for detection of implantation sites as described by Salewski. Necropsy examination included the external surface, all orifices, the cranial cavity, the external surfaces of the brain and spinal cord, and the thoracic, abdominal and pelvic cavities including the viscera. The following tissues were collected and placed in 10% neutral buffered formalin, except for testes and epididymides that were placed in Bouin's solution: coagulating gland, ovaries and oviduct, pituitary, prostate, seminal vesicles, testes with epididymides and vas deferens, uterus with vagina, and all gross lesion.

HISTOPATHOLOGY / ORGAN WEIGHTS
- The following organs were weighed: brain, kidneys, liver, ovaries, pituitary, testes, and epididymides. Paired organs were weighed collectively. Microscopic tissue evaluation was performed for the following tissues from the control and 1000 (25%) mg/kg/day group: epididymides, cervix, coagulating gland, ovaries, pituitary gland, prostate, seminal vesicles, testes, uterus, vagina, vas deferens, and all gross internal lesions.
Postmortem examinations (offspring):
SACRIFICE
- Surviving pups were euthanized and necropsied on post-natal day 4.

GROSS NECROPSY
- Gross lesions were preserved in 10% neutral buffered formalin.

HISTOPATHOLOGY / ORGAN WEIGHTS
- Histopathology was not conducted, and organ weights were not recorded.
Statistics:
The minimum significance level was 5% for comparing all treated groups to the control group; all tests for significance at the 5% probability level were two-tailed for the group comparisons. Nongravid animals were excluded from the statistical analysis following the mating period. Chi-square test with Yates correction factor was used for pup sex ratios, pup survival indices, mean number of stillborn and dead pups, and parental fertility indices. ANOVA (two-tailed with Dunnett's test was used for F0 body weights and weight gain, gestation and lactation body weights and weight gains, parental food consumption, mean litter weights, length of gestation, live litter sizes, and organ weights. The Kolmogorov-Smirnov (one-tailed) test was used for histopathological findings.
Reproductive indices:
Female mating index (%) = (number of females with evidence of mating/total number of females used for mating) X 100

Male mating index (%) = (number of males with evidence of mating/total number of males used for mating) X 100

Female fertility index (%) = (number of females with confirmed pregnancy/total number of females used for mating) X 100

Male fertility index (%) = (number of males siring at least one litter/total number of males used for mating) X 100



Offspring viability indices:
Live litter size = (total viable pups day 0/number of litters with viable pups day 0)

Viability index (%) = (pups viable on day 1 or 4/pups viable on day 0) X 100

Results and discussion

Results: P0 (first parental animals)

General toxicity (P0)

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:
no effects observed
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
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)

Decreased body weight gain was observed at 1000 (5%) and 1000 (25%) mg/kg/day in males during weeks 0 to 1, 1 to 2, 2 to 3, and 3 to 4. Cumulative body weight gains for treated males also were significantly decreased for weeks 0 to 1, 0 to 2, 0 to 3, 0 to 4, and 0 to 5. Female body weights and body weight gains were not effected throughout the treatment period including gestation and lactation period. There were no other treatment-related effects.

Effect levels (P0)

Dose descriptor:
NOAEL
Effect level:
>= 1 000 mg/kg bw/day
Sex:
male/female
Basis for effect level:
other: Based on the lack of effects on reproductive performance

Results: F1 generation

General toxicity (F1)

Clinical signs:
no effects observed
Mortality / viability:
no mortality observed
Body weight and weight changes:
no effects observed
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)

There were no treatment-related effects on the offspring.

Effect levels (F1)

Dose descriptor:
NOAEL
Remarks:
Neonatal
Generation:
F1
Effect level:
>= 1 000 mg/kg bw/day
Sex:
male/female
Basis for effect level:
other: There were no treatment-related effects on pup body weights, sex ratios, live litter sizes, viability indices, and general physical conditions. Necropsy findings of the pups were unaffected by test article administration with either formulation.

Overall reproductive toxicity

Reproductive effects observed:
not specified

Any other information on results incl. tables

Body Weight Changes in Males (grams; mean ± s.d.)

Weeks

Groups (12 males per group)

0 mg/kg

1000 mg/kg (5%)

1000 mg/kg (25%)

0 to 1

42±9.0

37±5.8

34*±6.7

1 to 2

29±2.7

27±5.2

25±5.8

2 to 3

32±5.7

27*±5.5

29±5.1

3 to 4

33±7.0

26±6.3

26*±9.8

4 to 5

5±6.8

8±3.3

7±5.2

 

 

 

 

0 to 1

42±9.0

37±5.8

34*±6.7

0 to 2

71±12.7

64±8.7

59*±11.2

0 to 3

104±14.7

91*±9.1

88**±13.8

0 to 4

137±20.1

117*±10.5

113**±21.2

0 to 5

142±21.3

125±11.6

120*±20.4

* Significantly different from control group at 0.05 level using Dunnett's test

** Significantly different from control group at 0.01 level using Dunnett's test

Only the results for the base oil control group are reported below.

There were no clinical findings and growth rates and food consumption values were normal. Fertility indices and mating indices for males and females were both 100%. At necropsy, there were no consistent findings and the animals were considered to be normal. Organ weights and histopathology was considered normal.

Applicant's summary and conclusion

Conclusions:
Reproductive performance was not adversely affected at any dose level evaluated. There were no neonatal toxicity observed at any dose level. There were no differences in terms of systemic toxicity between either of the dose formulations.
Executive summary:

Justification for Read Across

This substance is similar to the feedstocks for most of current dewaxing operations that produce the finished paraffin and microcrystalline waxes. These lubricant base oil data may serve as the basis for a worst case assessment of the reproductive potential of paraffin and microcrystalline waxes and are summarised in this section.

 

In a reproduction/developmental screening study, a lubricant base oil (IP 346 < 3 wt%) was administered by gavage at a dose of 1000 mg/kg (bw) to a group of 12 male and 12 female Sprague-Dawley rats. Rats designated F0animals were dosed for a minimum of 14 days prior to mating. Dosing was continued after mating until a total dosing period of 30 days had elapsed for males and until day 4 of lactation for females (39 days). The animals were observed twice daily for appearance, behaviour, morbidity and mortality. Males and females were also observed during dosing and for one hour thereafter. Male F0body weights were recorded weekly. Female F0body weights were also recorded weekly until evidence of mating was observed and then on gestation days 0, 7, 14 and 20 and on lactation days 1 and 4. Food consumption was also recorded for F0(both sexes). Animals were paired on a 1:1 basis. Positive evidence of mating was confirmed either by the presence of sperm in a vaginal smear or a vaginal plug. The day when evidence of mating was identified was termed Day 0 of gestation.

 

The following fertility indices were calculated: - Female mating index; Male mating index; Female fertility index; and Male fertility index. All females were allowed to deliver their young naturally and rear them to post-natal day 4. Females were observed twice daily during the period of expected parturition for initiation and completion of parturition and for signs of dystocia. After parturition, litters were sexed and examined for evidence of gross malformations, numbers of stillborn and live pups. Litters were examined daily, and each pup received a detailed physical examination on days 1 and 4 of lactation. All abnormalities were recorded. The live litter size and viability index were calculated. All surviving pups were necropsied on post-natal day 4. A complete gross examination was made on all animals at necropsy. Selected organs of parental animals were weighed, and a wide range of tissues were fixed for subsequent histopathological examination.

 

There were no clinical findings and growth rates and food consumption values were normal. Fertility indices and mating indices for males and females were both 100%. At necropsy, there were no consistent findings, and the animals were considered to be normal. Organ weights and histopathology were considered normal. The NOAEL for this study was 1000 mg/kg/day.

 

This study received a Klimisch score of 1 and is classified as reliable without restriction because it was performed in compliance with OECD 421 and conducted according to GLP.