Alkenes, C10-13

Toxicity to reproduction

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:

2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study is classified as reliable without restriction because the study closely followed GLP and OECD guidelines. The study is well documented and scientifically acceptable.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Octadecene

EC Number:

248-205-6

EC Name:

Octadecene

Cas Number:

27070-58-2

IUPAC Name:

octadec-1-ene

Details on test material:

This substance is very similar with regard to health endpoints to the substance being registered.
- Name of test material (as cited in study report): Octadecenes C18 compound
- Substance type: C18 isomerised olefin
- Physical state: Clear, colourless liquid
- Analytical purity: 96.7%
- Impurities (identity and concentrations): Carbon number C16 (1.84%), carbon number C20 (0.95%), dimers (0.48%)
- Purity test date: Not reported, certificate of analysis dated 2002-05-23
- Lot/batch No.: NB1394-51
- Stability under test conditions: Stable up to 10 days when prepared in corn oil and refrigerated.
- Storage condition of test material: Ambient conditions

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Incorporated, Portage, Michigan
- Age at study initiation: (P) approximately 9 wks
- Weight at study initiation: (P) Males: 311 to 394 grams; Females: 201 to 262 grams
- Housing: Group housed upon arrival and then individually in suspended stainless steel cages.
- Diet (e.g. ad libitum): Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: 33 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 to 23 degrees Celsius
- Humidity (%): 38 to 51%
- Air changes (per hr): 10 to 15
- Photoperiod (hrs dark / hrs light): 12 hours dark/ 12 hours light

IN-LIFE DATES: From:2002-10-08 To: 2002-12-10

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: For each dose, a specified amount of octadecenes was weighed into a precalibrated beaker. A sufficient quantity of corn oil was added to the beaker to achieve the desired concentration and the solution was stirred for 30 minutes. Each test article solution was prepared fresh weekly, dispensed into daily aliquots and stored refrigerated in clear glass containers.

VEHICLE
- Justification for use and choice of vehicle (if other than water): Not reported
- Concentration in vehicle: 100, 500, or 1000 mg/kg/day
- Amount of vehicle (if gavage): 5 mL/kg
- Lot/batch no. (if required): RT0457

Details on mating procedure:

- M/F ratio per cage: 1:1
- Length of cohabitation: maximum of two weeks
- Proof of pregnancy: vaginal plug / sperm in vaginal smear referred to as day 0 of pregnancy
- Further matings after two unsuccessful attempts: If no evidence of copulation was observed after two weeks, the female was separated from her mate and the mating phase was concluded.
- After successful mating each pregnant female was caged (how): individually in a suspended steel cage and transferred to individual plastic nesting box containing bedding material around gestation day 18.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Concentration verification analyses were performed on the vehicle and each dosing solution for the first, third, fifth and final preparations. Duplicate samples were collected from the required dosing solutions following preparation and analyzed by KAR Laboratories, Inc., Kalamazoo, Michigan. The analytical method used was not reported.

Duration of treatment / exposure:

P (males): Two weeks prior to mating, during mating, and four weeks following mating.
P (females): Two weeks prior to mating, during mating, during gestation, and following parturition.

Frequency of treatment:

Once daily

Details on study schedule:

- Age at mating of the mated animals in the study: Approximately 9 weeks

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 100, 500, or 1000 mg/kg/day
Basis:
actual ingested
5.0 mL/kg of dose formulations of 20, 100, or 200 mg/mL were used

No. of animals per sex per dose:

12

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Dosage levels were selected in an attempt to produce graded responses to the test article. The high-dose level was expected to produce some toxic effects, but not excessive lethality. The mid-dose level was expected to produce none to minimal observable effects and the low-dose level was expected to produce no observable effects.

Positive control:

No data reported.

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Mortality/general health checks were performed twice daily (morning and afternoon). Cage-side observations were performed daily within approximately one-half hour to two hours following dosing.
- Other: Details regarding specific cage-side observations were not provided in the study report.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: weekly beginning on the day of dose initiation and on the day of scheduled euthanasia for all animals. For P females, additional observations made daily during gestation and lactation.

BODY WEIGHT: Yes
- Time schedule for examinations: P (males): weekly and on the day of scheduled euthanasia; P (females): weekly until evidence of mating was observed. Following positive evidence of mating, weights recorded on gestation days 0, 7, 14 and 20. Following parturition, weights recorded on lactation days 1 and 4.

Oestrous cyclicity (parental animals):

Not examined

Sperm parameters (parental animals):

Parameters examined in P male parental generations: Testis weight, epididymides weight

Litter observations:

STANDARDISATION OF LITTERS
- Performed on day 4 postpartum:no
PARAMETERS EXAMINED
The following parameters were examined in offspring: number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain

GROSS EXAMINATION OF DEAD PUPS: yes, for external and internal abnormalities; possible cause of death was not determined for pups born or found dead.

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals were sacrificed after all females were euthanized.
- Maternal animals: All surviving animals were sacrificed on lactation day 4.

GROSS NECROPSY
- Gross necropsy consisted of examination of the external surfaces of the body, all orifices, and the cranial, thoracic, abdominal and pelvic cavities and their contents. Uterine contents were examined and the number of implantation sites and number of corpora lutea (per ovary) were recorded.

HISTOPATHOLOGY / ORGAN WEIGHTS
Paired organ weights were obtained for testes and epididymides for all male rats. The ovaries, testes and epididymides collected at necropsy from control and 1000 mg/kg/day animals were processed for histopathological examination.

Postmortem examinations (offspring):

SACRIFICE
- Offspring were sacrificed on lactation day 4.

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations focusing on structural abnormalities with an emphasis on reproductive organs.
HISTOPATHOLOGY / ORGAN WEIGHTS
No histopathological analysis was conducted on sacrificed offspring.

Statistics:

Data, including body weights, body weight changes, food consumption, implantation sites, corpora lutea, gestation length and mean live litter size, were analyzed by ANOVA. If significance was observed with ANOVA, control to treatment group comparisons were performed using Dunnett’s test. Count data were analyzed using R x C Chi-Square test followed by Fisher’s Exact Test for copulation and fertility indices, pup sex ratios, the number of live and dead pups per group (on lactation day 0) and pup survival (after lactation day 0). Absolute and relative organ weights were analyzed for homogeneity of variance using Bartlett’s test. If significance was detected with Bartlett’s test (p<0.01), multiple group comparisons proceeded using the Kruskal-Wallis non-parametric ANOVA, followed by Dunn’s test, when p<0.05. If significance was not detected with Bartlett’s test, parametric
procedures were used to analyze the data, i.e., ANOVA followed by Dunnett’s test when p<0.05. All statistical analyses were performed using the SLI Alpha ReproTox computer system (version 1.0.0 or later). All analyses were two-tailed with a minimum significance level of 5% (p<0.05). The statistical methods used were appropriate.

Reproductive indices:

A mating index, a female fertility index, and a gestation index were calculated.

Offspring viability indices:

A live birth index and pup surviving 4 day index were calculated.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

no effects observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Organ weight findings including organ / body weight ratios:

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:

no effects observed

Reproductive performance:

no effects observed

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS): No mortalities were observed in males or females treated with octadecenes. Most of the clinical signs were unremarkable in both males and females in the octadecenes-treated groups compared to controls. Mean food consumption of females in the 500 mg/kg/day group was statistically higher than controls during gestation days 7 to 14 and 14 to 20. These differences were not considered toxicologically meaningful since they did not follow a consistent pattern and were increases rather than decreases.

REPRODUCTIVE FUNCTION: SPERM MEASURES (PARENTAL ANIMALS): There were no statistically significant differences in the absolute or relative testes or epididymides weights of octadecenes-treated animals compared to controls.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS):The P female mating and fertility indices were 100% in the vehicle control, 100, 500 and 1000 mg/kg/day groups. The P gestation index was 100% in the vehicle control, 100, 500, and 1000 mg/kg/day groups. The mean gestation length was 21.8 days in the vehicle control, 500 and 1000 mg/kg/day groups and 21.9 days in the 100 mg/kg/day group. All 12 P females in each dose group completed delivery.

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)

VIABILITY (OFFSPRING): The mean number of pups delivered and the live birth and viability indices were comparable between the octadecenes-treated animals and the control.

CLINICAL SIGNS (OFFSPRING): No remarkable findings were noted in pups during lactation days 0 through 4.

BODY WEIGHT (OFFSPRING): There were no statistically significant or toxicologically meaningful differences in mean pup weights in the octadecenes-treated groups compared to controls on lactation days 1 and 4.

ORGAN WEIGHTS (OFFSPRING): Not examined

GROSS PATHOLOGY (OFFSPRING): No remarkable gross necropsy findings were noted for pups found dead, euthanized for cause or euthanized on lactation day 4. A low incidence of commonly occurring findings was noted sporadically throughout the groups; none of the findings followed a consistent pattern or dose response.

HISTOPATHOLOGY (OFFSPRING): Not examined

Effect levels (F1)

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

ca. 1 000 mg/kg bw/day

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

No tables included based on negative findings.

Applicant's summary and conclusion

Conclusions:

All animals in the vehicle control, 100, 500 and 1000 mg/kg/day groups survived to scheduled euthanasia. Most of the clinical signs that were observed during the course of the study were generally unremarkable in both males and females and did not appear to follow any dose response pattern.
There were no toxicologically meaningful differences noted in P mean body weights, body weight change or food consumption between the vehicle control and octadecenes-treated groups. The female mating and fertility indices and mean gestation lengths were comparable between the vehicle control and octadecenes-treated groups. The mean number of pups delivered and the live birth and viability indices were comparable between the control and octadecenes-treated groups. The mean live pups, per litter and the pup sex ratio were comparable between the control and octadecenes-treated groups on lactation days 0 and 4.

No remarkable internal gross necropsy findings were noted for P males or females in the vehicle control or test article-treated groups at scheduled euthanasia. There were no statistically significant or toxicologically meaningful differences in the absolute or relative testes or epididymides weights of males in the test article-treated groups compared to controls. There were no test article-related microscopic lesions noted in the testes, epididymides or ovaries from the vehicle control and 1000 mg/kg/day groups. No remarkable findings were noted in the pups during lactation days 0-4. There were no statistically significant or toxicologically meaningful differences in mean pup weights in the test article-treated groups compared to controls on lactation days 1 and 4. No remarkable gross necropsy findings were noted for pups found dead, euthanized for cause or euthanized on lactation day 4. Based on the results of this study, a dosage level of 1000 mg/kg/day was considered a no-observed-adverse-effect level (NOAEL) for reproductive and developmental effects.

Executive summary:

Justification for Read Across

Several criteria justify the use of the read across approach to fill data gaps for isomerised olefins; alpha, internal, linear and branched – multiple carbon number substances using isomerised olefins; alpha, internal, linear and branched - single carbon number substance analogues. Studies indicate that changing the carbon number, the location of the double bond, or adding branching does not measurably alter the effects on mammalian health endpoints. There is a consistent toxicity potency pattern for isomerised olefins with a range of carbon numbers and they are considered to have minimal acute toxicity potential. Genotoxicity studies indicate that these materials are not mutagenic. No adverse systemic toxicity was observed in a combined 28 -day systemic and reproductive/developmental screening study in which rats were exposed to octadecene. The toxicological profile of single carbon number isomerised olefins described above indicates a low hazard potential for human health. Since multiple carbon number isomerised olefins are comprised of a mixture of single carbon number isomerised olefins, no significant toxicological differences are expected between the two categories of substance and read across between these two categories can be justified.

In a reproduction/developmental screening study, octadecenes, dissolved in corn oil, was administered to Sprague-Dawley rats (12 sex/dose) by gavage at dose levels of 0, 100, 500, or 1000 mg/kg/day for 42 days.

Parents and offspring were observed for clinical signs of toxicity, mortality, mating, parturition, lactation, off-spring growth and maturity. Body weight and food consumption determinations were also conducted periodically through the study period. All parents and offspring were subjected to necroscopy following termination or death. 

There was no mortality observed in animals in the control, 100, 500, or 1000 mg/kg dose group. No treatment-related or dose-dependant signs of clinical toxicity were noted in rats at any dose level. Mean body weight, body weight change and food consumption was observed to be normal in all treatment animals when compared with the controls. Parent female mating, fertility, and mean gestation lengths were observed to be comparable with controls as were the mean number of pups delivered and live birth and viability indices. Mean live pups/litter and sex ratio/litter were also found to be normal and comparable to those observed in control animals.

 

Gross necroscopy revealed no remarkable differences between octadecenes-treated and control animals. There were no microscopic lesions observed in male or female rats treated with octadecenes and no statistically significant differences in absolute or relative epididymides weight were noted in treated males when compared with control males. There were no statistically significant differences observed in pup weights on lactation days 1 and 4 and gross necroscopy on lactation day 4 revealed no treatment-related effects.

 

Based on the lack of adverse systemic effects observed in the study, the developmental/reproductive toxicity NOAEL for octadecenes was reported as 1000 mg/kg.This study received a Klimisch score of 1 and is classified as reliable without restriction because it closely followed OECD guidelines and was GLP compliant.