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Toxicological information

Toxicity to reproduction

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Administrative data

Endpoint:
one-generation reproductive 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:
2005-05-27 to 2006-03-23
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study is classified as reliable without restriction because it was conducted according to GLP, is scientifically acceptable and appears to have adhered to the OECD guideline recommendations.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report Date:
2007

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 415 [One-Generation Reproduction Toxicity Study (before 9 October 2017)]
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
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): Alkane 4
- Substance type: Poly alpha olefin (1-dodecene trimer, hydrogenated)
- Physical state: Liquid
- Analytical purity: Not reported
- Lot/batch No.: DCS-120804
- Stability under test conditions: Not reported
- Storage condition of test material: Room temperature in the dark
- Other: Clear colourless liquid

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River (U.K.) Limited
- Age at study initiation: (P): 6 to 8 weeks; (F1): 3 weeks
- Weight at study initiation: (P) Males: 205 to 280 grams; Females: 148 to 205 grams
- Fasting period before study: No
- Housing: Groups of four in polypropylene cages prior to mating; one male to one female during mating; Post-mating, males returned to original cages and females housed individually during gestation and lactation
- Diet (e.g. ad libitum): Rodent PMI 5002 (Certified) diet (BCM IPS Limited, London, UK) ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21±2ºC
- Humidity (%): 55 ±15%
- Air changes (per hr): At least 15 per hour
- Photoperiod (hrs dark / hrs light): 12 hrs dark/12 hrs light

IN-LIFE DATES: From: 2005-06-22 To: 2005-10-20

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
arachis oil
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: Test material was prepared on a weekly basis at the appropriate concentrations as a solution in Arachis oil BP and stored at 4ºC in the dark.

VEHICLE
- Justification for use and choice of vehicle (if other than water): Not reported
- Concentration in vehicle: 0, 12.5, 62.5, or 250 mg/mL depending on the dosage
- Amount of vehicle (if gavage): 4 mL/Kg
- Purity: Not reported
Details on mating procedure:
- M/F ratio per cage: 1:1
- Length of cohabitation: 21 days
- Proof of pregnancy: Vaginal plug in situ and/or sperm in vaginal smear referred to as day 0 of pregnancy
- Further matings after two unsuccessful attempts: No. There is no data on repeated mating attempts in the study
- After successful mating each pregnant female was caged (how): Females were transferred to individual cages and dosing continued during the subsequent gestation and lactation phases of the study.
- Any other deviations from standard protocol: None reported
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Samples of dosing formulations at 250 mg/ml were also analysed for achieved concentration on a weekly basis during the study. The results indicatethat prepared high dose formulations were within ± 12% of the nominal concentration.
Duration of treatment / exposure:
Approximately 139 days (~20 weeks)
Frequency of treatment:
Daily (except for females during parturition)
Details on study schedule:
- F0 parental animals not mated until 10-11 weeks post-exposure.
- Age at mating of the mated animals in the study: 13 weeks for females; 16 to 18 weeks for males
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 50, 250, 1000 mg/kg bw/day
Basis:
other:
No. of animals per sex per dose:
24 per sex per dose
Control animals:
yes
Details on study design:
- Dose selection rationale: The dose levels were chosen by the Sponsor based on available toxicological data.
- Rationale for animal assignment (if not random): Animals were allocated to dose groups using a randomisation procedure based on stratified
bodyweights (Table No. 1).
Positive control:
A positive control was not employed in the study design.

Examinations

Parental animals: Observations and examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Prior to dosing and at weekly intervals before pairing, ten animals/sex from each dose group were observed cage-side for functional and behavioural changes.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Immediately prior to dosing and then 1 to 5 hours post-dosing from Monday through Friday. On the weekend, animals were observed prior to dosing, immediately after dosing and at 1 hour post dosing.

BODY WEIGHT: Yes
- Time schedule for examinations: Males: Day 0 and once a week thereafter; Females: Weekly during maturation and daily during mating; Post-mating bodyweights were recorded on days 1, 4, 7, 14, and 21 post-coitum and on Days 1, 4, 7, 14 and 21 post partum for females that littered.

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: No, During the maturation period, weekly food consumption was recorded for each cage of adults. Food consumption was not recorded during the period of co-habitation during the mating phase but was re-instigated on a weekly basis for males once this was completed. For females showing evidence of mating, food consumption was recorded for the periods covering days 1 to 7, 7 to 14, and 14 to 21 post coitum and following littering for the periods covering days 1 to 7, 7 to 14 and 14 to 21 post partum.
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes, weekly food conversation efficiency (bodyweight gain/food intake) was calculated for both sexes for the pre-pairing maturation phase of the study.

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule for examinations: Water intake was observed daily by visual inspection of water bottles for any overt change.

OTHER: Ophthalmoscopic Examination - Eyes of 10 animals/sex from the control and high-dose group were examined pre-treatment and prior to mating (during Week 10).
Oestrous cyclicity (parental animals):
A vaginal smear was prepared for each female and the stage of the oestrous cycle or the presence of sperm was recorded. The presence of sperm
within the vaginal smear and/or vaginal plug in situ was taken as positive evidence of mating.
Sperm parameters (parental animals):
Parameters examined in 10 [F0] male parental generations from each treatment group: Testis weight, epididymis weight, sperm count in epididymides; atrophy of testes
Litter observations:
STANDARDISATION OF LITTERS
- Performed on day 1 postpartum: Yes
- All live pups were examined.

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring: Number and sex of pups, still births, live births, presence of gross anomalies, weight gain, physical or behavioural abnormalities

GROSS EXAMINATION OF DEAD PUPS: Yes, for external and internal abnormalities; possible cause of death was determined for pups born or found dead
Postmortem examinations (parental animals):
SACRIFICE
- Male animals: All surviving adult males were killed shortly before termination of the females and litters commenced (week 17).
- Maternal animals: Non-pregnant adult females were killed on or after day 25 post coitum. Surviving adult females were killed at weaning (day 21 post partum).

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera. Additionally, any macroscopic abnormalities were recorded.

HISTOPATHOLOGY / ORGAN WEIGHTS
The tissues indicated in Table No. 2 and Table No. 3 were prepared for microscopic examination and weighed, respectively.
Postmortem examinations (offspring):
SACRIFICE
- The F1 offspring were sacrificed at 21 days post partum.
- These animals were subjected to postmortem examinations (macroscopic and/or microscopic examination) as follows: A full external and internal examination was conducted and any macroscopic abnormalities were recorded.

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

HISTOPATHOLOGY / ORGAN WEIGTHS
The tissues indicated in Table No. 2 and Table No. 3 were prepared for microscopic examination and weighed, respectively.
Statistics:
Data were processed to give group mean values and standard deviations where appropriate. Haematological, blood chemical, organ weight (absolute and relative to terminal bodyweight), weekly bodyweight gain, litter weights, offspring bodyweights and quantitative functional performance data were assessed for dose response relationships by linear regression analysis, followed by one way analysis of variance (ANOVA) incorporating Levene’s test for homogeneity of variance. Where variances were shown to be homogenous, pairwise comparisons were conducted using Dennett’s test. Where Levene’s test showed unequal variances the data were analysed using non-parametric methods: Kruskal-Wallis ANOVA and Mann-Whitney ‘U’ test. Non-parametric methods were used to analyse implantation loss, offspring sex ratio and developmental landmarks and reflexological responses. Chi-squared analysis was used for differences in the incidence of lesions occurring with an overall frequency of 1 or greater while the Kruskal-Wallis one-way non-parametric analysis of variance was utilized for the comparison of severity grades for the more frequently observed graded conditions.
Reproductive indices:
1] Pre-coital interval - Calculated as the time elapsing between initial pairing and the observation of positive evidence of mating.

2] Fertility Indices – For each dose group, 2 indices as indicated below were calculated:

Mating Index (%): (Number of animals mated/Number of animals paired) x 100

Pregnancy Index (%): (Number of pregnant females/ Number of animals mated) x 100

3] Gestation length: Calculated as the number of days of gestation including the day for observation of mating and the start of parturition. Where the start of parturition occurred overnight, the total was adjusted by subtracting half a day.

4] Parturition Index (%): (Number of females delivering live offspring/Number of pregnant females) x 100

Offspring viability indices:
1] Live birth and viability indices: The following indices were calculated for each group from group mean data:

Live Birth Index (%) = (Number of offspring alive on Day 1/ Number of offspring born) x 100

Viability Index 1 (%) = (Number of offspring alive on Day 4/ Number of offspring alive on Day 1) x 100

Viability Index 2 (%) = (Number of offspring alive on Day 7/ Number of offspring alive on Day 4) x 100

Viability Index 3 (%) = (Number of offspring alive on Day 14/ Number of offspring alive on Day 7) x 100

Viability Index 4 (%) = (Number of offspring alive on Day 21/ Number of offspring alive on Day 14) x 100

Viability Index 5 (%) = (Number of offspring alive on Day 21/ Number of offspring alive on Day 1) x 100

2] Sex ration (% males): Group mean values calculated from each litter value on Day 1 and 21 using the following formula:

Sex ration (% males) = (Number of male offspring/ Total number of offspring) x 100

3] Implantation losses: Group mean percentile pre-implantation and post implantation loss were calculated as follows:

% pre - implantation loss = (Number of Corpora Lutea - Number of implantation sites/ Number of corpora lutea) x 100

% post - implantation loss = (Group number of implantation sites - Number of offspring/ Number of implantation sites) x 100

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 specified

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:
no effects observed
Reproductive function: sperm measures:
no effects observed
Reproductive performance:
no effects observed

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS): There were two unscheduled deaths during the study, neither of which were considered treatment-related. No clinically observable signs of toxicity were detected in test or control animals throughout the study period.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS): Bodyweight and bodyweight gain of males and females (including the gestation and lactation phases) at dosages of up to 1000 mg/kg/day were unaffected by treatment throughout the study. Food consumption of males during the pre-pairing and post pairing phases of the study was unaffected by treatment at dosages of up to 1000 mg/kg/day. Food consumption of females during the pre-mating, gestation and lactation periods of the study was also not adversely affected by treatment at dosages up to 1000 mg/kg/day.

TEST SUBSTANCE INTAKE (PARENTAL ANIMALS): No data

REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS): The distribution of pre-coital intervals for treated animals was essentially similar to control with the majority of animals showing evidence of mating within four days of pairing. The pattern of mating observed for all groups was consistent with females showing a normal oestrous cycle and mating at the first oestrus opportunity, and this indicated that oestrous cycling had been unaffected by treatment at dosages up to 1000 mg/kg/day.

REPRODUCTIVE FUNCTION: SPERM MEASURES (PARENTAL ANIMALS): There were no effects on the reproductive function of male rats observed during the study

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS): There were no treatment-related effects on mating performance or fertility.

ORGAN WEIGHTS (PARENTAL ANIMALS): Intergroup differences in absolute and bodyweight-relative organ weights for either sex were not indicative of any adverse effect of treatment.

GROSS PATHOLOGY (PARENTAL ANIMALS): Neither the type, incidence nor distribution of macroscopic finding observed at necropsy for decedent animals or for animals killed at scheduled termination indicated any adverse effect of treatment for either sex.

HISTOPATHOLOGY (PARENTAL ANIMALS): No treatment-related changes were observed.

Effect levels (P0)

Dose descriptor:
NOAEL
Effect level:
ca. 1 000 mg/kg bw/day
Sex:
male/female
Basis for effect level:
other: Based on the lack of treatment-related effects observed throughout maturation, mating, gestation and lactation phases of the study.
Remarks on result:
other: Generation: P and F1 (migrated information)

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:
no effects observed
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Histopathological findings:
no effects observed

Details on results (F1)

VIABILITY (OFFSPRING): Litter size and offspring survival were considered to have been unaffected by maternal treatment at dosages of up to 1000 mg/kg/day. Mean numbers of corpora lutea, implantation, offspring at birth and live offspring at Day 1 post partum in treated groups were essentially similar to control. Subsequent offspring survival to weaning in treated groups was also similar to control. Sex ratio for offspring at birth and live
offspring at Day 1 of age and weaning (day 21) was similar in all groups and did not indicate any selective effect of survival for either sex.

CLINICAL SIGNS (OFFSPRING): No toxicologically significant clinical findings were observed.

BODY WEIGHT (OFFSPRING): No adverse treatment-related effects on offspring bodyweight were observed through the study period.

SEXUAL MATURATION (OFFSPRING): There were no adverse effects on sexual maturation observed in the offspring.

GROSS PATHOLOGY (OFFSPRING): The macroscopic findings observed for interim and terminal kill offspring throughout the dose groups were consistent with normally expected low incidence findings in pups of the age examined and were of no toxicological importance.

Overall reproductive toxicity

Reproductive effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
The oral administration of Alkane 4 to rats by gavage at a maximum dose level of 1000 mg/kg/day, throughout maturation, mating, gestation and lactation resulted in no treatment-related effects. The ‘No Observed Effect Level’ for adult toxicity and reproductive and developmental toxicity
was therefore considered to be 1000 mg/kg/day.
Executive summary:

Justification for Read Across

Several criteria justify the use of the read across approach to fill data gaps for the poly alpha olefin 1-decene trimer and tetramer hydrogenated (CAS number 68649-12-7) using alkane 4 (1-dodecene, trimer, hydrogenated) as an analog. Both of these compounds are poly alpha olefins, i.e., highly branched isoparaffinic chemicals produced by oligomerization of 1-octene, 1-decene, and/or 1-dodecene. They have similarities in chemical structure and physiochemical properties. The literature also indicates that alkanes with 30 or more carbon atoms are unlikely absorbed when administered orally. In turn, studies indicate that they have similar health effect endpoints. Both of these poly alpha olefins have low order acute toxicity and repeated dose toxicity. Additionally gene mutations assays in bacterial cells, as well as in vitro chromosomal aberrations in mammalian cells assays demonstrate no evidence of genotoxicity regardless of metabolic activation. In vivo chromosomal aberrations assays in rats and mice also show no mutagenic potential regardless of metabolic activation. There do not appear to be any toxicological differences between 1-decene trimer and tetramer hydrogenated and alkane 4. Therefore, read across between 1-decene trimer and tetramer hydrogenated and alkane 4 can be justified.

In a one-generation reproduction study, Alkane 4 was administered orally, once daily, by gavage to three groups each of twenty-four male and twenty-four female Sprague-Dawley Crl:CD® (SD) IGS BR strain rats, at dose levels of 1000, 250 and 50 mg/kg/day. A further group of twenty-four male and twenty-four female rats received the vehicle alone to serve as a control.

 

There were two unscheduled deaths on the study, occurring in the control and 250 mg/kg/day dosage groups, neither of which was associated with treatment. There were no signs of clinical toxicity observed in either sex at any of the doses tested. Behavioural and functional performance remained unaffected in male and female rats treated with Alkane 4. Sensory reactivity, body weight, food and water consumption were unaffected as were fertility and mating performance. Haematological and clinical chemistry assessments revealed no significant treatment-related effects on male and female rats.

 

No treatment-related effects on offspring growth or development were detected. Litter sizes from birth to weaning were essentially similar across all dose groups. Gross necroscopy did not reveal any remarkable findings and neither did histopathology.

 

The oral administration of Alkane 4 to rats by gavage at a maximum dose level of 1000 mg/kg/day, throughout maturation, mating, gestation and lactation resulted in no treatment related effects. Thus, the NOAEL for adult toxicity and reproductive and developmental toxicity was considered to be 1000 mg/kg/day.

 

This study received a Klimisch score of 1 and is classified as reliable without restriction because it was conducted according to GLP, is scientifically acceptable and appears to have adhered to the OECD guideline recommendations.