Tetracosanol

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

not stated

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Draft OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

Principles of method if other than guideline:

conducted according to Draft OECD 422 Combined repeat dose and reproductive/developmental toxicity screening test

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Octadecan-1-ol

EC Number:

204-017-6

EC Name:

Octadecan-1-ol

Cas Number:

112-92-5

Molecular formula:

CH3(CH2)17OH

IUPAC Name:

octadecan-1-ol

Test animals

Species:

rat

Strain:

Wistar

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Moellegard Breeding Centre
- Age at study initiation: 8 (males) and 7 (females) weeks
- Weight at study initiation: not specified
- Fasting period before study: Not specified
- Housing: 2 rats/cage for acclimatization period then individually
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 8 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±2
- Humidity (%): 55±10
- Air changes (per hr): not specified
- Photoperiod (hrs dark / hrs light): fluorescent light was on from 8 pm to 8 am

IN-LIFE DATES: no data

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on exposure:

DIET PREPARATION
- Diet preparation involved first mixing the octadecanol with the barley component, the proportion of which varied for each dose level. The other components of the diet were then added.
- Rate of preparation of diet (frequency): not specified
- Mixing appropriate amounts with (Type of food): IT chow 101 diet
- Storage temperature of food: not specified

Analytical verification of doses or concentrations:

no

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1:1
- Length of cohabitation: up to 22 days
- After 14 days of unsuccessful pairing replacement of first male by another male with proven fertility.
- Further matings after two unsuccessful attempts: no
- Proof of pregnancy: vaginal plug referred to as day 0 or, if the plug was recorded during the morning, day 1 of pregnancy
- Any other deviations from standard protocol: none

Duration of treatment / exposure:

Females up to 54 days, premating, mating and gestation until post natal day 5.
Males also treated.

Frequency of treatment:

continuous in diet

Duration of test:

From 14 days prior to mating then throughout mating and gestation until post natal day 5

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

1 500 ppm (nominal)

Remarks:

100 mg/kg bw/day

Doses / concentrations 2

Dose / conc.:

7 500 ppm (nominal)

Remarks:

500 mg/kg bw/day

Doses / concentrations 3

Dose / conc.:

30 000 ppm (nominal)

Remarks:

2000 mg/kg bw/day

No. of animals per sex per dose:

12

Control animals:

yes, plain diet

Details on study design:

- Dose selection rationale: Doses chosen from the results of a preliminary test.
- Rationale for animal assignment (if not random): Randomized into 4 groups with the same mean body weight

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: No

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: not specified

BODY WEIGHT: Yes
- Time schedule for examinations: During the experiment the males were weighed once/week. The females were weighed during the premating period and during pregnancy once/week. Pup litter weight was determined on days 1 and 4 after birth.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on postnatal day 5
- Organs examined: liver, kidney, adrenals, brain, heart, spleen, ovaries, thymus and other organs with observed pathological changes.

OTHER: Total gross pathological examinations were performed on each animal at necropsy and organ weights determined for the liver, kidneys and thymus.

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: No data
- Number of late resorptions: No data
- Other: number of resorptions was examined but it is not specified whether these were early or late.

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: all per litter
- Skeletal examinations: No
- Head examinations: Yes: all per litter

Statistics:

Statistical analysis made on all data using the SAS-stat program. All statistically significant findings were further evaluated by means of Dunnett’s t-test to assess possible inter-group differences.

Indices:

Pregnancy rate

Historical control data:

none

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:no effects

Details on maternal toxic effects:
- Body weight: No treatment related effects.
- Food/water consumption: No treatment related effects.
- Description, severity, time of onset and duration of clinical signs: None reported.
- Pregnancy rate: There was no statistically significant difference in pregnancy rates (confirmed using a Chi-squared test) although they were reduced in treated groups C 92%, 100 & 500 mg/kg 75%, 2000 mg/kg/day 67% these were within the normal historical control range according to the investigators (actual historical control data not presented).
- Fertility index: Not reported
- Precoital interval: Not reported
- Duration of gestation: Comparable in treated and control dams.
- Gestation index: Not reported
- Changes in lactation: Not reported
- Changes in estrus cycles: Not reported
- Mortality: None
- Number of implantations: No significant differences in the numbers of implantations between treated and control groups. (Mean 13 in controls and low dose, 15 in mid and high dose groups). Resorptions mean for controls and low dose 0, for mid and high dose 1).
- Number of corpora lutea: No significant differences between treated and control groups (mean controls 13, low and mid dose 14, high dose 15).
- Ovarian primordial follicle counts: Not reported

Effect levels (maternal animals)

Key result

Dose descriptor:

NOAEL

Effect level:

2 000 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: No adverse effect observed

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
- Litter size and weights: No effect of treatment (mean litter size 11.73, 10.0, 13.6 and 13.38 for controls, low, mid and high dose respectively). Litter
weights day 1 mean 69, 61, 75 and 75 g; Day 4 mean 96, 84, 101 and 101 g for controls, low, mid and high dose respectively)
- Sex and sex ratios: No treatment related effects.
- Post natal survival until day 5: Similar in treated and control groups.
- Foetal anomalies: There were no treatment related changes in the incidence of external or visceral malformations visible on macroscopic examination.

Effect levels (fetuses)

Key result

Dose descriptor:

NOAEL

Effect level:

2 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No adverse effect observed

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

no

Applicant's summary and conclusion

Conclusions:

In a reliable study, development was assessed as part of a combined repeat dose and reproductive/developmental toxicity study, conducted according to draft OECD guideline 422. The NOAEL for maternal and foetotoxicity in rats was 2000 mg/kg bw/day (highest dose level). There was no evidence of teratogenicity from the limited examination of the pups that was carried out. The result is read across from octadecan-1-ol (CAS 112-92-5).

Executive summary:

Based on the weight of evidence from other alcohols across the category and the combined repeat dose/reproductive/developmental study with octadecan-1-ol, it is concluded that octadecan-1-ol is unlikely to be a developmental toxicant in the absence of maternal toxicity.