4-methylanisole

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to GLP and current testing guidelines.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

4-methylanisole

EC Number:

203-253-7

EC Name:

4-methylanisole

Cas Number:

104-93-8

Molecular formula:

C8H10O

IUPAC Name:

1-methoxy-4-methylbenzene

Details on test material:

- Name of test material (as cited in study report): p-Cresolmethylether
- Physical state: Liquid / colorless, clear
- Analytical purity: 98.6 %
- Lot/batch No.: 10745009T0
- Stability under test conditions: The stability of test substance in Olive oil (which is similar to corn oil) was demonstrated for a period of 7 days at room temperature.
- Storage condition of test material: Room temperature, protected from light

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH,
- Age at study initiation: 11 - 12 wks
- Weight at study initiation: male animals: 290.9 g - 320.2 g; female animals: 186.4 g - 220.2 g
- Housing: individually in Makrolon type M III cages supplied by Becker & Co., Castrop-Rauxel, Germany (floor area of about 800 cm²). Pregnant females were provided with nesting material (cellulose wadding) toward the end of gestation. For enrichment, wooden gnawing blocks were added (Typ NGM E-022 supplied by Abedd® Lab. and Vet. Service GmbH, Vienna, Austria).
- Diet : ad libitum; ground Kliba maintenance diet mouse/rat “GLP” meal (Provimi Kliba SA, Kaiseraugst, Switzerland)
- Water: ad libitum
- Acclimation period: 5-6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 30-70
- Air changes (per hr): 15 times
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: 21 Dec 2009- 09 Feb 2010 (administration period)

Administration / exposure

Route of administration:

dermal

Vehicle:

corn oil

Details on exposure:

TEST SITE
- Area of exposure: at least 10% of the body surface
- Type of wrap if used: semiocclusive dressing, consisting of 4 layers of porous gauze dressing ("Verbandmull Ph. Eur.", Lohmann GmbH & Co KG, Neuwied, Germany) and an elastic dressing (Fixomull Stretch, Beiersdorf AG, Hamburg, Germany).


REMOVAL OF TEST SUBSTANCE
- Washing (if done): After removal of the dressing, the treated skin was washed with lukewarm water
- Time after start of exposure: 6 hours

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 4 ml/kg body weight
- Concentration (if solution): 2.5; 7.5; 25 g/100ml

Details on mating procedure:

- M/F ratio per cage: 1 / 1 ratio
- Length of cohabitation: maximum of 2 weeks
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy
- Further matings after one unsuccessful attempt: no
- After successful mating each pregnant female was caged individually

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

The duration of treatment covered premating period of 2 weeks and a mating period (max. of 2 weeks) in both sexes, approximately 1 week post-mating in males, and the entire gestation period until gestation day (GD) 19 in females. The females were not treated at the end of gestation and during lactation.

Frequency of treatment:

6 hours/day; 7 days/week

Details on study schedule:

- Age at mating of the mated animals in the study: Sixteen days after the beginning of treatment

Doses / concentrations

Remarks:

Doses / Concentrations:
100, 300, 1000 mg/kg bw/d
Basis:

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Positive control:

not applicable

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: once daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: once daily

BODY WEIGHT: Yes
- Time schedule for examinations: once a week until sacrifice
During the mating period the parental females were weighed on the day of positive evidence of sperm (GD 0) and on GD 7, 14 and 20.
Females with litter were weighed on the day of parturition (PND 0) and on PND 4.

FOOD CONSUMPTION:
- Food consumption for each animal determined: Yes
Food consumption was not determined in females without positive evidence of sperm during gestation periods and in females without litter during lactation period.
Food consumption was not determined during the mating period
Food consumption of the F0 females with evidence of sperm was determined on GD 0, 7, 14 and 20.
Food consumption of F0 females, which gave birth to a litter, was determined on PND 1 and 4.

Oestrous cyclicity (parental animals):

not assessed

Sperm parameters (parental animals):

not assessed

Litter observations:

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring:
number and sex of pups (Sex ratio), stillbirths, live births, postnatal mortality, presence of gross anomalies, clinical symptoms, body weights


GROSS EXAMINATION OF DEAD PUPS:
Pups were examined externally, eviscerated and their organs were assessed macroscopically.

Postmortem examinations (parental animals):

SACRIFICE
At the end of the study, the animals were sacrificed (males on study day 32, females on study day 50) after a fasting period (withdrawal of food) for at least 16-20 hours.

GROSS NECROPSY
- Gross necropsy was performed.

HISTOPATHOLOGY / ORGAN WEIGHTS
Epididymides, testes, ovaries, livers were weighed.
Histopathology was performed for all gross lesions and liver (all dose groups), epididymides, testes, ovaries, and treated/untreated skin (high dose group and controls).
Uterus and ovaries were removed and the implantation sites were counted. To determine the number of implantation sites in apparently non-pregnant animals, the uteri from those females were stained in 10% ammonium sulfide solution for about 5 minutes according to the method of SALEWSKI.

Postmortem examinations (offspring):

SACRIFICE
- The F1 offspring were sacrificed at 4 days of age.
- These animals were subjected to postmortem examinations (macroscopic examination) as follows:

GROSS NECROPSY
Pups were examined externally, eviscerated and their organs were assessed macroscopically.

Statistics:

DUNNETT-test: Food consumption (parental animals), body weight and body weight change (parental animal/ pups; for the pup weights, the litter means were used), number of mating days, duration of gestation, number of pups delivered per litter, implantation sites, post implantation loss.
FISHER'S EXACT test: Male and female mating index, male and female fertility index, gestation index, females with liveborn pups, females with stillborn pups, females with all stillborn pups, live birth index, pups stillborn, pups died, pups cannibalized, pups sacrificed moribund, viability index, number of litters with affected pups at necropsy.
WILCOXON-test: Proportions of affected pups per litter with necropsy observations
KRUSKAL-WALLIS test with a WILCOXON-test as post test: Weight parameters

Reproductive indices:

Male/female mating index, Male/female fertility index, Gestation index, Live birth index, Postimplantation loss

Offspring viability indices:

Viability index

Results and discussion

Results: P0 (first parental generation)

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
In test group 1 (100 mg/kg bw/d) one female animal was sacrificed prematurely on GD 15 because of aggressiveness and, therefore, impossibility of treatment. No treatment-related findings were observed for male and female animals of any test group.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
No changes in food consumption were observed for all test groups during premating, gestation and lactation period.
No changes in body weight and body weight change values were observed for all test groups during premating, gestation and lactation period.


REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
Male/female mating index was 100% in all test groups.
4/10 males of test group 100 mg/kg bw/d and 1/10 males of 300 mg/kg bw/d did not generate F1 pups (no histomorphological correlate).
The mean duration until sperm was detected (GD 0) amounted to 2.6, 2.5, 3.0, and 3.4 days for 0, 100, 300 and 1000 mg/kg bw/d, respectively. Differences between the test groups were assessed as being spontaneous in nature and without biological or toxicological relevance.
In group 100 mg/kg bw/d, a significant increase of postimplantation loss by 18.8% was observed (no differences in the 300, 1000 mg/kg bw/d groups compared to control).
Gestation index was not significantly decreased in any test group.
Mean number of F1 pups delivered per dam was not significantly decreased in any test group.
Rate of liveborn/stillborn pups was not affected in any test group.

ORGAN WEIGHTS (PARENTAL ANIMALS)
None of the mean absolute or relative weight parameters showed relevant differences when compared to the control group and they were considered to be within the normal range.

GROSS PATHOLOGY (PARENTAL ANIMALS)
All gross lesions observed in test animals occurred singularly and were considered to be spontaneous lesions in origin and not related to treatment.

HISTOPATHOLOGY (PARENTAL ANIMALS)
The sacrificed animal of test group 100 mg/kg bw/d showed markedly increased mitotic figures in the liver. The apoptotic rate was only minimally increased. All other findings were single observations which were considered to be incidental and spontaneous in origin and without any relation to treatment.

Effect levels (P0)

1

Dose descriptor:

NOAEL

Remarks:

general systemic toxicity

Effect level:

>= 1 000 mg/kg bw/day

Sex:

male/female

Basis for effect level:

other: No test substance related adverse effects observed.

2

Dose descriptor:

NOAEL

Remarks:

Fertility

Effect level:

>= 1 000 mg/kg bw/day

Sex:

male/female

Basis for effect level:

other: No test substance related adverse effects observed.

Results: F1 generation

Details on results (F1)

VIABILITY (OFFSPRING)
A significant increase of pups that died during lactation was not observed for any test group.

CLINICAL SIGNS (OFFSPRING)
F1 pups did not show adverse clinical signs up to scheduled sacrifice on PND 4.

BODY WEIGHT (OFFSPRING)
Mean pup body weights/pup body weight changes in all dose groups were comparable to controls.

GROSS PATHOLOGY (OFFSPRING)
No abnormal findings were observed during pup necropsy.

Effect levels (F1)

Dose descriptor:

NOAEL

Remarks:

Developmental toxicity

Generation:

F1

Effect level:

>= 1 000 mg/kg bw/day

Sex:

male/female

Basis for effect level:

other: No test substance related adverse effects observed.

Overall reproductive toxicity

Reproductive effects observed:

not specified