4-formyl-2-methoxyphenyl isobutyrate

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

Oral (Dietary) Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test in the Rat_ Givaudan Key study 2016

Link to relevant study records

Reference

Endpoint:

reproductive toxicity, other

Remarks:

Oral (Dietary) Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test in the Rat

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23 July 2014 - 23 June 2016

Reliability:

1 (reliable without restriction)

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Specific details on test material used for the study:

- Name of test material (as cited in study report): Isobutavan
- Physical state: colourless to pale yellow liquid
- Lot/batch No.: SC00011161
- Expiration date of the lot/batch: 08 May 2016
- Storage condition of test material: Sealed container, 2 to 8°C in the dark

Species:

rat

Strain:

other: Crl:WI(Han) strain

Details on species / strain selection:

Rats are obtained from Charles River Laboratories, Margate, UK. The rat was selected because it is a readily available rodent species acceptable to the regulatory authorities and recommended for reproduction studies because of its reproductive characteristics.

Sex:

male/female

Details on test animals or test system and environmental conditions:

At the start of dosing, males weighed between 289.5 and 376.9 g, females weighed between 177.4 and 221.7 g and all animals were 10 to 12 weeks old. The animals were housed in groups of up to two (pre-pairing and post-pairing), one female with one male (pairing) or singly (mated females).

Route of administration:

oral: feed

Type of inhalation exposure (if applicable):

not specified

Vehicle:

unchanged (no vehicle)

Details on exposure:

The dietary route of administration was chosen because it is an acceptable and commonly used route of exposure for regulatory studies of this type.

Details on mating procedure:

During the pairing procedure one male was housed with one female of the same treatment group for up to 15 days. Females which had not shown evidence of mating by Day 10 of the pairing period were paired with proven males of the same treatment group for up to five days. Mating was confirmed by the presence of a vaginal plug in situ or sperm in a vaginal washing. On confirmation of mating, vaginal washing was discontinued and the male was removed. The day on which mating was confirmed was designated Day 0 of gestation.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Formulations were prepared at 300 and 25000 mg Isobutavan/kg diet and analysed for stability and homogeneity. Samples for homogeneity analysis were also taken from formulations prepared for use on the first and last days of dosing. Samples for analysis of achieved concentration were taken from formulations prepared for use on the first and last days of dosing. Samples were analysed by the Formulations Analysis section of the Central Dispensary at Covance.

Duration of treatment / exposure:

The test article was administered, ad libitum, in the diet to males for two weeks prior to pairing, during the pairing period and a further two weeks before necropsy. The males were provided with diet containing test article for a minimum of six weeks prior to necropsy.
The test article was administered, ad libitum, in the diet to females for two weeks prior to pairing, during pairing and until Day 4 post-partum, inclusive. The females were allowed to litter and rear their offspring to Day 4 post-partum

Frequency of treatment:

ad libitum

Dose / conc.:

0 mg/kg bw/day (nominal)

Remarks:

Group 1 "Control" : 10 males and 10 females

Dose / conc.:

100 mg/kg bw/day (nominal)

Remarks:

Group 2 "Low" : 10 males and 10 females

Dose / conc.:

300 mg/kg bw/day (nominal)

Remarks:

Group 3 "Intermediate" : 10 males and 10 females

Dose / conc.:

1 000 mg/kg bw/day (nominal)

Remarks:

Group 4 "High" : 10 males and 10 females

No. of animals per sex per dose:

1 dose concentration per group of 10 males and 10 females

Control animals:

yes, concurrent no treatment

Details on study design:

Dose levels were based on the absence of findings at the limit dose in a 14-day dietaryrange-finding study. The high dose was selected to indicate toxicity or its absence at the limit dose. The intermediate dose was based on a standard progression increase from the low dose. The low dose was chosen to approximate a No Observed Adverse Effect Level (NOAEL) value for a similar substance.

Positive control:

No

Parental animals: Observations and examinations:

The following were assessed: clinical observation, body weight, food intake, mating, litter data, functional observations and tests, locomotor activity, haematology, clinical chemistry, organ weights, gross pathology and microscopic pathology.

Oestrous cyclicity (parental animals):

Yes

Sperm parameters (parental animals):

Yes

Litter observations:

Yes

Postmortem examinations (parental animals):

Yes

Postmortem examinations (offspring):

Yes

Clinical signs:

no effects observed

Dermal irritation (if dermal study):

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

no effects observed

Water consumption and compound intake (if drinking water study):

no effects observed

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Other effects:

no effects observed

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

Key result

Dose descriptor:

NOAEL

Effect level:

>= 1 000 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: NOAEL for males and females was 1000 mg/kg bw/day.

Remarks on result:

not determinable due to absence of adverse toxic effects

Key result

Critical effects observed:

no

Lowest effective dose / conc.:

1 000 mg/kg bw/day (nominal)

Treatment related:

no

Dose response relationship:

no

Relevant for humans:

no

Clinical signs:

no effects observed

Clinical signs:

no effects observed

Dermal irritation (if dermal study):

not examined

Mortality / viability:

no mortality observed

Body weight and weight changes:

no effects observed

Behaviour (functional findings):

not examined

Developmental immunotoxicity:

not examined

Key result

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

1 000 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: NOAEL for males and females was 1000 mg/kg bw/day

Remarks on result:

not determinable due to absence of adverse toxic effects

Key result

Critical effects observed:

no

Lowest effective dose / conc.:

1 000 mg/kg bw/day (nominal)

Treatment related:

no

Dose response relationship:

no

Relevant for humans:

no

Key result

Reproductive effects observed:

no

Lowest effective dose / conc.:

1 000 mg/kg bw/day (nominal)

Treatment related:

no

Dose response relationship:

no

Relevant for humans:

no

In conclusion, Isobutavan administered in the diet to male and female rats at 100, 300 or 1000 mg Isobutavan/kg bodyweight/day elicited no adverse effects. Under the conditions of the current study, the no-observed-adverse-effect-level (NOAEL) for adult toxicity and reproductive and developmental toxicity was established as nominal 1000 mg Isobutavan/kg body weight/day (achieved mean high dose level of 986.4 mg/kg/day for males and 1215.3 mg/kg/day for females).

Conclusions:

In conclusion, Isobutavan administered in the diet to male and female rats at 100, 300 or 1000 mg Isobutavan/kg bodyweight/day elicited no adverse effects.

Under the conditions of the current study, the no-observed-adverse-effect-level (NOAEL) for adult toxicity and reproductive and developmental toxicity was established as nominal 1000 mg Isobutavan/kg body weight/day (achieved mean high dose level of 986.4 mg/kg/day for males and 1215.3 mg/kg/day for females).

Executive summary:

The study was performed in accordance to the OECD 422 guidelines (Adopted 22 March 1996), which were current at the time this study was conducted. The dietary route of administration was chosen because it is an acceptable and commonly used route of exposure for regulatory studies of this type.

The test article was administered, ad libitum, in the diet to males for two weeks prior to pairing, during the pairing period and a further two weeks before necropsy. The males were provided with diet containing test article for a minimum of six weeks prior to necropsy. The test article was administered, ad libitum, in the diet to females for two weeks prior to pairing, during pairing and until Day 4 post-partum, inclusive. The females were allowed to litter and rear their offspring to Day 4 post-partum. The following were assessed: clinical observation, body weight, food intake, mating, litter data, functional observations and tests, locomotor activity, haematology, clinical chemistry, organ weights, gross pathology and microscopic pathology.

Diet formulations were considered acceptable for use. The mean results were within the range of 101 to 109% of nominal (target range 85 to 110% of nominal). Test article consumption was within 20% of the target dose with only a few exceptions, all of which involved consumptions greater than the target dose. All animals survived until their scheduled kill. There were no clinical observations that were considered to be related to the test article.

All animals gained weight over the duration of the study. Although there were some fluctuations and differences between groups in body weight gain, there was no clear dose relationship and these were considered most likely due to palatability of the diet containing Isobutavan and not indicative of toxicity. There was a dose-dependent decrease in food consumption in males across all dose levels between Days 1 and 4 of the pre-pairing phase compared to the control males. Males offered 1000 mg Isobutavan/kg body weight/day continued to consume less diet than the control males through the rest of the pre-pairing phase and throughout the post-pairing phase. There was no similar pattern for females during this phase. There was no effect on clinical pathology and no effect in the neuro-behavioural tests conducted. An assessment of the reproductive function revealed no adverse effects. Qualitative assessment of the testis did not indicate any abnormalities in the integrity of the various cell types present within the different stages of the spermatogenic cycle. There was no effect of Isobutavan on organ weights. Macroscopically, tissues were unremarkable and there were no microscopic findings indicative of Isobutavan-related effects. An assessment of the development of the first generation to Day 4 post-partum revealed no adverse effects.

In conclusion, Isobutavan administered in the diet to male and female rats at 100, 300 or 1000 mg Isobutavan/kg bodyweight/day elicited no adverse effects. Under the conditions of the current study, the no-observed-adverse-effect-level (NOAEL) for adult toxicity and reproductive and developmental toxicity was established as nominal 1000 mg Isobutavan/kg body weight/day (achieved mean high dose level of 986.4 mg/kg/day for males and 1215.3 mg/kg/day for females).

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Effects on developmental toxicity

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available