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Toxicological information

Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: OECD combined repeat dose and reproductive/developmental toxicity screening test
Cross-reference
Reason / purpose for cross-reference:
reference to same study

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1996

Materials and methods

Principles of method if other than guideline:
Thymol was studied for oral toxicity in rats in an OECD combined repeat dose and reproductive/developmental toxicity screening test at doses of 0 (vehicle), 8, 40, 200 mg/kg day.
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
Thymol
EC Number:
201-944-8
EC Name:
Thymol
Cas Number:
89-83-8
Molecular formula:
C10H14O
IUPAC Name:
thymol
Details on test material:
Test substance: Thymol (purity: 99.6%)

Test animals

Species:
rat
Strain:
other: Crj:CD (SD)

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
other: 3% gum arabic solution
Analytical verification of doses or concentrations:
not specified
Details on mating procedure:
no data
Duration of treatment / exposure:
males: 43 days
females: from 14 days before mating to day 3 of lactation
Frequency of treatment:
daily
Duration of test:
terminal kill:
males: 44 days
females: day 4 of lactation
No. of animals per sex per dose:
10 males + 10 females/group
Control animals:
yes, concurrent vehicle

Results and discussion

Results: maternal animals

Effect levels (maternal animals)

open allclose all
Dose descriptor:
NOEL
Effect level:
200 mg/kg bw/day
Based on:
test mat.
Basis for effect level:
other: maternal toxicity
Remarks on result:
not determinable due to absence of adverse toxic effects
Dose descriptor:
NOEL
Effect level:
200 mg/kg bw/day
Based on:
test mat.
Basis for effect level:
other: developmental toxicity
Remarks on result:
other: see 'Remarks'
Remarks:
The compound exerted no effects on reproductive parameters such as the estrous cycle, mating index, fertility index, gestation lenght, number of corpora lutea or implatations, the implantation index, gestation index, delivery index, parturition or maternal behaviour. Birth weight and body weight gain tended to be low in the 200 mg/kg group neonates. There were no significant differences in numbers of offspring or live offspring at birth, the sex ratio, live birth index or viability index.

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:no effects

Effect levels (fetuses)

Dose descriptor:
NOEL
Effect level:
200 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: No abnormal findings ascribable to the compound were found on external examination, or in terms of clinical signs or necropsy finding for the neonates.
Remarks on result:
not determinable due to absence of adverse toxic effects

Fetal abnormalities

Abnormalities:
no effects observed

Overall developmental toxicity

Developmental effects observed:
no

Any other information on results incl. tables

The compound exerted no effects on reproductive parameters such as the estrous cycle, mating index, fertility index, gestation lenght, number of corpora lutea or implatations, the implantation index, gestation index, delivery index, parturition or maternal behaviour. Birth weight and body weight gain tended to be low in the 200 mg/kg group neonates. There were no significant differences in numbers of offspring or live offspring at birth, the sex ratio, live birth index or viability index.

Applicant's summary and conclusion

Executive summary:

Thymol was studied for oral toxicity in rats in an OECD combined repeat dose and reproductive/developmental toxicity screening test at doses of 0 (vehicle), 8, 40, 200 mg/kg day.

The compound exerted no effects on reproductive parameters such as the estrous cycle, mating index, fertility index, gestation lenght, number of corpora lutea or implatations, the implantation index, gestation index, delivery index, parturition or maternal behaviour. Birth weight and body weight gain tended to be low in the 200 mg/kg group neonates. There were no significant differences in numbers of offspring or live offspring at birth, the sex ratio, live birth index or viability index. No abnormal findings ascribable to the compound were found on external examination, or in terms of clinical signs or necropsy finding for the neonates.