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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: GLP study, with acceptable deviation from OECD 414.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report Date:
1997

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EPA OTS 798.4900 (Prenatal Developmental Toxicity Study)
Deviations:
yes
Remarks:
predates current guideline OPPTS 870.3700 (1998) which requires longer dosing period
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Deviations:
yes
Remarks:
study predates current (2001) guideline which requires longer dosing period
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): furfural
- Physical state: clear. yellowish to dark amber liquid
- Analytical purity: 99.4% (during study confirmed by GC-TCD to be 99.8% and 100%)
- Lot/batch No.: 1218

Test animals

Species:
rat
Strain:
other: Crl:CD®(SD)BR
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, Inc., Portage, Michigan, USA
- Age at study initiation: approximately 12 weeks when paired for breeding
- Weight at study initiation: 225-290 g
- Fasting period before study: none
- Housing: individually housed in wire-mesh cages except during mating
- Diet (e.g. ad libitum): PMI Feeds, Inc.© Certified Rodent LabDiet© 5002, ad libitum
- Water (e.g. ad libitum): municipal water via an automatic system ad libitum
- Acclimation period: two weeks
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 71-73°F (equivalent to 22-23°C).
- Humidity (%): 34.7-49.4%
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): artificial light, 12 hours light, 12 hours dark
IN-LIFE DATES: From: April 1, 1997 To: April 25, 1997

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Remarks:
(reverse osmosis treated water, deionised and sparged with nitrogen)
Details on exposure:
VEHICLE
- Justification for use and choice of vehicle (if other than water): not relevant
- Concentration in vehicle: 0, 10, 20, and 30 mg/mL
- Amount of vehicle (if gavage): 5 mL/kg bw
- Lot/batch no. (if required): no data
- Purity: no data
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Dosing solutions were prepared weekly. Samples taken for analytical verification of furfural concentrations: top, middle and bottom samples (pre-test samples) for homogeneity and 8-day stability; middle samples from all solutions of week 1 and 2 of dosing for accuracy of concentration. Analysis byby UV-spectroscopy (no dilution or work-up). Validation (a calibration curve) was provided and acceptable.
The dosing solutions were homogeneous (RSD in range 0.8-1.2%), and stable for eight days at room temperature protected from light (concentrations after storage 98-99% of the time zero concentrations). The solutions that were used for dose administration and were analyzed had concentrations within 2% of target.
Details on mating procedure:
- Impregnation procedure: cohoused.
- If cohoused:
- M/F ratio per cage: one male per female
- Length of cohabitation: no data
- If unsuccessful pairing replacement of first male by another male with proven fertility: no data
- Further matings after two unsuccessful attempts: no data
- Verification of same strain and source of both sexes: yes
- Proof of pregnancy: vaginal plug / sperm in vaginal smear referred to as day 0 of gestation
Duration of treatment / exposure:
days 6-15 of gestation.
Dosing was terminated between gestation days 10-14 for the 150 mg/kg bw/day group due to significant maternal toxicity. The animals were retained on study to assess reversibility.
Frequency of treatment:
treatment once daily
Duration of test:
21 days (Caesarian section was performed on day 20 of presumed gestation)
No. of animals per sex per dose:
25 females
Control animals:
yes, concurrent vehicle
Details on study design:
On gestation day 20, laparohysterectomy was performed on all surviving animals.

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily for moribundity and mortality
DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: once daily from day 0 through 20 of presumed gestation, and in addition about 1 hour post-dosage on day 6 through 15 of presumed gestation
BODY WEIGHT: Yes
- Time schedule for examinations: on day 0 and day 6 through 16 and 20 of presumed gestation
FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Time schedule for examinations: on day 0 and day 6 through 16 and 20 of presumed gestation
WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No
POST-MORTEM EXAMINATIONS: Yes
- Gestation day 20
- Organs examined: uterus excised and weighed; thoracic, pelvic and abdominal cavities were examined for gross lesions.
Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Other: numbers of live and dead fetuses were recorded; uteri that appeared non-gravid were stained according to Salewski for detection of early implantation loss.
Fetal examinations:
- External examinations: Yes: [all per litter]. Fetuses were also weighed and sex was determined
- Soft tissue examinations: Yes: [all per litter]
- Skeletal examinations: Yes: [all per litter]
- Head examinations: Yes: [half per litter were placed in Bouin’s fixative for soft tissue examination by the Wilson’s sectioning technique; remaining half by a mid-coronal slice]
Statistics:
Maternal body weights and body weight changes, gravid uterine weights, maternal net body weight changes, food consumption, corpora lutea, total implantations, fetal body weights: one-way analysis of variance, followed by Dunnett’s test.
Litter proportions of Intra-uterine data, malformations, variations: Kruskal-Wallis test followed by Mann-Whitney U-test.
All tests 2-sided minimum 5% significance level.
Indices:
Pre and post implantation loss
Historical control data:
Historical control data were provided.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:yes

Details on maternal toxic effects:
Mortality: For the 150 mg/kg/day group, dosing was terminated on gestation days 10-14 (depending on start date) due to significant maternal toxicity. In the 100 and 150 mg/kg/day groups, 3 and 16 females, respectively, died between gestation days 6 and 15. All other maternal animals survived to the scheduled necropsy on gestation day 20.
Clinical observations: Treatment-related findings in the 50, 100 and/or 150 mg/kg/day groups included hypoactivity, vocalization, decreased defecation, red material around the eyes and mouth, labored respiration, rales, rapid respiration, gasping, prostration and lethargy. Tremors and head held low were noted sporadically in the 50 mg/kg/day group and more frequently in the 100 and 150 mg/kg/day groups. In addition, exophthalmia was observed in all of the treated groups from gestation days 6-18.
Body weight and food consumption: In the 150 mg/kg/day group, a mean body weight loss and reductions in food consumption were observed during gestation days 6-9. Body weight gain and food consumption remained inhibited in the surviving females in this group during gestation days 9-12. Body weight gain and food consumption in this group were comparable to the control group values following the termination of dosing (gestation days 12-16 and 16-20). Mean body weights, body weight gains, net body weights, net body weight gains, gravid uterine weights and food consumption in the 50 and 100 mg/kg/day groups were unaffected by treatment.

Effect levels (maternal animals)

open allclose all
Dose descriptor:
NOAEL
Effect level:
< 50 mg/kg bw/day (nominal)
Based on:
test mat.
Remarks:
(purity was 99.4% or higher)
Basis for effect level:
other: maternal toxicity
Dose descriptor:
NOAEL
Effect level:
100 mg/kg bw/day (nominal)
Based on:
test mat.
Remarks:
(purity was 99.4% or higher)
Basis for effect level:
other: developmental toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
A slightly reduced mean fetal body weight in the 150 mg/kg/day group was interpreted to be an equivocal indication of developmental toxicity. Intrauterine growth and survival were unaffected by test article administration in the 50 and 100 mg/kg/day groups.
The malformations observed in the treated groups were considered to be spontaneous in origin.
The fetal developmental variations were observed infrequently or at a similar frequency in the control group.

Effect levels (fetuses)

Dose descriptor:
NOAEL
Effect level:
100 mg/kg bw/day (nominal)
Based on:
test mat.
Remarks:
(purity was 99.4% or higher)
Basis for effect level:
other: teratogenicity

Fetal abnormalities

Abnormalities:
not specified

Overall developmental toxicity

Developmental effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
Based on the results of this study, the NOAEL (no observable adverse effect level) for maternal toxicity was considered to be less than 50 mg/kg/day and the NOAEL for developmental toxicity was considered to be 100 mg/kg/day. However, a complete assessment of the potential prenatal toxicity of furfural in the 150 mg/kg/day group was precluded by maternal mortalities, a reduced number of litters available for evaluation and limited duration of administration.
Executive summary:

The potential maternal toxicity and developmental toxicity of furfural administered by oral gavage were evaluated. Groups of 25 Crl:CDO(SD)BR rats were dosed once daily from gestation days 6 through 15 with 0, 50, 100 or 150 mg/kg bw/day. Dosing of 150 mg/kg bw/day was terminated prematurely (gestation days 10 to 14) due to significant maternal toxicity including lethality.

For the 100 and 150 mg/kg/day groups, 3 and 16 females, respectively, died between gestation days 6 and 15. Treatment-related clinical findings occurred in all furfural treated groups. Body weight and food consumption were adversely affected by 150 mg/kg/day only. The NOAEL (no observable adverse effect level) for maternal toxicity was considered to be less than 50 mg/kg/day on the basis of the treatment-related clinical findings.

The NOAEL for teratogenicity and developmental toxicity was considered to be 100 mg/kg/day. A complete assessment of the potential prenatal toxicity of furfural in the 150 mg/kg/day group was precluded by maternal mortalities, a reduced number of litters available for evaluation and limited duration of administration.