Butyl glycollate

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1990-09-17 to 1990-12-19

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Reference 2

Reference Type:

other: Expert judgement

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Butyl glycollate

EC Number:

230-991-7

EC Name:

Butyl glycollate

Cas Number:

7397-62-8

Molecular formula:

C6H12O3

IUPAC Name:

butyl glycolate

Constituent 2

Reference substance name:

Polysolvan O

IUPAC Name:

Polysolvan O

Constituent 3

Reference substance name:

Glycolic acid-n-butyl ester

IUPAC Name:

Glycolic acid-n-butyl ester

Details on test material:

- Name of test material (as cited in study report): Polysolvan O (butyl glycollate)
- Physical state: liquid
- Analytical purity: about 97.3%
- Impurities (identity and concentrations): 0.1% unknown, <0.1% n-butanol, <0.1% di-n-butyl ether, 0.2% chloro acetic acid-n-butyl ester, 2.1% butoxy acetic acid n-butyl ester; <0.1% di-glycolic acid di-n-butylester, 0.3% water, 0.005% glycolic acid
- Purity test date: 09-Aug-1988
- Lot/batch No.: 123103, 09-Aug-1988
- Stability under test conditions: stable
- Storage condition of test material: in the dark, 20 °C

Test animals

Species:

rat

Strain:

Wistar

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Hoechst Kastengrund, Germany
- Age at study initiation: about 65 – 70 days
- Weight at study initiation: about 193 ± 12 g
- Fasting period before study: none
- Housing: single
- Diet (e.g. ad libitum): ad libitum, standard chow (Altromin 1310, Lage, Germany)
- Water (e.g. ad libitum): ad libitum, tap water
- Acclimation period: at least 7 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21-23 °C
- Humidity (%): 44-60%
- Air changes (per hr): 16-20 times/hr
- Photoperiod (hrs dark / hrs light): 12 hrs dark/12 hrs light

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: sesame oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
Daily, prior to application

VEHICLE
- Justification for use and choice of vehicle (if other than water): low solubility in water, high solubility in sesame oil
- Concentration in vehicle: 0, 12.5, 50, 250 g/L
- Amount of vehicle (if gavage): 5 ml/g bw

Analytical verification of doses or concentrations:

not specified

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1:1
- Length of cohabitation: over night
- Verification of same strain and source of both sexes: yes
- Proof of pregnancy: sperm in vaginal smear referred to as day 1 of pregnancy
- Any other deviations from standard protocol: no

Duration of treatment / exposure:

7 - 16 pc (counting from day 1 of pregnancy)

Frequency of treatment:

daily

Duration of test:

From mating until necropsy on day 21 pc

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day

Doses / concentrations 2

Dose / conc.:

62.5 mg/kg bw/day

Doses / concentrations 3

Dose / conc.:

250 mg/kg bw/day

Doses / concentrations 4

Dose / conc.:

1 250 mg/kg bw/day

No. of animals per sex per dose:

20 - 23 pregnant females

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale:
Dose selection was based on a range finding study. Each 3 pregnant rats were treated with dose levels of 1000 and 2000 mg/kg bw/day orally by gavage during gestation days 7 - 16 (counting from day 1 of pregnancy). At 2000 mg/kg bw/day 2/3 females were prematurely sacrificed after 2 treatments on gestation day 8 due to severe clinical symptoms. The reminder survived treatment but revealed no implantations at necropsy. 1000 mg/kg bw/day led to clinical findings, body weight loss or retarded body weight gain, reduced food consumption but not to premature deaths. The fetuses revealed signs of retardation.

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: once/week and one day after last application (days 1-7, 7-14, 14-17, 17-21)

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/ 10 g body weight/day: Yes
once/week and one day after last application (days 1-7, 7-14, 14-17, 17-21)

WATER CONSUMPTION: No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 21
- Organs examined: complete necropsy
- Organ weights: heart, liver, kidneys, spleen

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: pre-, post implantation loss, total resorptions, placental weight

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter
-Other: live fetuses, sex, fetal weight, crown/rump length

Statistics:

- Standard-MANOVA with sequentially rejective multiple comparison: Body weight, body weight during gestation, organ weights:
- Non-parametric Puri/Sen with sequentially rejective multiple comparison : Daily food consumption (g/100 g body weight during gestation)
- Mantel/Haenszel test (x²- test) with sequentially rejective multiple comparison: No. of implantation, corpora lutea, live fetuses, intra-uterine deaths
- MANOVA with sequentially rejective multiple comparison corrected for random litter effect: fetal body weight, crown/rump length, placental weight
- Exact Fishers test (one tailed): morphological findings in fetuses

Historical control data:

Historical control data were provided and used for comparison (1719 - 1767 control values).

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

body weight reduction at the high dose

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

at the hig dose

Food efficiency:

not specified

Ophthalmological findings:

not examined

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

slightly increased kidney weight

Gross pathological findings:

no effects observed

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

not specified

Maternal developmental toxicity

Number of abortions:

no effects observed

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
1250 mg/kg bw/day: one premature death on gestation day 17 and one premature sacrifice due to severe clinical signs on gestation day 14, clinical findings in form of respiratory noise and pilo-erection, reduced food consumption and body weight/body weight gain, increased kidney weights
62.5 and 250 mg/kg bw/day: no treatment-related effects

Effect levels (maternal animals)

1

Dose descriptor:

NOAEL

Effect level:

250 mg/kg bw/day (nominal)

Basis for effect level:

other: maternal toxicity

2

Dose descriptor:

NOAEL

Effect level:

250 mg/kg bw/day (nominal)

Basis for effect level:

other: developmental toxicity

Maternal abnormalities

Abnormalities:

effects observed, treatment-related

Localisation:

other: severe clinical signs, reduced food consumption and body weights, increased kidney weights

Results (fetuses)

Fetal body weight changes:

effects observed, treatment-related

Description (incidence and severity):

reduced body weight, short body length.

Changes in sex ratio:

not specified

Changes in litter size and weights:

effects observed, treatment-related

Description (incidence and severity):

in the high dose

External malformations:

effects observed, treatment-related

Description (incidence and severity):

at the high dose which was higher than the limited odse

Skeletal malformations:

effects observed, treatment-related

Description (incidence and severity):

only at the high dose which was higher than the limited dose including: The fetuses showed malformations in the morphological examination
on the head, trunk, spine and hind limbs. The deformities involved exencephaly, cranioschisis totalis, indicated and pronounced forms of one
Hydrocephalus internus, dysplasia of the skull bones, brachygnathia superior, cleft lip, anophthalmia, Lens aplasia, spina bifida totalis, scoliosis, omphalocele,
Gastroschisis and bends on the hind limbs. Dartiber minor anomalies and variations were also accumulated found on the spine, ribs and sternum.

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
1250 mg/kg bw/day: reduced fetal weight, reduced crown/rump length, increased incidence in retardation of skeleton, reduced placental weight. Morphological alterations in form of an increased incidence of external and skeletal malformations of head, rump, vertebral column and hind limbs (exencephaly, craniochisis totalis, hydrocephalus internus, dysplasia of skull bones, bachygnathia, aplasia lentis, craniochisis, anophthalmia, spina bifida, scoliosis, omphalocele, gastrochisis, bend hind limbs). In addition, increased incidence of variations of vertebra column, ribs and sternebrae.
62.5 and 250 mg/kg bw/day: no treatment-related effects

Effect levels (fetuses)

1

Dose descriptor:

NOAEL

Effect level:

250 mg/kg bw/day (nominal)

Basis for effect level:

other: teratogenicity

2

Dose descriptor:

NOAEL

Effect level:

250 mg/kg bw/day (nominal)

Basis for effect level:

other: embryotoxicity

Fetal abnormalities

Abnormalities:

effects observed, treatment-related

Localisation:

skeletal: vertebra

skeletal: hindlimb

Description (incidence and severity):

exencephaly, cranioschisis totalis, indicated and pronounced forms of one Hydrocephalus internus, dysplasia of the skull bones, brachygnathia superior, cleft lip, anophthalmia, Lens aplasia, spina bifida totalis, scoliosis, omphalocele, Gastroschisis and bends on the hind limbs. Dartiber minor anomalies and variations were also accumulated found on the spine, ribs and sternum.

Overall developmental toxicity

1

Developmental effects observed:

not specified

2

Developmental effects observed:

yes

Lowest effective dose / conc.:

250 mg/kg bw/day

Treatment related:

yes

Relation to maternal toxicity:

developmental effects occurring together with maternal toxicity effects, but not as a secondary non-specific consequence of maternal toxicity effects

Dose response relationship:

no

Relevant for humans:

no

Any other information on results incl. tables

Summary of maternal data:

mg/kg bw/day	0	62.5	250	1250
Pregnant females	20	20	20	20
Intercurrent deaths	0	0	0	2
Females with abortion	0	0	0	1
Females at termination with live fetuses	20	20	20	17
Food consumption GD 7-14 (mean g/day)	19.2	18.7	18.7	16.6
Food consumption GD 14 - 17 (mean g/day)	20.1	20.4	20.0	16.5
Body weight GD 7 (mean g/day)	229.6	229.4	223.4	225.9
Body weight GD 14 (mean g/day)	258.9	260.7	253.5	244.2*
Body weight GD 17(mean g/day)	277.3	280.3	275.3	255.9*
Body weight GD 21 (mean g/day)	329.5	334.0	329.8	307.1*
Body weight gain GD 0-21 (mean g/day)	132.9	138.8	140.3	113.1*
Liver weight (g)	13.88	14.07	14.15	13.82
Kidney weight (g)	1.58	1.57	1.63	1.76*
Corpora lutea (mean)	15.2	15.1	15.2	15.0
Implantation sites (mean)	13.3	13.7	13.8	13.6
Pre-implantation loss mean%	12.94	9.04	9.20	8.95
Post-implantation loss mean%	6.36	4.59	1.19	8.53
Mean early resorptions (total))	0.9 (18)	0.5 (10)	0.15 (3)	1.06 (18)
Mean late resorptions (total)	0.0 (0)	0.1 (2)	0.0 (0)	0.12 (2)
Mean No. of live fetuses	12.4	13.1	13.6	12.5
* p < 0.05

 

Incidence of selective fetal effects (fetus/litter incidences)

mg/kg bw/day	0	62.5	250	1250
No. of fetuses examined	130	136	140	109
No. of litter examined	20	20	20	17
Mean No. of live fetuses	12.4	13.1	13.6	12.5
Male fetuses %	48.39	51.53	48.90	49.06
Mean fetal weight (g)	3.5	3.5	3.5	2.8*
Mean crown/rump length (mm)	35.9	36.1	36.3	32.1*
Mean placental weight (g)	0.45	0.44	0.46	0.38*
External retarded fetus	0/0	2/2	1/1	8/7*
Distended kidney pelvis	1/1	3/3	5/5	6*/5
Omphalocele with protrusions	0/0	0/0	0/0	4*/3
Several external, head, jaw, eye, abdominal cavity, skull malformations	0/0	0/0	0/0	1/1
Several head, jaw, eye, abdominal cavity, skull, vertebral column malformations	0/0	0/0	0/0	1/1
Several head, jaw, oral cavity, eye, abdominal cavity, hindlimb, skull malformations	0/0	0/0	0/0	1/1
Skull bones slight/not ossified	37/14	37/14	20/10	55*/15
Non ossified cervical vertebra arch	0/0	0/0	0/0	4*/1
fused cervical vertebra arch	0/0	0/0	0/0	5*/2
Thoratic vertebrae arches and centra/ribs variations	0/0	0/0	0/0	28*/9*
Lumbar vertebrae centra variations	0/0	0/0	0/0	13*/7*
Caudal vertebrae centra variations	7/3	8/5	10/5	56*/16*
Extra vertebrae/ribs	5/4	3/3	3/2	60*/16*
Sternebrae variations	7/5	3/3	8/7	33*/14*
Non-/weakly ossified sternebrae	20/12	32/14	27/15	90*/17*
Extra rib (at 7^thcervical vertebra)	0/0	1/1	0/0	4*/3
Non-ossified metacarpale 5	13/7	23/11	16/6	78*/17*
Hindpaw phalanx non ossified	2/2	4/2	4/2	32*/13*
* p < 0.05

 

Applicant's summary and conclusion

Conclusions:

Polysolvan O (butyl glycollate, 97.3%) was administered to pregnant Wistar rats orally by gavage from implantation at gestation day (GD) 7 through GD 16 (counting from day 1 of pregnancy) at dose levels of 0, 62.5, 250 and 1250 mg/kg bw/day.

The dose levels of 62.5 and 250 mg/kg bw/day were tolerated without maternal or developmental toxicity and especially without morphological alterations in the fetuses.

The no observed adverse effects level (NOAEL) for maternal toxicity as well as for developmental toxicity including teratogenicity was 250 mg/kg bw/day.

Executive summary:

The prenatal developmental toxicity of Polysolvan O (butyl glycollate, 97.3%) was investigated in pregnant female Wistar rats. Each 20 pregnant females received dose levels of 0, 62.5, 250 and 1250 mg/kg bw/day orally by gavage from implantation at gestation day (GD) 7 through GD 16 (counting from day 1 of pregnancy). The test item was dissolved in sesame oil.

 

This study is assessed as appropriate and valid since it was performed according to an internationally accepted testing guideline and according to GLP. Reporting, assessment and data presentation in the study report was considered as appropriate.

 

Signs of maternal toxicity occurred at 1250 mg/kg bw/day only and consisted of one premature death on gestation day 17. One additional dams had to be sacrificed due to severe clinical signs on gestation day 14. At this dose level, clinical findings in form of respiratory noise and pilo-erection was noted. Food consumption and body weight/body weight gain were reduced and there was an increase in kidney weights.

The oral administration of the test substance to the dams at all 3 dose levels had no influence on the gestational parameters.

 

Signs of prenatal developmental toxicity including morphological alterations were only observed at 1250 mg/kg bw/day. The findings occurred in form of reduced fetal weight, reduced crown/rump length and lower placental weights. Morphological alterations were observed in form of an increased incidence of external and skeletal malformations of head, rump, vertebral column and hind limbs (exencephaly, craniochisis totalis, hydrocephalus internus, dysplasia of skull bones, bachygnathia, aplasia lentis, craniochisis, anophthalmia, spina bifida, scoliosis, omphalocele, gastrochisis, bend hind limbs). In addition, there was a general retardation of the fetal skeleton and an increased incidence of variations of vertebra column, ribs and sternebrae.

 

The dose levels of 62.5 and 250 mg/kg bw/day were tolerated without maternal or developmental toxicity and especially without morphological alterations in the fetuses.

 

Conclusion

Polysolvan O (butyl glycollate, 97.3%) was shown to induce prenatal developmental toxicity including morphological alterations in Wistar rats at a maternal toxic dose level only. The no observed adverse effects level (NOAEL) for maternal toxicity as well as for developmental toxicity including teratogenicity was 250 mg/kg bw/day.