2-chloroethanol

Developmental toxicity / teratogenicity

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: see 'Remark'

Remarks:

The study is comparable to OECD Guideline 414 with acceptable restrictions (reduced exposure period during organogenesis; no details about the test substance; limited recording of clinical signs; no data about food consumption and necropsy in results section). The i.v. injection is a worst case consideration compared with physiological exposure route. A quality assurance report is available (high quality standard, but not GLP).

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Teratogenic evaluation of ethylene chlorohydrin (ECH) in mice and rabbits

Author:

LaBorde JB, Kimmel CA, Jones-Price C, Marks TA, and Ledoux TA

Year:

1982

Bibliographic source:

Toxicologist 2: 71

Reference 2

Reference Type:

publication

Title:

Unnamed

Year:

1985

Reference 3

Reference Type:

publication

Title:

Unnamed

Year:

1983

Report date:

1983

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

no

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2-chloroethanol

EC Number:

203-459-7

EC Name:

2-chloroethanol

Cas Number:

107-07-3

Molecular formula:

C2H5ClO

IUPAC Name:

2-chloroethan-1-ol

Details on test material:

Source: Eastman Kodak Co., Rochester, NY 14650 (via NTP)
Identification Nos : P-10608-1, RO-2182-S79, LBI #759, 5-16-79
Purity: pure compound, no further data
no further details

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Franklin's Rabbitry (1st preliminary study) or Dutchland Laboratories, Inc. (Denver, PA) for all other experiments
- Age at study initiation: at arrival appr. 6 months
- Weight at study initiation: 3.1 to 5.8 kg at gestation day (gd) 0 (main study 3.1-5.3 kg)
- Fasting period before study: no
- Housing: housed singly
- Diet (e.g. ad libitum): Purina Certified Rabbit Chow (5322)
- Water (e.g. ad libitum): autoclaved/ deionized/glass -distilled or deionized/filtered water
- Acclimation period: 2weeks


ENVIRONMENTAL CONDITIONS
- Temperature (°C): no data (automated)
- Humidity (%): no data (automated)
- Air changes (per hr): 12-14
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

intravenous

Vehicle:

other: sterile 5% dextrose in water

Details on exposure:

females were rank ordered by body weight and assigned to treatment groups; constant application volume 0.3 ml; test substance solved in 5% dextrose; test substance solution formulated daily just prior to injection; concentration related to dose level; in the main study (161 females total) rabbits distributed across treatment groups (untreated control, 0, 9, 18 or 36 mg/kg/day, iv) on six insemination dates; injection: one minute duration into the marginal ear vein, alternating injection sites each day.

Preliminary study 1
contaminated rabbits; vehicle control (n=2) or 40 mg/kg bw/day (n=3). 1/3 rabbits died at gd 12; in surving animals pregnancy confirmed at gd 30. No further data documented below.

Preliminary study 2
healthy rabbits; 0, 10, 20, 30 or 40 mg/kg bw/day on gd6-14, 3-5 pregnant rabbits per dose for evaluation (initial n=5 per group).

Main study: see below

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

samples stored at 4°C; analysis as soon as possible by gas chromatography (2 calibration runs).
Preliminary studies: results indicated that formulations fell within a range of 70 to 126% of the nominal concentrations.
Main study: Analytical data obtained for 97.5% of the dosage formulations; assays conducted as early as the day of formulation or as late as "3 months post-dosing"; formulations fell within a range of 75 to 117% of the nominal concentration with one exception: 18 mg/kg/day group dosed on gd 7 with a formulation which contained 155% of the nominal concentration, thus yielding a dose of 28 mg/kg/day.

Details on mating procedure:

females were artificially inseminated; to induce ovulation, the females iv injected with pituitary luteinizing hormone (1 mg/kg bw) no more than two hours prior to insemination. Ejaculates collected from males and checked for quality.

Duration of treatment / exposure:

gestation day (gd) 6- 14

Frequency of treatment:

once daily

Duration of test:

gd 30

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 9, 18, 36 mg/kg bw/day
Basis:
other: nominal

No. of animals per sex per dose:

initially 17-23 rabbits per dose; 17-22 animals evaluated; 15-21 confirmed-pregnant females

Control animals:

yes, concurrent no treatment

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: results of preliminary studies
- Rationale for animal assignment (if not random): random by body weight

Examinations

Maternal examinations:

DETAILED CLINICAL OBSERVATIONS: Yes
"during treatment" no further details and at termination
BODY WEIGHT: Yes
Time schedule: gd 0, daily on gd 6-14 and at termination (gd 30)

FOOD CONSUMPTION: No data
WATER CONSUMPTION: No data
POST-MORTEM EXAMINATIONS: Yes, necropsy performed

Ovaries and uterine content:

sacrifice time, liver weight, gravid uterine weight and status of uterine contents ( i.e. implantation sites, resorptions, dead fetuses, live fetuses) recorded; uteri of dams with no apparent implants treated with a solution of 10% ammonium sulfide in order to visualize possible implantation sites.

Fetal examinations:

Live fetuses dissected from the uterus, anesthetized with 0.05 ml (approximately 50 mg/kg bw) ip sodium pentobarbital; live litter size recorded and individual fetuses were weighed and examined for gross morphological abnormalities. All live fetuses examined for visceral malformations employing the Staples' fresh tissue dissection method; all live fetuses decapitated following dissection and the heads fixed in Bouin's solution for free hand sectioning and examination; all fetal carcasses were prepared with Alizarin Red S stain and examined for skeletal malformations.

Statistics:

nonparametric statistics in order to identify dose-response trends
For ordinal, interval and ratio level measurements the data presented as mean + - S.E.M. using the dam or litter as the experimental unit for measures of toxicity and teratogenicity .
Kruskal-Wallis oneway analysis of variance by ranks
Mann-Whitney U test (two-tailed)
Jonckheere's test for k-independent samples (trend test)
two-tailed Fisher's Exact test for pairwise comparisons
randomization test for dose-response trends
alpha level was 0.05 and significance level at p<0.05

Historical control data:

no data

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
Main study
Administration of 0, 9, 18 or 36 mg/kg bw/day on gd 6-14 resulted in mortality rates of 4.3% (1/23), 5.2% (1/19), 13.6% (3/22) and 15.0% (3/20), respectively. No unscheduled deaths occurred among 17 untreated females. Death occurred during exposure period only in mid dose (1/3) and high dose group (3/3), other deaths at gd 29 (not discussed by the authors). No clinical signs prior to death.
Clinical signs included hyperactivity, lacrimination and diarrhea, but no apparent relation to the test substance was observed.
Measures of maternal body weight (gd 0, 6, 10, 14 and 30), mateinal weight gain (i .e ., weight gain during gestation, weight gain during treatment and absolute weight gain), gravid uterine weight and maternal liver weight were not found to differ statistically among treatment and vehicle groups.
No effects on % pregnant dams at sacrifice.

Effect levels (maternal animals)

1

Dose descriptor:

NOAEL

Effect level:

36 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: developmental toxicity

2

Dose descriptor:

NOAEL

Effect level:

9 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
Main study
Examination of uterine contents see Table below.
Sacrifice on gd 30 revealed no differences among groups in the percentage of resorbed, dead, nonlive (i.e., dead plus resorbed) or affected (i.e., nonlive plus malformed) fetuses per litter. Nor were average live litter size, percentage of males per litter or average fetal body weight per litter altered by the treatment .
Teratogenicity
No evidence of a treatment-related teratogenic effect was observed, even at the highest dose. Malformed fetuses occurred at a rate of 1.7% (3/175 fetuses
examined), 5.6% (9/159), 3.6% (4/111), 2.9% (4/136) at dose levels of 0 (vehicle). 9, 18, 36 mg/kg bw/day, respectively; 6.8% (10/145) fetuses occurred in the untreated control group. No statistically significant differences were observed for the percentage of malformed fetuses per litter, nor for the proportion of litters with one or more malformed fetuses.

Effect levels (fetuses)

Dose descriptor:

NOAEL

Effect level:

36 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: developmental toxicity / teratogenicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

Preliminary study 2

mortality: 0/5, 0/3, 0/5, 0/4 and 1/4 (gd10) at 0, 10, 20, 30 or 40 mg/kg/day, respectively.

Clinical signs during treatment: lacrimation in one female each from the 20 and 30 mg/kg bw/day groups; localized damage to the ear vein(s) (i .e . inflammation swelling, blockage and/or collapse) in one female from the 30 mg/kg bw/day group and 4 females from the high dose group. No statistically significant differences for maternal body weight (gd 0, 6, 10, 14 or 30), maternal weight gain during gestation, weight gain durlng treatment, absolute maternal weight gain ( i.e., gestational weight gain minus gravid uterine weight), or maternal liver weight; gravid uterine weight showed an apparent but nonsignificant trend toward decreased weight;

Developmental toxicity

significant trend toward decreased implantation sites per litter (significant decrease at 20 mg/kg bw/day); did not occur in the main study. Significant dose-related decreases were observed for the percentage of dead fetuses. Other effects were not statistically significant.

Comment: low number of animals.

Conclusion: in the main study similar dose levels were used.

Developmental toxicity in New Zealand White rabbits after i.v. injection of 2-chloroethanol at gestation day 6-14

Means +- standard error of mean

Parameter	Dose in mg/kg bw/day
	Untreated control	Vehicle control	9	18	36
Pregnant dams	15	21	18	17	16
Implantation sites per litter	10.13+-0.86	9.19+-0.66	9.67+-0.72	7.41+-0.76	10.06+-0.50
Resorptions per litter	0.40+-0.21	0.67#+-0.28	0.72+-0.27	0.82#+-0.39	1.31+-0.48
% Resorptions per litter	3.8+-1.8	10.7+-5.1	6.2+-2.0	12.4+-6.5	13.0+-4.9
% Litters with resorptions	26.7	33.3	44.4	29.4	56.3
% Dead fetuses per litter	0.4+-0.4	1.6+-1.6	0.9+-0.6	0.5+-0.5	2.4+-1.1
% Dead & resorbed per litter	4.2+-2.1	12.3+-5.3	7.1+-2.4	12.9+-6.4	15.3+-4.9
% Dead, resorbed, and malformed per litter	11.4+-3.3	13.7+-5.4	12.9+-4.3	16.2+-6.4	17.3+-5.1
Number of litters with live fetuses	15	20	18	16	16
Average fetal body weight/litter	43.6+-2.5	43.7+-1.5	42.1+-1.8	47.5+-2.4	43.3+-2.0
% Males per litter	49.7+-3.1	49.9+-4.2	48.9+-4.2	50.0+-4.1	51.3+-4.2
Number of fetuses with gross malformations	0	0	0	0	0
Visceral malformations: No. of fetuses (no. of litters)	3 (3)	0(0)	3(2)	2(2)	0(0)
Skeletal malformations: no. of fetuses (no. of litters)	7(6)	3(3)	6(4)	2(2)	4(3)

#: One female had all resorptions

Applicant's summary and conclusion

Conclusions:

No evidence for a embryo/fetotoxic or teratogenic effect was observed in rabbits after i.v. application, even at dosages which were lethal to greater than 10% of treated females.

Executive summary:

The study is comparable to OECD Guideline 414 with acceptable restrictions (reduced exposure period during organogenesis; no details about the test substance; limited recording of clinical signs; no data about food consumption and necropsy in results section). The i.v. injection is a worst case consideration compared with physiological exposure route. A quality assurance report is available (high quality standard, but not GLP).

In a teratogenic study new Zealand White rabbits were i.v. injected once daily at gestation day (gd) 6 -14 with 0 (vehicle), 9, 18, 36 mg/kg bw/day. Additionally data on an untreated control group were presented. 15 -21 pregnant dams were evaluated at termination (gd 30). Except a slight increase in mortality (4.3, 5.2, 13.6, 15.0% at 0 (vehicle), 9, 18, 36 mg/kg bw/day, respectively) no maternal toxicity was detected. Dams were sacrificed gd 30 and cesarian section performed. All parameters of developmental toxicity revealed negative results, no increase in the incidence of external, visceral or skeletal malformations was found.

Conclusion: No evidence for a embryo/fetotoxic or teratogenic effect was observed in rabbits after i.v. application, even at dosages which were lethal to greater than 10% of treated females.