2-chlorobuta-1,3-diene

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1975. No additional information

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The redacted summary gives no indication of compliance with test guidance but given the conduct ofth study appears to pre-date the formal pubication of most test guidance under OCED auspices and also pre-dates the introduction of GLP principles, the reliability has been assessed from whether the objectives of the study were met in a scientifically valid manner. The report indicates this was the case.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1975

Report date:

1975

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

A programme of studies was prepared to determine the inhalation toxicity of chloroprene. This screening investigation was intended to elucidate earlier Soviet work at low concentrations (<1ppm) over repeated exposures giving doses of 2074 ppm hrs in the Soviet publication and 2200 ppm hrs in the current study.
To test for reproductive effects a small scale investigation was initiated to ascertain whether the number of pups sired by test males compared to numbers of pups sired by control males showed whether losses occured following exposure to chloroprene

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

chloroprene

IUPAC Name:

chloroprene

Constituent 2

Reference substance name:

2-chloro-1,3-butadiene

IUPAC Name:

2-chloro-1,3-butadiene

Details on test material:

- Name of test material (as cited in study report): 2-chloro-1,3-butadiene (ß-chloroprene)

- Physical state: liquid
- Analytical purity: Not stated

- Composition of test material, percentage of components: A sample of the test liquid, held at room temperature for5 hours, was analysed by gas chromatography and found to contain <50 ppm dimer and 0.03% alpha-chloroprene. This was stated to be not significantly different from the original composition

- Lot/batch No.: No information available
- Expiration date of the lot/batch: No information available

- Stability under test conditions: Stability confirmed over 5 hours at room temperature
- Storage condition of test material: Liquid ß-chloroprene kept at less than -20°C until required.

Test animals

Species:

rat

Strain:

other: ChR-CD

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Not stated - Charles River derived animals
- Age at study initiation: (P) x wks; (F1) x wks: No information
- Weight at study initiation: (P) Males: x-x g; Females: x-x g; (F1) Males: x-x g; Females: x-x g No information
- Fasting period before study: No information
- Housing: No details - males were housed in the exposure chambers during exposure and during non-exposure periods presumably in standard rodent caging

- Diet (e.g. ad libitum): ad libitum during non-exposure periods
- Water (e.g. ad libitum): ad libitum during non-exposure periods
- Acclimation period: Not stated


ENVIRONMENTAL CONDITIONS
- Temperature (°C): No details provided
- Humidity (%): No details provided
- Air changes (per hr): No details provided
- Photoperiod (hrs dark / hrs light): No details provided


IN-LIFE DATES: From: Not stated To: Not stated

Administration / exposure

Route of administration:

inhalation

Type of inhalation exposure (if applicable):

whole body

Vehicle:

not specified

Details on exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: 1.4 m³ stainless steel chambers
- Method of holding animals in test chamber: Not stated but the battery of inhalation tests have all used similar exposure scenarios and it is presumed the wire cages holding the rats were arranged in the exposure chanber to provide whole body exposure.
- Source and rate of air: Room air, no rate provided
- Method of conditioning air: Not stated
- System of generating particulates/aerosols: liquid chloroprene, allowed to reach room temperature
- Temperature, humidity, pressure in air chamber: No data - supplied air for atmosphere generation was at room temperature
- Air flow rate: Not stated
- Air change rate: Not stated
- Method of particle size determination: Not stated
- Treatment of exhaust air: No details provided


TEST ATMOSPHERE
- Brief description of analytical method used: gas chromatograph with flame ionisation detector
- Samples taken from breathing zone: yes

Details on mating procedure:

The report contains details for two study phases - a sbacute inhalation exposure and a screening test for reproductive toxicity. Exposure methods were the same for both investigations but the five treated male rtas and five control rats allocated to the reproductive screen were involved in a mating phase, involving eight sequential mating trials.


- M/F ratio per cage: in each mating trial one male was housed with three, untreated, virgin females (ChR-CD strain)
- Length of cohabitation: seven days
- Proof of pregnancy: [vaginal plug / sperm in vaginal smear] referred to as [day 0 / day 1] of pregnancy No data
- After successful mating each pregnant female was caged (how): Following mating, the females were individually housed and allowed to raise the pups to weaning
- Any other deviations from standard protocol: Screening test only - limited number of animals used and the parameter used for evaluation of any effect wascomparison of the number of pups per litter sired by treated or untreated males.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Liquid ß-chloroprene was stored at -20°C and allowed to reach room temperature for atmosphere generation. The liquid was delivered into a room air airstream at a constant rate and the resultant vapour was introduced into the exposure chamber. Samples of the chamber atmosphere were obtained at half-hour intervals throughout the exposure period by trapping chloroprene in toluene. The resulting mixture was analysed by gas chromatography using a flame ionisation detector
The average chamber concentration achieved for the subacute study, with a nominal concentration of 25 ppm, was 22.4 ppm and the average for the reproduction study was 21.5 ppm

Duration of treatment / exposure:

4 hours per day for 22 days

Frequency of treatment:

daily

Details on study schedule:

In the earlier Soviet work, male rats wre exposed for 4h/day for 48 days at 10.8 ppm. The present study investigated the same overall dose (2074 ppm hrs) by exposing male rats to 4 h exposure to 25 ppm for 22 days (2200 ppm hrs)

In the subacute study fifteen test and ten control rats, weighing between 150 and 200g, were allocated to the study and exposed via inhalation to a 25 ppm chloroprene atmosphere for 22 consecutive days. Necropsy was performed one (8 test and 5 control) or 14 days (7 test and 5 controls) after the last exposure.

In the reproduction study, five test and five control animals were allocated and exposed as per the sub acute study. All animals were terminated 60 days after final exposure. In the interim period the males were housed with three virgin females for a week in a series of 8 mating periods. The females raised litters to weaning

Doses / concentrations

Remarks:

Doses / Concentrations:
25 ppm
Basis:
nominal conc.

No. of animals per sex per dose:

15 males in subacute test group, ten males in control

5 males in test group for embyotoxicity and 5 controls. Each male was mated with three females on each of eight weeks = 240 females

Control animals:

yes, sham-exposed

Details on study design:

- Dose selection rationale: Dose selected to replicate previous investigations
- Rationale for animal assignment (if not random): random

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
BODY WEIGHT: Yes

Oestrous cyclicity (parental animals):

Not applicable

Sperm parameters (parental animals):

Not investigated

Litter observations:

STANDARDISATION OF LITTERS: No

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring:
male mating index; viability index; lactation index

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: In subacute study terminated 1 or 14 days after last exposure
- male animals: in reproduction study terminated 60 days after last exposure


GROSS NECROPSY
- Gross necropsy of the subacute study males included weighing of organs - lung, heart, liver, kidney, testis and thymus.
- Gross necropsy of the reproduction study followed by histopathological examination of the reproductive organs.

HISTOPATHOLOGY / ORGAN WEIGHTS
The following tissues were prepared for microscopic examination :
trachea, lung, thyroid, parathyroid, heart, oesophagus, stomach, intestine, pancreas, liver, kidney , testis, epididymis, adrenal, lymph node, spleen, bone marrow, thymus, brain, eye and skin.
the testes and epididymides were examined from the reproduction study.

Postmortem examinations (offspring):

SACRIFICE
- The F1 offspring not selected as parental animals and all F2 offspring were sacrificed at [#?] days of age.
- These animals were subjected to postmortem examinations (macroscopic and/or microscopic examination) as follows:


GROSS NECROPSY
- Gross necropsy consisted of [external and internal examinations including the cervical, thoracic, and abdominal viscera.]


HISTOPATHOLOGY / ORGAN WEIGTHS
The tissues indicated in Table [#] were prepared for microscopic examination and weighed, respectively.

Statistics:

No details given in report

Reproductive indices:

male mating index - percentage of successful matings
viability index - percentage of pups that survive for 4 or more days
lactation index - percentage of pups alive at 4 days and surviving the 21 day lactation phase

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Body weight and weight changes:

not examined

Food consumption and compound intake (if feeding study):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Other effects:

not examined

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

effects observed, treatment-related

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
No clinical signs of toxicity observed in any of the subacute test or the reproductive screening test animals.
There were no mortalities.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
Body weight gains among test rats were similar to those of the controls


REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
There were no notable differences in reproductive performance between treated and control rats
test group control
mating index 66.7 70.8
pups/litter 11.65 11.75
viability index 95.9 96.7
lactation index 99.5 99.0
weanling bodyweight 44.1 43.9
There were no notable differences between reproduction parameters for test and control animals.

ORGAN WEIGHTS (PARENTAL ANIMALS)
There were no treatment related changes in organ weights in either the subacute or reproductive phases of the study. The mean relative testis weight
calculated for male rats two weeks after exposure to cloroprene showed no difference between test and control groups.

HISTOPATHOLOGY (PARENTAL ANIMALS)
There were no treatment related changes in histopathology in either the subacute or reproductive phases of the study.

Effect levels (P0)

Dose descriptor:

NOAEC

Effect level:

25 ppm (nominal)

Sex:

male

Results: F1 generation

General toxicity (F1)

Clinical signs:

not specified

Mortality / viability:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Sexual maturation:

effects observed, treatment-related

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

not specified

Histopathological findings:

not specified

Details on results (F1)

VIABILITY (OFFSPRING)
The viability index for the test group was 95.9 and 96.7 for the control group


BODY WEIGHT (OFFSPRING)
Weanling bodyweight was 44.1 for the test group and 43.9 for the control

The number of pups per litter was 11.65 for the test group and 11.75 for the control

There were no differences in any of the offspring parameters that were attributable to treatment with chloroprene

Overall reproductive toxicity

Reproductive effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

No effects of chloroprene inhalation exposure at 25 ppm were evident in a subacute investigation or in a reproduction screening assay,

Executive summary:

Two investigations were included in the report - a subacute toxicity study and a screening study foor male reproductive performance.

Treatment was the same for both sets of rats. 15 test and 10 control rats were allocated to the subacute study; 5 test males and 5 control males were treated prior to an eight week mating cycle.

The test animals were exposed by inhalation to an atmosphere containing 25 ppm chloroprene for 4 hours per day for a period of 22 days.

There were no clinical signs of reaction to treatment in either study and bodyweight gains for the test rats were similar to controls in both studies. Analytical results for the mean chamber concentration indicated achieved dose levels of 22.4 ppm for the subacute study and 21.5 ppm for the reproduction phase.

Gross and microscopic pathology revealed no treatment related changes attributable to chloroprene.

In the reproduction study the results for several parameters were as follows:

test group control

mating index 66.7 70.8

pups/litter 11.65 11.75

viability index 95.9 96.7

lactation index 99.5 99.0

weanling bodyweight 44.1 43.9

There were no notable differences between reproduction parameters for test and control animals.

No effects of chloroprene inhalation exposure at 25 ppm were evident in a subacute investigation or in a reproduction screening assay, no effects on reproductive performance, organs or function were noted.