Dichlorodifluoromethane

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

Effects on experimental animals of long-term inhalation of trichloroethylene, carbon tetrachloride, 1,1,1-trichloroethane, dichlorodifluoromethane, and 1,1-dichloroethylene.

Author:

Prendergast JA, Jones RA, Jenkins LJ Jr, Siegel J.

Year:

1967

Bibliographic source:

Toxicol Appl Pharmacol., vol. 10, no. 2, p. 270-89.

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: groups of animals were exposed to dichlorodifluoromethane daily for 30 exposures, or as a continuous exposure for 90 days.
- Short description of test conditions:
- Parameters analysed / observed:

GLP compliance:

no

Remarks:

Prior to GLP guidelines

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Dichlorodifluoromethane

EC Number:

200-893-9

EC Name:

Dichlorodifluoromethane

Cas Number:

75-71-8

Molecular formula:

CCl2F2

IUPAC Name:

dichlorodifluoromethane

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Matheson Gas Company, East Rutherford, New Jersey

Test animals

Species:

other: rats, guinea-pigs, monkeys, rabbits, dogs

Strain:

other: as stated in the publication: 15 Sprague-Dawley or Long-Evans, 15 Hartley guinea-pigs, 3 squirrel monkeys, 3 New-Zealand rabbits, 2 beagle dogs

Sex:

not specified

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: no data
- Age at study initiation: no data
- Weight at study initiation: 192 g (range: 145-244g) at start of the repeated exposure study; 213 g (range: 165-262g) at the start of the continuous exposure study
- Housing:
- Diet : not specified
- Water : ad libitum
- Acclimation period:

DETAILS OF FOOD AND WATER QUALITY: commercial dry chow.

ENVIRONMENTAL CONDITIONS : (exposure chambers)
- Temperature (°C): 75 to 80°F (23 to 26.7°C)
- Humidity (%): 50%
- Air changes (per hr): 1.23 m3/ minute
- Photoperiod (hrs dark / hrs light): no data

IN-LIFE DATES: no data

Administration / exposure

Route of administration:

inhalation: gas

Type of inhalation exposure:

whole body

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: chamber (no details)
- Source and rate of air: no data
- Method of conditioning air: a stream of pure gaseous dichlorodifluoromethane from a high-pressure cylinder was metered through a rotameter into a mixing bottle and carried into the chember where it was diluted to the atrget concentration with air.
- Temperature, humidity, pressure in air chamber: 75-80°F (23.6-26.6 °C), 50% humidity, negative pressure at 2.0 inches if water
- Air flow rate: 1.25 m3/minute
- Air change rate: no data
- Treatment of exhaust air: no data

TEST ATMOSPHERE
- Brief description of analytical method used: continous monitoring of chamber concentrations by infrared analysis.
- Samples taken from breathing zone: no data

VEHICLE (if applicable)
- Justification for use and choice of vehicle: no data
- Composition of vehicle: air

Analytical verification of doses or concentrations:

yes

Remarks:

Infrared analysis

Details on analytical verification of doses or concentrations:

Infrared analysis. A stream of chamber air was drawn through a variable pathlength gas cell fitted to an infrared spectrophotometer. The instrument was locked on the analytical wavelength selected for the contaminant and the percent transmission was continuously recorded. The contaminant level was then read from a graph of concentration vs percent transmission previously prepared by vaporizing known amounts of the test material in the gas cell.
Chemical analysis were performed daily and correlated with nominal input data.

Duration of treatment / exposure:

- repeated exposure study: 30 exposures
- continuous exposure study: 90 days

Frequency of treatment:

- Repeated exposures: Daily 8 hours/day, 5 days/week for a total of 30 exposures
- Continuous exposure for 90-day, except for feeding the animals and servicing the chambers (< 2% of the total chamber time)

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/m³ air

Doses / concentrations 2

Dose / conc.:

4 136 mg/m³ air

Remarks:

30 repeated exposures (Mean +/- SD 87)

Doses / concentrations 3

Dose / conc.:

3 997 mg/m³ air

Remarks:

90-day continuous exposure (Mean +/- SD 113)

No. of animals per sex per dose:

15 rats per dose (sex not specified)

Control animals:

yes, concurrent no treatment

Positive control:

no

Examinations

Observations and examinations performed and frequency:

DETAILED CLINICAL OBSERVATIONS: yes
All animals were routinely examined for signs of toxicity, marked alterations in behaviour, physical appearance, respiration pattern, locomotor activity and prostration.

BODY WEIGHT: Yes
- Time schedule for examinations: prior to exposure, at monthly intervals and at the termination of the study.

HAEMATOLOGY: Yes
- Time schedule for collection of blood: no data
- Anaesthetic used for blood collection: Not specified
- Animals fasted: Not specified
- How many animals: Not specified
- Parameters examined : Total and differential Leukocyte counts, Hemoglobin concentration, Hematocrit, before and after the exposure

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood:
- Animals fasted: Yes / No / Not specified
- How many animals:
- Parameters examined:
* Reduced nicotinamide adenine dinucleotide (NADH), reduced nicotinamide adenine dinucleotide phosphate ( NADPH), activities of succinic dehydrogenase ( SDH ), lactic dehydrogenase ( LDH), isocitric dehydrogenase ( ICD), glucose-6-phosphate dehydrogenase ( GGPD), and p-hydroxybutyric dehydrogenase (B-OHBD).
* Alkaline phosphatase activity
* Serum glutamic-pyruvic transaminase levels
* Serum urea nitrogen concentrations
* Liver lipids

URINALYSIS: Not specified

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes : heart, lung, liver, spleen, kidney

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Description (incidence and severity):

Repeated exposure: No signs of toxicity were observed in the rat survivors.
Continuous exposure: no visible signs of toxicity

Mortality:

mortality observed, treatment-related

Description (incidence):

Rats: (no details on day)
1/15 in the repeated exposure group
2/15 in the continuous exposure group
7/304 controls

Guinea-pigs:
1/15 in the continuous exposure group.

No mortality observed in the other groups and species.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

* Repeated exposure: no effect reported
* continuous exposure: No effects reported in rats. Body weights of the rabbits and guinea-pigs were depressed.

Food consumption and compound intake (if feeding study):

not examined

Ophthalmological findings:

not examined

Clinical biochemistry findings:

not specified

Behaviour (functional findings):

no effects observed

Description (incidence and severity):

No details

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

* Repeated exposure: several rats and guinea pigs, had varying degrees of lung congestion.
Other organs appeared normal.
No effects were reported in rats, but guinea-pigs showed focal necrosis of the liver, but which could not be defintely attributed to the exposure.

* Continuous exposure: high incidence of varying degrees of lung congestion in rats, rabbits, monkeys, guinea-pigs.
In guinea-pigs, submassive necrosis of the liver was noted in the surviving guinea-pigs.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

* Repeated exposure: non-specific interstitial inflammatory changes in the lungs of both treated and control animals.
- Several guinea-pigs showed focal necrosis or fatty infiltration of the liver.
- one monkey had heavy pigment deposits in the liver, spleen, kidney.

* Continuous exposure: non-specific interstitial inflammatory changes in the lungs (all species)
- one guinea-pig showed a focal giant cell pneumonitis. All guinea-pig liver sections: slight to extensive fatty infliltration of the hepatic cells; several sections with focal or submassive necrosis of the liver. It could not be determined if this toxic response was due to the continuous exposure or to the higher susceptibility of the guinea-pigs, already noted in other studies.

Histopathological findings: neoplastic:

not specified

Effect levels

Key result

Dose descriptor:

NOAEC

Effect level:

ca. 3 997 mg/m³ air (nominal)

Based on:

test mat.

Sex:

not specified

Target system / organ toxicity

Key result

Critical effects observed:

no