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Toxicological information

Repeated dose toxicity: inhalation

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Administrative data

Endpoint:
short-term repeated dose toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: (1a) GLP Guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 412 (Subacute Inhalation Toxicity: 28-Day Study)
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
Pentafluoroethane
EC Number:
206-557-8
EC Name:
Pentafluoroethane
Cas Number:
354-33-6
Molecular formula:
C2HF5
IUPAC Name:
1,1,1,2,2-pentafluoroethane
Details on test material:
- Name of test material (as cited in study report): HFC-125
- Substance type: fluorinated alkane
- Physical state: gas
- Analytical purity: > 99.5%
- Impurities (identity and concentrations): not reported
- Composition of test material, percentage of components: Pure substance
- Isomers composition: n/a
- Purity test date: not reported
- Lots/batches No.: BR070, BR163, BR016
- Expiration date of the lot/batch: not reported
- Stability under test conditions: stable
- Storage condition of test material: stored in pressure gas cylinders at room temperature

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Japan
- Age at study initiation:
- Weight at study initiation:
- Fasting period before study:
- Housing:
- Diet (e.g. ad libitum):
- Water (e.g. ad libitum):
- Acclimation period:


ENVIRONMENTAL CONDITIONS
- Temperature (°C):
- Humidity (%):
- Air changes (per hr):
- Photoperiod (hrs dark / hrs light):


IN-LIFE DATES: From: To:

Administration / exposure

Route of administration:
inhalation
Type of inhalation exposure:
whole body
Vehicle:
other: unchanged (no vehicle)
Details on inhalation exposure:
HFC-125 vapours were generated by metering the gaseous HFC-125 form a cylinder into stainless tubing through the flow meter. The vapour was
diluted with filtered air to the desired concentrations.
Chamber concentrations were obtained by varying the gas flow rate in the chambers.
FIltered air alone was metered in an identical way in the control chamber. The atmospheric concentrations were monitored at intervals of 15 minutes
by GC analysis.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
GC analysis:
chamber atmosphere was sampled with an automatic system (0.2 ml/sample) and analysed with a Shimadzu GC-8AIF GC.
Technical details: Detector: flame ionization detector; Column: 3m x 3mm I.D. stainless steel packed with 20% DC-200 liquid phase on a 60/80 mesh chromosorb W solid phase; Program: isotherm 60°C.
A standard curve was obtained by measuring the signal of several concentrations of pure HFC-125.
Duration of treatment / exposure:
4 weeks
Frequency of treatment:
6 hrs/day, 5 days/week
Doses / concentrations
Remarks:
Doses / Concentrations:
5000, 15000 and 50000 ppm
Basis:
nominal conc.
No. of animals per sex per dose:
10
Control animals:
yes
Details on study design:
- Dose selection rationale: Based on the low toxicity observed in the acute study
- Rationale for animal assignment: After the quarantine period, the animals were divided in groups of 10 rats/sex by means of a computerised
"adequate stratification method". The fluctuation of body weight means was kept within 20% in each group.
- Post-exposure recovery period in satellite groups: 2 additional groups of 10 rats/sex were exposed to 0 and 50,000 ppm for 4 weeks and
subsequently kept for a 2-week recovery period.

Positive control:
No

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: before exposure period. day 1, 2 and 5 on the 1st week of exposure. Weekly as from the second week of exposure
and throughout the exposure and the recovery period till to the day before termination.

FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes, weekly

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at termination
- Anaesthetic used for blood collection: Yes
- Animals fasted: Yes 12-24 h before the withdrawal
- How many animals: all
- Parameters checked in table 1 were examined.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at termination
- Animals fasted: Yes, 12-24 h before the withdrawal
- How many animals: All
- Parameters checked in table 2 were examined.

URINALYSIS: Yes
- Time schedule for collection of urine: 5th day of the 4th and 6th weeks
- Metabolism cages used for collection of urine: No data
- Animals fasted: No data
- Parameters examined: see table 3
Sacrifice and pathology:
ORGAN WEIGHT: Yes, see table 4

GROSS PATHOLOGY: At the end of the study all animals were subjected to gross pathology examination

HISTOPATHOLOGY: Yes, see table 5

Other examinations:
PEROXISOME PROLIFERATION:
- the livers of all animals exposed to 0 and 50,000 ppm were checked for peroxisome proliferation.

Statistics:
Dunnett's test was used for determining the significant difference of test values of bodyweight, food consumption, blood chemistry, haematology
and organ weight. The X2 test was used for determining the significant differences of urinary test values. T-test was used for the statistical analysis of the recovery groups parameters and for determining the significant differences

Results and discussion

Results of examinations

Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
no effects observed
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
no effects observed
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
no effects observed
Details on results:
CLINICAL SIGNS AND MORTALITY
No mortality was observed. Skin ulcer was observed for one female of high-dose group during treatment and recovery period. No other clinical
signs were observed

BODY WEIGHT AND WEIGHT GAIN
There were no differences in body weight among the treated groups and the control group.

FOOD CONSUMPTION
There were no differences in food consumption among the treated groups and the control group.

FOOD EFFICIENCY
--

WATER CONSUMPTION
--

OPHTHALMOSCOPIC EXAMINATION
--

HAEMATOLOGY AND CLINICAL CHEMISTRY (Tab 6)
A statistically higher mean corpuscolar haemoglobin concentration (MCHC) was measured in the males of high dose group, compared to control.
however no dose dependence was observed. No haematological changes were observed in treated animals in comparison to controls at the end of
the recovery period.
Males of high-dose group had a statistically higher concentration of plasma phospholipids compared to control.
Males exposed to 5000 and 15000, but not 50000 ppm had a lower albumine content.
Males of the exposed recovery group had a statistically higher plasma albumine and total protein values compared to control recovery group.

URINALYSIS
No treatment related findings were observed in urinalysis

NEUROBEHAVIOUR
--

ORGAN WEIGHTS
No treatment related findings were observed.

GROSS PATHOLOGY
No dose-related changes were observed in treated animals at the end of exposure and recovery period.

HISTOPATHOLOGY
No compound related changes were found at the end of exposure and recovery periods.

OTHER FINDINGS: Peroxisome proliferation
A higher activity was measured in liver samples of male high-dose group in comparison to control. However the female high-dose group had a lower activity compared to control.

Effect levels

Dose descriptor:
NOAEL
Effect level:
>= 50 000 ppm
Sex:
male/female
Basis for effect level:
body weight and weight gain
clinical biochemistry
clinical signs
food consumption and compound intake
gross pathology
haematology
histopathology: non-neoplastic
mortality
organ weights and organ / body weight ratios
urinalysis

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

 Table 6.Findings in haematology and blood chemistry in males (**=p<0.01; *=p<0.05)

Main group

MCHC(g/dl) 

Albumin(g/dl) 

Phopsholipid(mg/dl) 

 control

34.0+/-0.3

 3.8+/-0.1 

98+/-14

 5000 ppm

34.8+/-0.3

3.7+/-0.1*

98+/-10

 15000 ppm

 34.5+/-0.3 

3.7+/-0.1*   

103+/-12 

 50000 ppm

34.5 +/-0.4**

3.8 +/-0.1

113+/-14* 

 RECOVERY

 

 

 

 control

34.8+/-1.3 

6.1 +/-0.2

115 +/-14

 50000 ppm

34.2+/-0.4

6.3+/-0.2* 

114+/-22 

Applicant's summary and conclusion

Conclusions:
50,000 ppm was considered the NOAEL of the study.
Executive summary:

Groups of 10 male and 10 female Sprague Dawley rats were exposed to 0, 5000, 15,000 and 50,000 ppm (0, 24,544, 73,632 and 245,440 mg/m3) HFC-125 for 28 days (6 hours/day, 5 days/week).  Two additional groups were exposed to 0 and 50,000 ppm HFC-125 and were allowed to recover for two weeks after the exposure period.

No mortality was observed in this study.  There were no treatment-related clinical signs of toxicity and differences in body weight and food consumption among the treated and the control groups, neither after the exposure nor after the recovery period.  Some effects were observed in the haematology and blood chemistry analysis.  In particular, a very slight, not dose-related increase in mean corpuscular haemoglobin concentration was measured in the males of all the treatment groups at the end of the exposure period; only the increase at the highest dose was statistically significant in comparison with the controls.  Males exposed to 5,000 and 15,000, but not to 50,000 ppm, showed a slightly lower serum albumin content. A slight increase in serum phospholipids concentration was measured in the males of high-dosed group, at the end of exposure period.  No haematological findings were observed in the recovery groups.  Neither macroscopic nor microscopic changes were observed during gross pathology and histological examinations, respectively.  Study of peroxisomal proliferation gave equivocal results, since a slightly higher activity of peroxisomal beta-oxidation was measured in the males of the high-dosed group in comparison to control; while a lower activity was measured in the females of the same group. 50,000 ppm was considered the NOAEC of this study in view of the low toxicological relevance of most of the observed effects.