Registration Dossier

Administrative data

Description of key information

A reliable OECD 407 study is available conducted in accordance with GLP.

Key value for chemical safety assessment

Toxic effect type:
dose-dependent

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records
Reference
Endpoint:
short-term repeated dose toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 5 February 2007 to 24 August 2007
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
No analytical validation of doses
Reason / purpose for cross-reference:
reference to same study
Qualifier:
according to guideline
Guideline:
OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.7 (Repeated Dose (28 Days) Toxicity (Oral))
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
(19 December 2006)
Limit test:
no
Species:
rat
Strain:
Wistar
Remarks:
WU (Crl: WI(WU), outbred)
Details on species / strain selection:
The rat was used because this species is considered suitable for this type of study, and is usually required by regulatory agencies.
This strain was used because it is routinely used at the testing facility for this type of studies.
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Females nulliparous and non-pregnant: no data
- Age at study initiation: Six weeks old
- Weight at study initiation: From 162 to 196 g for males and from 113 to 132 g for females
- Fasting period during study: yes for the collection of blood from fasted rats at necrospy
- Housing: The rats were housed in macrolon cages with wood shavings, (Lignocel, type 3/4, Rettenmaier, Rosenberg, Germany) as bedding material and shreds of paper as environmental enrichment (Enviro-dri, Lillico, Betchworth, England). The cages and bedding were changed weekly. Each cage contained 5 males or 5 females (groups 1-4) or up to 3 males or 3 females (reserve rats/ positive control group). The cages were divided over the cage racks in Latin square order. On the day of FOB testing and motor activity assessment, the animals were temporarily kept singly in macrolon cages.
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: yes, 14 days

DETAILS OF FOOD AND WATER QUALITY: The rats were fed a commercial rodent diet (Rat & Mouse No. 3 Breeding Diet, RM3) obtained from SDS, Special Diets Services, Witham, England. Each batch of the RM3 diet is analysed by the supplier for nutrients and contaminants. During the study, the feed was provided as a powder in stainless steel cans, covered by a perforated stainless steel plate that served to prevent spillage.
Each cage was supplied with domestic mains tap-water suitable for human consumption (quality guidelines according to Dutch legislation based on EC Council Directive 98/83/EC).

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21-24°C
- Humidity (%): 40-70%
- Air changes (per hr): 10 per hour
- Photoperiod (hrs dark / hrs light): 12 hours light, 12 hours dark

IN-LIFE DATES: From: 31 January 2005 To: 13 March 2005
Route of administration:
oral: gavage
Vehicle:
other: Corn oil (5 ml/kg bw)
Details on oral exposure:
PREPARATION OF DOSING SOLUTIONS: The test substance was administered once daily by oral gavage, as a dilution in corn oil for 28 consecutive days. Controls were treated with vehicle (corn oil) only.

Dilutions of the test substance in the vehicle were prepared weekly, and stored in tightly closed plastic vials (one vial per group per day) in a refrigerator (2-10°C). The vehicle for dosing the controls was stored similarly.
The test substance was formulated as a dilution in corn oil. Prior to use, any possible traces of water in the corn oil were removed by adding Zeolite 4A (Zeochem AG, CH-8707 Uetikon, Switzerland) to the corn oil, and gently stirring on a magnetic stirrer.
To avoid any contact with moisture, the formulations were prepared and portioned in a glove bag (Aldrich AtmosBag Z530220-1EA) flushed with nitrogen. The vehicle for the controls was handled similarly.
The formulations were prepared as follows:
*High-dose dilution:
- To obtain the high-dose level used during day 0, 1 and 2 (40 mg/mL), eight gram of Monofluoroetbylene carbonate was added to an appropriate volume of corn oil (about 50% of the intended final volume) and stirred on a magnetic stirrer. Then the volume was made up with corn oil to 200 mL and stirred again, until visibly homogeneous.
- The high-dose dilutions used during day 3 - 6 (20 mg/mL) were obtained by 1:1 diluting the above high-dose dilution with corn oil.
- To obtain the high-dose level used from day 7 (20 mg/mL), five gram of Monofluoroethylene carbonate was added to an appropriate volume of corn oil (about 50% of the intended final volume) and stirred on a magnetic stirrer. Then the volume was made up with corn oil to 250 mL and stirred again, until visibly homogeneous.
*Lower dose dilutions:
The lower dose levels (8 mg/mL and 2 mg/mL) were obtained by mixing the high-dose dilution with the appropriate volumes of corn oil, and subsequent stirring on a magnetic stirrer.

VEHICLE
- Concentration in vehicle: 10, 40 and 200/100 mg/kg bw/day
- Amount of vehicle (if gavage): 5 mL/kg body weight/day
Analytical verification of doses or concentrations:
no
Duration of treatment / exposure:
Test duration: 28 days
Frequency of treatment:
The frequency of dosing was once daily (7 days/week). Twice weekly, the dose volumes were adjusted to the latest recorded body weights for each individual rat, to maintain a constant dose level in terms of the animal's body weight.
Dose / conc.:
0 mg/kg bw/day (nominal)
Remarks:
Control group (Corn oil)
Dose / conc.:
10 mg/kg bw/day (nominal)
Remarks:
Low-dose group
Dose / conc.:
40 mg/kg bw/day (nominal)
Remarks:
Mid-dose group
Dose / conc.:
200 mg/kg bw/day (nominal)
Remarks:
High-dose group from day 0 to day 2
Dose / conc.:
100 mg/kg bw/day (nominal)
Remarks:
High-dose group from day 3
Because of mortality and weight loss in high-dose rats, the high-dose level was reduced to 100 mg/kg body weight/day from day 3 of the study.
No. of animals per sex per dose:
5 males and females per group
For the high-dose group, one male and one female that were found dead were replaced by reserve rats from day 3.
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: The dose-levels were selected in agreement with the Sponsor, on the basis of the results of a preliminary 7-day range-finding toxicity study by oral route (dose-levels: 0, 10, 30 and 100 mg/kg bw/day) performed in the same species (TNO Study Number 7336/01).
The daily oral administration of Monofluoroethylene carbonate to male rats, at levels up to 100 mg per kg body weight during 7 consecutive days, was well tolerated by the rats.
There were no treatment-related clinical signs or mortality. Growth, feed and water intake, organ weights or macroscopic findings at necropsy were not affected by the administration of the test substance in any group.
Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: At least once a day
All abnormalities, signs of ill health or reactions to treatment were recorded.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Detailed clinical observations outside the home cage were performed once weekly starting in the week before the start of the treatment.

BODY WEIGHT: Yes
- Time schedule for examinations: The body weight of each animal was recorded twice a week, starting at day 0 (initiation of treatment). In addition, final (fasted) body weights were determined on the day of scheduled necropsy (day 28).

FOOD CONSUMPTION:
Food consumption was measured per cage by weighing the feeders, starting at initiation of treatment (day 0). The consumption was measured over successive periods of 3 or 4 days. The results were expressed in g per animal per day.

WATER CONSUMPTION:
Possible differences in water consumption between groups were assessed by visual inspection of the drinking bottles.

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: At the end of the treatment period.
- Anaesthetic used for blood collection: Yes, C02/02 anaesthesia
- Animals fasted: Yes, for an overnight period before necropsy
- How many animals: All animals
- Parameters checked in table 1 (attached document) were examined.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: At the end of the treatment period.
- Animals fasted: Yes, for an overnight period before necropsy
- How many animals: All animals
- Parameters checked in table 2 (attached document) were examined.

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: In week 4
- Dose groups that were examined: All animals
- Battery of functions tested: Functional Observational Battery and motor activity

IMMUNOLOGY: No
Sacrifice and pathology:
GROSS PATHOLOGY: Yes
The animals were examined for macroscopic changes.

ORGAN WEIGHT: Yes
The following organs of all animals killed on day 28 were weighed (paired organs together) as soon as possible after dissection to avoid drying. Relative organ weights were calculated from the absolute organ weights and the terminal body weight:
adrenals
brain
epididymides
heart
kidneys
liver
spleen
testes
thymus

HISTOPATHOLOGY: Yes (see table 3 in the attached document)
Histopathological examination (by light microscopy) was performed on all tissues and organs listed below, of all animals of the control group and the high-dose group (1). Gross lesions were examined microscopically in all rats of all dose groups. On the basis of pathological findings in the high-dose group, the examination of the stomach was extended to all rats of all dose groups. Examination of the kidneys was extended to the lower-dose groups to elucidate the significance of some (background) pathological findings in the high-dose group.
(1) The two rats that were found dead on day 3 were not examined microscopically because relevant tissue was not available. Instead, the 2 substituting animals (treated from day 3) were examined microscopically.

List:
adrenals
axillary lymph nodes
brain (2)
caecum
colon
duodenum
epididymides
GALT (gut associated lymphoid tissue, including Peyer's patches)
heart
ileum
jejunum
kidneys
liver
lungs
mesenteric lymph nodes
nerve-peripheral (sciatic)
oesophagus
ovaries
prostate
rectum
spinal cord (3)
spleen
sternum with bone marrow
stomach (4)
testes
thymus
thyroid witb parathyroids
trachea/bronchi
urinary bladder
uterus (with cervix)
vagina

(2): three levels were examined microscopically (brain stem, cerebrum, cerebellum).
(3): retained in vertebral column, at least three levels were examined microscopically (cervical, midthoracic and lumbar).
(4): Non glandular ('forestomach') and glandular (fundus, pylorus) parts were examined.



Other examinations:
NECROPSY OF INTERCURRENT DEATHS
High-dose female 23 and high-dose male 40, were found dead on day 3 of the study, and were replaced by reserve animals. Because of cannibalism, macroscopic and microscopic examination of the decedent rats was not possible. Necropsy was conducted on high-dose male 38, which was found dead on day 5 of the study. Also in this case, however, macroscopic examination and collection of tissues were seriously hampered by cannibalism. As far as possible, the tissues of animal 38 were collected and preserved in a neutral aqueous phosphate-buffered 4 per cent solution of formaldehyde.
Statistics:
The following procedures were used to evaluate the results:
- Body weights, clinical pathology data measured on continuous or semi-continuous scales, organ weights: an automatic Decision Tree which determines whether a dose-related trend is present and, if so, the lowest dose level affected. Where there is no trend effect, possible statistically significant differences between the control and treatment groups are identified. For body weights, the pre-treatment ( day - 1) body weight is used as covariate.

The Decision Tree process is summarized in an attached document.

Clinical signs:
no effects observed
Description (incidence and severity):
The other findings observed were common for rats of this strain and age, and occurred at random incidence. Therefore they were not ascribed to the treatment.
Mortality:
mortality observed, treatment-related
Description (incidence):
Two rats of the high-dose group (female 23 and male 40) were found dead on day 3 of the study, following dosing with 200 mg/kg bw/day on days 0, 1 and 2. Post-dosing signs observed in these rats on day 1 and/or day 2 were piloerection and/or lethargy. These two rats were replaced by reserve animals, and from day 3 of the study the high-dose levels was reduced to 100 mg/kg bw/day.
On day 5 of the study, another male of the high-dose group (male 38) was found dead. Signs noted in this rat were a.o. piloerection, lethargy, salivation, blepharospasm and hypothermia.
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
Up to day 3 of the study, the treated rats of the high-dose group (200 mg/kg bw/day) lost weight or showed distinct growth retardation. Hence, on day 3 of the study, body weights of high-dose rats differed statistically significantly from the controls. From day 3, after the high-dose level had been reduced to 100 mg/kg bw/day, the high-dose rats gradually recovered, and from day 14 (females) or 21 (males) the differences with the controls were no longer statistically significant.
There were no other statistically significant differences in body weights among the groups, apart from a fortuitously increased final body weight in low-dose males.
Food consumption and compound intake (if feeding study):
no effects observed
Description (incidence and severity):
Food intake was considerably decreased in the high-dose group in the first week of the study (in females up to day 3; in males up to day 7). There were no other noticeable differences in food intake between the test groups and the controls.
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
no effects observed
Description (incidence and severity):
Visual inspection of the drinking bottles did not reveal any differences in water consumption between groups.
Ophthalmological findings:
not examined
Haematological findings:
effects observed, non-treatment-related
Description (incidence and severity):
* Red blood cell variables and clotting potential: Prothrombin time was statistically significantly decreased in males of ail dose groups.
The percentage of reticulocytes was slightly, though statistically significantly increased in high-dose males.
* Total and differential white blood cell counts: The percentage of neutrophils was statistically significantly increased in the high-dose group in both sexes white the percentage of lymphocytes tended to be decreased (statistically significant in high-dose males only). These changes were reflected in an increase in the absolute number of neutrophils in the high-dose group (statistically significant in high-dose males only).
The absolute number and the percentage of monocytes were statistically significantly increased in high-dose males.
Clinical biochemistry findings:
effects observed, non-treatment-related
Description (incidence and severity):
A number of changes in clinical chemistry variables reached the level of statistical significance, viz:
- Glucose concentration was increased in high-dose females.
- lnorganic phosphate concentration was increased in mid-dose and high-dose males.
- Potassium concentration was increased in high-dose males.
- The albumin/globulin ratio was slightly increased in high-dose males. The parameters from which this calculated value was derived were not significantly affected.
Urinalysis findings:
not examined
Behaviour (functional findings):
no effects observed
Description (incidence and severity):
The results of the neurobehavioural observations and motor activity assessment did not indicate any neurotoxic potential of monofluoroethylene carbonate in rats.
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
effects observed, non-treatment-related
Description (incidence and severity):
- The relative weight of the kidneys was markedly increased in the high-dose group in both sexes (statistically significant in high-dose males). The absolute kidney weight was statistically significantly increased in high-dose females.
- The relative weight of the liver was statistically significantly increased in high-dose females. The relative weight of this organ was also increased in males of the low-and mid-dose group, while the absolute liver weight was increased in low-dose males.
The significance of these findings in males is doubtful because they were not confirmed in high-dose males and, in the mid-dose group, was due to only one animal showing a very high value.
- The absolute weight of the spleen was statistically significantly increased in low-dose males. This change was neither reflected in significant changes in the relative weight of this organ, nor confirmed at higher dose-levels, and is probably due to a higher terminal weight of low-dose males.
Gross pathological findings:
effects observed, non-treatment-related
Description (incidence and severity):
Gross examination of the surviving rats revealed erosion(s) in the stomach of 3 high-dose females. Haemorrhage(s) in the stomach were observed in a few animals including one male control. The other changes occurred at random incidence and represent common background pathology in rats of this strain and age.
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Description (incidence and severity):
Microscopic examination revealed treatment-related changes in the stomach of mid-, and high-dose rats. Hyperplasia (thickening) of the epithelium of the non-glandular stomach was noted in all surviving rats of the high-dose group and in most rats of the mid-dose group. In the high-dose group, this finding was associated with focal (slight to severe) inflammation of the stomach wall (the severity score of the inflammation depending on its extension, viz subepithelial to transmural (throughout the wall) mixed inflammatory cell infiltrate with or without ulceration). In the mid-dose group, only slight indications of inflammation of the non-glandular stomach (scored as (very) slight focal subepithelial mononuclear cell infiltrate) were noted in two males only.
The other microscopic observations are common findings in rats of this strain and age. They occurred only incidentally or at random or similar incidences amongst the groups including controls and were, therefore, not considered to be related to treatment.
Histopathological findings: neoplastic:
not examined
Details on results:
The administration of Monofluoroethylene carbonate by daily oral gavage resulted in local effects in the non-glandular stomach (hyperplasia of the epithelium) in most rats of the mid-dose group and in all surviving rats of the high-dose group. This finding was associated with focal inflammation of the stomach wall in all rats of the high-dose group, while minimal indications of inflammation (focal subepithelial mononuclear cell infiltrate) were noted in two males of the mid-dose group. The changes in differential white blood cell counts (increases in neutrophils and monocytes) in this group may be secondary to the inflammatory process. Similarly, the slight increase in reticulocytes in males of the high-dose group might be associated with ulceration of the stomach wall.

No toxicological significance was attached to the slightly decreased prothrombin time in males of all treatment groups, because these findings occurred in one sex only and the values were within the range of recent historical control data (overall mean: 35.0 sec, lowest mean: 29.7 sec, highest mean: 40.5 sec; n=12). Moreover, in case of liver damage, prothrombin time is prolonged rather than shortened. Therefore, the slightly shortened prothrombin time in males of all treatment groups was not ascribed to treatment.

The increase in relative weight of the kidneys in the high-dose group was not accompanied by treatment related changes in renal morphology. However, because the mean weight of this organ was markedly (13-15%) increased in both sexes, this finding is ascribed to the treatment.

The relevance of the increased inorganic phosphate concentration in mid-dose and high-dose males is unclear. Hyperphosphatemia is usually secondary to inability of the kidneys to excrete phosphate, but histopathological examination of the kidneys did not reveal treatment-related changes. The mean values were not clearly within the range of recent historical control data (overall mean: 2.9 mmol/L, lowest mean: 1.9 mmol/L, highest mean: 3.5 mmol/L; n=20). Therefore these changes in males of the mid- and high-dose group are prudently ascribed to the treatrnent.

The increase in relative weight of the liver in high-dose females was only slight and not accompanied by treatment-related histopathological changes in this organ. Therefore this finding may be fortuitous.
Key result
Dose descriptor:
NOAEL
Effect level:
10 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
histopathology: non-neoplastic
Key result
Critical effects observed:
yes
Lowest effective dose / conc.:
40 mg/kg bw/day (nominal)
System:
gastrointestinal tract
Organ:
stomach
Treatment related:
yes
Dose response relationship:
yes
Relevant for humans:
not specified

Table 1: Mean body weights (g)

Males

Group

Sex

 

Day numbers relative to Start Date

-1

0

3

7

10

14

17

21

24

27

28(3)

1M

Mean

S.D.

N

170.96

9.48

5

175.14

10.40

5

198.10

10.82

5

219.72

11.27

5

240.76

11.16

5

259.00

11.41

5

271.10

12.79

5

286.44

13.84

5

296.96

13.15

5

309.36

13.02

5

292.52

12.97

5

2M

Mean

S.D.

N

172.04

9.25

5

178.32

10.90

5

198.72

10.90

5

224.04

13.86

5

247.78

12.98

5

271.80

13.66

5

284.72

13.49

5

302.42

14.82

5

316.86

14.36

5

330.62

15.35

5

313.92*

14.79

5

3M

Mean

S.D.

N

171.92

10.88

5

177.34

11.55

5

199.70

11.63

5

226.72

13.02

5

247.68

15.28

5

263.68

13.44

5

279.38

15.51

5

297.22

19.95

5

307.10

21.51

5

317.16

22.49

5

304.10

21.06

5

4M

Mean

S.D.

N

170.08

8.48

4(1)

174.35

9.34

4(1)

155.25*

10.33

4(1)

185.35**

31.33

4(2)

212.18**

26.54

4(2)

235.20**

25.93

4(2)

251.03**

22.72

4(2)

272.60

21.09

4(2)

285.73

21.85

4(2)

296.43

21.72

4(2)

280.73

21.97

4(2)

Females

1F

Mean

S.D.

N

116.28

3.78

5

118.64

4.14

5

133.74

3.91

5

145.58

4.84

5

158.04

7.19

5

171.48

8.53

5

179.22

7.89

5

186.30

9.89

5

195.62

13.24

5

198.06

11.46

5

186.98

11.33

5

2F

Mean

S.D.

N

115.90

3.57

5

119.82

4.83

5

134.00

4.77

5

148.44

5.33

5

159.98

7.96

5

171.28

9.17

5

176.08

9.66

5

185.70

7.71

5

196.88

9.29

5

197.58

12.11

5

187.22

10.90

5

3F

Mean

S.D.

N

115.62

3.99

5

119.00

4.27

5

133.96

5.90

5

148.06

7.10

5

159.20

6.38

5

170.82

7.52

5

178.90

8.13

5

190.60

8.75

5

199.16

9.92

5

201.22

8.75

5

191.50

8.89

5

4F

Mean

S.D.

N

115.75

3.90

4(1)

118.98

4.04

4(1)

115.68**

7.84

4(1)

137.56**

9.97

5

151.34*

9.19

5

166.96

9.24

5

172.10

5.95

5

182.16

6.40

5

194.74

7.36

5

193.52

5.05

5

184.44

4.02

5

Group 1 – Control

Group 2 – 10 mg/kg bw/day

Group 3 – 40 mg/kg bw/day

Group 4 – 200 mg/kg bw/day on day 0, 1 and 3 then 100 mg/kg bw/day from day 3

Statistical analysis (default decision tree; covariate: day -1 body weight): * = p < 0.05; ** = p < 0.01

(1): Because of the death of two rats of the high-dose group (female 23 and male 40), the high-dose level was reduced from day 3 of the study. The two decedents were replaced by reverse rats which were treated from day 3 of the study. The data obtained in the decedent rats up to day 3 are not summarized in this table.

(2): One high-dose male (male 38) was found dead on day 5 of the study (and was not replaced)

(3): Body weights after overnight fasting

Legend of the following tables (below):

Group 1 – Control

Group 2 – 10 mg/kg bw/day

Group 3 – 40 mg/kg bw/day

Group 4 – 200 mg/kg bw/day on day 0, 1 and 3 then 100 mg/kg bw/day from day 3

Statistical analysis (default decision tree): * = p < 0.05; ** = p < 0.01

(1): Two rats of the high-dose group (female 23 and male 40) substituted decedent animals, and were treated from day 3.

Table 2: Mean haematological findings in blood collected from the abdominal aorta at necropsy

Males

Group

Sex

 

Prothrom

Time

Lymphocytes

Neutrophils

Monocytes

s

%

%

%

1M

Mean

S.D.

N

36.32

2.20

5

91.68

1.72

5

5.64

1.55

5

1.12

0.26

5

2M

Mean

S.D.

N

33.76*

0.87

5

90.86

0.90

5

6.14

0.90

5

1.28

0.20

5

3M

Mean

S.D.

N

32.70**

1.54

5

89.92

2.09

5

6.74

1.62

5

1.34

0.30

5

4M

Mean

S.D.

N(1)

31.98**

1.25

4

85.95**

3.28

4

10.45**

3.09

4

1.95**

0.47

4

Females

1F

Mean

S.D.

N

31.00

1.04

5

91.46

1.61

5

5.80

1.62

5

1.18

0.42

5

2F

Mean

S.D.

N

31.50

1.14

5

92.62

0.92

5

4.20

0.60

5

1.30

0.28

5

3F

Mean

S.D.

N

31.46

1.14

5

92.66

1.30

5

4.50

1.37

5

1.10

0.32

5

4F

Mean

S.D.

N(1)

30.80

0.58

5

86.24

7.49

5

10.86*

7.42

5

1.22

0.24

5

Table 3: Mean results of clinical chemistry in plasma collected from the abdominal aorta at necropsy

Males

Group

Sex

 

Albumin / Globulin

Glucose Plasma

PO4

K

 

mmol/L

mmol/L

mmol/L

1M

Mean

S.D.

N

1.092

0.067

5

6.876

0.300

5

3.232

0.152

5

5.28

0.29

5

2M

Mean

S.D.

N

1.058

0.066

5

7.770

0.614

5

3.304

0.092

5

5.20

0.22

5

3M

Mean

S.D.

N

1.162

0.066

5

7.896

0.712

5

3.442*

0.079

5

5.38

0.13

5

4M

Mean

S.D.

N(1)

1.230*

0.103

4

6.710

0.865

4

3.720**

0.344

4

5.73*

0.22

4

Females

1F

Mean

S.D.

N

1.296

0.065

5

5.662

0.835

5

2.924

0.210

5

5.22

0.23

5

2F

Mean

S.D.

N

1.238

0.022

5

6.314

1.190

5

3.096

0.186

5

5.22

0.38

5

3F

Mean

S.D.

N

1.252

0.077

5

5.752

0.726

5

3.112

0.113

5

5.26

0.30

5

4F

Mean

S.D.

N(1)

1.222

0.031

5

6.876*

0.314

5

3.088

0.116

5

5.56

0.30

5

Table 4: Mean terminal body weights (g), absolute organ weights (g) and relative organ weights (g/kg body weight)

Males

Group

Sex

 

Body weight

Kidneys

Liver

Spleen

Kidneys relative

Liver relative

g

g

g

g

g/kg bw

g/kg bw

1M

Mean

S.D.

N

292.52

12.97

5

1.984

0.160

5

9.172

0.401

5

0.5422

0.0471

5

6.786

0.558

5

31.34

0.59

5

2M

Mean

S.D.

N

313.92*

14.79

5

2.224

0.201

5

10.770*

0.509

5

0.6280*

0.0360

5

7.080

0.481

5

34.32*

0.71

5

3M

Mean

S.D.

N

304.10

21.06

5

2.060

0.160

5

10.246

1.470

5

0.6044

0.0502

5

6.778

0.370

5

33.56*

2.35

5

4M

Mean

S.D.

N(1)

280.73

21.97

4

2.180

0.020

4

8.865

0.489

4

0.5503

0.0470

4

7.803**

0.585

4

31.63

1.46

4

Females

1F

Mean

S.D.

N

186.98

11.33

5

1.368

0.081

5

5.526

0.577

5

0.4058

0.0478

5

7.348

0.768

5

29.52

1.77

5

2F

Mean

S.D.

N

187.22

10.90

5

1.330

0.080

5

5.520

0.396

5

0.3890

0.0355

5

7.104

0.111

5

29.48

1.08

5

3F

Mean

S.D.

N

191.50

8.89

5

1.362

0.050

5

5.576

0.461

5

0.4490

0.0648

5

7.116

0.213

5

30.06

1.34

5

4F

Mean

S.D.

N(1)

184.44

4.02

5

1.532*

0.158

5

5.964

0.219

5

0.4126

0.0253

5

8.312

0.919

5

32.32**

1.04

5

Conclusions:
Because the administration of the low-dose level did not induce any changes that were considered to be of toxicological significance, the no-observed-adverse-effect level (NOAEL) in the present study is placed at 10 mg monofluoroethylene carbonate/kg body weight/day.
As the effects observed in stomach are a local effect (hyperplasia of the epithelium), no classification is warranted.
Executive summary:

The toxicity of Monofluoroethylene carbonate was examined in a repeated-dose (28 -day) oral toxicity study with four groups of 5 male and 5 female Wistar rats. The test substance was administered as a dilution in corn oil by daily gastric gavage at levels of 0 (vehicle controls), 10, 40 and 200 mg/kg body weight/day. Because of mortality and weight loss in high-dose rats, the high-dose level was reduced to 100 mg/kg body weight/day from day 3 of the study.

One male and one female rat of the high-dose group were found dead on day 3 of the study, following dosing with 200 mg/kg bw/day on days 0, 1 and 2. Post-dosing signs observed in these rats were piloerection and lethargy. (These two rats were replaced by reserve animals, which were treated with 100 mg/kg bw/day from day 3 of the study).

On day 5 of the study, another male of the high-dose group was found dead. Signs noted in this rat were piloerection, lethargy, salivation, blepharospasm and coldness.

There were no other treatment-related clinicat signs.

Neurobehavioural observations and motor activity assessment did not indicate any neurotoxic potential of the test substance.

Up to day 3 of the study, the treated rats of the high-dose group (200 mg/kg bw/day) lost weight or showed distinct growth retardation. From day 3, after the high-dose level had been reduced to 100 mg/kg bw/day, the high-dose rats gradually recovered, and from day 14 (females) or 21 (males), body weights in this group did no longer differ from the controls. Food intake was considerably decreased in the high-dose group in the first week of the study only.

Haematology was conducted in all surviving rats at the end of the treatment period.

Prothrombin time was decreased in males of all dose groups. The percentage of reticulocytes was slightly increased in high-dose males.

The absolute number and the percentage of neutrophils were increased in the high-dose group in both sexes. The percentage of lymphocytes was decreased, and the absolute number and the percentage of monocytes were increased in high-dose males.

Clinical chemistry was conducted in all surviving rats at the end of the treatment period.

Inorganic phosphate concentration was increased in mid-dose and high-dose males. Glucose concentration was increased in high-dose females. Potassium concentration and the albumin/globulin ratio were increased in high-dose males.

The relative weight of the kidneys was increased in the high-dose group in both sexes. The relative weight of the liver was increased in high-dose females. The relative weight of this organ was also increased in males of the low-and mid-dose group, but this finding was not confirmed in high-dose males.

Gross examination at necropsy revealed erosion(s) in the stomach of 3 high-dose females. Upon histopathological examination, thickening of the epithelium (epithelial hyperplasia) of the non-glandular stomach was noted in all surviving rats of the high-dose group and in most rats of the mid-dose group. In the high-dose group, this finding was associated with focal inflammation of the stomach wall. In the mid-dose group, only slight indications of inflammation of the non-glandular stomach were noted in two males.

It was concluded that the no-observed-adverse-effect level (NOAEL) of Monofluoroethylene carbonate in this study was 10 mg /kg body weight/day.

As the effects observed in stomach are a local effect (hyperplasia of the epithelium), no classification is warranted.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
NOAEL
10 mg/kg bw/day
Study duration:
subacute
Species:
rat
Quality of whole database:
Study conducted in accordance with GLP and OECD guidance. Klimisch score of 2 given as no test substance verification was conducted.
System:
gastrointestinal tract
Organ:
stomach

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Justification for classification or non-classification

With regards to the available OECD 407 study, because the administration of the low-dose level did not induce any changes that were considered to be of toxicological significance, the no-observed-adverse-effect level (NOAEL) is placed at 10 mg monofluoroethylene carbonate/kg body weight/day. As the effects observed in stomach are a local effect (hyperplasia of the epithelium), no classification is warranted. In the available OECD 421 study, similar effects in the stomach were observed with the NOAEL placed at 5 mg/kg/day based on the doses utilised. As before the effects in the stomach were considered local effects and no classification with respect to this organ is warranted.

With regards to the OECD 421 study, effects on the teeth (fluorosis of the maxillary incisor) were noted at 15 and 50 mg/kg/day. The guidance values (effective dose causing an adverse effect) included in CLP to assist in classification are; Category 1 ≤ 30 mg/kg/day and Category 2 > 30 ≤ 300 mg/kg/day (for a sub-acute study).

 

In this particular study the NOAEL falls below the cut off value (i.e. < 30 mg/kg/day) as well as the effective dose and accordingly STOT RE Category 1 in relation to the teeth is appropriate for this substance.