2-furoic acid

Endpoint summary

Description of key information

Repeated dose toxicity:oral:

Groups of 12 male and 12 female rats were fed 0, 0.1, 0.5, 0.8 or 1.2% fumaric acid, and groups of 12 male rats were fed 0, 0.5, 1 or 1.5% fumaric acid for 2 years.A very slight increase in mortality rate and some testicular atrophy was observed after administration of 1.5% fumaric acid (approximately 750 mg/kg bw/day). Gross and microscopic examination of major organs revealed no abnormalities. Two rats receiving 1% or 0.5% had stomach inflammation. The authors of this study concluded that inanition was partly responsible for testicular atrophy. In the study with female rats, no adverse effects on reproductive organs were observed after administration of up to 1.2% fumaric acid in the diet. Based on the low incidence of mortality of male rats, 1.2% is very near a NOAEL for chronic exposure to fumaric acid (600 mg/kg bw). The 1.2% NOAEL (600 mg/kg bw/day) derived from the available long term rat toxicity data was confirmed as the appropriate point of departure by two reviews - The International Programme on Chemical Safety (WHO 1975 Food Additive Series 6) report and the findings of the European Commission DG C Report of the Scientific Committee on animal nutrition on the safety of fumaric acid.

Repeated dose toxicity: inhalation:

The acute inhalation toxicity study need not be conducted because exposure to humans via inhalation route is not likely taking into account due to the low vapour pressure of the test chemical, which is reported to be 13.73 Pa. = 0.103 mmHg.Thus, exposure to inhalable dust, mist and vapour of the chemical is highly  unlikely. Therefore this study is considered for waiver.

Repeated dose toxicity: Dermal:

The acute dermal toxicity value for test chemical (as provided in section 7.2.3) is >2000 mg/kg body weight. Given the use of the chemical; repeated exposure by the dermal route is unlikely since the use of gloves is common practice in industries. Thus, it is expected that test chemical shall not exhibit 28 day repeated dose toxicity by the dermal route. In addition, there is no data available that suggests that test chemical shall exhibit repeated dose toxicity by the dermal route. Hence this end point was considered for waiver.

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:

chronic toxicity: oral

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Justification for type of information:

Data for the target chemical is summarized based on the structurally similar read across chemicals

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

other: As mentioned below

Principles of method if other than guideline:

The study was a chronic exposure feeding study (conducted prior to development of the guidelines), limited to the evaluation of body weight, food consumption and histopathology of the main organs.

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

other: 2.Osborne-Mendel 3.Fischer 344/DuCrj

Sex:

male

Details on test animals or test system and environmental conditions:

2. The animals were male and female weanling rats (21-days) of the Osborn-Mendel strain. All animals were kept in individual cages in a room with temperature and humidity controlled for the duration of the experiment. Animals were given free access to their respective diets and water.

3.Animals: Five-week-old SPF male and female F344/DuCrj rats (Charles River Laboratories Japan,
Inc.) were fed and acclimated for 1 week and then divided into 2 groups. Feeding conditions: White
flakes were used as bedding in a plastic cage. The animals were fed in a animal feeding room of a
semi-barrier system

Route of administration:

other: 2. oral: feed 3.both feed and water

Details on route of administration:

Not specified

Vehicle:

other: 2. cod liver oil added to moisten diet 3. Not specified

Details on oral exposure:

2. Weanling rats (21 days) were fed diets containing fumaric acid for two years. The basic diet consisted of ground commercial rat biscuits with 1% added cod-liver oil. Fumaric acid was mixed with the basic diet using a rotary batch mixer.
3.Experiment I
Calcium lactate was dissolved in ion-exchanged water at concentrations of 5, 2.5, 1.25, 0.6, and
0.3% since it was water-soluble and stable. Each experimental group was given ad libitum one of
these solutions as the drinking water for 13 weeks. The control group was similarly given only ionexchanged water. Each group was given ad libitum elemental diet (CRF-1 manufactured by Orien
tal Yeast Co., Ltd.). The highest dose was set based on the fact that the maximum solubility of this
product in water was 5%. Each 5 male and female rats from each group were used, and all the survi
ving animals were sacrificed for autopsy in the 13th week.
Experiment II
Ten male and ten female were used. Calcium lactate was mixed at 30, 20, 10, 5, and 0% in the stan
dard blend of purified diet [B-blend powder diet (Oriental Yeast Co., Ltd.)] and given ad libitum to the
animals for 20 weeks. Each 5 male and female rats from each group were autopsied in the 8th week
after the start of the experiment, and the remaining rats were sacrificed for autopsy in the 20th week.
Experiment III
Twenty male rats were divided into 2 groups. One group was given the B-blend powder diet, while the
other group was given at libitum the CRF-1 solid diet. The rats in both groups were given ad libitum
ion-exchanged water as the drinking water. Five rats from each group were sacrificed in the 4th week
after the start of the experiment and the remaining rats were sacrificed for autopsy in the 8th week.

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

No data

Duration of treatment / exposure:

2. 2 years
3. 13 weeks

Frequency of treatment:

2. Ad libitum in feed
3.13 weeks

Remarks:

Experiment I(0, 0.1, 0.5, 0.8 and 1.2% nominal in diet)/2

Remarks:

Experiment II(0, 0.5, 1.0, and 1.5% nominal in diet)/2

Remarks:

Experiment I (0, 0.3, 0.6, 1.25, 2.5, 5% in water) /3

Remarks:

Experiment II (0, 5, 10, 20, 30 % in food)/3.

No. of animals per sex per dose:

2. Experiment 1 (0, 0.1, 0.5, 0.8 and 1.2%): 12 males and 12 females per group.
Experiment 2 (0, 0.5, 1.0 and 1.5%): 12 males

3.10

Control animals:

yes, plain diet

Details on study design:

2. Two experiments were conducted concurrently, employing two different dosing regimens. The first experiment included both male and female rats, exposed to 0, 0.1, 0.5, 0.8 and 1.2% fumaric acid in the diet. The second experiment was conducted in order to compare the toxicities of fumaric and maleic acids more closely; male rats were fed diets containing 0, 0.5, 1.0 and 1.5% fumaric or maleic acid.

3.

Positive control:

2.None

Observations and examinations performed and frequency:

2.Individual animal weights and food consumption were determined at weekly intervals.
3.CAGE SIDE OBSERVATIONS: Minimal
BODY WEIGHT: Yes
FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g
food/kg body weight/day: Yes
FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted
averages from the consumption and body weight gain data: No data
WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
HAEMATOLOGY: Yes
- Time schedule for collection of blood: 8 wks / end of study
CLINICAL CHEMISTRY: Yes
URINALYSIS: Yes

Sacrifice and pathology:

2. Gross pathology and histopathology of lung, heart, liver, spleen, pancrease, stomach, small intestine, kidney, adrenal and testis.
Additional structures examined by histopathology include colon, bone marrow, leg bones, leg muscles, lymph nodes, uterus, ovary, thyroid and parathyroid.
3.GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: No data

Other examinations:

None

Statistics:

No details

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

2. Mortality in the high dose group was significant but low mortality rates evident in lower dose groups (detailed information not provided in study report)
3. No data

Mortality:

mortality observed, treatment-related

Description (incidence):

2.Mortality in the high dose group was significant but low mortality rates evident in lower dose groups
3. No data

Body weight and weight changes:

no effects observed

Description (incidence and severity):

2.weight gains recorded for males and females at each dose level showed no treatment related effects (data were presented for 1 year only3. No data

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

2.Food consumption over the first 26 weeks of the study and second 26 weeks were compared for each treatment group. No statistically significant changes observed (no detailed information is included in the study report).
3. No data

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

2.Sporadic findings reported but no treatment relationship established
3. No data

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Details on results:

2. At two years, there were only 2 animals living on 1.5% fumaric acid.; other dose levels had no effect on mortality rate. Animals fed 1.5% fumaric acid showed more atrophy of the testis and 2 rats fed 0.5% and 1.0% fumaric acid showed phlegmonous gastritis.
3. All observed effects could be attributed to calcium overload/imbalance. No lactate toxicity was
observed.

Dose descriptor:

NOEL

Remarks:

2.

Effect level:

ca. 600 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Low incidence of mortality seen at a dose level of 1.5%

Dose descriptor:

NOAEL

Remarks:

3.

Effect level:

50 000 mg/L drinking water

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

Critical effects observed:

not specified

Conclusions:

A NOAEL of (600 mg/kg bw/day) was observed in a 2 year study in Groups of 12 male and 12 female rats.

Executive summary:

Data available for the test chemical and read across chemicals was reviewed to determine the repeated dose oral toxic nature of test chemical. The study is as mentioned below:

1)Groups of 12 male and 12 female rats were fed 0, 0.1, 0.5, 0.8 or 1.2% fumaric acid, and groups of 12 male rats were fed 0, 0.5, 1 or 1.5% fumaric acid for 2 years.A very slight increase in mortality rate and some testicular atrophy was observed after administration of 1.5% fumaric acid (approximately 750 mg/kg bw/day). Gross and microscopic examination of major organs revealed no abnormalities. Two rats receiving 1% or 0.5% had stomach inflammation. The authors of this study concluded that inanition was partly responsible for testicular atrophy. In the study with female rats, no adverse effects on reproductive organs were observed after administration of up to 1.2% fumaric acid in the diet. Based on the low incidence of mortality of male rats, 1.2% is very near a NOAEL for chronic exposure to fumaric acid (600 mg/kg bw). The 1.2% NOAEL (600 mg/kg bw/day) derived from the available long term rat toxicity data was confirmed as the appropriate point of departure by two reviews - The International Programme on Chemical Safety (WHO 1975 Food Additive Series 6) report and the findings of the European Commission DG C Report of the Scientific Committee on animal nutrition on the safety of fumaric acid.

2)In a subchronic toxicity study (similar to OECD 408), Calcium lactate was administered to Fischer 344/DuCrj rats. In Experiment I, Calcium lactate was mixed at 5, 2.5, 1.25, 0.6, and 0.3 % in the drinking water and the rats were given this solution ad libitum for 13 weeks. As a result, the inhibition of body weight gain in the 5% group fell within 10% of that in the control group. Some examination values showed variations in the hematological and hematobiochemical studies, but no controversial findings were obtained in the pathohistological search. Since the highest solubility of Calcium lactate is 5%, experiments II and III were carried out by giving blended diet in order to study the toxicity at higher doses. In experiment II, Calcium lactate was mixed at concentrations of 30, 20, 10, and 5% in the B-blend powder diet and then the rats were given this diet ad libitum for 20 weeks. In experiment III, the rats were given the CRF-1 or the B-blend powder diet ad libitum for 8 weeks. As a result, in experiment II, nephrocalcinosis was observed in all the groups including the control group. The degree of the lesion was in reverse correlation with the administered concentrations of calcium and the lesion was seen more intensely in female rats. In experiment III, nephrocalcinosis resulting from the administration of the B-blend diet was already observed in the 4th week. Nephrocalcinosis as observed in experiments II and III was attributable to the small Ca/P value in the B-blend diet.

From the above results, the optimal dose for a long-term toxicity/carcinogenicity study has been determined to be 5 and 2.5% based on the values obtained from experiment I.

Based on the data available for the target chemical and read across chemical, test chemical is not likely to classify as a toxicant upon repeated exposure by oral route.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

600 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

Data is from K2 peer reviewed publication

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: inhalation

Data waiving:

other justification

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Quality of whole database:

Waiver

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: dermal

Data waiving:

other justification

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Quality of whole database:

Waiver

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Repeated dose toxicity: Oral

Data available for the test chemical and read across chemicals was reviewed to determine the repeated dose oral toxic nature of test chemical. The study is as mentioned below:

1)Groups of 12 male and 12 female rats were fed 0, 0.1, 0.5, 0.8 or 1.2% fumaric acid, and groups of 12 male rats were fed 0, 0.5, 1 or 1.5% fumaric acid for 2 years.A very slight increase in mortality rate and some testicular atrophy was observed after administration of 1.5% fumaric acid (approximately 750 mg/kg bw/day). Gross and microscopic examination of major organs revealed no abnormalities. Two rats receiving 1% or 0.5% had stomach inflammation. The authors of this study concluded that inanition was partly responsible for testicular atrophy. In the study with female rats, no adverse effects on reproductive organs were observed after administration of up to 1.2% fumaric acid in the diet. Based on the low incidence of mortality of male rats, 1.2% is very near a NOAEL for chronic exposure to fumaric acid (600 mg/kg bw). The 1.2% NOAEL (600 mg/kg bw/day) derived from the available long term rat toxicity data was confirmed as the appropriate point of departure by two reviews - The International Programme on Chemical Safety (WHO 1975 Food Additive Series 6) report and the findings of the European Commission DG C Report of the Scientific Committee on animal nutrition on the safety of fumaric acid.

2)In a subchronic toxicity study (similar to OECD 408), Calcium lactate was administered to Fischer 344/DuCrj rats. In Experiment I, Calcium lactate was mixed at 5, 2.5, 1.25, 0.6, and 0.3 % in the drinking water and the rats were given this solution ad libitum for 13 weeks. As a result, the inhibition of body weight gain in the 5% group fell within 10% of that in the control group. Some examination values showed variations in the hematological and hematobiochemical studies, but no controversial findings were obtained in the pathohistological search. Since the highest solubility of Calcium lactate is 5%, experiments II and III were carried out by giving blended diet in order to study the toxicity at higher doses. In experiment II, Calcium lactate was mixed at concentrations of 30, 20, 10, and 5% in the B-blend powder diet and then the rats were given this diet ad libitum for 20 weeks. In experiment III, the rats were given the CRF-1 or the B-blend powder diet ad libitum for 8 weeks. As a result, in experiment II, nephrocalcinosis was observed in all the groups including the control group. The degree of the lesion was in reverse correlation with the administered concentrations of calcium and the lesion was seen more intensely in female rats. In experiment III, nephrocalcinosis resulting from the administration of the B-blend diet was already observed in the 4th week. Nephrocalcinosis as observed in experiments II and III was attributable to the small Ca/P value in the B-blend diet.

From the above results, the optimal dose for a long-term toxicity/carcinogenicity study has been determined to be 5 and 2.5% based on the values obtained from experiment I.

Subacute repeated oral toxicity study was performed to determine the oral toxic nature of test chemical upon repeated exposure for 14 days. The study was performed using male Sprague Dawley rats. The test chemical was dissolved in 1% CMC and used at dose levels of 0 or 20 mg/Kg/day.On day 7 and 14, the animals were bled between 7:30-8:30 a.m. Serum Cholesterol and triglycerides were determined. The animals were sacrificed on day 14. Test chemical at 20 mg/kg/day orally suppressed the serum cholesterol levels 50% and serum triglyceride levels 42% after 14 days in rats. The HDL cholesterol content was elevated 34% on day 14. The VLDL and LDL cholesterol levels were not reduced at this dose. Based on the data available, the No Observed adverse effect level (NOAEL) for test chemical is considered to be 20 mg/Kg bw.

Based on the data available for the target chemical and read across chemical, test chemical is not likely to classify as a toxicant upon repeated exposure by oral route.

Repeated dose toxicity: inhalation:

The acute inhalation toxicity study need not be conducted because exposure to humans via inhalation route is not likely taking into account due to the low vapour pressure of the test chemical, which is reported to be 13.73 Pa. = 0.103 mmHg.Thus, exposure to inhalable dust, mist and vapour of the chemical is highly  unlikely. Therefore this study is considered for waiver.

Repeated dose toxicity: Dermal:

The acute dermal toxicity value for test chemical (as provided in section 7.2.3) is >2000 mg/kg body weight. Given the use of the chemical; repeated exposure by the dermal route is unlikely since the use of gloves is common practice in industries. Thus, it is expected that test chemical shall not exhibit 28 day repeated dose toxicity by the dermal route. In addition, there is no data available that suggests that test chemical shall exhibit repeated dose toxicity by the dermal route. Hence this end point was considered for waiver.

Justification for classification or non-classification

Based on the data available for the target chemical,test chemical is not likely to classify as a toxicant upon repeated exposure by oral route. For repeated inhalation and repeated dermal toxicity wavier was added so, not possible to classify.