2-ethyl-3-hydroxy-4-pyrone

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Remarks:

A ombined chronic toxicity/carcinogenicity and one generation study, in which the animals were mated to produce an F1 litter to assess the reproductive/developmental toxicity. Less animals were used compared to the current OECD Guidelines

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

Comparable to guideline study. Not all the raw study results have been published in the publication, limited information available on methods, 1st generation included, but number of animals is lower than currently required. The study was reviewed by the JECFA (2006) as part of their safety evaluation (JECFA (2006). Safety evaluation of certain food additives. Who Food Additives Series:56. Prepared by the sixty fifth meeting of the Joint FAO/WHO Expert Committee on Food Additives (JECFA). World Health Organization, Geneva

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Reference

Endpoint:

chronic toxicity: oral

Remarks:

Combined Chronic Toxicity / Carcinogenicity Study

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1968

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

Not all the raw study results have been published in the publication, limited information available on methods (no guideline followed, no info regarding dosing preparation). The study was reviewed by the JECFA (2006) as part of their safety evaluation (JECFA (2006). Safety evaluation of certain food additives. Who Food Additives Series:56. Prepared by the sixty fifth meeting of the Joint FAO/WHO Expert Committee on Food Additives (JECFA). World Health Organization, Geneva).The study was also considered valid by the EFSA expert panel (EFSA Journal 2015;13(9):4244).

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 453 (Combined Chronic Toxicity / Carcinogenicity Studies)

Version / remarks:

1981, EFSA assignment

GLP compliance:

no

Remarks:

pre-GLP

Limit test:

no

Species:

rat

Strain:

other: Charles River weanling albino

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River
- Age at study initiation: weanling
- Housing: Individual
- Diet: Ground rat food mixed with the test substance
- Water (e.g. ad libitum): ad libitum

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Mixing appropriate amounts with (Type of food): Rockland Ground Rat Food

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

None

Duration of treatment / exposure:

2 years

Frequency of treatment:

Daily

Dose / conc.:

200 mg/kg bw/day (nominal)

Dose / conc.:

100 mg/kg bw/day (nominal)

Dose / conc.:

50 mg/kg bw/day (nominal)

No. of animals per sex per dose:

25

Control animals:

yes, concurrent no treatment

Details on study design:

10 males and 10 females were mated to produce two separate litters, in order to test reproductive toxicity (described in the endpoint on reproductive toxicity)

Positive control:

not applicable

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes

DETAILED CLINICAL OBSERVATIONS: No

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: 0, 3, 6, 9, 12, 18 and 24 months
- Anaesthetic used for blood collection: Not specified
- Animals fasted: No
- How many animals: 5 males and 5 females per group
- Parameters checked: Hemoglobin, hematocrit, red blood cells, white blood cells, differential count

URINALYSIS: Yes
- Time schedule for collection of urine: 0, 3, 6, 9, 12, 18 and 24 months
- Metabolism cages used for collection of urine: Yes
- Animals fasted: overnight water deprivation, not fasted.
- Parameters checked: color, volume, specific gravity, pH, blood, albumin, glucose, and microscopic examination of the sediment after centrifugation

NEUROBEHAVIOURAL EXAMINATION: No

IMMUNOLOGY: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
The following organs were evaluated: heart, lung, liver, kidney, pancreas, spleen, thymus, mesenteric lymph node, adrenals, thyroid, brain, hypophysis, uterus and ovary;

HISTOPATHOLOGY: Yes
The following tissues were evaluated: brain (sectioned at the optic chiasm, mammillary body, cerebellum, pons, and medulla oblongata), cervical spinal cord, hypophysis, eye, parotid gland, thyroid and parathyroid, thymus, heart, lung, sternum, rib, aorta, liver, spleen, pancreas, kidneys, adrenals, stomach (fore and hind), small and large intestine (four levels), mesenteric lymph node, reproductive tract (all levels), urinary bladder, skeletal muscle, femoral nerve, femoral bone marrow, skin and mammary gland

Statistics:

No data

Clinical signs:

no effects observed

Description (incidence and severity):

All parameters were considered normal.

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Description (incidence and severity):

The body weight of test and control animals evolved in a comparable manner over the 2 year exposure period

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

All parameters were considered normal.

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

One control rat developed anemia (RBC, 1.8 x 10^3 /mm3; hemoglobin, 8.0 % and hematocrit,18.5 %) of unknown etiology.

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

All parameters were considered normal.

Urinalysis findings:

effects observed, non-treatment-related

Description (incidence and severity):

All rats showed a tendency toward albuminuria; All other parameters were considered normal.

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

All parameters were considered normal.

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

Pathologic changes consistent with aged rats were observed primarily in the pulmonary, endocrine, urinary, and cardiovascular systems.

Neuropathological findings:

not examined

Description (incidence and severity):

No specific neurotoxicity examination was performed.

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

Pathologic changes consistent with aged rats were observed primarily in the pulmonary, endocrine, urinary, and cardiovascular systems.

Histopathological findings: neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

Neoplasia occurred in a random manner with no apparent relationship between number, location, or type of tumors and treatment. This was due presumably to the advanced age of the animals.

Other effects:

effects observed, non-treatment-related

Description (incidence and severity):

Ethyl maltol had no effect on fertility, gestation, parturition, lactation, or fetal development. A fall in fertility was noted in test and control groups at the second mating. This was due presumably to the advanced age of the animals.

Key result

Dose descriptor:

NOAEL

Effect level:

>= 200 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: highest dose tested

Key result

Critical effects observed:

no

Refer to Tables 4 -6 in publication attached.

Conclusions:

This chronic oral toxicity study (feeding) in rats (similar to OECDTG 453) did not report any treatment-related effects. Based on these findings, a NOAEL of >=200 mg/kg bw/day was established.

Executive summary:

In a combined chronic toxicity/carcinogenicity study (Gralla et al., 1969), Ethyl Maltol was administered to 4 groups of Charles River weanling albino male and female rats (25/sex/group) in the diet at dose levels of 0, 50, 100 and 200 mg/kg bw/day daily for 2 years.

There were no effects observed on clinical signs, mortality, body weights, food consumption, clinical biochemistry and organ weight. There was a non-treatment-related effect observed on urinalysis; all rats showed a tendency toward albuminuria, with other parameters normal. There were non-treatment-related effects observed on gross pathology and (non)-neoplastic histopathology, due to the advanced age of the animals; changes were consistent with aged rats or there was no apparent relationship between effect and treatment.

The NOAEL (male/female) was >=200 mg/kg bw/day.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1969

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD 415 (A Combined /Chronic Toxicity/Carcinogenicity /study and one generation study; animals were mated to produce an F1 litter to assess the reproductive/developmental toxicity. Less animals were used compared to the current OECD Guidelines)

Deviations:

yes

Remarks:

A Combined /Chronic Toxicity study/Carcinogenicity /study and one generation study, in which the animals were mated to produce an F1 litter to assess the reproductive/developmental toxicity. Less animals were used compared to the current OECD Guidelines

GLP compliance:

no

Remarks:

pre-GLP

Limit test:

no

Test material

Test material information

1

Reference substance name:

2-ethyl-3-hydroxy-4-pyrone

EC Number:

225-582-5

EC Name:

2-ethyl-3-hydroxy-4-pyrone

Cas Number:

4940-11-8

Molecular formula:

C7H8O3

IUPAC Name:

2-ethyl-3-hydroxy-4H-pyran-4-one

Test material form:

solid

Test animals

Species:

rat

Strain:

other: Charles River Weanling Albino

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River
- Age at study initiation: weanling
- Housing: Individual
- Diet: Ground rat food mixed with the test substance
- Water (e.g. ad libitum): ad libitum

Administration / exposure

Route of administration:

oral: feed

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
DIET PREPARATION
- Mixing appropriate amounts with (Type of food): Rockland Ground Rat Food

Analytical verification of doses or concentrations:

not specified

Details on mating procedure:

Between 15 and 21 and 30 and 36 weeks, 10 males and 10 females per level were mated to produce two separate litters.
Age at mating of the mated animals in the study: 15-21 and 30-36 weeks

Duration of treatment / exposure:

2 years

Frequency of treatment:

daily

Duration of test:

2 years

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

200 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

100 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

50 mg/kg bw/day (nominal)

No. of animals per sex per dose:

25

Control animals:

yes, concurrent no treatment

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes

DETAILED CLINICAL OBSERVATIONS: No

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes

FOOD EFFICIENCY: No

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: 3, 6, 9, 12, 18 and 24 months
- Anaesthetic used for blood collection: Not specified
- Animals fasted: No
- How many animals: 5 males and 5 females per group
- Parameters checked: Hemoglobin, hematocrit, red blood cells, white blood cells, differential count

URINALYSIS: Yes
- Time schedule for collection of urine: 3, 6, 9, 12, 18 and 24 months
- Metabolism cages used for collection of urine: Yes
- Animals fasted: overnight water deprivation, not fasted.
- Parameters checked: color, volume, specific gravity, pH, blood, albumin, glucose, and microscopic
examination of the sediment after centrifugation

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No
- Number of corpora lutea: No
- Number of implantations: No
- Number of early resorptions: No
- Number of late resorptions: No
- Other: Uterus and ovaries weiged and microscopically examined

Fetal examinations:

Fetuses were not examined
- External examinations: No
- Soft tissue examinations: No
- Skeletal examinations: No
- Head examinations: No

Examinations were performed in pups.

Statistics:

No data

Indices:

Methods are not specified

Historical control data:

No data

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

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:

effects observed, non-treatment-related

Description (incidence and severity):

One control rat developed anemia (RBC, 1.8 x 103 /mm3; hemoglobin, 8.0g % and hematocrit,18.5 %) of unknown etiology.

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

effects observed, non-treatment-related

Description (incidence and severity):

All rats showed a tendency toward albuminuria; All other parameters were considered normal.

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

effects observed, non-treatment-related

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

Pathologic changes consistent with aged rats were observed primarily in the pulmonary, endocrine, urinary, and cardiovascular systems.

Histopathological findings: neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

Neoplasia occurred in a random manner with no apparent relationship between number, location, or type of tumors and treatment. This was due presumably to the advanced age of the animals.

Maternal developmental toxicity

Number of abortions:

not examined

Pre- and post-implantation loss:

not examined

Total litter losses by resorption:

not examined

Early or late resorptions:

not examined

Dead fetuses:

not specified

Changes in pregnancy duration:

no effects observed

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): no effects observed

Changes in number of pregnant:

effects observed, non-treatment-related

Description (incidence and severity):

A fall in fertility was noted in test and control groups at the second mating. This was due presumably to the advanced age of the animals.

Other effects:

no effects observed

Effect levels (maternal animals)

Key result

Dose descriptor:

NOAEL

Effect level:

>= 200 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: Highest dose tested

Results (fetuses)

Fetal body weight changes:

not examined

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): no effects observed

Reduction in number of live offspring:

no effects observed

Changes in sex ratio:

no effects observed

Changes in litter size and weights:

no effects observed

Changes in postnatal survival:

no effects observed

External malformations:

no effects observed

Skeletal malformations:

no effects observed

Visceral malformations:

not specified

Effect levels (fetuses)

Key result

Dose descriptor:

NOAEL

Effect level:

>= 200 mg/kg bw/day (nominal)

Based on:

test mat.

Remarks:

No direct exposure (only via parents)

Sex:

male/female

Basis for effect level:

other: highest dose tested

Overall developmental toxicity

Key result

Developmental effects observed:

no

Any other information on results incl. tables

Refer to Tables 3 - 6 in attached publication.

Applicant's summary and conclusion

Conclusions:

In a ombined chronic toxicity/carcinogenicity and one generation study in Charles River rats with Ethyl Maltol, the NOAEL (parental, offspring) was ≥200 mg/kg bw/day.

Executive summary:

In a combined chronic toxicity/carcinogenicity and one generation study (Gralla et al., 1969), Ethyl Maltol was administered to 4 groups of Charles River male and female rats (25/sex/group) in the diet at dose levels of 0, 50, 100 and 200 mg/kg bw/day daily for 2 years. Between 15 and 21 and 30 and 36 weeks, 10 males and 10 females per level were mated to produce two separate litters. The offspring were killed at weaning. In the parental group, five of each sex were killed after 1 year and the remaining five of each sex at the end of the study.

All dose levels of ethyl maltol were well tolerated throughout the 2-year feeding period. The test and control animals grew and maintained the body weight in a comparable manner. After two years on test, one control rat had a massive anemia of unknown etiology. Otherwise, all hematologic values for test and control animals were within normal ranges. All rats showed a tendency toward albuminuria; otherwise, urinalysis values were essentially normal. Pathologic changes consistent with aged rats were observed primarily in the pulmonary, endocrine, urinary, and cardiovascular systems. Neoplasia occurred in a random manner with no apparent relationship between number, location, or type of tumors and treatment.

A fall in fertility was noted in test and control groups at the second mating but controls were affected also (60% conception at 200 mg/kg bw/day, 50% conception for controls). This was due presumably to the advanced age of the animals. Ethyl maltol had no effect on gestation, parturition or lactation.

Ethyl maltol had no effect on fetal development and no gross internal abnormalities were noted. In the 1st F1 litter, at 0 mg/kg bw/day, the 21 day survival rate was 93%; at 200 mg/kg bw/day it was 92%. In the 2nd F1 litter, at 0 mg/kg bw/day, the 21 day survival rate was 49%; at 200 mg/kg bw/day it was 66%. There was no difference in the average weight of pups at 21 days lactation between controls and treated groups.

The NOAEL (parental/offspring) was ≥200 mg/kg bw/day.