Formaldehyde, reaction products with ethylenediamine

Endpoint summary

Description of key information

On the basis of this 28-Day Repeated Dose Oral Toxicity study with formaldehyde, reaction products with ethylenediamine in male and female Wistar rats with dose levels of 100, 300, and 800 mg/kg body weight day, the following conclusions can be made:

At 800 mg/kg BW increased clinical symptoms were found which indicate discomfort of the animals. Furthermore, decreased thymus weight as well as increased adrenal weight indicates stress of the animals, too. An additional tissue besides the stomach occurred probably due to the local irritant effect of the test item. Pathologically, test item-related lesions of toxicological significance were seen in the kidney and comprised mild or moderate tubular degeneration/regeneration at the inner cortex in all rats treated at 800 mg/kg/day. Hence, the dosage of 800 mg/kg BW is assumed to induce adverse effects within this study.

Key value for chemical safety assessment

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:

28 day oral - September 25 - October 30, 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Qualifier:

according to guideline

Guideline:

EU Method B.7 (Repeated Dose (28 Days) Toxicity (Oral))

GLP compliance:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Route of administration:

oral: gavage

Vehicle:

water

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

28 days

Frequency of treatment:

Daily

Remarks:

Doses / Concentrations:
100 mg/kg bw/day
Basis:
nominal in water

Remarks:

Doses / Concentrations:
300 mg/kg bw/day
Basis:
nominal in water

Remarks:

Doses / Concentrations:
800 mg/kg bw/day
Basis:
nominal in water

No. of animals per sex per dose:

3 groups of test animals, one dose level per group, and a control group. The 4 groups comprised of 5 males and 5 females rats each one.

Control animals:

yes, concurrent vehicle

Observations and examinations performed and frequency:

- Body weight and food consumption: weekly.
- Clinical observations: at least once a day.
- Morbidity and mortality: twice daily, except on weekends and public holidays when observations were made once daily.
- Detailed cage side observations considering spontaneous activity, lethargy, recumbent position, convulsions, tremors, apnoea, asphyxia, vocalisation, diarrhoea, changes in skin and fur, eyes and mucous membranes (salivation, discharge), piloerection and pupil size were made outside the home cage in a standard arena once before the first administration and at least once a week thereafter.
- Ophthalmological examination, using an ophthalmoscope was made on all animals before the first administration and in the last week of the treatment period.
- Functional Observations: Once before the first exposure and once in the fourth week of exposure multiple detailed behavioural observations were made outside the home cage using a functional observational battery of tests.
- Haematology: Haematological parameters were examined at the end of the treatment prior to or as part of the sacrifice of the animals.
- Blood Coagulation: Coagulation parameters were examined at the end of the treatment prior to or as part of the sacrifice of the animals.
- Clinical Biochemistry: Parameters of clinical biochemistry were examined at the end of the treatment prior to or as part of the sacrifice of the animals.
- Urinalysis: A urinalysis was performed with samples collected from all animals prior to or as part of the sacrifice of the animals. Additionally, urine colour/ appearance were recorded.

Sacrifice and pathology:

- Pathology: One day after the last administration (study day 29) all surviving animals of the treatment period were sacrificed using anesthesia and subjected to a detailed gross necropsy which includes careful examination of the external surface of the body, all orifices and the cranial, thoracic and abdominal cavities and their contents.
- Organ Weight: The wet weight of the organs of all sacrificed animals was recorded as soon as possible. Paired organs were weighed separately. Organ weights of animals found dead or euthanised for animal welfare reasons were not recorded.
- Histopathology: The following organs were examined histopathologically after preparation of paraffin sections and haematoxylin-eosin staining: brain (cerebrum, cerebellum and pons), spinal cord, eye, liver, kidneys, adrenal glands, stomach, small and large intestines (including Peyer´s patches), thymus, thyroid glands, spleen, lung and trachea, mammary glands, skin.

Statistics:

A statistical assessment of the results of the body weight, food consumption, parameters of haematology, blood coagulation and clinical biochemistry and absolute and relative organ weights were performed for each gender by comparing values of dosed with control animals of the main groups using a one-way ANOVA and a post-hoc Dunnett Test. These statistics were performed with GraphPad Prism V.5.01 (p<0.05 was considered as statistically significant).

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

No mortality occurred in the control or any of the dose groups during the treatment period of this study. These clinical signs observed in MD and HD group were signs of discomfort which are – as individual findings – considered to be of toxicological relevance but not to be adverse.

Mortality:

mortality observed, treatment-related

Description (incidence):

No mortality occurred in the control or any of the dose groups during the treatment period of this study. These clinical signs observed in MD and HD group were signs of discomfort which are – as individual findings – considered to be of toxicological relevance but not to be adverse.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Slightly attenuated body weight gain. Not statistical significant.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

Slight tendency towards attenuated food consumption. Not statistical significant.

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

no effects observed

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

Increase in: MCV, MCH, basophils and PLT.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

Changes in ASAT and TBA.

Urinalysis findings:

effects observed, treatment-related

Description (incidence and severity):

High protein levels as well as a high specific gravity were found in one animal.

Behaviour (functional findings):

not specified

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Changes in brain, thymus, pituitary glands, adrenals, liver, spleen, ovaries and uteri.

Gross pathological findings:

not specified

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Kidney: mild or moderate tubular degeneration/regeneration at the inner cortex in all rats treated at 800 mg/kg/day. Stomach: esions indicative of a sustained local irritant effect of the test item formulation.

Histopathological findings: neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Stomach, as a consequence of local irritant effect of the test item formulation: erosions, ulcers, epithelial hyperplasia of the nonglandular mucosa, superficial hyperplasia/basophilia of the glandular mucosa.

Dose descriptor:

NOAEL

Effect level:

300 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: The 300 mg/kg bw group showed signs of discomfort, but effects observed in the higher dose group were not confirmed at this dose.

Critical effects observed:

not specified

Conclusions:

NOAEL: 300 mg/kg bw/day.

Executive summary:

On the basis of this 28-Day Repeated Dose Oral Toxicity study with formaldehyde, reaction products with ethylenediamine in male and female Wistar rats with dose levels of 100, 300, and 800 mg/kg body weight day, the following conclusions can be made:

At 800 mg/kg BW increased clinical symptoms were found which indicate discomfort of the animals. Furthermore, decreased thymus weight as well as increased adrenal weight indicates stress of the animals, too. An additional tissue besides the stomach occurred probably due to the local irritant effect of the test item. Pathologically, test item-related lesions of toxicological significance were seen in the kidney and comprised mild or moderate tubular degeneration/regeneration at the inner cortex in all rats treated at 800 mg/kg/day. Hence, the dosage of 800 mg/kg BW is assumed to induce adverse effects within this study.

In MD group, clinical signs of discomfort were found. Furthermore, decreased thymus weights indicate stress, too. A non significant increase of TBA in serum is not confirmed by other liver markers or histopathology. Furthermore, histological analysis do not confirm the adverse kidney findings in this MD dose level. Hence, the MD dose is assumed to induce stress and discomfort of the animals. However, these findings were mostly related to the local irritant effects of the test item. Hence, an adverse effect, relevant in humans, cannot be stated. The No Observed Adverse Effect Level is assumed to be 300 mg/kg BW within this study (MD group).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

300 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

The study is well reported and performed according to GLP.

Organ:

kidney

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

The repeated dose toxicity study showed the following clinical effects: mainly salivation and moving the bedding. The 28-day toxicity study revealed also changes in body and organs weights and test item-related lesions in kidneys. The NOAEL could be identified at 300 mg/kg bw/day.

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:

Acute toxicity testing indicates that the oral route is the most sensitive for toxicological findings.

Repeated dose toxicity: via oral route - systemic effects (target organ) digestive: stomach; urogenital: kidneys

Justification for classification or non-classification

Effects observed in the repeated dose toxicity study are not sufficient to classify formaldehyde, reaction products with ethylendiamine for Specific Target Organ Toxicity after repeated exposure, according to Regulation 1272/2008/EC.