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Toxicological information

Repeated dose toxicity: dermal

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Administrative data

Endpoint:
short-term repeated dose toxicity: dermal
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report Date:
1991

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 410 (Repeated Dose Dermal Toxicity: 21/28-Day Study)
GLP compliance:
yes (incl. certificate)
Remarks:
testing lab.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
1.2-ethane diole (ethylene glycol) with inhibitors > 92.5% ethylene glycol, < 1.42% na-p-tert-butyl-benzoate

Test animals

Species:
dog
Strain:
Beagle
Sex:
male
Details on test animals and environmental conditions:
Age of the dogs: 2 - 2.5 years
Identification: using four-digit numbers, tattooed in the right ear
The animals used were free of any illness signs.
The mean body weight was 16.4 kg at the beginning of the study.
The animals were housed singly in kennels.
The illumination period was the same as the natural day/night rhythm.
Weekly body weight determinations was done and the daily food intake of each animals was determined.
Each dog was offered a pelleted diet (daily 500 g).
Drinking water was available ad libitum during the study period.
Before blood and urine collection as well as before necropsy, a fasting period of 16 hours was warranted.

Administration / exposure

Type of coverage:
other: clipped skin
Vehicle:
unchanged (no vehicle)
Details on exposure:
Before application period, the dogs were shaved on the back, flanks, front and waist. The test substance was given daily (undiluted) to the clipped skin. The application area was about 60% of the total body surface. The test substance was not washed off.
Analytical verification of doses or concentrations:
yes
Duration of treatment / exposure:
4 weeks
Frequency of treatment:
daily
Doses / concentrationsopen allclose all
Dose / conc.:
0.5 other: ml/kg bw (analytical dose)
Dose / conc.:
2 other: ml/kg bw (analytical dose)
Dose / conc.:
8 other: ml/kg bw (analytical dose)
No. of animals per sex per dose:
5
Control animals:
yes, concurrent no treatment
Details on study design:
In range-finding studies over a study period of 14 days (dermal application), no symptoms were seen given the test substance in concentrations of 1.5 ml for 14 days or 3.0 ml for 21 days. 12 ml of the test substance showed lethality after 6 and 14 days of exposure.
For the 4-week dermal study, 8.0 ml were used as highest concentration, 2.0 and 0.5 ml were used as lower concentrations.

Examinations

Observations and examinations performed and frequency:
Daily food consumption and body weight determination.
Clinical symptoms twice a day.
Sacrifice and pathology:
Check of dead animals twice a day.
All animals were assessed by gross pathology and then a histopathological examination was carried out.
Statistics:
yes

Results and discussion

Results of examinations

Clinical signs:
effects observed, treatment-related
Description (incidence and severity):
High dose group: Individual animals showed signs of toxicity, such as staggering gait, weakness of the extremities, vomiting, lateral position, diarrhea, etc.; moreover, reduced feed consumption and loss of body weight were observed.
Dermal irritation:
not specified
Mortality:
mortality observed, treatment-related
Description (incidence):
High dose group: The applied test substance led to the premature death of 4 of the 5 male dogs used (3 of them sacrificed in a moribund state; one animal died) and caused apathy and/or somnolence in all male dogs.
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
High dose group: loss of body weight was observed.
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
High dose group: reduced feed consumption was observed.
Haematological findings:
effects observed, treatment-related
Description (incidence and severity):
High dose animals only. No further details available.
Clinical biochemistry findings:
effects observed, treatment-related
Description (incidence and severity):
High dose group: All male dogs showed signs of renal insufficiency to a varying degree. Increased creatinine and urea levels in the plasma and changes in the urinalyses, such as an increased incidence of calcium oxalate crystals and renal and round epithelial cells, were the main findings. Polyuria and therefore reduced urine specific gravity were also observed. There were numerous other clinicochemical and hematological findings apart from these major changes.
Urinalysis findings:
effects observed, treatment-related
Description (incidence and severity):
High dose group: Polyuria and therefore reduced urine specific gravity were also observed.
Mid dose group: Urinalysis findings: There were sporadically calcium oxalate crystals, initial signs of polyuria and an increased incidence of round and squamous epithelial cells in one male dog in each case.
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Description (incidence and severity):
High dose animals: All male dogs had signs of oxalate nephrosis (intratubular oxalate crystals and liquefaction foci) and diffuse impairment of spermatogenesis; testicular atrophy was found in some cases. Uremic gastroenteritis was diagnosed in the dogs that died or were sacrificed prematurely.
Mid dose group: Testicular atrophy with moderate diffuse impairment of spermatogenesis was observed in one animal. However, this was potentially attributed to another substance present in the test material and therefore not associated with treatment with DEG (as potentially were the testicular effects seen in the high dose animals).
Details on results:
Low dose group: After dermal application of 0.5 ml test substance/kg body weight, there were no definite changes that might be causally related to the test substance applied in any of the examinations carried out.

Effect levels

Dose descriptor:
NOAEL
Effect level:
ca. 2 other: mL/kgbw.day
Based on:
test mat.
Sex:
male
Basis for effect level:
clinical signs
mortality
body weight and weight gain
food consumption and compound intake
clinical biochemistry
urinalysis
histopathology: non-neoplastic
Remarks on result:
other:
Remarks:
Nephrotoxicity and oxalate nephrosis were observed in the male dogs of the 8.0 ml/kg body weight group with specific clinical, clinicochemical, hematological, urinalysis and gross-pathological and histopathological changes definitely corresponds to the signs that are known from intoxication with pure monoethylene glycol. At 2.0 ml/kg there were some oxalate crystals in the urine but due to the absence of histopapthological effects considered as not adverse. Thus the overall NOAEL was 2.0 ml/kg bw.

Target system / organ toxicity

Critical effects observed:
yes
Lowest effective dose / conc.:
8 other: mL/kg
System:
urinary
Organ:
kidney
Treatment related:
yes
Dose response relationship:
yes
Relevant for humans:
yes

Applicant's summary and conclusion

Conclusions:
The oxalate nephrosis observed in the male dogs of the 8.0 ml/kg body weight group with specific clinical, clinicochemical, hematological, urinalysis and gross-pathological and histopathological changes definitely corresponds to the signs that are known from intoxication with pure monoethylene glycol. Further studies are required to establish whether the severe testicular damage that was found in all dogs at 8.0 ml/kg and in one dog at 2.0 ml/kg was caused by Na p-tert.-butyl benzoic acid (PTBBA), a typical testicular toxicant and a minor constituent of Glysantin G 105.
LD50 dermal (dog): > 2000 mg/kg