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Diss Factsheets

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2015
Report date:
2015

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Principles of method if other than guideline:
Male and female rats were exposed nose-only to 2590 mg (maximum attainable concentration) of the test substance/m³ for 4 hours. Mortality, clinical signs, reflex measurements rectal temperature and body weights were examined during the 14 days post observation period. A gross-pathological examination was performed on day 14 after exposure to the test item. To identify exposure-related effects, comparisons with vehicle control were performed. This control was exposed to an atmosphere using essentially similar exposure conditions as were used for the test item.
GLP compliance:
yes
Test type:
standard acute method

Test material

Constituent 1
Reference substance name:
zinc, 5,5'-azobis-2,4,6(1H,3H,5H)-pyrimidinetrione complexes and melamine
IUPAC Name:
zinc, 5,5'-azobis-2,4,6(1H,3H,5H)-pyrimidinetrione complexes and melamine
Test material form:
aerosol dispenser: not specified
Remarks:
migrated information: aerosol
Details on test material:
Test item: Zinc-Azo barbituric acid / Melamine used as micronized
Chemical name: Reaction mass of zinc, 5,5'-azobis-2,4,6(1 H,3H,5H)-pyrimidinetrione complexes and melamine
CAS name: Zinc, 5,5'-azobis-2,4,6(1 H,3H,5H)pyrimidinetrione complexes and melamine
CAS number: 264233-58-1
Empirical formula: C8H4N6O6Zn x 2 H20 and C3H6N6
Stability: Stability certified for the duration of study
Storage conditions: room temperature
Appearance: solid, red-brown powder
Purity: 96.5 %

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose only
Vehicle:
air
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 h
Concentrations:
0 mg/m³ (control group)
2590 mg/m³ (test group); 2590 mg/m³ was the maximum attainable concentration)
No. of animals per sex per dose:
N /Group/sex Concentration (mg/m³)
1/m 0
2/m 2590
1/w 0
2/w 2590
Control animals:
yes

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
>= 2 590 mg/m³ air
Based on:
test mat.
Exp. duration:
4 h
Remarks on result:
other: 2590 mg/m³ was the maximum attainable concentration.

Any other information on results incl. tables

One group of female and male rats was nose-only exposed to the solid aerosol of the test item at the maximum attainable concentration of 2590 mg/m³ in the animals breathing zone (limit test). In order to achieve the required mass median aerodynamic diameter (MMAD) the test item was micronized using a ball-mill. Rats of the control group were exposed to air under otherwise identical circumstances.

The results can be summarized as follows:

The respirability of the aerosol was adequate and in compliance of test guidelines [the mass median aerodynamic diameter (MMAD) was 3.86 µm, the geometric standard deviation (GSD) was 2.59]. Efforts have been made to generate the maximum attainable concentration of 2590 mg/m³ test item in consideration of particle size distribution according OECD test guideline 403.

Mortality did not occur during the course of the study. All rats exposed to 2590 mg/m³ revealed clinical symptoms (e.g. bradypnea, labored breathing, irregular breathing, motility reduced, atony, high-legged gait, cyanosis, piloerection, haircoat ungroomed, fur orange stained, reduced reflexes). Furthermore animals exposed to the test item showed significant reduction in incremental body weight gain and absolute body weight when compared to control animals as well as significant decreased body temperatures in comparison to controls. Gross pathological findings were seen in all six animals exposed to 2590 mg/m3 on day 14 (light-colored areas and orangecolored areas in the lungs, orange discolorations in the lung-associated lymph nodes).

In summary, there is evidence of low acute inhalation toxicity in rats after exposure (4h) of the aerosolized test item. The LC50 is> 2590 mg/m³.

Applicant's summary and conclusion

Executive summary:

A study on the acute inhalation toxicity of Zinc-Azo barbituric acid / Melamine (henceforward referred to as test item) in rats has been conducted in accordance with OECD TG#403 (2009). Test procedures were adapted so as to comply also with the EU Directive 92/69/EEC, and especially OECD GD#39 (2009). One group of female and male rats was nose-only exposed to the solid aerosol of the test item at the maximum attainable concentration of 2590 mg/m³ in the animals breathing zone (limit test). In order to achieve the required mass median aerodynamic diameter (MMAD) the test item was micronized using a ball-mill. Rats of the control group were exposed to air under otherwise identical circumstances.

The results can be summarized as follows:

The respirability of the aerosol was adequate and in compliance of test guidelines [the mass median aerodynamic diameter (MMAD) was 3.86 µm, the geometric standard deviation (GSD) was 2.59]. Efforts have been made to generate the maximum attainable concentration of 2590 mg/m³ test item in consideration of particle size distribution according OECD test guideline 403.

Mortality did not occur during the course of the study. All rats exposed to 2590 mg/m³ revealed clinical symptoms (e.g. bradypnea, labored breathing, irregular breathing, motility reduced, atony, high-legged gait, cyanosis, piloerection, haircoat ungroomed, fur orange stained, reduced reflexes). Furthermore animals exposed to the test item showed significant reduction in incremental body weight gain and absolute body weight when compared to control animals as well as significant decreased body temperatures in comparison to controls. Gross pathological findings were seen in all six animals exposed to 2590 mg/m3 on day 14 (light-colored areas and orangecolored areas in the lungs, orange discolorations in the lung-associated lymph nodes).

In summary, there is evidence of low acute inhalation toxicity in rats after exposure (4h) of the aerosolized test item. The LC50 is> 2590 mg/m³.

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