Registration Dossier

Administrative data

Endpoint:
short-term repeated dose toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with national standard methods with acceptable restrictions
Remarks:
Incomplete histopathology. Only one dose tested. Atmosphere analyzed gravimetrically only.

Data source

Reference
Reference Type:
publication
Title:
Retinopathy from inhaling 4,4'-methylenedianiline aerosols
Author:
Leong BKJ, Lund JE, Groehn JA, Coombs JK, Sabaitis CP, Weaver RJ & Griffin RL
Year:
1987
Bibliographic source:
Fund.Appl.Toxicol. 9: 645-58

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
- Principle of test: Guinea pigs were exposed for 2 weeks to aerosols of the test item.
- Short description of test conditions: Animals were exposed nose-only. After the 2 weeks of exposure the exposed animals were kept for a 2-week "incubation" period.  
- Parameters analysed / observed: Following a 2-week incubation period, each animal was tested for dermal irritation, dermal sensitization (0.05, 2, 20, 200 mg test item/mL PEG) followed by tests for pulmonary sensitization in tracheostomized animals (200 mg test item/mL PEG). The animals were then killed, and histopathologically examined (only few organs were investigated, no histopathology on the upper respiratory tract).


 
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Purity: 94.6 % Test substance, 2.1 % of test substance isomere, plus small percentages of trimers and monoformamide

Test animals

Species:
guinea pig
Strain:
other: albino Hartley and pigmented guinea pigs of mixed variety
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Weight at study initiation: 350 - 539 g
- Housing: individually in regular caging facilities
- Diet: ad libitum
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose only
Vehicle:
other: polyethylene glycol 200 (PEG)
Remarks on MMAD:
MMAD / GSD: The average aerosol particle size was 2.4 micrometers as determined by light scattering.
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- System of generating particulates/aerosols: The test atmosphere was generated by atomizing a solution of 200 mg test item/mL PEG into an air elutriator.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Air samples were taken through preweighed glass filters (1 L/min for 5 min). The quantity of test item-PEG was determined gravimetrically. The actual quantity was calculated with the density of the solution.
The aerosol particle size distribution was monitored using a light scattering particle size analyser.
Duration of treatment / exposure:
10 exposures in 14 days
Frequency of treatment:
4 hours/day; 5 days/week
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/L air
Remarks:
time-weighted average aerosol concentration
Dose / conc.:
0.44 mg/L air
Remarks:
time-weighted average aerosol concentration
No. of animals per sex per dose:
8
Control animals:
yes, concurrent no treatment
Details on study design:
Post-exposure period: 14 days

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: not specified

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule:
Irritation assay:
Observations for erythema and edema were performed 1, 2, 3, 4, and 24 h postapplication and graded according to the Draize procedure.

Pulmonary sensitization assay:
Measurement of the lung insufflation pressures (LIP) following aerosol application of 10 and 50 µl (200mg MDA/ml PEG) to tracheostomized and cannulated animals.
Sacrifice and pathology:
GROSS PATHOLOGY: No data
HISTOPATHOLOGY: Yes, eyes, lungs, liver, kidney, spleen

Results and discussion

Effect levels

Key result
Dose descriptor:
LOAEL
Effect level:
0.44 mg/L air
Sex:
male

Any other information on results incl. tables

During exposures no overt respiratory distress was observed. Ten 4 h-exposures to 0.44 mg/mL test item aerosol produced no visible symptoms in guinea pigs (albino and pigmented). Even after challenge by dermal application of a solution of the test item in polyethylene glycol (2, 20 or 200 mg/mL) 2 weeks after the last inhalation application no symptoms were detected. Likewise challenge with an test item-PEG aerosol (200 mg/mL) did not result in changes in lung insufflation pressure of tracheostomized guinea pigs. There was slight body weight loss during the exposure days, and recovery during the 2 resting weekend days. It was said that this might have been due to stress rather than exposure to the test item, since the trends in body weight gain for the entire experimental period were comparable between the exposed and control animals. 
The most prominent histopathological findings were degeneration of the inner and outer segments of the photoreceptor cells and the pigmented epithelial cell layer of the retina in both kinds of guinea pig.
7/16 exposed animals had pulmonary granulomas against 1/8 control animals. The granulomas were small and consisted of an aggregate of macrophages surrounded by a think mantle of lymphocytes. MDA particles were not evident. 3/16 exposed animals had a slight to mild granulomatous pneumonitis, as had 1/8 control animals which had received a challenge dose of test item-PEG aerosol during the pulmonary sensitization test. There were no histological changes in liver or kidneys related to test item-PEG treatments.

Applicant's summary and conclusion