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Repeated dose toxicity: inhalation

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Administrative data

Endpoint:
short-term repeated dose toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report date:
2019

Materials and methods

Test guidelineopen allclose all
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 412 (28-Day (Subacute) Inhalation Toxicity Study
Deviations:
yes
Remarks:
reduced exposure period, males only
Qualifier:
equivalent or similar to guideline
Guideline:
EU Method B.8 (Subacute Inhalation Toxicity: 28-Day Study)
Deviations:
yes
Remarks:
reduced exposure period, males only
GLP compliance:
not specified
Remarks:
The study was performed in a GLP certified institute according to standard methods and procedures but no GLP-compliance statement is included.
Limit test:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[N-(4-chloro-2,5-dimethoxyphenyl)-3-oxobutyramide]
EC Number:
226-939-8
EC Name:
2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[N-(4-chloro-2,5-dimethoxyphenyl)-3-oxobutyramide]
Cas Number:
5567-15-7
Molecular formula:
C36H32Cl4N6O8
IUPAC Name:
2,2'-[(3,3'-dichlorobiphenyl-4,4'-diyl)didiazene-2,1-diyl]bis[N-(4-chloro-2,5-dimethoxyphenyl)-3-oxobutanamide]
Test material form:
solid: nanoform

Test animals

Species:
rat
Strain:
Wistar
Details on species / strain selection:
Crl:WI(Han)
Sex:
male
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River
- Females (if applicable) nulliparous and non-pregnant: not applicable
- Age at study initiation: ca. 7 weeks
- Weight at study initiation: ca 240 g

- Housing:
- Diet (e.g. ad libitum): ad lib. except during exposure
- Water (e.g. ad libitum): ad lib. except during exposure
- Acclimation period: 13 d

DETAILS OF FOOD AND WATER QUALITY:
The rats were housed together (up to 5 animals per cage) in Typ 2000P ca. 2065 cm2
(polysulfone cages) supplied by TECNIPLAST, Germany. Dust-free wooden bedding was used
in this study (the present supplier is documented in the raw data). For enrichment wooden
gnawing blocks (Typ NGM E-022), supplied by Abedd® Lab. and Vet. Service GmbH, Vienna,
Austria and Play Tunnel, large (Art. 14153); PLEXX b.v., Elst, Netherlands were added.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 30-70
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
inhalation: dust
Type of inhalation exposure:
nose only
Vehicle:
clean air
Mass median aerodynamic diameter (MMAD):
> 0.4 - <= 0.6 µm
Details on inhalation exposure:
The nose-only exposure technique was preferably selected for this dust inhalation study to minimize fur contamination of the animals with the substance, which cannot be avoided during whole-body exposure. Fur contamination may lead to an additional dermal and oral uptake (animals preen as their fur becomes contaminated). Thus an estimation of an nominal dose, taken up by the animals and its correlation to a toxic effect becomes more difficult.
Furthermore, by using the dynamic mode of operation with a low-volume chamber, the equilibrium characteristic of this exposure technique is favorable: t99 (the time to reach 99% of t he final target concentration) is shorter as compared to whole-body chambers with a higher chamber volume.
A positive pressure was maintained inside the exposure systems by adjusting the air flow of the exhaust air system. This ensured that the aerosol in the breathing zones of the animals was not diluted by laboratory air.
In order to accustom the animals to exposure they were treated with supply air under conditions comparable to exposure on two days before start of exposure (pre-exposure period). Then all t est groups were exposed for 6 hours on each workday over a time period suitable to reach 5 exposures.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Study means and standard deviations of test substance concentrations
Test group Target concentration (mg/m³) Measured concentration (mg/m³) Nominal concentration (mg/m³) Effectiveness of generation (%)
Mean SD
0 - - - - -
1 3 3,2 0,4 4,1 78,0
2 10 10,0 0,5 11,1 90,1
3 30 30,1 2,5 36,6 82,2
Duration of treatment / exposure:
6h x 5 days + 3 weeks recovery
Frequency of treatment:
daily
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/m³ air (nominal)
Dose / conc.:
3 mg/m³ air (nominal)
Dose / conc.:
10 mg/m³ air (nominal)
Dose / conc.:
30 mg/m³ air (nominal)
No. of animals per sex per dose:
16 males
Control animals:
yes, concurrent vehicle
Details on study design:
Nine week old male Wistar rats (16 rats per concentration group) were nose only exposed to fresh air (control group) or dust of the test substance at concentrations of 3, 10, and 30 mg/m3 (low, mid, and high concentration) for 6 hours per day and 5 days. Body weight, mortality, and clinical observations were determined during the study. One half of the rats was examined at the end of the exposure period, whereas the other half was examined at the end of a 3 week post-exposure period by determining clinical pathology parameters including bronchoalveolar lavage with clinico-chemical and cytological evaluation of lavage fluid, organ weights and all histopathological changes.
Positive control:
no

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes / No / Not specified
- Time schedule: before, during and after exposure period (3/day)

BODY WEIGHT: Yes
- Time schedule for examinations: start & end of exposure period, then 2x weekly

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Not specified

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: Not specified

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood:
- Anaesthetic used for blood collection: Yes (Isofluran)
- Animals fasted: Yes
- How many animals: all
- Parameters: WBC, RBC, HGB, MCV, HCT, MCHC, PLT, diff. count, Retic.

CLINICAL CHEMISTRY: Yes
- Parameters: ALAT, ASAT, GGT, ALP, phosphate, Ca, urea, creatinine, Glucose, Bilirubin, Albumin, Triglycerides, Protein, Globuline, Cholesterol,

URINALYSIS: No

BRONCHOALVEOLAR LAVAGE FLUID (BALF): Yes / No / Not specified
- Time schedule for analysis: end of exposure or end of recovery
- Dose groups that were examined: all
- Number of animals: all
- Parameters: total & diff. cell count; protein, GGT, LDH, alk. Phosphatase, NAG;
Antigens: rat MCP-1, rat CINC-1/IL-8, M-CSF, osteopontin

LUNG BURDEN: No
Sacrifice and pathology:
GROSS PATHOLOGY: Yes (see table)
HISTOPATHOLOGY: Yes (see table)

Results and discussion

Results of examinations

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):
not examined
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):
At the end of the exposure period, absolute and relative monocyte counts of group 1 were
lower compared to those of the control group. This was also true for absolute monocyte counts
of group 3. However, the changes were not dose-dependent and therefore they were regarded
as incidental and not treatment-related.
After three weeks of recovery, in groups 2 and 3 red blood cell counts were higher compared
to controls. This was the only changed parameter in these animals at this date and therefore,
it was regarded as maybe treatment-related but not adverse
Clinical biochemistry findings:
effects observed, non-treatment-related
Description (incidence and severity):
At the end of the administration period in groups 1 and 3 cholesterol levels were higher
compared to controls. Cholesterol values were not dose-dependently changed. The cholesterol
mean in group 3 was slightly above the historical control range (cholesterol 1.53-2.17 mmol/L,
PART III, Supplement). However, this was the only changed parameter in these individuals at
this date. Therefore, this alteration was regarded as probably treatment-related but not
adverse.
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Description (incidence and severity):
In the lungs of all treated animals, there was an increase in number of alveolar macrophages, which contained golden-brown particles within their cytoplasm. An increase in number with increasing concentration was observed. In addition, all animals of test group 2 and 3 (10 and 30 mg/m³) revealed a minimal to slight hypertrophy/hyperplasia mainly of the terminal bronchi. One male of test group 2 (10 mg/m³) and all males of test group 3 (30 mg/m³) revealed minimal infiltration of neutrophils within the bronchiolar epithelium which was regarded to be treatment related and adverse. Almost all animals showed the same particles observed in alveolar histiocytes within the bronchus associated lymphoid tissue (BALT). These findings were regarded to be treatmentrelated
but not to be adverse.
Mediastinal and tracheobronchial lymph nodes in all males of test group 3 (30 mg/m³) showed the same particles described for the lungs were observed within histiocytes within the lymph node. This finding was regarded to be treatment-related
Nasal cavity in group 3 animals contained the same golden-brown particles as observed in the lungs on the surface of the nasal mucosa. This was regarded to be treatment-related.
In the trachea of one test group 3 (30 mg/m³) animal minimal golden-brown particles were observed within the submucosa in the region of the carina. This finding was regarded to be treatment-related.

After the recovery period in test group 2 and 3 (10 and 30 mg/m³) still a minimal to slight increase in alveolar histiocytes containing golden-brown particles within their cytoplasm was observed. In test group 1 (3 mg/m³) the number of histiocytes was not increased when compared to control, but still golden-brown particles were present within the cytoplasm. All treated animals revealed the same particles within the bronchus associated lymphoid tissue (BALT). These findings were regarded to be treatment-related but not to be adverse. All other findings occurred either individually or were biologically equally distributed over control and treatment groups. They were considered to be incidental or spontaneous in origin and without any relation to treatment.
Histopathological findings: neoplastic:
no effects observed
Other effects:
effects observed, treatment-related
Description (incidence and severity):
Bronchoalveolar lavage fluid (BAL)

Cytology in BAL: At the end of the administration period, absolute and relative lymphocyte, neutrophil and monocyte counts in the BALF were increased in group 3, although this did not lead to an alteration of the total cell counts in BALF. The mentioned relative cell counts were increased in favor of relative macrophages counts in this test group. After the three weeks recovery period, cell counts were back in the range of the controls.

Enzymes and protein in BAL
No treatment-related adverse changes regarding BAL enzyme activities and total protein levels in BAL were observed. After one week of inhalation lactate dehydrogenase (LDH) and γ-glutamyl transferase (GGT) activities in group 3 were slightly higher compared to controls, but the changes were minimal (< 2fold) and therefore they were regarded as treatment-related but not adverse. After the recovery period, all enzyme activities were in the control range.

Antigens in BAL
After the administration period in group 3 monocyte chemoattractant protein-1 (MCP-1) and cytokine-induced neutrophil chemoattractant-1 (CINC-1/IL-8) levels were slightly increased.
CINC-1/IL-8 values were already higher in group 2, but the levels of the latter parameter were not dose-dependently changed and therefore, this change was regarded as incidental and not treatment-related.

Effect levels

Key result
Dose descriptor:
NOAEC
Effect level:
> 30 mg/m³ air
Based on:
test mat.
Sex:
male
Basis for effect level:
body weight and weight gain
clinical biochemistry
clinical signs
dermal irritation
gross pathology
haematology
histopathology: non-neoplastic
mortality
organ weights and organ / body weight ratios
other: Bronchoalveolar lavage fluid (BAL)

Target system / organ toxicity

Key result
Critical effects observed:
no

Applicant's summary and conclusion

Conclusions:
Inhalation exposure of rats to 30 mg/m³ Pigment Yellow 83 transparent on 5 consecutive days caused increased absolute and relative lymphocyte, neutrophils and monocyte counts in bronchoalveolar lavage. Consistently, minimal infiltration of neutrophils within bronchiolar epithelium was observed. Neutrophil infiltration was also observed at 10 mg/m³. All effects were reversible within 3 weeks exposure-free recovery period. Thus, under current study conditions, the no observed adverse effect concentration (NOAEC) for local effects was 3 mg/m³ for Pigment Yellow 83 transparent. The systemic NOAEC is above 30 mg/m³ (high concentration group). Target organ is the lung.
Executive summary:

The purpose of this 5 day-inhalation study with 3 weeks recovery period was to determine the pulmonary toxicity in rats using a short term bioassay including bronchoalveolar lavage with clinico-chemical and cytological evaluation of lavage fluid and pathological examination of the lung. The No Observed Adverse Effect Concentration (NOAEC) after 5 days inhalation exposure to dust of Pigment Yellow 83

transparent was determined. In addition, recovery group animals were examined after an exposure-free period of 3 weeks to detect any reversibility or progression of potential toxic effects.

Nine week old male Wistar rats (16 rats per concentration group) were exposed nose only to fresh air (control group) or dust of the test substance at concentrations of 3, 10, and 30 mg/m³ (low, mid, and high concentration) for 6 hours per day and 5 days.

Body weight, mortality, and clinical observations were determined during the study. One half of the rats was examined at the end of the exposure period, whereas the other half was examined at the end of a 3 week post-exposure period by determining clinical pathology parameters including bronchoalveolar lavage with clinico-chemical and cytological evaluation of lavage fluid, organ weights and all histopathological changes.

During the exposure period the target concentrations were reached. The particle size resulted in MMADs between 0.4 and 0.6 μm with GSDs around 3. The calculated mass fractions of particles below 3 μm aerodynamic size is greater than 90 %. Thus, the aerosols were highly respirable for rats and a very high proportion of the aerosol particles reached the lungs.

Test group 3 (30 mg/m³), main group

• Increased absolute and relative lymphocyte, neutrophil and monocyte cell counts in the BALF

• Increased monocyte chemoattractant protein-1 (MCP-1) levels in the BALF

• Minimal infiltration of neutrophils within bronchiolar epithelium of all animals in test group.

Test group 2 (10 mg/m³), main group

• Minimal infiltration of neutrophils within bronchiolar epithelium of one animal in test group;

Test group 1 (3 mg/m³), main group

• No treatment-related effects

Recovery group animals: Test group 3 (30 mg/m³), test group 2 (10 mg/m³), test group 1 (3 mg/m³)

• No treatment-related effects

The no observed adverse effect concentration (NOAEC) for local effects was 3 mg/m³ for Pigment Yellow 83 transparent. The systemic NOAEC is above 30 mg/m³ (high concentration group). Target organ is the lung.