2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[N-(2-methoxyphenyl)-3-oxobutyramide]

Endpoint summary

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

Year of publication: 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: comparable to guideline study

Objective of study:

other: bioavailability of cleavage products

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD Guideline 412 (Repeated Dose Inhalation Toxicity)

Deviations:

yes

Remarks:

e.g. no data on haematology, because the main subject of the study was the investigation of the bioavailability and not the investigation of toxicity after repeated exposure

GLP compliance:

yes

Remarks:

Performance and documentation was on the basis of GLP according to the German Chemikaliengesetz, but the test was not under supervision of the quality assurance unit

Radiolabelling:

no

Species:

rat

Strain:

other: Wistar Crl:(WI)BR

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River, Germany
- Age at study initiation: about 3 month
- Weight at study initiation: about 430 g
- Fasting period before study: no data
- Housing: Makrolon cages
- Individual metabolism cages: yes
- Diet: Altromin Pellet-Feed (1324N) or Altromin no Pellet-Feed (1321N) ad libitum
- Water: drinking water ad libitum
- Acclimation period: at least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24°C
- Humidity (%): 40-70%
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12 h/12 h

Route of administration:

other: intratracheal instillation

Vehicle:

other: suspension in isotonic saline containing 1% (w/v) Tween 80

Details on exposure:

- intratrachel instillation of 0.3 ml of suspension

Duration and frequency of treatment / exposure:

once per week for 4 consecutive weeks (day 1, 8, 15, 22 and 29 of the experiment)

Remarks:

Doses / Concentrations:
0, 10, 20 mg/animal per application

No. of animals per sex per dose / concentration:

12 males per group in the control and test substance group (6 of the animals were sacrificed on day 31 and 6 animals survived till the end of the 4 weeks post exposure period)
- 6 males in the positive control group

Control animals:

yes, concurrent vehicle

Positive control reference chemical:

5 times 7.31 mg 3,3'-dichlorobenzidine (CAS 91-94-1) or 5 times 5,6 mg Direct Red 46 (CAS 6548-29-4) per animal

Details on study design:

- Dose selection rationale: ascertainment of the maximum tolerable dose in a pretest

Details on dosing and sampling:

BIOAVAILABILITY STUDY
- Tissues and body fluids sampled: urine, faeces, blood, organs (lung, liver, spleen, kidney, urinary bladder, gastro intestinal tract, mamma)
- Time and frequency of sampling of urine and faeces: on day 1, 2, 3, 7, 8, 9, 14, 15, 16, 21, 22, 23, 28, 29, 30 for the animals which were sacrificed on day 31
- Time and frequency of sampling of urine and faeces: on day 28, 29, 30, 35, 42, 49, 56 for the animals which were sacrificed on day 57 at the end of the post exposure period
- Time and frequency of sampling of blood and organs: after sacrifice on day 31 or 57

Statistics:

no data

One animal of the negative control group had to be killed in a moribund condition on day 4. There was no direct correlation to the treatment obvious. Body-weight development was normal. The test substance was deposited in the lung: The test substance was detectable in macrophages, in the alveolar and intrabronchiolar region. Lung weights were elevated at the end of the exposure period and still elevated at the end of the post exposure period. Bronchio-alveolar hyperplasia and interstitial fibrosis were detected and persisted till the end of the observation period. Pigment loaded macrophages were also detected in lung associated lymph nodes, which showed increased weight and reactive lymphoide hyperplasia. Effects persisted till the end of the observation time. 3,3'-Dichlorobenzidine was not detectable in urine, faeces or bound to haemoglobin after acid hydrolysis of the matrices. 3,3'-Dichlorobenzidine was traceable in the urine of several animals of the control group (2 animals sacrificed on day 31 and 5 animals sacrificed on day 57). The authors of the report concluded that this was probably due to a contamination of the collecting containers. Pigment content of the lungs determined at the end of the exposure period was about 50 - 60% of the applied dose. The pigment content of the lungs did not decline during the post exposure period. 3,3'-dichlorobenzidine treatment: Animals treated with 3,3'-dichlorobenzidine excreted about 3% of the applied dose via urine (about 194000 ng on day 1 and 226000 ng on day 29) during the first 24 h after dosing. Urinary excretion declined rapidly thereafter: about 10400 ng/24 h during the second and 1030 ng/24 h during the third 24 hours after dosing. The average urinary excretion on the day before the 5th application was 59 ng/24 h. Excretion of 3,3'-dichlorobenzidine via faeces was delayed in comparison to excretion via urine: About 3.6% ( 262 µg; day 1 and 2) or 2.6% (190 µg, day 29 and 30) were excreted within 48 hours after application. At sacrifice about 1496 ng 3,3'-dichlorobenzidine were bound per g haemoglobin.

Conclusions:

Interpretation of results (migrated information): other: the test substance has a high potential to persist in the lung due to the significantly limited clearance capacity of the lung as a consequence of the particle overload; no 3,3'-dichlorobenzidine is bioavailable from the test substance
Analysis of urine, faeces and haemoglobin revealed that no 3,3'-dichlorobenzidine is liberated from the test substance after intratracheal instillation.

Executive summary:

Male Wistar rats were exposed for five times to 10 or 20 mg test item/animal by intratracheal instillation at weekly intervals. Urine and faeces were collected during the exposure and 28 days observation period, blood was collected at the end of the exposure and post observation period. Urine, faeces and haemoglobin were analysed for the presence of 3,3'-dichlorobenzidine after acid hydrolysis, the pigment content of the lungs was determined gravimetrically and the lungs and lung associated lymph nodes were investigated histopathologically. The pigment was deposited in the lung and persisted in the lung during the observation period. No 3,3'-dichlorobenzidine was detectable in the urine, faeces and haemoglobin of treated rats during the exposure period. Traces of 3,3'-dichlorobenzidine were detected in control animals, probably due to impurities of the analytical instruments.

Reference 2

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

year of publication: 1994

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well documented publication which meets basic scientific principles

Objective of study:

other: bioavailability of a probable cleavage product

Principles of method if other than guideline:

measurement of hemoglobin adducts after in vivo treatment

GLP compliance:

no

Radiolabelling:

no

Species:

rat

Strain:

Wistar

Sex:

not specified

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Duration and frequency of treatment / exposure:

4 weeks

Remarks:

Doses / Concentrations:
0.2%

No. of animals per sex per dose / concentration:

up to 4

Control animals:

yes, plain diet

Positive control reference chemical:

3,3'-dichlorobenzidine (DCB)

Details on absorption:

- measurable hemoglobin adducts in 2/3 animals after 2 weeks and in 3/3 animals after 4 weeks of application (limit of detection: 6 ng/g hemoglobin)
- the authors calculated that 0.6% of the total dose were decomposed in the intestine and a corresponding amount of DCB was absorbed

- after single oral application no measurabel hemoglobin adducts could be detected

- after single intratracheal instillation minimal amounts of DCB-hemoglobin adducts (3.3 µmol/mol Hb) and monoacetylated DCB-hemoglobin adducts (2.2 µmol/ml Hb) were detected; control animals showed similar values (1.8 and 1.3 µmol/mol Hb. respectively)

Conclusions:

Interpretation of results (migrated information): bioaccumulation potential cannot be judged based on study results
After single oral application or single intratracheal instillation no hemoglobin adducts of DCB, the possible cleavage product of the test item, were detectable. Hemoglobin adducts detected after repeated oral application indicated that 0.6% of the total dose of the test item were decomposed in the intestine and a corresponding amount of DCB was absorbed.

Executive summary:

The bioavailability of the hypothetical metabolite 3,3'-dichlorobenzidine of Pigment Yellow 17 after single intratracheal instillation, single oral application or 4 week exposure via diet was investigated in Wistar rats by analysis of hemoglobin adducts. No hemoglobin adducts were detected after single oral application. Low amounts of hemoglobin adducts which were in the range of the values measured for control animals were detected in rats after single intratracheal application. Based on the low amounts of hemoglobin adducts measured in rats after repeated oral application the authors calculated that 0.6% of the total dose of Pigment Yellow 17 were decomposed in the intestine and a corresponding amount of DCB was absorbed.

Reference 3

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

year of publication: 1996

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well documented publication which meets basic scientific principles

Objective of study:

other: bioavailability of the hypothetical cleavage product 3,3'-dichlorobenzidine (DCB) from the submission substance after oral application

Principles of method if other than guideline:

investigation of formation of DCB-hemoglobin and DNA-adducts

GLP compliance:

no

Radiolabelling:

no

Species:

rat

Strain:

Wistar

Sex:

female

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Duration and frequency of treatment / exposure:

4 weeks

Remarks:

Doses / Concentrations:
0.2% in diet (corresponding to 165 mg/kg bw)

No. of animals per sex per dose / concentration:

6 females

Control animals:

no

Positive control reference chemical:

DCB, application via drinking water

Details on distribution in tissues:

- no DCB or AcDCB-hemoglobin adducts were detectable (limit of detection: 0.1 ng/g hemoglobin)
- no DNA-adducts were detectable in the liver (limit of detection 0.08 ng/g DNA)

- no signs of toxicity were noticed during the 4 week treatment period

- food consumption and body weight development were similar in treated and in control animals

Conclusions:

Interpretation of results (migrated information): other: the test item is not betabolically splitted into 3,3'-dichlorobenzidine and no 3,3'-dichlorobenzidine is bioavailable after oral exposure
The results indicate that the test item is not metabolically splitted into DCB and that no DCB becomes bioavailable after repeated oral application of the test item.

Executive summary:

Female Wistar rats were treated for 4 weeks with 0.2% C.I. Pigment Yellow 17 in the diet (165 mg/kg bw/day). The hypothetical release of 3,3'-dichlorobenzidine was investigated by analysis DCB-hemoglobin adducts and DCB-DNA-adduct levels in the liver. Neither DCB-hemoglobin adducts nor DCB-DNA-adducts in the liver were detectable. The results indicate that the test item is not metabolically splitted into DCB and that no DCB is bioavailable after oral ingestion of the test item.

Reference 4

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

From 4 DEC 1989 to 18 DEC 1989

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study (OECD TG 403)

Reason / purpose for cross-reference:

reference to same study

Objective of study:

other: bioavailability of cleavage products

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: EU Method B.2 (Acute Toxicity (Inhalation))

Deviations:

no

GLP compliance:

yes

Radiolabelling:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Route of administration:

inhalation: dust

Vehicle:

unchanged (no vehicle)

Details on exposure:

TYPE OF INHALATION EXPOSURE: nose only

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: cylindrical plastic cage
- Exposure chamber volume: 60 L
- Method of holding animals in test chamber: each animal was in a plastic tube
- Source and rate of air: laminar air stream of 1000 L/hour at 4 bar from above
- System of generating particulates/aerosols: dustgenerator "Wright Dust Feed" of L. Adams Ltd., London, UK
- Method of particle size determination: "Anderson-Kaskadenimpaktor Mark III" of Anderson Samples Inc, Atlanta, USA
- Treatment of exhaust air: exhaust device at the basement of the exposure chamber in line with a diverse system of filters

TEST ATMOSPHERE ANALYSIS
- Brief description of analytical method used: gravimetric measurement: The test atmosphere was sucked through filters ("Experimentiertrommelgasfilter", Elster AG, Mainz-Kastel, Germany; as well as a fibre glass and a membrane filter (diameter of pores 0.65 µm) Satorius Membranfilter GmbH, Göttingen, Germany) by means of vacuum. The exhaust quantity was 3 L/min, which resulted in an air flow of 1.25 m/sec. The filters were positioned in an exsiccator 24 h before use. The filters were weighed before and after each measurement by means of electrical scales.

TEST ATMOSPHERE
- Particle size distribution: < 0.6 µm to > 10.3 µm
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): 1.0 - 1.1/ 2.3 - 2.8

Duration and frequency of treatment / exposure:

4 h, single exposure

Remarks:

Doses / Concentrations:
230 mg/m³ air

No. of animals per sex per dose / concentration:

6/sex/treatment group
1/sex/control group

Control animals:

yes, concurrent no treatment

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations: twice a day
- Frequency of weighing: weekly
- Necropsy of survivors performed: yes

Details on dosing and sampling:

- Control urine and blood samples were collected from control animals.
- On day 1, 2 and 7 one male and one female were sacrificed to obtain blood samples. Final sacrifice of the remaining 3 animals/sex was on day 14 of the observation period.
- Urin samples were collected starting on the day of exposure till day 7 of the observation period and the last night before sacrifice.
- To collect urine the rats were placed in metabolism cages overnight without witdrawal of food and water. For technical reasons urine was collected continously on day 6 and 7.
- Blood was collected via puncture of the retro-orbital plexus.

No 3,3'-dichlorobenzidine was detected either in urine, even in those pretreated with beta-glucuronidase/arylsulfatase (detection limit 5 ng/ml) or blood serum (detection limit 10 ng/0.5 ml).

Conclusions:

Interpretation of results (migrated information): other: no 3,3'-dichlorobenzidine detectable in urine and serum after inhalation exposure
On the basis of this study it is highly improbable that the test substance undergoes metabolic splitting to the parent amine 3,3'-dichlorobenzidine in the rat after inhalation exposure.

Executive summary:

Rats were exposed by inhalation to the technically highest administrable concentration of the test substance of 230 mg/m³ air for 4 h (nose only). Inhalability of the dust was guaranteed by a mass-median aerodynamic diameter of 1.0 -1.1 µm. For 14 days after exposure, urine and serum samples were analysed for 3,3'-dichlorobenzidine. No 3,3'dichlorobenzidine could be detected either in urine or blood (detection limit 5 ng/ml urine or 10 ng/0.5 ml blood).

Reference 5

Endpoint:

basic toxicokinetics, other

Type of information:

other: Evaluation of available information, expert statement

Adequacy of study:

key study

Study period:

2021

Reliability:

2 (reliable with restrictions)

Justification for type of information:

Evaluation of available information. No specific studies are required

Details on absorption:

A prerequisite for a relevant absorption is that the substance can be dissolved in either aque-ous (e.g., gastrointestinal fluid, blood plasma, sweat) or lipophilic (e.g., lipoproteins, lipid membranes, triglycerides) media or in both. C.I. Pigment Yellow 17 can be considered insol-uble because it has an extremely low solubility in water (2,6 µg/L) and n-octanol (6,8 µg/L). Therefore, it is unlikely that C.I. Pigment Yellow 17 becomes systemically bioavailable after oral, dermal or inhalation exposure.
Based on the sub-chronic oral toxicity study with C.I. Pigment Yellow 12 absorption of tox-icologically significant amounts via the gastrointestinal tract is considered unlikely, since C.I. Pigment Yellow 12 did not show any effects on inner organs and blood or urine. No metabo-lites were determined.
The skin sensitisation studies with C.I. Pigment Yellow 12 indicate no local dermal bioavail-ability. Systemic availability also seems to be negligible after dermal exposure since no sys-temic signs of intoxication were seen after occlusive administration of 500 mg C.I. Pigment Yellow 17 per kg body weight in rabbits in the acute dermal irritation study.
Dermal absorption is, therefore, considered unlikely.
In the unlikely event of exposure to aerosolized pigment in respirable form, the substance is considered to behave like an inert dust. Therefore, the deposited pigment particles will mostly be cleared from the lung via the mucocilliary transport. As the pigment will not dis-solve quickly in the lung surfactant, the only efficient way the pigment can enter the body is via phagocytosis of pigment particles by lung macrophages followed by migration of the macrophages into the interstitium and into the draining lymph nodes. However, the internal dose delivered via this mechanism can be considered negligible.

Details on distribution in tissues:

The repeated dose toxicity study with C.I. Pigment Yellow 12 did not indicate any relevant histopathological changes in any of the investigated organs. In the sub-chronic inhalation study local effects were seen in the lungs, which were interpreted as the normal “clean-up” of the lung after inert dust exposure.
This may indicate that the pigment either does not affect specific organs as targets, i.e., is non-toxic, or is not distributed within the body in significant amounts. As indicated above, the physico-chemical parameters of the pigment support the conclusion that the pigment is not absorbed into the body and thus does not become systemically available. There were also no other signs of deposition of the pigment in any organ not exposed directly (except portal of entry: skin, lung, gut) including excretory organs, like the kidney, indicating that even exposure to high doses of the pigment does not lead to bioaccumulation in special compart-ments of the body.
Based on the available information on absorption distribution of the test material in the body in significant amounts is unlikely and specific hotspots of distribution cannot be identified.
Thus, it is concluded, that C.I. Pigment Yellow 17 is not systemically available at relevant concentrations within the organism.
There were no signs of bioaccumulation of the test material. The only exception could be the lung as portal of entry after prolonged exposure to excessive concentrations of dust (lung overload). This view is supported by the physical-chemical properties (solubility in water and octanol).

Details on excretion:

Considering the physico-chemical properties and the molecular structure and size of the mol-ecules and the absence of any indication of absorption and/or metabolism it is assumed that excretion, if any, is likely to occur via faeces. This notion is confirmed by the discoloration of faeces observed in the oral studies as the only alteration.

Details on metabolites:

Since the solution of the substance in cellular fluid or cellular membranes is a prerequisite for its metabolism, it is unlikely that the insoluble pigment becomes accessible for metabo-lizing systems in relevant amounts.
Diarylide yellow pigments are not or only to a negligible extend cleaved, taking into ac-count the negative results obtained with C.I. Pigment Yellow 17 in investigations on kinetic behavior.
The results of the mutagenicity tests provide qualitative information on the metabolic fate of C.I. Pigment Yellow 17. In the mutagenicity tests, the pigment as well as its close struc-tural analogues PY12 and PY13 proved to be non-mutagenic in the absence as well as in the presence of an exogenous metabolizing system, indicating that the pigment, even direct-ly exposed to metabolizing enzymes, is not converted into toxic or genotoxic metabolites. This conclusion is also supported by the lack of any morphological and histopathological changes of organs involved in xenobiotic metabolism, such as the liver, in the subacute and sub-chronic toxicity studies with C.I. Pigment Yellow 12. Furthermore, the missing skin or eye irritating or skin sensitizing properties argue against any interaction with biological ma-terial.
Therefore, C.I. Pigment Yellow 17 is considered to just pass through the intestinal tract without significant metabolism.

Bioaccessibility (or Bioavailability) testing results:

Bioavailability not likely

Conclusions:

Based on all available data, C.I. Pigment Yellow 17 does not exhibit conspicuous toxicoki-netic behaviour in the sense of accumulative and/or delayed effects with regard to the indi-vidual parameters absorption, distribution, metabolism and excretion. The only exception could be the lung as portal of entry after prolonged exposure to excessive concentrations of dust (lung overload).
The results from studies with dermal exposure indicate that C.I. Pigment Yellow 17 has a no relevant dermal absorptive potential. C.I. Pigment Yellow 17 is most probably not absorbed from the gastrointestinal tract in significant amounts.
Indications of an intense metabolism or a bio-accumulative potential do not exist as no tox-icity occurred even after chronic exposure, which points to no bio-accumulation potential and complete excretion of all possibly systemically available C.I. Pigment Yellow 17 and/or me-tabolites.

Executive summary:

Based on the available data base on C.I. Pigment Yellow 17 relevant information exists to make a qualitative evaluation of the toxicokinetic profile of this compound. This is in line with animal welfare considerations because additional animal tests can be avoided by such an evaluation. The substance is available in nano-form. The available data have partly been generated with non-specified material, but the conclusions drawn are considered valid for the nano form as well, because the material is chemically identical, and the physical properties are widely overlapping.

 

The results of basic toxicity testing give no reason to anticipate unusual characteristics regarding the toxico-kinetics of C.I. Pigment Yellow 17.C.I. Pigment Yellow 17 is not absorbed from the gastro-intestinal tract in toxicologically significant amounts. The data indicate that there is no relevant dermal absorption. After inhalation unspecific reactions to unreactive dust can be expected. Indications of a bio-accumulative potential as well as metabolism towards genotoxic sub-structures do not exist. Excretion of traces of possibly systemically available C.I. Pigment Yellow 17 and/or metabolites via faeces is likely.

Description of key information

Based on the available data base on C.I. Pigment Yellow 17 relevant information exists to make a qualitative evaluation of the toxicokinetic profile of this compound. This is in line with animal welfare considerations because additional animal tests can be avoided by such an evaluation. The substance is available in nano-form. The available data have partly been generated with non-specified material, but the conclusions drawn are considered valid for the nano form as well, because the material is chemically identical, and the physical properties are widely overlapping.

 

The results of basic toxicity testing give no reason to anticipate unusual characteristics regarding the toxico-kinetics of C.I. Pigment Yellow 17.C.I. Pigment Yellow 17 is not absorbed from the gastro-intestinal tract in toxicologically significant amounts. The data indicate that there is no relevant dermal absorption. After inhalation unspecific reactions to unreactive dust can be expected. Indications of a bio-accumulative potential as well as metabolism towards genotoxic sub-structures do not exist. Excretion of traces of possibly systemically available C.I. Pigment Yellow 17 and/or metabolites via faeces is likely.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential