N,N'-(2,5-dichloro-1,4-phenylene)bis[4-[[2-chloro-5-(trifluoromethyl)phenyl]azo]-3-hydroxynaphthalene-2-carboxamide]

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17.9. - 5.11.2008

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Guideline study conducted according to GLP. No analytical verification of test item stability and homogenity. No tables with individual data. No scoring system for severety of histopathology findings. Comparison to historical control data sometimes mentioned in the freetext, but no actual data provided.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Version / remarks:

(1995)

Deviations:

yes

Remarks:

No analytical monitoring of test substance. Data for individual animals not reported.

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.7 (Repeated Dose (28 Days) Toxicity (Oral))

Version / remarks:

(2008)

Deviations:

yes

Remarks:

No analytical monitoring of test substance

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

N,N'-phenylene-1,4-bis[4-[(2,5-dichlorophenyl)azo]-3-hydroxynaphthalene-2-carboxamide]

EC Number:

223-460-6

EC Name:

N,N'-phenylene-1,4-bis[4-[(2,5-dichlorophenyl)azo]-3-hydroxynaphthalene-2-carboxamide]

Cas Number:

3905-19-9

Molecular formula:

C40H24Cl4N6O4

IUPAC Name:

3,3'-[(2,2'',5,5''-tetrachloro-1,1':4',1''-terphenyl-4,4''-diyl)bis(triaz-2-ene-3,1-diylcarbonyl)]di(2-naphthol)

Test material form:

solid: bulk

Details on test material:

- Name of test material (as cited in study report): C.I. Pigment Red 166
- Physical state: red powder
- Analytical purity:ca. 99%
- Impurities (identity and concentrations): water (up to 1%)
- Stability: 15 years
- Storage condition of test material: at room temperature

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: SPF breeding, VELAZ s.r.o., Kolec u Kladna, Czech Republic
- Age at study initiation: 6 -7 weeks
- Mean group weight range at study initiation: males, 182.20 - 183.24 g; females, 136.16 - 136.78 g
- Fasting period before study: the animals starved before blood collection for approximately 18 hours but they received drinking water ad libitum.
- Housing: 2-3 rats of the same sex in one plastic cage (40x25x20 cm) containing sterilised clean shavings of soft wood.
- Diet (e.g. ad libitum): sterilised complete peleted diet for rats and mice in SPF breeding (ST 1 BERGMAN) was offered ad libitum.
- Water (e.g. ad libitum): sterilised drinking water with a quality corresponding to Regulation No. 252/2004 Czech Coll. of Law (Health Ministry) was offered ad libitum.
- Acclimation period: at least 5 days
- Diet, water and bedding analysis for contaminants: the standard pelleted laboratory animal diet is analysed for nutrients (once a year) and each batch is microbiologically examined on a regular basis. Certificates of analysis of water (performed twice a year) also are available. Bedding (sterilised clean shavings of soft wood) are examined for bacteriological contaminants once a year. Analysis of diet, water and bedding, did not reveal any findings that could affect study integrity.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3
- Humidity (%): 30 - 70
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12 / 12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

olive oil

Remarks:

(Batch No.: L 701 151 and L 803 142; manufactured by Dr. Kulich Pharma s.r.o., Hradec Kralové, Czech Republic)

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS
The test substance is insoluble in many solvents. Low solubility of the test substance was declared by the Sponsor and it was also checked up during the substance identity verification. In this study the substance was found also insoluble in olive oil. Therefore the test substance was administered as an olive oil suspension. A suitable analytical method was not found for homogeneity and stability testing. Since undissolved particles of the test substance are easily visible in the application form, homogeneity was checked by eye (suspensions were mixed for 15 minutes by magnetic stirrer).The concentrations of suspensions at every dose level were adjusted to ensure the administration of 1 mL/100 g bw. The test substance suspension in olive oil was prepared daily and mixed for 15 minutes by magnetic stirrer just prior administration. The vehicle control group received olive oil in the same volume, without test substance.

TREATMENT
The treated and control groups were administered daily for the period of 28 days. Oral administration was chosen on the request of sponsor. The animals were treated 7 days per week at the specified time (8.00 - 10.00 am).

Analytical verification of doses or concentrations:

no

Details on analytical verification of doses or concentrations:

No suitable analytical method was available for homogeneity and stability testing. Since undissolved particles of the test substance are easily visible in the application form, homogeneity was checked by eye (suspensions were mixed for 15 minutes by magnetic stirrer).

Duration of treatment / exposure:

28 days

Frequency of treatment:

Once daily, 7 days per week

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

1 000 mg/kg bw/day (actual dose received)

Doses / concentrations 2

Dose / conc.:

400 mg/kg bw/day (actual dose received)

Doses / concentrations 3

Dose / conc.:

0.16 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

Five animals per sex and dose group

Control animals:

yes, concurrent vehicle

Details on study design:

DOSE SELECTION RATIONALE
The doses were selected with respect to the results of a dose-range finding experiment.
SATELLITE GROUPS
A control (vehicle) satellite group as well as a 1000 mg/kg bw/day satellite group, each consisting of five animals per sex were added. These two groups were subjected to a treatment-free post exposure period of 14 days (i.e. day 29 to 42 of experiment).

Examinations

Observations and examinations performed and frequency:

CLINICAL OBSERVATIONS (GENERAL AND DETAILLED) AND MORTALITY
The animals were subjected to general clinical observation daily, during the administration period.
The animals were subjected to detailled clinical observation once prior test initiation and weekly thereafter. At the first part of observation behaviour of animals in the cage was monitored: posture, position of eyelids, tonic or clonic movements, piloerection, stereotypes or bizarre behaviour. The second part was the observation during removal from cage: reaction to handling, elasticity of skin, colour of mucous membranes, salivation, lacrimation, cleanliness of fur around foramina.
Check for mortality was done daily.

BODY WEIGHT
Body weight was recorded weekly.

FOOD CONSUMPTION
Food consumption was recorded weekly.

WATER CONSUMPTION
Water consumption was recorded twice a week

OPHTHALMOSCOPIC EXAMINATION
None

HAEMATOLOGY AND CLINICAL CHEMISTRY
Blood samples were collected on day 29 of study for the main groups and on day 43 for the satellite groups. The blood samples were collected from the orbital plexus under light ether narcosis into PVC test tubes containing anticoagulation systems.
Haematology analyser Coulter and Coagulometer were used for examination and the following parameters were considered: Total erythrocyte count RBC, Mean corpuscular volume MCV, Haematocrit HCT, Haemoglobin concentration HGB, Total leucocyte count WBC, Total platelet count PLT, Partial thromboplastin time APTT, Prothrombin time PT, Fibrinogen FIB, Granulocytes GRAN, Lymphocytes LYM, Monocytes MON.
The biochemical parameters were measured in the serum of the blood samples, which was obtained by centrifugation; the separated serum was collected individually. The following parameters were determined by automatic biochemical analysers: Glucose GLU, Cholesterol total T-Cho, Urea BUN, Bilirubin total T-Bil, Aspartate aminotransferase AST, Alanine aminotransferase ALT, Alkaline phosphatase ALP, Calcium Ca, Phosphorus IP, Protein total T-Pro, Protein albumin ALB, Creatinine Crea, Sodium Na, Potassium K, Chloride Cl.

URINALYSIS
Urine was collected on day 28 of study for the main groups and on day 42 for the satellite groups. For this purpose the rats were kept in metabolic cages and urine was collected for two hours. Immediately before entering metabolic cages the animals were administered with 2 mL/100 g bw of drinking water by gavage. The following parameters were considered: Volume, Colour, Cloud, Odour, Glucose GLU, Protein PRO, Bilirubin BIL, Urobilinogen URO, pH, specific gravity, Blood BLD, Ketones KET, Nitrites NIT, Leucocytes LEU.


NEUROBEHAVIOURAL EXAMINATION
This observation was done at the end of administration period at main groups or at the end of recovery period at satellite groups. During functional examination, the sensory reactivity on auditory, visual, proprioceptive stimuli and pupillary reflex were evaluated and motor activity assessment was conducted. Moreover the individual observations of grip strength were performed using dynamometer. Measurements were made on pectoral legs, pelvis legs, and all four legs; grip power was expressed in Newtons.

Sacrifice and pathology:

At the end of study the experimental animals were narcotised and sacrificed by cutting the neck spine and medulla. The cranial, thoracic and abdominal cavities were examined and then the organs were collected for weighing, gross pathology and histopathology.

ORGAN WEIGHTS
The absolute and relative weights of liver, kidneys, adrenals, gonads (testes or ovaries), epididymides or uterus, thymus, spleen, brain, pituitary gland and heart were recorded/calculated.

GROSS PATHOLOGY
A revision of the external surface of the body, of all orifices and the cranial, thoracic and abdominal cavities were carried out. Organs for consequent pathological examination were taken out and stored in containers with fixative (buffered 4% formaldehyde).


HISTOPATHOLOGY
Tissue specimens fixed in 4% buffered formaldehyde were processed by routine paraffin technique and stained by hematoxyline-eosine. Cryotome sections of liver and kidneys were stained by oil red for neutral lipids. Samples of following tissues and organs were considered for histopathology: Adrenal glands, Ovaries, Aorta, Pancreas, Brain (- cerebellum, mid-brain, cortex), Jejunum, Ileum, Caecum, Pituitary gland, Cervix of uterus, Prostate gland, Coagulation gland, Salivary glands (mandibular), Colon, Sciatic nerve, Duodenum, Seminal vesicles, Epididymides, Skeletal muscle, Female mammary gland area, Skin, Femur (bone marrow), Spinal cord (midthoracic), Heart, Spleen, Stomach, Testes, Kidneys, Thymus, Liver, Thyroid, Lungs, Trachea, Lymph nodes (mesenteric, paraaortal), Urinary bladder, Oesophagus, Uterus, all gross lesions.

Statistics:

The ANOVA test - Analysis of Variance (QC.Expert 2.5) at significance level 0.05 was used for the statistical analysis. This statistical analysis was used for the results of haematology, blood chemistry, urinalysis, biometry of organs and body weight. Control group with vehicle was compared with three treated groups and satellite control with vehicle was compared with the satellite treated group. The results statistically significant on probability level 0.05 were indicated.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food efficiency:

no effects observed

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

no effects observed

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

In 2 of 5 males of the high dose group (1000 mg/kg bw), enlarged paraortal nodes and in one of them enlarged mesenterial nodes with changed colour were recorded.

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

reactive hyperplasia of paraaortic lymph nodes (grade not specified) in 2/5 males at 1000 mg/kg bw

Details on results:

FOOD CONSUMPTION
No adverse effect on dietary intake and food efficiency was observed. It was noticed that the application of the test substance caused temporary colouring of the chyme but without marked effect on function of digestive tract. For details, see table below.

WATER CONSUMPTION
Water consumption decreased in both sexes treated with 1000 mg/kg bw/day during the application period. However, urinalysis revealed no changes of concern, thus indicating that the finding was of no toxicological relevance. For details, see table below.

HAEMATOLOGY
All parameters were within the historical control range. Occasionally parameters showed a statisical difference to the control group. There was however no dose-response relationship. Consdering that all parameters were within the historical control range, the changes are considered to be incidental and to be not related to the treatment.

CLINICAL CHEMISTRY
All parameters were within the historical control range. Occasionally parameters showed a statisical difference to the control group. There was however no dose-response relationship. Consdering that all parameters were within the historical control range, the changes are considered to be incidental and to be not related to the treatment.
The measured concentration of urea was below the historic control almost in all females at the middle dose level. Due to absence of changed hepatic parameters or histopathological changes in liver or kidneys, this effect was considered to be of no toxicological importance.

URINALYSIS
Urinalysis showed significantly decreased pH values only in females at the end recovery period. At the end application period there were detected only sporadic presences of protein, cloud or urobilinogen at all dose levels. No microscopic changes were found which could be associated to these sporadic changes; thus they were considered to be of no toxicological importance.

NEUROBEHAVIOUR
Functional observation evidenced no effect of the test substance.

ORGAN WEIGHTS
Sporadic significant changes in weight affecting brain and pituitary gland only were noticed at the end of the recovery period. Differences in absolute or relative weight of liver were sporadically recorded in males and females but were not associated to microscopic changes in this organ. Thus, differences in incidence of findings between control and treatment groups were considered to be of no toxicological significance.

GROSS PATHOLOGY AND HISTOPATHOLOGY
Pathological examination revealed possibly treatment changes in two of the males at the end of application period. Enlarged paraortal nodes (2 of 5 males, none in females) and enlarged mesenterial nodes with changed colour (1 of five males, none in females) were recorded at the highest dose level of 1000 mg/kg bw/day. Histopathology showed reactive hyperplasia of unknown severety of the paraaortic lymph nodes in the two males of the high dose group. No individual data is included in the report, but this information could later be retrieved directly from the CRO. Incidence of reactive hyperplasia in control animals was reported to be zero to two per study.
No neoplastic findings were recorded by histopathological examination.

Effect levels

1

Dose descriptor:

NOEL

Effect level:

400 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male

Basis for effect level:

clinical signs

food consumption and compound intake

other: 2 males affected: Enlarged paraortal nodes with reactive hyperplasia (n =2) and enlarged mesenterial nodes with changed colour (n=1) at of 1000 mg/kg bw/day.

2

Dose descriptor:

NOEL

Effect level:

1 000 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Body weight data:

Mean group body weight (g) for the male rats
Main study (28 days treatment)
Test group	0 mg/kg bw/d	160 mg/kg bw/d	400 mg/kg bw/d	1000 mg/kg bw/d
Day 0	182.54	182.28	183.24	182.22
Week 1	225.46	223.52	217.92	219.02
Week 2	258.36	258.26	249.50	252.76
Week 3	284.16	283.78	272.12	280.18
Week 4	306.16	306.86	289.38	305.74
Recovery groups (28 days treatment + 14 days recovery)
Day 0	182.20	-	-	182.80
Week 1	221.30	-	-	222.02
Week 2	251.34	-	-	255.34
Week 3	275.84	-	-	284.62
Week 4	295.84	-	-	309.72
Week 5	311.14	-	-	325.14
Week 6	320.48	-	-	338.26

Mean group body weight (g) for the female rats
Main study (28 days treatment)
Test group	0 mg/kg bw/d	160 mg/kg bw/d	400 mg/kg bw/d	1000 mg/kg bw/d
Day 0	136.58	136.66	136.60	136.72
Week 1	155.26	156.12	154.42	156.46
Week 2	167.54	170.64	166.90	172.40
Week 3	178.06	179.50	175.14	180.98
Week 4	190.24	190.42	182.74	186.50
Recovery groups (28 days treatment + 14 days recovery)
Day 0	136.16	-	-	136.78
Week 1	152.42	-	-	156.98
Week 2	164.50	-	-	172.04
Week 3	175.98	-	-	181.92
Week 4	186.28	-	-	190.68
Week 5	190.76	-	-	199.04
Week 6	194.86	-	-	206.00

Food consumption data:

Mean food consumption (g/animal/day) for male and females rats
Main study (28 days treatment)
Test group	0 mg/kg bw/d		160 mg/kg bw/d		400 mg/kg bw/d		1000 mg/kg bw/d
Sex	M	F	M	F	M	F	M	F
Week 1	21.09	13.84	19.43	14.77	18.47	12.68	17.76	13.57
Week 2	19.27	12.07	17.91	12.66	17.12	10.44	16.79	12.15
Week 3	18.53	11.46	16.92	11.67	16.15	10.44	16.95	11.30
Week 4	18.60	12.16	15.86	11.00	16.95	9.87	17.22	11.50
Recovery groups (28 days treatment + 14 days recovery)
Week 1	20.63	13.85	-		-		17.53	13.37
Week 2	18.49	12.18	-		-		17.61	11.57
Week 3	17.61	11.31	-		-		18.19	10.65
Week 4	18.19	11.51	-		-		18.32	11.34
Week 5	19.59	13.06	-		-		18.94	14.01
Week 6	19.87	13.09	-		-		20.29	13.74

Water consumption data:

Mean water consumption (mL/animal/day) for male and females rats
Main study (28 days treatment)
Test group	0 mg/kg bw/d		160 mg/kg bw/d		400 mg/kg bw/d		1000 mg/kg bw/d
Sex	M	F	M	F	M	F	M	F
Week 1	40.00	31.71	37.43	33.14	36.86	32.00	36.57	32.29
Week 2	37.14	28.29	35.14	30.57	34.00	28.00	38.57	31.43
Week 3	39.43	32.86	39.14	34.57	38.00	31.71	36.29	33.71
Week 4	40.57	35.71	39.14	36.29	38.57	31.43	36.29	31.43
Recovery groups (28 days treatment + 14 days recovery)
Week 1	39.71	33.14	-		-		35.14	29.14
Week 2	36.57	28.00	-		-		34.57	27.71
Week 3	40.00	34.00	-		-		38.00	30.29
Week 4	40.57	34.29	-		-		36.29	30.57
Week 5	40.57	35.14	-		-		39.71	34.29
Week 6	40.57	32.29	-		-		37.14	30.86

Haematological data for females (means)
dose group	0	140	400	1000	recovery 0	recovery 1000
RBC (10 exp6/uL)	6.57	6.87	6.72	6.82	7.03	6.9
MCV	53.9	54.6	53.4	53.7	53.4	54.1
Haematocrit (%)	35.6	37.5	35.9	36.6	37.6	37.2
Haemogloblin (g/100ml)	12.6	13	12.7	13	13.3	13.2
WBC (1000 /uL)	3.8	4.1	3.7	3.6	4.5	4.7
Platelets (1000 /uL)	900	919	919	820	865	929
APTT (S)	24	26	28	26	26	25
Protrombine Time (s)	25	26	28	26	26	25
Fibrinogen (g/L)	1.66	1.8	1.81	1.82	1.76	2.06
Granulocytes (%)	6.5	5.6	6.8	4.5	5.4	6.4
Lymphocytes (%)	86.9	87.1	81	87.6	86.3	84
Monocytes (%)	6.6	7.3	12.1	7.9	8.2	9.6
Haematological data for males (means)
dose group	0	140	400	1000	recovery 0	recovery 1000
RBC (10 exp6/uL)	6.65	7.01	7.94	6.83	7.08	7.26
MCV	53.9	55.8	53.8	56.2	51.3	53.8
Haematocrit (%)	35.8	38.9	37.7	38.3	37.6	39.2
Haemogloblin (g/100ml)	12.5	13.3	13.2	13	13.3	13.5
WBC (1000 /uL)	7.18	6.84	6.36	7.26	6.22	7.94
Platelets (1000 /uL)	879	893	787	730	826	827
APTT (S)	28.8	25.2	36.2	43.5	40.8	34.9
Protrombine Time (s)	25	32.2	31.8	29.4	33	28.9
Fibrinogen (g/L)	2.23	2.27	2.23	2.43	2.66	2.43
Granulocytes (%)	9.56	7.56	6.5	5.7	7.6	9
Lymphocytes (%)	83.7	86.3	85.1	87	80.7	81.8
Monocytes (%)	6.8	6.1	8.4	7.3	11.5	9.2