Monosodium aqua-[5-[[2,4-dihydroxy-5-[(2-hydroxy-3,5-dinitrophenyl)azo]phenyl]azo]-2-naphthalensulfonate], iron complex

Endpoint summary

Description of key information

oral

rat (OECD 409)  NOAEL (m/f): 55 mg/kg bw/day  (BASF AG, 1988)

dermal

Actually, there is no information available.

inhalation

Actually, there is no information available.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Remarks:

Department of Toxicology, BASF AG

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Dr . Karl Thomae GmbH, Biberach a. d. Riss, FRG
- Age at study initiation: 42 d
- Weight at study initiation: mean 162 g (males), 134 g (females)
- Housing: singly in type DK III stainless steel wire cages, supplied by BECKER & CO., Castrop-Rauxel, FRG (floor area about 900 cm2)
- Diet (e.g. ad libitum): was ground Kliba rat/mouse "A" maintenance diet, GLP 343 meal, supplied by Klingentalmühle AG, CH-4303 Kaiseraugst, Switzerland; ad libitum
- Water (e.g. ad libitum): tap water; ad libitum
- Acclimation period: 5 days


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

Route of administration:

oral: drinking water

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
Drinking water solutions were prepared twice a week by weighing the test substance and then disolving it in-drinking water using a magnetic stirrer. The stability of the drinking water solutions was confirmed over a period of 5 days. The concentration of the drinking water solutions was verified on the basis of one sample of each concentration, taken at the start of the study, in a double determination.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The content of Säurebraun 6229 in the drinking water was determined by the UV-VIS method.

Duration of treatment / exposure:

28 days

Frequency of treatment:

continously by drinking water

Remarks:

Doses / Concentrations:
500, 5000, 10000 ppm
Basis:
nominal in water

No. of animals per sex per dose:

5

Control animals:

yes, concurrent no treatment

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- Cage side observations checked in table.


DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: at each weighing, thus once a week


BODY WEIGHT: Yes
- Time schedule for examinations: All the animals were weighed once a week. The body weight was always determined on the same day of the week and at the same time of the day


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: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No


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: No


WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule for examinations: determined twice a week


OPHTHALMOSCOPIC EXAMINATION: No


HAEMATOLOGY: Yes
- Time schedule for collection of blood: 9 days (female animals, 10000 ppm ) or 25 days after the beginning of administration (blood sampling 1)
- Anaesthetic used for blood collection: No
- Animals fasted: No
- How many animals: all
- Parameters examined: hemoglobin, erythrocytes, hematocrit, mean hemoglobin content per erythrocyte, mean corpuscular volume, mean corpuscular hemoglobin concentration, platelets, leukocytes, differential blood count, prothrombin time


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: 9 days (female animals, 10000 ppm ) or 25 days after the beginning of administration (blood sampling 1)
- Animals fasted: no
- How many animals: all
- Parameters examined: total bilirubin, creatinine, urea, sodium, potassium, total protein, glucose, inorganic phosphate, calcium, chloride, triglycerides, cholesterol albumin, glutamic-pyruvic transaminase, alkaline phosphatase, glutamic-oxalacetic transaminase


URINALYSIS: Yes
- Time schedule for collection of urine: 29 days after the beginning of treatment
- Metabolism cages used for collection of urine: No data
- Animals fasted: No data
- Parameters examined: pH, protein, glucose, ketones, bilirubin, blood, nitrite, urobilinogen, sediment


NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes: liver, kidneys, spleen, adrenals, heart, testes, gastrointestinal tract and all gross lesions

Statistics:

- ANOVA followed by DUNNETT's test: body weights
- WILLIAMS test: absolute organ weights
- t- test: blood and plasma examinations
- chi-square test in corresponding two by two contingency tables: urinalysis

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

brown feces from day 1 for all concentrations and yellow urine from day 10;
- one female showed a yellowish brown smear in the anogenital region, and this started with day 7 after the beginning of the administration period

Mortality:

mortality observed, treatment-related

Description (incidence):

10000 ppm:
- 2/5 animals died 14 days after the beginning of the administration period.
- 1 female animal was sacrificed in a moribund state on day 18 after the beginning of the study; due to their poor state of health, remainin g females were sacrificed prematurely on day 9 after the beginning of the administration period

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

10000 ppm:
- pronounced reduction in body weight in 3/5 females and reduction in body weight throughout the study in males
5000 ppm:
- reduction in body weight in the male and female animals throughout the study

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

10000 ppm:
- severe reduction in feed consumption in 3/5 females
- in males, reduction in feed consumption in the 1st week of the study followed by an increase to above the control values
5000 ppm:
- reduced feed consumption in the female animals in the 1st to 3rd week of the study and in the male animals in the first half of the study

Water consumption and compound intake (if drinking water study):

effects observed, treatment-related

Description (incidence and severity):

10000 ppm:
- extreme reduction in water consumption in 4/5 females
- reduced water consumption in 3/5 males in the 1st week of the study followed by an increase in water consumption to above the control values
5000 ppm:
- reduced drinking water consumption in 3 of 5 male and female animals, approaching or exceeding the control values during the study

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

10000 ppm:
- in females increase in the following values: prothrombin time, hemoglobin, erythrocyte count, hematocrit, mean corpuscular volume (MC V), polymorphonuclear neutrophils and atypical lymphocytes as well as polychromasia. Decrease in mean hemoglobin content per erythro cyte (MCH), mean corpuscular hemoglobin concentration (MCHC) and platelet count
- in males increase in the polymorphonuclear neutrophil count and increased incidence of polychromasia and anisocytosis
5000 ppm
- reduction in glucose and hemoglobin values in the male animals
- increase in polymorphonuclear neutrophils and monocytes in both sexes and increase in the cholesterol and leukocyte, lymphocyte and platelet counts in the male animals
- increased polychromasia in the male and female rats and increased anisocytosis in the male animals

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

10000 ppm:
- In females increase in the following values: urea, sodium, inorganic phosphate, chloride, glutamic pyruvic transaminase, glutamic oxalac etic transaminase. Decrease in total protein and albumin
- In males increased urea levels
5000 ppm:
- reduction in total protein and albumin concentrations in both sexes

Urinalysis findings:

effects observed, treatment-related

Description (incidence and severity):

5000 ppm:
- increase in the inorganic phosphate concentration and urea levels and increased excretion of renal epithelial cells in the female animals

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

10000 ppm:
- Necrotizing typhlitis and edemas in the cecum in males and females
5000 ppm.
- necrotizing typhlitis and edemas of the cecum in the male and female animals
- necrotizing colitis in the male rats

Details on results:

CLINICAL SIGNS AND MORTALITY
10000 ppm:
- 2/5 animals died 14 days after the beginning of the administration period.
- 1 female animal was sacrificed in a moribund state on day 18 after the beginning of the study; due to their poor state of health, remainin g females were sacrificed prematurely on day 9 after the beginning of the administration period
- a blackish brown colored feces from day 1 on; yellowish brown colored urine from day 10 on
5000 ppm:
- blackish brown colored feces in males and females from day 1 on
- addition showed yellowish brown colored urine from day 10 on
- one female showed a yellowish brown smear in the anogenital region, and this started with day 7 after the beginning of the administratio n period
500 ppm:
- blackish brown colored feces in males and females
- addition showed yellowish brown colored urine from day 10 on


BODY WEIGHT AND WEIGHT GAIN
10000 ppm:
- pronounced reduction in body weight in 3/5 females and reduction in body weight throughout the study in males
5000 ppm:
- reduction in body weight in the male and female animals throughout the study


FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study)
10000 ppm:
- severe reduction in feed consumption in 3/5 females
- in males, reduction in feed consumption in the 1st week of the study followed by an increase to above the control values
5000 ppm:
- reduced feed consumption in the female animals in the 1st to 3rd week of the study and in the male animals in the first half of the study


WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study)
10000 ppm:
- extreme reduction in water consumption in 4/5 females
- reduced water consumption in 3/5 males in the 1st week of the study followed by an increase in water consumption to above the control values
5000 ppm:
- reduced drinking water consumption in 3 of 5 male and female animals, approaching or exceeding the control values during the study


HAEMATOLOGY
10000 ppm:
- in females increase in the following values: prothrombin time, hemoglobin, erythrocyte count, hematocrit, mean corpuscular volume (MC V), polymorphonuclear neutrophils and atypical lymphocytes as well as polychromasia. Decrease in mean hemoglobin content per erythro cyte (MCH), mean corpuscular hemoglobin concentration (MCHC) and platelet count
- in males increase in the polymorphonuclear neutrophil count and increased incidence of polychromasia and anisocytosis
5000 ppm
- reduction in glucose and hemoglobin values in the male animals
- increase in polymorphonuclear neutrophils and monocytes in both sexes and increase in the cholesterol and leukocyte, lymphocyte and platelet counts in the male animals
- increased polychromasia in the male and female rats and increased anisocytosis in the male animals


CLINICAL CHEMISTRY
10000 ppm:
- In females increase in the following values: urea, sodium, inorganic phosphate, chloride, glutamic pyruvic transaminase, glutamic oxalac etic transaminase. Decrease in total protein and albumin
- In males increased urea levels
5000 ppm:
- reduction in total protein and albumin concentrations in both sexes


URINALYSIS
5000 ppm:
- increase in the inorganic phosphate concentration and urea levels and increased excretion of renal epithelial cells in the female animals

GROSS PATHOLOGY
10000 ppm:
- Necrotizing typhlitis and edemas in the cecum in males and females
5000 ppm.
- necrotizing typhlitis and edemas of the cecum in the male and female animals
- necrotizing colitis in the male rats

Dose descriptor:

NOAEL

Effect level:

> 55 mg/kg bw/day (actual dose received)

Sex:

male

Basis for effect level:

clinical biochemistry

haematology

Dose descriptor:

NOAEL

Effect level:

> 55 mg/kg bw/day (actual dose received)

Sex:

female

Basis for effect level:

clinical biochemistry

haematology

Critical effects observed:

not specified

Based on additional testing , the authors concluded that the increase in bilirubin detected in the urine is due to an interfering reaction of

the test substance with the test method used. Therefore, the increased bilirubin levels in the urine are not regarded as having any pathognostic relevance.

Substance intake (mg/kg bw/d):

Dose group	Sex	Days
		1 - 7	8 - 14	15 - 21	22 - 28
500 ppm	male	63	54	46	45
	female	73	57	53	47
5000 ppm	male	536	636	728	736
	female	489	635	732	665
10000 ppm	male	897	1984	1670	1465
	female	772	x	x	x

Body weights (g):

Dose group	Sex	Day
		0	7	14	21	28
control	male	161.0 ± 6.6	211.3 ± 12.6	249.6 ± 15.1	277.6 ± 14.0	296.8 ± 15.2
	female	133.5 ± 4.4	160.6 ± 7.1	182.7 ± 5.8	195.8 ± 10.6	209.4 ± 15.1
500 ppm	male	162.0 ± 6.6	212.3 ± 11.9	252.1 ± 18.0	283.7 ± 17.9	312.3 ± 19.9
	female	133.9 ± 4.8	162.6 ± 6.6	186.0 ± 10.8	203.4 ± 11.7	210.4 ± 12.9
5000 ppm	male	160.3 ± 5.3	169.7 ± 15.6*	184.3 ± 26.9**	212.7 ± 19.2**	235.8 ± 20.6**
	female	133.3 ± 3.6	130.5 ± 23.1	143.4 ± 34.9*	175.0 ± 13.2*	185.9 ± 12.1*
10000 ppm	male	161.0 ± 5.2	146.8 ± 39.2**	209.1 ± 15.3**	244.8 ± 9.9*	273.9 ± 5.7
	female	133.5 ± 4.0	107.3 ± 33.2**	x	x	x
Different from control: *p<0.05; **p<0.01 (Anova + Dunett's, two sided)

Conclusions:

The substance was tested for repeated dose toxicity oral in rats following OECD 407-. Under the experimental conditions the NOAEL resulted > 55 mg/kg bw/ day (mena value) for males and females.

Executive summary:

The substance was tested for repeated dose toxicity oral in rats following OECD 407 . Ten wistar rats for each group were exposed to the substance by oral, dissolving the substance in the drinking water at the following concentrations 500, 5000 and 10000 ppm, corresponding ca to 55, 645 or 1358 mg/kg bw/day (mean uptake of test substance by male (m) and female (f) animals)

. Mortality was observed at the highest dose. Clinical signs as coloured feces and urine at all doses. Biochemisry and hematological findings were recorded at 5000 and 10000 ppm as well as urinalysis. Under the experimental conditions the NOAEL resulted > 55 mg/kg bw/ day (mena value) for males and females.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

55 mg/kg bw/day

Study duration:

subacute

Species:

rat

Additional information

oral

A 28-day subacute study was conducted according to OECD guideline 407 with rats which received 55, 645 or 1358 mg/kg bw/day (mean uptake of test substance by male (m) and female (f) animals) of test substance in drinking water. The animal’s state of health was checked each day, examinations of blood, urine and clinical chemistry parameters were performed. Gross and histopathology were done at the end of the study period.

 

No substance related effects, except discoloured feces and urine, were seen in the lowest dosing group in both sexes.

 

In both higher dosing groups substance-related toxic effects were observed:

Mortality: animals died or had to be killed particularly due to non-specific reactions caused by cachexia and exsiccosis or the moribund status of the animals (2 male rats (1358 mg/kg bw/day; day 14) died, 1 female rat (645 mg/kg bw/day; day 18) and all female rats of the highest dose group (1358 mg/kg bw/day; day 9) were killed due to their bad/moribund general state).

Pathology: in the 645 and 1358 mg/kg bw/day groups substance-specific toxic effects, i.e. mild to moderate lesions to the kidneys (1358 mg/kg bw/day (m/f); hyperemia, tubulonephrosis), cecum and colon (645 and 1358 mg/kg bw/day (m/f); necrotizing typhlitis, edema and colitis), were observed. Depletion of lymphatic tissue in spleen and thymus in the highest dose group was reported, however, this was ascribed to the bad general state of the animals (inanition atrophy).

Clinical chemistry / hematology: the pathologic observations correlated well with clinical parameters that indicated renal dysfunction (decrease of total protein and albumin and increase of urea (m/f), cholesterol (m) and phosphate in blood and epithelial cells of kidney in urine (f)) and inflammatory conditions (increase of neutrophil granulocytes (m/f), monocytes and lymphocytes (m)) also in the 645 mg/kg bw/day dose groups. Clincal data indicate therefore that the no adverse effect level is between 55 and 645 mg/kg bw/day. Furthermore, increased occurrence of polychromasia and anisocytosis was observed that indicated an effect on the red blood cell count.

The most sensitive adverse effect was that animals, that received 645 or 1358 mg/kg bw/day came down with necrotizing typhlitis, intestinal edemas and colitis. This was identified as primary adverse effect. As secondary effect, clinical parameters were altered that indicated inflammation and renal dysfunction or capacity overload. The latter was supported by the appearance of mild lesions to the kidney and appearance of renal epithelial cells in urine.

A possible interpretation of the primary toxic effect could be that a substance-metabolite released by intestinal bacteria (e.g. by azo-reduction) could harm the intestinal epithelium. 1) Due to the fact that ulcerations in the stomach did not appear in the repeated dose study it is likely that the intestinal microflora plays a dominant role, 2) ulcerations occur around the cecum, which represents the primary bacterial inoculation site of the intestine.

Toxicokinetic data revealed that rat intestinal bacteria were able to degrade the test substance presumably via an azo-reductive mechanism (BASF toxicokinetic study). Possible metabolites generated from the test substance by azo-reduction are picramic acid (4,6 -dinitro-2 -amino-phenol), cleve acid (1 -aminonaphthalene-6 -sulfonic acid) and 1,3 -dihydroxy-m-phenylenediamine. The toxicokinetic study showed that cleve acid was detectable (20%; HPLC-analysis) under the experimental conditions after 24 h incubation of the test substance with intestinal bacteria. Picramic acid was not detectable, but detection could have been impaired due to further reduction of the metabolite's nitro-groups within the incubation time by bacterial nitroreductase. Bacterial nitroreductase shows similar activities in cecal extracts compared to azoreductase (Mallett et al (1983) Appl Environm Microbiol, 46(3):591 -595) The last metabolite was not detected.

The first metabolite, picramic acid, is a strong acid with a dissociation constant of pKa=1 (CAS 96 -91 -3; Toxnet, ChemIDPlus-module); A BASF study (1987; acute oral toxicity (gavage in olive oil); 10A0363/871112; male Fischer rats) showed mortality of test animals at 200 and 300 mg/kg bw after single administration of the metabolite. This was supported by an additional BASF study (1987; acute oral toxicity (gavage in water); 10A0363/871111; male and female Fischer rats) which showed mortality at 200 and 300 mg/kg bw of test substance as well as an impaired general state of animals that received 75,200 or 300 mg/kg bw of test substance. In both studies no gross pathological changes were observed after 14 d or in died animals except discolored stomach mucosa. The potential of the metabolite to induce mucosal irritation was observed in another study. Picramic acid (0.1 ml of a 2.5% aqueous sodium picramate solution buffered to pH 7) was irritating to the eye mucosa (rabbit eye; Huntington Research Centre, 1976; summarized in Journal of the American College of Toxicology, Vol.11, No.4, 1992, Final Report on the Safety Assessment of Sodium Picramate). The second metabolite, cleve's acid, is a weaker acid with a dissociation constant of pKa=3.7 (CAS 119 -79 -9; Beilstein). If those metabolites have been generated in situ by bacterial reductases in a setting where test sustance is delivered contiuously, even low levels of the metabolites could have been responsible for the damage of the intestinal mucosa. The presence of an intestinal necrosis/inflammation could also explain the secondary clinical symptoms (inflammatory conditions, renal dysfunction) mentioned above.

 

In summary, substance-related toxic effects were observed in the 645 and 1358 mg/kg bw/day groups. The NOAEL has to be described as 55 mg/kg bw/day uptake of test substance.

 

dermal

Actually, there is no information available.

 

inhalation

Actually, there is no information available.

Justification for classification or non-classification

Based on the GHS and the EU criteria for classification and labelling, according to the above mentioned 28 -day subacute study the concentration/uptake (C) range for classification of toxic effects is 30<C<300 mg/kg bw/day. Substance-related toxic effects were observed at 645 mg/kg bw/day mean uptake of test substance (range 489 -736 mg/kg bw/day).

Therefore there is currently no need for classification of effects due to repeated oral exposure to the test substance. There are no data available given to classify the test substance for repeated dermal or inhalative toxicity.