2,2'-[[3-acetamido-4-[(2-chloro-4-nitrophenyl)azo]phenyl]imino]diethyl diacetate

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

October 26th 1998 to November 18th 1998

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Version / remarks:

OECD Guideline For Testing of Chemicals, 474 Genetic Toxicology, Mammalian Erythrocyte Micronucleus Test, Adopted 21st, July 1997

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.12 (Mutagenicity - In Vivo Mammalian Erythrocyte Micronucleus Test)

Version / remarks:

EEC Directive 92/69, L 383 A, Annex B. 12., p. 154-156

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.5395 (In Vivo Mammalian Cytogenetics Tests: Erythrocyte Micronucleus Assay)

Version / remarks:

U.S. EPA: OPPTS 870.5395 Health Effects Test Guidelines; Mammalian Erythrocyte Micronucleus Test, August 1998

Deviations:

no

GLP compliance:

yes

Type of assay:

other: Mammalian Erythrocyte Micronucleus Test

Test material

Test material information

Constituent 1

Reference substance name:

2,2'-[[3-acetamido-4-[(2-chloro-4-nitrophenyl)azo]phenyl]imino]diethyl diacetate

EC Number:

216-251-6

EC Name:

2,2'-[[3-acetamido-4-[(2-chloro-4-nitrophenyl)azo]phenyl]imino]diethyl diacetate

Cas Number:

1533-78-4

Molecular formula:

C22H24ClN5O7

IUPAC Name:

2,2'-[[3-acetamido-4-[(2-chloro-4-nitrophenyl)azo]phenyl]imino]diethyl diacetate

Test material form:

solid: particulate/powder

Test animals

Species:

mouse

Strain:

NMRI

Details on species / strain selection:

Species of animals: mouse
Strain of animals: HsdWin:NMRI
The mouse has been chosen for this study since it provides a convenient in vivo mammalian model.

Sex:

male/female

Details on test animals or test system and environmental conditions:

Species of animals: mouse
Strain of animals: HsdWin:NMRI
Origin (supplier) of animals: Harlan Winkelmann GmbH, Gartenstrasse 27, 33178 Borchen
Animal identification: fur marking with KMn04 and cage numbering
Body weight at start of study
male animals:
mean = 33.9 g (=100%)
min = 32.0 g (- 5.6 %)
max = 38.0 g (+ 12.1 %)
n = 15
female animals:
mean = 27.3 g (=100%)
min = 26.0 g (- 4.8 %)
max = 29.0 g (+ 6,2 %)
n = 15

Age at the start of study: male/female animals approximately 7 weeks
Randomization procedure: randomization schemes 98.0890 and 98.0891
Animal maintenance: in fully air-conditioned rooms in makrolon cages type 3 (five animals per cage) on soft wood granulate
Room temperature: 22 ± 3°C
Relative humidity: 50 ± 20%
Lighting times: 12 hours daily
Acclimatization: 5 days under study conditions
Food: rat/mice diet ssniff® R/M-H (V 1534), ad libitum ssniff® GmbH, Postbox 2039, 59480 Soest
Water: tap water in plastic bottles, ad libitum

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

Tylose HEC 4000

Details on exposure:

On the days of administration the test substance was suspended in Tylose HEC 4000 (0.5% w/v) at the appropriate concentration. A magnetic stirrer was used to keep the preparation homogeneous until dosing had been completed.

Duration of treatment / exposure:

48 hours

Frequency of treatment:

twice at an interval of 24 hours

Post exposure period:

24 hours

Doses / concentrations

Dose / conc.:

2 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

5 males/5 females per dose group (test, vehicle/negative control & positive control)

Control animals:

yes

yes, concurrent vehicle

Positive control(s):

Name or number of compound (I.N.N. or U.S.A.N): cyclophosphamide
Synonyms: Endoxan®
Formula of the compound: C7H15Cl2N2P – H2O
CAS-Register number: 50-18-0
Supplier of reference compound: ASTA Medica AG
Batch number: 6035758
Certificate of analysis: certified by the supplier

Formulation of reference compound: CPA dissolved in distilled water on the second day of experiment; final concentration: 0.5 % (w/v)

Examinations

Tissues and cell types examined:

2000 polychromatic erythrocytes were counted for each animal. The number of cells with micronuclei was recorded, not the number of individual micronuclei. In addition, the ratio of polychromatic erythrocytes to 200 total erythrocytes was determined.

Details of tissue and slide preparation:

Animals were killed by carbon dioxide asphyxiation 24 hours after dosing. For each animal, about 3 ml fetal bovine serum was poured into a centrifuge tube. Both femora were removed and the bones freed of muscle tissue. The proximal ends of the femora were opened and the bone marrow flushed into the centrifuge tube. A suspension was formed. The mixture was then centrifuged for 5 minutes at approx. 1200 rpm, after which almost all the supernatant was discarded. One drop of the thoroughly mixed sediment was smeared onto a cleaned slide, identified by project code and animal number and air-dried for about 12 hours.

Staining was performed as follows:
- 5 minutes in methanol
- 5 minutes in May-Grűnwald's solution
- brief rinsing twice in distilled water
- 10 minutes staining in 1 part Giemsa solution to 6 parts buffer solution, pH 7.2 (Weise)
- rinsing in distilled water
- drying
- coating with Entellan®

Evaluation criteria:

Both biological and statistical significances were considered together for evaluation purposes.
A substance is considered positive if there is a significant increase in the number of micronucleated polychromatic erythrocytes compared with the concurrent negative control group. A test substance producing no significant increase in the number of micronucleated polychromatic erythrocytes is considered non-mutagenic in this system.

Statistics:

Main parameter for the statistical analysis, i.e. validity assessment of the study and mutagenicity of the test substance, was the proportion of polychromatic erythrocytes with micronuclei out of the 2000 counted erythrocytes. All bone marrow smears for evaluation were coded to ensure that the group from which they were taken remained unknown to the investigator.
A one-sided Wilcoxon-Test was evaluated to check the validity of the study. The study was considered as valid in case the proportion of polychromatic erythrocytes with micronuclei in the positive control was significantly higher than in the negative control (p=0.05).
If the validity of the study had been shown the following sequential test procedure for the examination of the mutagenicity was applied: Based on a monotone-dose relationship one-sided Wilcoxon tests were performed starting with the highest dose group. These test were performed with a multiple level of significance of 5%

Results and discussion

Test results

Key result

Sex:

male/female

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

All animals survived after treatment. Red colored urine but no signs of toxicity were observed.
The bone marrow smears were examined for the occurrence of micronuclei in red blood cells.
The incidence of micronucleated polychromatic erythrocytes in the dose group of C.l. Disperse Red 167 was within the normal range of the negative control groups. No statistically significant increase of micronucleated polychromatic erythrocytes was observed. The ratio of polychromatic erythrocytes to total erythrocytes remained essentially unaffected by the test compound and was not less than 20% of the control values.
Cyclophosphamide (Endoxan) induced a marked and statistically significant increase in the number of polychromatic erythrocytes with micronuclei, thus indicating the sensitivity of the test system.

Any other information on results incl. tables

Summary tables and statistics

Test compound:C.I. Disperse Red 167

Sex	Dose mg/kg bwt.	Killing time	Number		Poly/Ery   Mean	Poly/Ery SD Mean	Poly with MN   Mean	Poly with MN [%] Mean	Poly with MN SD Mean
			of animals	Poly counted
Male Male Male	0 – Control 2000 50 – Endoxan	24 h 24 h 24 h	5 5 5	2000 2000 2000	0.48 0.58 0.42	0.07 0.06 0.04	1.6 1.0 60.6	0.08 0.05 3.03	0.03 0.04 0.69
Female Female Female	0 – Control 2000 50 – Endoxan	24 h 24 h 24 h	5 5 5	2000 2000 2000	0.54 0.52 0.44	0.05 0.08 0.05	1.2 3.2 53.8	0.06 0.16 2.69	0.07 0.10 0.59

 

Sex	Dose mg/kg bwt.	Killing time	Number		Poly/Ery   Mean	Poly/Ery SD Mean	Poly with MN   Mean	Poly with MN [%] Mean	Poly with MN SD Mean	Mut. I.
			of animals	Poly counted
Pooled Pooled Pooled	0 – Control 2000 50 – Endoxan	24 h 24 h 24 h	10 10 10	2000 2000 2000	0.51 0.55 0.43	0.07 0.07 0.04	1.40 2.10 57.20*	0.1 0.1 2.9	0.05 0.09 0.63	1.0 1.5 40.9

Mut. I. = Mutagenic Index

Control = Vehilce Tylose HEC 4000 (0.5% (w/v))

* = significantly different from control (p<0.05)

 

A cross comparison of individual data and pooled data may show discrepancies since the values are rounded.

 

Table of individual data

Test compound:C.I. Disperse Red 167

Group	Animal number	Sex	Dose mg/kg b.w.	Poly/200Ery	Poly with MN	Poly/Ery	Poly with MN [%]
1 1 1 1 1 1 1 1 1 1	1 2 3 4 5 6 7 8 9 10	Male Male Male Male Male Female Female Female Female Female	0 – Control 0 – Control 0 – Control 0 – Control 0 – Control 0 – Control 0 – Control 0 – Control 0 – Control 0 – Control	114 78 97 102 91 111 99 123 97 113	2 2 1 2 1 0 2 1 0 3	0.57 0.39 0.49 0.51 0.46 0.56 0.50 0.62 0.49 0.57	0.10 0.10 0.05 0.10 0.05 0.00 0.10 0.05 0.00 0.15
2 2 2 2 2 2 2 2 2 2	31 32 33 34 35 36 37 38 39 40	Male Male Male Male Male Female Female Female Female Female	2000 2000 2000 2000 2000 2000 2000 2000 2000 2000	119 131 97 113 119 115 90 102 90 125	0 1 2 1 1 2 3 6 4 1	0.60 0.66 0.49 0.57 0.60 0.58 0.45 0.51 0.45 0.63	0.00 0.05 0.10 0.05 0.05 0.10 0.15 0.30 0.20 0.05
3 3 3 3 3 3 3 3 3 3	21 22 23 24 25 26 27 28 29 30	Male Male Male Male Male Female Female Female Female Female	50 – Endoxan 50 – Endoxan 50 – Endoxan 50 – Endoxan 50 – Endoxan 50 – Endoxan 50 – Endoxan 50 – Endoxan 50 – Endoxan 50 – Endoxan	73 96 83 79 84 80 82 79 100 95	79 71 56 49 48 58 61 33 60 57	0.37 0.48 0.42 0.40 0.42 0.40 0.41 0.40 0.50 0.48	3.95 3.55 2.80 2.45 2.40 2.90 3.05 1.65 3.00 2.85

 

 

Historical control values

 

Based on OECD 474, adopted 1997:

		Micronucleated PCE / 2000 PCE						PCE / Ery (200 Ery counted)
Vehicle	Sex	N	Mean	STD	Min	Med	Max	N	Mean	STD	Min	Med	Max
DMA / PEG / citrate buffer	Female	5	2.4	0.89	1	3	3	5	0.43	0.06	0.37	0.42	0.51
	Male	5	3.8	2.49	2	2	7	5	0.45	0.07	0.35	0.45	0.52
Deionized water	Female	25	1.88	1.36	0	2	6	25	0.50	0.06	0.41	0.51	0.66
	Male	25	1.64	1.19	0	1	5	25	0.45	0.07	0.33	0.46	0.59
Sesame oil	Female	5	2	1.58	0	2	4	5	0.50	0.08	0.40	0.51	0.60
	Male	5	3	1.58	1	3	5	5	0.48	0.10	0.34	0.47	0.59
Total	Female	35	1.97	1.32	0	2	6	35	0.49	0.07	0.37	0.50	0.66
	Male	35	2.14	1.65	0	2	7	35	0.46	0.07	0.33	0.46	0.59

PCE: Polychromatic Erythrocytes

NCE: Normochromatic Erythrocytes

Ery: Total Erythrocytes (PCE + NCE)

Applicant's summary and conclusion

Conclusions:

The results lead to the conclusion that Disperse Red 167:1 did not lead to a substantial increase of micronucleated polychromatic erythrocytes and is not mutagenic in the micronucleus test under the conditions described in this report. The substance is not classifiable according to CLP criteria.

Executive summary:

The micronucleus test was carried out with the test item. The test compound was suspended in Tylose HEC 4000 (0.5% w/v) and was given twice at an interval of 24 hours as an orally dose of 2000 mg per kg body weight to male and female mice, based on the results of a previous dose range finding assay (see preliminary study).

According to the test procedure the animals were killed 24 hours after administration.

 

Endoxan® was used as positive control substance and was administered once orally at a dose of 50 mg per kg body weight.

 

The number of polychromatic erythrocytes containing micronuclei was not increased.

The ratio of polychromatic erythrocytes to total erythrocytes in both male and female animals remained unaffected by the treatment with the test item and was not less than 20% of the control value.

 

Endoxan® induced a marked statistically significant increase in the number of polychromatic cells with micronuclei, indicating the sensitivity of the test system. The ratio of polychromatic erythrocytes to total erythrocytes was not changed to a significant extent.

 

Under the conditions of the present study the results indicate that Disperse Red 167:1 is not mutagenic in the micronucleus test.