N,N'-diacetylhydrazine

Carcinogenicity

Description of key information

- Oral: negative, 2 year carcinogenicity bioassay with mice, no guideline followed, Bhide 1984

Key value for chemical safety assessment

Carcinogenicity: via oral route

Link to relevant study records

Reference

Endpoint:

carcinogenicity: oral

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: - meets generally accepted scientific principles - Documentation insufficient for thorough assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Swiss mice randomly distributed to groups so as to have the same number of males and females in each group (total 30 or 40).
- animals applied with DAH (1.1 mg/day per mouse) or distilled water 5 times a week by stomach tube
- Experiment 1: treatment until death or until sacrifice
- Experiment 2: 1.1 mg/day per mouse of DAH applied via gavage 5 times a week for 8 months
- Final examination: lungs examined macroscopically and fixed in 10% formalin, processed by routine histological process and sections (6 µm), stained with hematoxylin and eosin
- Statistical analysis performed by the chi-square-test.

GLP compliance:

no

Species:

mouse

Strain:

Swiss

Sex:

male/female

Details on test animals or test system and environmental conditions:

no data

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
Diacetylhydrazine dosed undiluted

VEHICLE
- n/a

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

Experiment 1: 16 - 22 months
Experiment 2: 8 months

Frequency of treatment:

5 d/week

Post exposure period:

none

Remarks:

Doses / Concentrations:
Experiment 1: 1.1 mg/d/animal
Basis:
actual ingested

Remarks:

Doses / Concentrations:
Experiment 2: 1.1 mg/d/animal
Basis:
actual ingested

No. of animals per sex per dose:

15 - 20 per sex and dose

Control animals:

other: yes, concurrent treated with distilled water (unknown amount)

Details on study design:

- Dose selection rationale: no data
- Rationale for animal assignment (if not random): random
- Rationale for selecting satellite groups: n/a
- Post-exposure recovery period in satellite groups: n/a
- Section schedule rationale (if not random): no data

Positive control:

no

Observations and examinations performed and frequency:

- Experiment 2: animals "observed"

Sacrifice and pathology:

- Final examination: lungs examined macroscopically and fixed in 10% formalin, processed by routine histological process and sections (6 µm), stained with hematoxylin and eosin

Statistics:

- Statistical analysis performed by the chi-square-test.

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

increased mortality at 0.8 mg/animal/d

Mortality:

mortality observed, treatment-related

Description (incidence):

increased mortality at 0.8 mg/animal/d

Body weight and weight changes:

not specified

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

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

not specified

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

not specified

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

effects observed, treatment-related

Description (incidence and severity):

raised lung tumor incidence in all acetyl hydrazine treatment groups, no statistically significant increase in any diacetylhydrazine treatment group

Details on results:

HISTOPATHOLOGY: NEOPLASTIC (if applicable)
- general:
• no significant difference in the tumor incidences between sexes in any dose group, therefore results pooled for sexes
• lung tumor types: adenoma and papillary adenocarcinoma, some of which were transplantable
• incidence of hemangiosarcomas not statistically different between control groups and treatment groups
• Experiment 1:
0.8 mg/animal/d: decreased tumor incidence of 0 % in survivors (20 survivors) as compared 13 % in controls
1.1 mg/animal/d: only 10 males survived, of these 3 developed lung tumors resulting in a tumor incidence of 30 % as compared 13 % in controls, this rise is not statistically significant.
• Experiment 2:
1.1 mg/animal/d for 8 months: tumor incidence of 10 % (in 19 survivors)

Relevance of carcinogenic effects / potential:

- The development of lung tumors after repeated oral gavage is indicative for a specific, systemic effect.
- Nevertheless the delivered information is so limited that the relevance of the reported effects cannot be thoroughly assessed.
- Obviously only surviving animals were included in the analysis of tumour incidents as in any of the dose groups the total number of animals adds up to 30 or 40 as reported to be initially entered into the study. Therefore the reported incidences have to be analysed with caution.

Dose descriptor:

NOAEL

Effect level:

>= 1.1 other: mg/animal/d

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Remarks on result:

other: Effect type: carcinogenicity

- Table 1: Tumor incidence in Swiss mice treated with DAH

Group	Male	Female	Combined/ tumor incidence (%)
Distilled water control	2/18	3/20	5/38 (13)
0.8 mg/day per mouse continuous	0/10	0/10	0/21 (0)
1.1 mg/day per mouse continuous	3/10	-	3/10 (30)
1.1 mg/day per mouse for 8 months only	2/11	0/8	2/19 (10)

Conclusions:

Diacetylhydrazine (DAH) were tested for their potential to increase the incidence of lung tumors in Swiss mice of both sexes after repeated oral treatment at 0.8 and 1.1 mg/animal/d (oral gavage, 5 d/week, treatment period 2 years and 8 months).
Diacetylhydrazine treatment did not lead to a statistically significant increase in the tumor incidence in any of the treatment groups as compared to the negative control group.

Executive summary:

In the study Bhide (1984) Diacetylhydrazine (DAH) were tested for their potential to increase the incidence of lung tumors in Swiss mice of both sexes after repeated oral treatment at 0.8 and 1.1 mg/animal/d (oral gavage, 5 d/week, treatment period 2 years (Experiment 1) and 8 months (Experiment 2, high dose only)).

Generally no significant difference was seen in the tumor incidences between sexes in any dose group, therefore results were pooled for sexes. Lung tumor types identified were adenoma and papillary adenocarcinoma, some of which were transplantable. The incidence of hemangiosarcomas was not statistically different between control groups and treatment groups and therefore is not regarded further.

For diacetylhydrazinedecreased tumor incidence of 0 % in survivors (20 survivors) was found as compared 13 % in controls in the 0.8 mg/animal/d groups of experiment 1. In the 1.1 mg/animal/d groups only 10 males survived until week 16 - 22. Of these 3 developed lung tumors resulting in a tumor incidence of 30 % as compared 13 % in controls. This rise is not statistically significant.

In experiment 2 the tumor incidence was 10 % (2 of 19 survivors) after treatment with 1.1 mg diacetylhydrazine/animal/d for 8 months.

Diacetylhydrazine treatment did not lead to a statistically significant increase in the tumor incidence in any of the treatment groups as compared to the negative control group.

Relevance of the presented results:

- The development of lung tumors after repeated oral gavage is indicative for a specific, systemic effect.

- Nevertheless the delivered information is so limited that the relevance of the reported effects cannot be thoroughly assessed.

- Obviously only surviving animals were included in the analysis of tumour incidents as in any of the dose groups the total number of animals adds up to 30 or 40 as reported to be initially entered into the study. Therefore the reported incidences have to be analysed with caution.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Study duration:

chronic

Species:

mouse

Quality of whole database:

Only one study available from the literature, which generally meets accepted scientific principles. However, documentation insufficient for thorough assessment.

Carcinogenicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Carcinogenicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The test material showed no potential for carcinogenicity in a mouse 2 year bioassay. Accordingly, the substance does not meet the criteria for classification according to commission Directive 2001/59/EC, Annex VI.

The test material showed no potential for carcinogenicity in a mouse 2 year bioassay. Accordingly, the substance does not meet the criteria for classification according to commission Regulation 1272/2008, Annex I, Part 3, 3.6.2

Additional information

Diacetylhydrazine was tested for its potential to increase the incidence of lung tumors in Swiss mice of both sexes after repeated oral treatment at 0.8 and 1.1 mg/animal/d (oral gavage, 5 d/week, treatment period 2 years and 8 months) (Bhide 1984). Treatment with the test material did not lead to a statistically significant increase in the tumor incidence in any of the treatment groups as compared to the negative control group.

Justification for selection of carcinogenicity via oral route endpoint:
Only one study available.