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Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1987
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1987
Report date:
1987

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Version / remarks:
1981
Deviations:
not specified
GLP compliance:
yes
Type of assay:
mammalian erythrocyte micronucleus test

Test material

Constituent 1
Chemical structure
Reference substance name:
(ethyl-3-oxobutanoato-O'1,O'3)(2-dimethylaminoethanolato)(1-methoxypropan-2-olato)aluminium(III), dimerised
EC Number:
402-370-2
EC Name:
(ethyl-3-oxobutanoato-O'1,O'3)(2-dimethylaminoethanolato)(1-methoxypropan-2-olato)aluminium(III), dimerised
Cas Number:
149057-70-5
Molecular formula:
C14H28AlNO6
IUPAC Name:
octaaluminium(3+) octakis((2Z)-4-ethoxy-4-oxobut-2-en-2-olate) octakis(1-methoxypropan-2-olate) octakis(2-(dimethylamino)ethan-1-olate)
impurity 1
Chemical structure
Reference substance name:
1-methoxypropan-2-ol
EC Number:
203-539-1
EC Name:
1-methoxypropan-2-ol
Cas Number:
107-98-2
Molecular formula:
C4H10O2
IUPAC Name:
1-methoxypropan-2-ol
Test material form:
liquid
Details on test material:
purified with vacum distillation, analyzed by Gel permeation chromatography as stated in one of the study reports

Test animals

Species:
mouse
Strain:
other: albino CFLP
Details on species / strain selection:
Seventy-seven male and seventy-seven female albino CFLP strain mice were supplied by Interfauna (UK) Limited, Wyton, Huntingdon, Cambridgeshire . At the start of the main study the males weighed 24 - 28g, and the females 24 - 28g, and were approximately five to eight weeks old. After a minimum acclimatisation period of five days the animals were selected at random and given a unique number within the study by ear punching and a number written on a colour coded cage card.
Sex:
male/female
Details on test animals or test system and environmental conditions:
The animals were housed in groups of up to five by sex in solid-floor polypropylene cages with sawdust bedding. With the exception of a 3-4 hour fast immediately before dosing and for approximately two hours after dosing, free access to mains drinking water and food (Rat and Mouse Expanded Diet No. 1, Special Diet Services Limited, Witham, Essex, U.K.) was allowed throughout the study. The animal room was maintained at a temperature of 19 - 22°C and relative humidity of 60 - 68t. The rate of air exchange was approximately 15 changes per hour and the lighting was controlled by a time switch to give 12 hours light and 12 hours darkness.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
Oil Arachi s B .P.
Details on exposure:
All animals were dosed once only at the appropriate dose level by gav-age using a metal cannula attached to a graduated syringe.
No. of animals per sex per dose:
5
Control animals:
yes
Positive control(s):
Cyclophosphamide Monohydrate

Examinations

Tissues and cell types examined:
bone marrow
Details of tissue and slide preparation:
Immediately following sacrifice (i.e. 24, 48 or 72 hours following dosing), one femur was dissected from each animal, aspirated with foetal calf serum (Flow Laboratories Ltd} and bone marrow smears prepared following centrifugation and re-suspension. The smears were air-dried, fixed in absolute methanol, defatted in xylene and stained in Leishman/Giemsa.
Evaluation criteria:
Evaluation of Slides
Stained bone marrow smears were examined at random using light micro-scopy at x 1000 magnification. The incidence of micronucleated cells per 1000 polychromatic erythrocytes (blue stained immature cells) per animal was scored. In addition, the number of normochromatic erythro-cytes (pink stained mature cells) associated with 1000 polychromatic erythrocytes were counted; these cells were also scored for incidence of micronuclei.
The ratio of·normochromatic to polychromatic erythrocytes was calcul-ated together with appropriate group mean values for males and females separately and combined.

Interpretation of Results
A comparison was made between the number of micronucleated polychromatic erythrocytes occuring in each of the three test material groups and the number occuring in the corresponding vehicle control groups. A positive mutagenic response is demonstrated when a statistically significant increase in the number of micronucleated polychromatic erythrocytes is observed for either the 24, 48 or 72 hour kill times. If the above criteria is not demonstrated, the test material is considered to be non-mutagenic under the conditions of the test.
A positive response for bone marrow toxicity is demonstrated when the treatment group mean normochromatic to po1ychromatic ratio is twice the vehic1e control value or when a treatment related increase is
shown to be statistically significant.
Statistics:
All data were statistically analysed using the Kruskal-Wallis one-way analysis of variance by ranks (Kruskal W.H. and Wallis W.A. 1952 J. Arn. Statist. Soc. 47 583); when this was significant (P < 0.05) paired comparisons were made using the Mann-Whitney U-test

Results and discussion

Test results
Key result
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
not examined
Remarks:
see vehicle control
Positive controls validity:
valid
Additional information on results:
Most animals treated with greater than 3000 mg/kg SA2/l/0A showed one or more clinical symptoms such as: hunched posture, pilo-erection, lethargy. decreased respiratory rate and ptosis, one and four hours after dosing. All surviving animals recovered and were normal on days one to three.
Based on the mortality data and clinical observations seen in the range-finding toxicity study a dose level of 5000 mg/kg was selected as a suitable "maximum tolerated dose" for the micronucleus study; being the highest dose level where no deaths were likely to occur.

Applicant's summary and conclusion

Conclusions:
In an OECD 474 micronucleus assay in mice, the test material, SA2/1/0A, was found not to produce micronuclei in polychromatic erythrocytes of mice under the conditions of the test.
Executive summary:

In an OECD 474 micronucleus assay in mice, the test material, SA2/1/0A, was found not to produce micronuclei in polychromatic erythrocytes of mice under the conditions of the test.