Registration Dossier

Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
2000
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
There is no data available on "in vitro mammalian chromosome aberration" or "in-vitro micronucleus" genetic toxicity studies with Acetoguanamine. According to Annex VIII of REACH regualtion before new tests are carried out to determine the listed enpoints of this Annex all available in-vitro data, in-vivo data, historical human data, validated (Q)SAR-data and data from structurally related substances (read-across approach) shall be assessed first. Therefore a literatur research was performed to find in-vitro data, in-vivo data or historical human data on genetic toxicity testing with Acetoguanamine. No records were found and in order to avoid unneccessary animal testing structurally related substances were searched. A structurally related substance is Benzoguanamine, for which further genetic toxicity data was found. Irrespective of metabolic activation Acetoguanamine was not able to induce reverse mutations in Salmonella typhimurium just as Benzoguanamine did not in the Ames test. The molecule structure of Acetoguanamine supports the negative effect. It is completely integrated in the structure of Benzoguanamine. There are no additional functional groups which could be relevant regarding structural alerts for mutagenicity. Since Benzoguanamine showed no obvious potential to impact genomic integrity it can be assumed that Acetoguanamine will show the same properties.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2000
Report Date:
2000

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
mouse
Strain:
NMRI
Sex:
male/female

Administration / exposure

Route of administration:
oral: gavage
Duration of treatment / exposure:
24hr, 48hr
Doses / concentrations
Remarks:
Doses / Concentrations:
male mice; 75, 150, 300 mg/kg b.w. |female mice; 50, 100, 200 mg/kg b.w.
Basis:

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
This substance was not mutagenic in bacteria [OECD TG 471 & 472]. It induced chromosomal aberration in CHL/IU cells with and without an exogenous metabolic activation system even under the soluble concentrations. It also gave a positive response in the human lymphocytes tested [OECD TG 473] and the mouse lymphoma TK assay [OECD TG 476] but only under the insoluble dose levels. The cytogenetic effect observed in in vitro assays however, could not be reproduced in the micronucleus tests in vivo [OECD TG 474]. Based on the weight of evidence, it could be concluded that this substance was not genotoxic in vivo.

Any other information on results incl. tables

STATISTICAL RESULTS:
-The highest dose (300 mg/kg for males and 200 mg/kg b.w. for females) was estimated by five pre-experiments to the suitable since higher concentrations were lethal. After treatment with the test item the number of NCEs was not substantially increased as compared to the mean value of NCEs of the vehicle control thus indicating that this substance at the indicated concentrations had no cytotoxic effectiveness in the bone marrow.
There was no biologically and statistically relevant enhancement in the frequency of the detected micronuclei after administration of the test item at any dose level or sampling time as compared to vehicle controle. 40 mg/kg b.w. cyclophosphamide administered orally was used as positive control which showed a substantial increase of induced micronucleus frequency.

-micronucleus test results
(A)Male animals

Test group Dose Sampling Sampling NCEs per
--- mg/kg b.w. time (hr) micronuclei(%) 2000 PCEs
vehicle 0 24 0.02 1566
BG 75 24 0.08 1562
BG 150 24 0.09 1814
BG 300 24 0.02 1582
CP 40 24 1.11 2033

Vehicle 0 48 0.01 1694
BG 75 48 0.02 1639
BG 150 48 0.08 1795
BG 300 48 0.07 1755

Vehicle 0 72 0.03 1610
BG 75 72 0.04 1417
BG 150 72 0.03 1549
BG 300 72 0.02 1645

(B)Female animals

Test group Dose Sampling Sampling NCEs per
--- mg/kg b.w. time (hr) micronuclei(%) 2000 PCEs
vehicle 0 24 0.03 1652
BG 50 24 0.03 1563
BG 100 24 0.09 1463
BG 200 24 0.04 1889
CP 40 24 0.98 1755

Vehicle 0 48 0.01 2113
BG 50 48 0.04 1727
BG 100 48 0.01 1628
BG 200 48 0.02 1945

Vehicle 0 72 0.02 1577
BG 50 72 0.02 1408
BG 100 72 0.04 1638
BG 200 72 0.01 1492

BG = benzoguanamine (2,4-diamino-6-phenyl-1,3,5-triazine)
CP = cyclo phosphamide

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
not genotoxic in vivo
Executive summary:

In a CD-1 mouse bone marrow micronucleus assay, 5 male and female were treated oral gavage with this substance at doses of 0, 75, 150, 300 mg/kg bw in male mice and 0, 50, 100, 200 mg/kg/bw.  Bone marrow cells were harvested at 24, 48, 72Hr post-treatment.  The vehicle was corn oil. 

 There were no signs of toxicity during the study. The positive control induced the appropriate response. There was not a significant increase in the frequency of micronucleated polychromatic erythrocytes in bone marrow after any treatment time.

This study satisfies the requirement for Test Guideline OECD 474 forin vivocytogenetic mutagenicity data.

As there is no data available on "in vitro mammalian chromosome aberration" or "in-vitro micronucleus" genetic toxicity studies (required by Annex VIII of REACH regulation) with Acetoguanamine this endpoint was read-acrossed from Benzoguanamine to Acetoguanamine. This was done in order to avoid unnecessary animal testing and to fulfill the claim of REACH regulation Annex VIII ("data from structurally related substances (read-across approach) should be assessed first before new tests are carried out). Justification for Read-Across see above in "Rationale for Reliability".