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EC number: 268-750-3
CAS number: 68134-38-3
Based on results of the in vitro tests performed following OECD 471 and OECD 476 , no mutagenic effects were observed.
Table 1: Summary of mean values without S9-mix from the pre-test
Table 3: Summary of mean values without S9-mix from the repeat tests
In a reverse gene mutation assay in bacteria, strains TA 1535, TA 100,
TA 1537, TA 98 of S. typhimurium were exposed to the test item (98.5%
purity) in methanol at concentrations of 8, 40, 200, 1000 and 5000
µg/plate (first/pre-test) and at concentrations of 25, 50, 100, 200,
400, 800 µg/plate (repeat test) in the presence and absence of mammalian
The test item was tested up to the limit concentration (5000 µg/plate).
Based on bacteriotoxic effects only the dose groups up to 1000 µg per
plate were used to a limited extent for assessment purposes. The
positive controls induced the appropriate responses in the corresponding
strains. In the studies with metabolic activation, a slight increase (up
to 1.6 fold) in the mutant count was observed. This slight increase was
not dose-dependent and did not occur in all experiments. In the studies
without metabolic activation no induction of mutant counts was observed.
Therefore, the test item is considered to be non-mutagenic with and
without S9 mix in the Salmonella/microsome test.
This study is classified as acceptable. The study satisfies the
requirement for Test Guideline OECD 471 for in vitro mutagenicity
(bacterial reverse gene mutation) data.
See Final Report
The test item (94.3% purity) was examined for mutagenic activity by
assaying for the induction of 5-trifluorothymidine resistant mutants in
mouse lymphoma L5178Y cells after in vitro treatment, in the absence and
presence of S9 metabolic activation, using a fluctuation method. The
test item was dissolved in dimethylsulfoxide (DMSO) at the concentration
of 434 mg/mL, corresponding to 4340 μg/mL in the final treatment medium
(0.01 M; upper limit indicated in the Study Protocol). A first
cytotoxicity assay was performed, both in the absence and presence of S9
metabolic activation, the test item was assayed at a maximum dose level
of 4340 μg/mL and at a wide range of lower dose levels: 2170, 1090, 543,
271, 136, 67.8, 33.9 and 17.0 μg/mL. In the absence of S9 metabolic
activation, using the 3 hour treatment time, no cells survived treatment
of 136 μg/mL or higher. At the next lower dose level of 67.8 μg/mL,
severe toxicity was observed, reducing relative survival (RS) to 14% of
the concurrent negative control value, while slight toxicity was noted
over the remaining levels tested. Using the 24 hour treatment time, no
cells survived to treatment at all dose levels tested, with the
exception of 17.0 μg/mL were RS was reduced to 1%. Following treatment
in the presence of S9 metabolic activation, using the short treatment
time (3 hours), no cells survived treatment of 271 μg/mL or higher.
Toxicity was seen over the remaining dose levels ranging from 1% to 66%
RS of the concurrent negative control value. An additional cytotoxicity
assay was performed using the 24 hour treatment time. The test item was
assayed at a maximum dose level of 17.0 μg/mL and at a wide range of
lower dose levels: 8.50, 4.25, 2.13, 1.06, 0.531, 0.266, 0.133 and
0.0664 μg/mL. Severe toxicity was seen at the two highest dose levels,
while at the next lower dose level of 4.25 μg/mL, moderate toxicity was
observed, reducing relative survival (RS) to 39% of the concurrent
negative control value. No toxicity was observed over the remaining dose
levels tested. Based on the results obtained in the preliminary trial,
two independent assays for mutation at the TK locus were performed using
the dose levels described in the following table:
Main Assay I (+/-S9): 68.0, 54.4, 43.5, 34.0, 17.0, 8.50 and 4.25 μg/mL
Main Assay II (-S9): 6.80, 5.23, 4.02, 2.01, 1.01 and 0.503
Main Assay II (+S9): 68.0, 45.3, 30.2, 20.1 and 13.0 μg/mL
Adequate levels of cytotoxicity, covering a range from the maximum to
slight or no toxicity, were observed in all treatment series. No
relevant increases in mutant frequencies were observed following
treatment with the test item, in the absence or presence of S9
metabolism. Negative and positive control treatments were included in
each mutation experiment in the absence and presence of S9 metabolism.
The mutant frequencies in the solvent control cultures fell within the
normal range. Marked increases were obtained with the positive control
treatments indicating the correct functioning of the assay system. It is
concluded that the test item does not induce mutation at the TK locus of
L5178Y mouse lymphoma cells in vitro in the absence or presence of S9
metabolic activation, under the reported experimental conditions.
Based on the in vivo test result, no mutagenic effect were observed.
Concentration: test item: 5 mg/kg bw; positive control: 20 mg/kg bw
* p<0.01 (tested by non-parametric Wilcoxon ranking test
In a NMRI mouse
bone marrow micronucleus assay (OECD 474), 5
treated intraperitoneal with
the test item (98.5%)
at doses of 0 and 5 mg/kg bw. Bone marrow cells were harvested at 16,
24 and 48 hours post-treatment.
The vehicle was physiological saline. There
were signs of toxicity during the study such as apathy, roughened fur,
staggering gait, spasm, difficulty in breathing and slitted eyes. One
animal died during the test period. The test item was tested
at an adequate dose based on the results from a dose range
finding study. The
positive control induced the appropriate response. There
was no significant increase in the frequency of micronucleated
polychromatic erythrocytes in bone marrow after any treatment time.
This study is
classified as acceptable. This
study satisfies the requirement for Test Guideline OECD 474 for in
Based on the both in vitro and in vivo tests, BY29 could be considered as not mutagen.
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