Fusidic acid

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Spiked Fusidic Acid was assayed for mutation in five histidine-requiring strains (TA98, TA100, TA1535, TA1537 and TA102) of Salmonella typhimurium, both in the absence and in the presence of metabolic activation (S-9) , in two separate experiments. The study was performed in accordance to OECD 471 (AMES test). No toxicological significant increases in the frequecy of revertant colonies with treatments at concentrations up to or approaching the lower limit of toxicity, in the absence and in the presence of a rat liver metabolic activation system (S-9). Hence, Spiked Fusidic Acid was found to be non-mutagenic.

Spiked Fusidic Acid was assayed for its ability to induce mutation at the tk locus (5-trifluorothymidine resistance) in mouse lymphoma cells using a fluctuation protocol (OECD 476). The study consisted of a cytotoxicity range-finding experiment followed by two independent experiments, each conducted in the absence and presence of metabolic activation by an Aroclor 1254 induced rat liver post-mitochondrial fraction (S-9). Spiked Fusidic Acid did not induce mutation at the tk locus of L5178Y mouse lymphoma cells when tested under the conditions employed in this study. The study was considerd to be valid based on the results from negative and positive controls. Thus, Spiked Fusidic Acid was found to be non-mutagenic under the conditions of this study.

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental work started on 24-Jan-2007 and was completed on 20-Feb-2007.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

adopted 1997

Deviations:

yes

Remarks:

plate counts were slightly above the historical ranges, they were all sufficiently comparable to be considered as characteristic and acceptable for demonstrating the correct strain and assay functioning.

Qualifier:

according to guideline

Guideline:

other: UKEMS Guideline

Version / remarks:

1990

Deviations:

yes

Remarks:

plate counts were slightly above the historical ranges, they were all sufficiently comparable to be considered as characteristic and acceptable for demonstrating the correct strain and assay functioning.

Qualifier:

according to guideline

Guideline:

other: ICH Harmonised Tripartite Guideline

Version / remarks:

1997

Deviations:

yes

Remarks:

plate counts were slightly above the historical ranges, they were all sufficiently comparable to be considered as characteristic and acceptable for demonstrating the correct strain and assay functioning.

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

Spiked Fusidic acid, batch number 0704514701

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Metabolic activation system:

both in the absence and in the presence of metabolic activation by an Aroclor 1254-induced rat liver post-mitochondrial fraction (S-9), in two separate experiments

Test concentrations with justification for top dose:

Concentrations based on range-finding study where toxicity was observed at a concentration of 200 ug/plate or higher

Experiment 1, using final concentrations of Spiked Fusidic Acid at 0.032, 0.16, 0.8, 4, 20, 100 and 500 μg/plate

Experiment 2, concentration ranges of 5.12 to 500 or 1250 μg/plate

Vehicle / solvent:

DMSO

Untreated negative controls:

yes

Remarks:

Negative controls comprised treatments with the vehicle sterile anhydrous analytical grade dimethyl sulphoxide (DMSO).

Positive controls:

yes

Positive control substance:

2-nitrofluorene

Positive controls:

yes

Positive control substance:

sodium azide

Positive controls:

yes

Positive control substance:

9-aminoacridine

Positive controls:

yes

Positive control substance:

mitomycin C

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

Positive controls:

yes

Positive control substance:

other:

Remarks:

2-aminoanthracene (AAN)

Details on test system and experimental conditions:

Bacteria Strain Type of mutation in the histidine gene
S. typhimurium TA98 frame-shift
S. typhimurium TA100 base-pair substitution
S. typhimurium TA1535 base-pair substitution
S. typhimurium TA1537 frame-shift
S. typhimurium TA102 base-pair substitution

Statistics:

The m-statistic was calculated to check that the data were Poisson-distributed (10), and Dunnett's test was used to compare the counts at each concentration with the control.

The presence or otherwise of a concentration response was checked by linear regression analysis (10). As multiple regression analysis calculations are
performed (at each concentration level), there is an increased incidence of values which will fall outside the 95 or 99% probability range, but are not due to compound related increases.

Therefore, a statistically significant regression analysis is not considered as a biologically relevant event unless accompanied by a statistically significant Dunnett’s test.

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

toxicity was only observed in experiment 2

Untreated negative controls validity:

valid

Remarks:

The mean numbers of revertant colonies on negative control plates were all considered acceptable,

Positive controls validity:

valid

Remarks:

The mean numbers of revertant colonies were significantly elevated by positive control treatments.

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

toxicity was only observed at the highest concentration tested (500 ug/plate and/or 1250 ug/plate)

Untreated negative controls validity:

valid

Remarks:

The mean numbers of revertant colonies on negative control plates were all considered acceptable,

Positive controls validity:

valid

Remarks:

The mean numbers of revertant colonies were significantly elevated by positive control treatments.

Key result

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

toxicity was only observed at the highest concentration tested (500 ug/plate and/or 1250 ug/plate)

Untreated negative controls validity:

valid

Remarks:

The mean numbers of revertant colonies on negative control plates were all considered acceptable,

Positive controls validity:

valid

Remarks:

The mean numbers of revertant colonies were significantly elevated by positive control treatments.

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

toxicity was only observed at the highest concentration tested (500 ug/plate and/or 1250 ug/plate)

Untreated negative controls validity:

valid

Remarks:

The mean numbers of revertant colonies on negative control plates were all considered acceptable,

Positive controls validity:

valid

Remarks:

The mean numbers of revertant colonies were significantly elevated by positive control treatments.

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

toxicity was only observed at the highest concentration tested (500 ug/plate and/or 1250 ug/plate)

Untreated negative controls validity:

valid

Remarks:

The mean numbers of revertant colonies on negative control plates were all considered acceptable,

Positive controls validity:

valid

Remarks:

The mean numbers of revertant colonies were significantly elevated by positive control treatments.

Experiment 1, using final concentrations of Spiked Fusidic Acid at 0.032, 0.16, 0.8, 4, 20, 100 and 500 μg/plate, plus negative (vehicle) and positive controls. Following these treatments, evidence of toxicity was observed in the absence and presence of S-9 at 500 μg/plate in all strains except TA98. Although no clear evidence of toxicity was seen in strain TA98, treatments in this strain were considered to have been performed at concentrations approaching toxic levels, based on the observations seen in the other test strains.

Following Experiment 2 treatments, clear evidence of toxicity was observed at either 500 μg/plate or 1250 μg/plate in all strains in the absence of S-9, and at either 200 μg/plate and above or 500 μg/plate (and above where applicable) in all strains in the presence of S-9.

Following Spiked Fusidic Acid treatments of all the tester strains, both in the absence and in the presence of a rat liver metabolic activation system (S-9), only Experiment 1 treatments of strain TA102 in the presence of S-9 resulted in any increase in revertant numbers that was statistically significant.

As the increase in Experiment 1 was neither doserelated nor reproducible, it was not considered to have been a biologically relevant or compound-related effect.

As no other strain treatments resulted in an statistically significant increases in revertant numbers, this study was considered to have provided no evidence of any Spiked Fusidic Acid mutagenic activity in this assay system.

Conclusions:

Spiked Fusidic Acid was assayed for mutation in five histidine-requiring strains (TA98, TA100, TA1535, TA1537 and TA102) of Salmonella typhimurium, both in the absence and in the presence of metabolic activation (S-9) , in two separate experiments. The study was performed in accordance to OECD 471. No toxicological significant increases in the frequecy of revertant colonies were recorded, thus it was concluded that Spiked Fusidic Acid does not induce mutation in five histidine-requiring strains (TA98, TA100, TA1535, TA1537 and TA102) of Salmonella typhimurium when tested under the conditions of this study. These conditions included treatments at concentrations up to or approaching the lower limit of toxicity, in the absence and in the presence of a rat liver metabolic activation system (S-9). Hence, Spiked Fusidic Acid was found to be non-mutagenic.

Executive summary:

Spiked Fusidic Acid was assayed for mutation in five histidine-requiring strains (TA98, TA100, TA1535, TA1537 and TA102) of Salmonella typhimurium, both in the absence and in the presence of metabolic activation (S-9) , in two separate experiments. The study was performed in accordance to OECD 471.

Two experiments (refered to as experiment 1 and 2) were conducted:

Experiment 1, using final concentrations of Spiked Fusidic Acid at 0.032, 0.16, 0.8, 4, 20, 100 and 500 μg/plate, plus negative (vehicle) and positive controls. Following these treatments, evidence of toxicity was observed in the absence and presence of S-9 at 500 μg/plate in all strains except TA98. Although no clear evidence of toxicity was seen in strain TA98, treatments in this strain were considered to have been performed at concentrations approaching toxic levels, based on the observations seen in the other tester strains.

Following Experiment 2 treatments, clear evidence of toxicity was observed at either 500 μg/plate or 1250 μg/plate in all strains in the absence of S-9, and at either 200 μg/plate and above or 500 μg/plate (and above where applicable) in all strains in the presence of S-9.

No toxicological significant increases in the frequecy of revertant colonies were recorded, thus it was concluded that Spiked Fusidic Acid does not induce mutation in five histidine-requiring strains (TA98, TA100, TA1535, TA1537 and TA102) of Salmonella typhimurium when tested under the conditions of this study. These conditions included treatments at concentrations up to or approaching the lower limit of toxicity, in the absence and in the presence of a rat liver metabolic activation system (S-9). Hence, Spiked Fusidic Acid was found to be non-mutagenic.

Reference 2

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental work started on 23-Jan-2007 and was completed on 13-Mar-2007.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

Version / remarks:

1997

Qualifier:

according to guideline

Guideline:

other: UKEMS Guideline

Version / remarks:

1990

Qualifier:

according to guideline

Guideline:

other: ICH Tripartite Harmonised Guideline on Genotoxicity S2A: Specific Aspects of Regulatory Tests

Version / remarks:

1995

Qualifier:

according to guideline

Guideline:

other: ICH Requirements for Registration of Pharmaceuti-cals for Human Use S2B, Genotoxicity: a Standard Battery for Genotoxicity Testing of Pharmaceuticals

Version / remarks:

Step 4, recommended for adoption 16 July 1997

GLP compliance:

yes

Type of assay:

other: gene mutation study in mammalian cells

Specific details on test material used for the study:

Batch number 0704514701

Species / strain / cell type:

mouse lymphoma L5178Y cells

Metabolic activation:

with and without

Metabolic activation system:

The mammalian liver post-mitochondrial fraction (S-9) used for metabolic activation

Vehicle / solvent:

DMSO

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

Negative controls comprised treatments with the vehicle, sterile anhydrous analytical grade dimethyl sulphoxide (DMSO) diluted 100-fold in the treatment medium.

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

Details on test system and experimental conditions:

positive control chemicals:
Chemical Source Stock* concentration (mg/mL) Final concentration (μg/mL) S-9
4-nitroquinoline Sigma-Aldrich Chemical 0.0150 0.150# -
1-oxide (NQO) Co, Poole, UK 0.0200 0.200# -

benzo(a)pyrene (BP) Sigma-Aldrich Chemical 0.200 2.00 +
Co, Poole, UK 0.300 3.00 +

* All solutions were prepared in anhydrous analytical grade dimethyl sulphoxide (DMSO). NQO
and BP solutions, if not used immediately, were stored as frozen aliquots at –80ºC nominal in the
dark.
# For Experiment 2 -S-9 (24 hour treatment), final NQO concentrations of 0.05 and 0.1 μg/mL
were tested.

Key result

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

with and without

Genotoxicity:

negative

Remarks:

The mutant frequency of the all the test concentrations were less than the sum of the mean control mutant frequency plus GEF, thus indicating a negative result.

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

Exp.1 134 μg/mL (+/- S-9) yielded 13% and 43 % RTG respectively. Exp. 2 (+ S-9): Complete tox. At 134.4 μg/mL. The highest conc. tested that provided >10% RTG was 67.19 μg/mL, which yielded 22% RTG.

Untreated negative controls validity:

valid

Remarks:

For the negative controls, the proportion of small colony mutants in the absence and presence of S-9 ranged from 35% to 36% in Experiment 1 and from 29% to 31% in Experiment 2

Positive controls validity:

valid

Remarks:

Marked increases in the number of both small and large colony mutants were observed following treatment with the positive control chemicals NQO and BP

Additional information on results:

Negative controls comprised treatments with the vehicle, sterile anhydrous analytical grade dimethyl sulphoxide (DMSO) diluted 100-fold in the treatment medium.

Positive control chemicals: 4-nitroquinoline 1-oxide (NQO) and benzo(a)pyrene (BP)

In the cytotoxicity range-finding experiment, 3 hour treatment, six concentrations of Spiked Fusidic Acid were tested in the absence and presence of S-9, separated by two fold intervals and ranging from 67.19 to 2150 μg/mL (maximum concentration limited by supplied formulation). Upon addition of the test article to the cultures, precipitate was observed at the highest three concentrations tested (537.5 to 2150 μg/mL). After the 3 hour treatment incubation period, precipitate was observed at the highest concentration tested (2150 μg/mL). The highest four concentrations tested (268.8 to 2150 μg/mL) were not plated due to excessive toxicity (based on cell count data).

In the cytotoxicity range-finding experiment, 24 hour treatment, nine concentrations of Spiked Fusidic Acid were tested in the absence of S-9, separated by two fold intervals and ranging from 8.398 to 2150 μg/mL. Upon addition of the test article to the cultures, precipitate was observed at the highest three concentrations tested (537.5 to 2150 μg/mL). After the 24 hour treatment incubation period, precipitate was observed at the highest concentration tested (2150 μg/mL). The highest four concentrations tested (268.8 to 2150 μg/mL) were not plated due to excessive toxicity (based on cell count data). Complete toxicity was observed at the highest concentration plated (134.4 μg/mL). The highest concentration tested that provided >10% RTG was 67.19 μg/mL, which yielded 22% RTG.

In the cytotoxicity range-finding experiment, 3 hour treatment, concentrations of Spiked Fusidic Acid were tested in the absence and presence of S-9 ranging from 67.19 to 2150 μg/mL (maximum concentration limited by supplied formulation). Due to extreme toxicity, the highest concentration plated was 134.4 μg/mL, which yielded 13% relative total growth (RTG) in the absence of S-9 and 47% RTG in the presence of S-9.

In the cytotoxicity range-finding experiment, 24 hour treatment, concentrations of Spiked Fusidic Acid were tested in the absence of S-9, ranging from 8.398 to 2150 μg/mL (maximum concentration limited by supplied formulation). The highest concentration to provide >10% RTG was 67.19 μg/mL, which yielded 22% RTG.

Accordingly, for the first experiment (3 hour treatment) concentrations of Spiked Fusidic Acid were chosen ranging from 20 to 150 μg/mL in the absence of S-9, and from 60 to 240 μg/mL in the presence of S-9. Due to extreme toxicity, the highest concentrations analysed were 120 and 160 μg/mL in the absence and presence of S-9, which yielded 17% and 11% RTG respectively.

In the second experiment concentrations of Spiked Fusidic Acid were tested ranging from 10 to 120 μg/mL in the absence of S-9 (24 hour treatment) and from 60 to 220 μg/mL in the presence of S-9 (3 hour treatment). Due to extreme toxicity, the highest concentrations analysed were 80 μg/mL in the absence of S-9 and 160 μg/mL in the presence of S-9, which yielded 14% and 13% RTG respectively.

Negative (vehicle) and positive control treatments were included in each mutation experiment in the absence and presence of S-9. Mutant frequencies in negative control cultures fell within acceptable ranges, and clear increases in mutation were induced by the positive control chemicals 4-nitroquinoline 1-oxide (without S-9) and benzo(a)pyrene (with S-9). Therefore the study was accepted as valid.

The mutant frequency of the all the test concentrations were less than the sum of the mean control mutant frequency plus GEF, thus indicating a negative result. No significant linear trend occurred with any experiment in the presence of S-9, and for treatments in the absence of S-9 in Experiment 2, but a very weak linear trend was observed in the absence of S-9 in Experiment 1. As no significant increase in mutant frequency occurred at any treatment concentration in Experiment 1, this observation alone is not considered sufficient to be indicative of any biologically relevant event.

It is concluded that Spiked Fusidic Acid did not induce mutation at the tk locus of L5178Y mouse lymphoma cells when tested under the conditions employed in this study. These conditions included treatments up to toxic concentrations in two independent experiments, in the absence and presence of a rat liver metabolic activation system (S-9).

Conclusions:

Spiked Fusidic Acid was assayed for its ability to induce mutation at the tk locus (5-trifluorothymidine resistance) in mouse lymphoma cells using a fluctuation protocol (OECD 476). Based on the results, it is concluded that Spiked Fusidic Acid did not induce mutation at the tk locus of L5178Y mouse lymphoma cells when tested under the conditions employed in this study. These conditions included treatments up to toxic concentrations in two independent experiments, in the absence and presence of a rat liver metabolic activation system (S-9). The study was considerd to be valid based on the results from negative and positive controls. Thus, Spiked Fusidic Acid was found to be non-mutagenic under the conditions of this study.

Executive summary:

Spiked Fusidic Acid was assayed for its ability to induce mutation at the tk locus (5-trifluorothymidine resistance) in mouse lymphoma cells using a fluctuation protocol (OECD 476). The study consisted of a cytotoxicity range-finding experiment followed by two independent experiments, each conducted in the absence and presence of metabolic activation by an Aroclor 1254 induced rat liver post-mitochondrial fraction (S-9).

The mutant frequency at all the test concentrations were less than the sum of the mean control mutant frequency plus GEF, thus indicating a negative result. No significant linear trend occurred with any experiment in the presence of S-9, and for treatments in the absence of S-9 in Experiment 2, but a very weak linear trend was observed in the absence of S-9 in Experiment 1. As no significant increase in mutant frequency occurred at any treatment concentration in Experiment 1, this observation alone is not considered sufficient to be indicative of any biologically relevant event.

It is concluded that Spiked Fusidic Acid did not induce mutation at the tk locus of L5178Y mouse lymphoma cells when tested under the conditions employed in this study. These conditions included treatments up to toxic concentrations in two independent experiments, in the absence and presence of a rat liver metabolic activation system (S-9). The study was considerd to be valid based on the results from negative and positive controls. Thus, Spiked Fusidic Acid was found to be non-mutagenic under the conditions of this study.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

A micronucleus test in mice was conducted in accordance to OECD Guideline 474 and following GLP. Groups of mice (NMRI strain), containing 10 males and 10 females, were exposed to a single oral dose of either 250 or 500 mg fusidic acid /kg bw. After 24 or 48 hours mice were sacrificed, the femora excised and bone marrow extracted. Sodium fusidate given orally to male and female mice in the fasting state at the dose levels of 250 and 500 mg/kg bw did not show any clastogenic potential in the in vivo micronucleus test.

Link to relevant study records

Reference

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration

Remarks:

micronucleus test in mice

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Sodium fusidate
Solid
Lot no. C1728
Purity 99.9 % by HPLC for anhydrate substance, 99.6 by titration for anhydrate substance.

Species:

mouse

Strain:

NMRI

Sex:

male/female

Details on test animals or test system and environmental conditions:

Bomholtgaard Breeding and Research Center, Ry, Denmark
Weight: Male 28g and female 25 g at
Number: 50 males and 50 females devided in 4 groups

Animals were placed 3 of one sex per cage. Dust free wood shavings were used for breeding material
Room temperature: 22.5°C
Relative humidity: 40-45%
Light/dark period: 12:12 hours
Free access to commercial rodent diet and tap water

Route of administration:

oral: unspecified

Vehicle:

phosphate buffer solution: (disodium edetate 0.5 mg; disodium hydrogen phosphate19.6 mg; citric acid 1mg; water 1 mL) Lot no. B4049A

Details on exposure:

doses given orally to fasted animals. Control given intraperitoneally. Both in a volume of 10 mL/kg

Duration of treatment / exposure:

single dose

Frequency of treatment:

single dose

Post exposure period:

24/48 hours

Dose / conc.:

0 mg/kg bw (total dose)

Dose / conc.:

250 mg/kg bw (total dose)

Dose / conc.:

500 mg/kg bw (total dose)

No. of animals per sex per dose:

10 males +10 females / group

Control animals:

yes

yes, concurrent vehicle

Positive control(s):

cyclophosphamide 25 mg/kg (6 males and 6 females exposed to positive control)

Tissues and cell types examined:

Femora excised and bone marrow extracted.
Polychromatic erythrocyte (PEC)/ Normochromatic erythrocyte (NCE) and Polychromatic erythrocyte (PECM)/ Normochromatic erythrocyte with micronuclei (NCEM)

Details of tissue and slide preparation:

Extracted bone marrow was centrifugated (1000 rpm). The supernantant was decanted and remaining cells resuspended and smears prepared in duplicate.
Smears were fixed in methanol (5min) and stained in May-GrünWald solution (20min) and Giemsa stain (25min). Hereafter rinsed in phosphate buffer (pH 6.5) and finally rinsed in distilled water.

Statistics:

Mann-Whitney test p ≤ 0.05 (=significant)

Key result

Sex:

male/female

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

valid

Negative controls validity:

not specified

Positive controls validity:

valid

Mean ratio (+SD) of polychromatic to Normochromatic Erythrocytes

	Samples male			Samples female
Group	24 h		48 h	24 h	48 h
Negative control (vehicle)	1.12 ± 0.27		1.03 ± 0.13	1.46 ± 0.31	1.08 ± 0.26
Sodium fusidate 250 mg/kg bw	1.02 ± 0.19		0.85 ± 0.17	0.88 ± 0.07	1.05 ± 0.12
Sodium fusidate 500 mg/kg bw	0.81 ± 0.17		0.86 ± 0.18	1.03 ± 0.24	0.84 ± 0.21
Cyclophosphamide 25 mg/kg bw i.p.	0.98 ± 0.05		0.66 ± 0.14	1.13 ± 0.20	0.96 ± 0.21

Mean incidence in percent (+SD) of micronucleated polychromatic erythrocytes

	Samples male			Samples female
Group	24 h		48 h	24 h	48 h
Negative control (vehicle)	0.04±0.05		0.02±0.04	0.04±0.05	0.06±0.05
Sodium fusidate 250 mg/kg bw	0.06±0.09		0.04±0.09	0.04±0.05	0.08±0.08
Sodium fusidate 500 mg/kg bw	0.04±0.05		0.00±0.00	0.00±0.00	0.06±0.09
Cyclophosphamide 25 mg/kg bw i.p.	1.77±0.45		1.60±0.62	0.87±0.31	0.53±0.15

Mean incidence percent (+SD) of micronucleated normochromatic erythrocytes

	Samples male			Samples female
Group	24 h		48 h	24 h	48 h
Negative control (vehicle)	0.14±0.11		0.02±0.04	0.03±0.08	0.00±0.00
Sodium fusidate 250 mg/kg bw	0.10±0.11		0.07±0.07	0.07±0.01	0.07±0.06
Sodium fusidate 500 mg/kg bw	0.03±0.04		0.04±0.05	0.00±0.00	0.04±0.09
Cyclophosphamide 25 mg/kg bw i.p.	0.19±0.16		1.08±0.29	0.04±0.07	0.59±0.09

Conclusions:

Sodium fusidate given orally to male and female mice in the fasting state at the dose levels of 250 and 500 mg/kg bw did not show any clastogenic potential in an in vivo micronucleus test. Thus, Sodium fusidate was considered to be non-clastogenic.

Executive summary:

A micronucleus test in mice was conducted in accordance to OECD Guideline 474 and following GLP.

Groups of mice (NMRI strain), containing 10 males and 10 females, were exposed to a single oral dose of either 250 or 500 mg fusidic acid /kg bw. After 24 or 48 hours mice were sacrificed, the femora excised and bone marrow extracted.

Sodium fusidate given orally to male and female mice in the fasting state at the dose levels of 250 and 500 mg/kg bw did not show any clastogenic potential in the in vivo micronucleus test.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Justification for classification or non-classification

Based on the available data base from in vitro and in vivo studies, no classification is proposed.