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Toxicological information

Genetic toxicity: in vivo

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Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Study period:
No data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP study similar to OECD guideline 474 with minor deviations: data about test substance purity, no certificate of analysis, animal bodyweight not followed, standard deviations not reported in the results.
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report Date:
1994

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
yes
Remarks:
no data about test substance purity; no certificate of analysis; animal bodyweight not followed; standard deviations not reported in the results
Principles of method if other than guideline:
Not applicable
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Mexoryl SAB
- Physical state: white cristalline powder
- Analytical purity: no data
- Lot/batch No.: op T 4 E

Test animals

Species:
mouse
Strain:
CD-1
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Limited, Margate, U.K.
- Fasting period before study: no
- Housing: in groups of 5 per cage
- Diet (e.g. ad libitum): SQC rat and mouse maintenance diet no. 1 (Special Diets Services Limited, Witham, England), ad libitum
- Water (e.g. ad libitum): tap water ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 50 ± 20
- Photoperiod (hrs dark / hrs light): 12 h/12 h

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Vehicle(s)/solvent(s) used: test substance: carboxymethylcellulose (CMC); positive control: 0.9% sterile saline
- Concentration of test material in vehicle: test substance: 0.5%; positive control: 0.4 mg/mL
Details on exposure:
No data
Duration of treatment / exposure:
Single administration
Frequency of treatment:
Single administration
Post exposure period:
Range finding study: 3 days
Main study: 24, 48 and 72 h
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
250 mg/kg bw
Basis:
actual ingested
Remarks:
Doses / Concentrations:
500 mg/kg bw
Basis:
actual ingested
Remarks:
Doses / Concentrations:
1000 mg/kg bw
Basis:
actual ingested
No. of animals per sex per dose:
5
Control animals:
yes, concurrent vehicle
Positive control(s):
Mitomycin C
- Route of administration: intraperitoneal injection
- Doses / concentrations: 4 mg/kg

Examinations

Tissues and cell types examined:
Bone marrow
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: based on the range finding study where animals exposed at 1000 mg/kg (highest dose tested) had no critical signs of toxicity

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): for each dose group, 5 males and 5 females were sacrified at 24, 48 and 72 h after dosing

DETAILS OF SLIDE PREPARATION:
Marrow cells were centrifuged at 800 rpm for 5 min, the supernatant withdrawn, and the cells re-suspended in a minimal volume of foetal calf serum. One drop of cell suspension was placed on each of 2 slides and was left to air dry for 24 hours before staining based on the method of Gollapudi and Kamra. Cells were fixed for 5 min in methanol, rinsed twice in deionised water, stained for 10 min in Giemsa and rinsed several times in tap water and finally in deionised water.

METHOD OF ANALYSIS: A minimum of 1000 polychromatic erythrocytes (PCE), including micronucleated PCE, were counted for each animal.
Evaluation criteria:
Based on statistical analysis and the toxicity shown by PCE/NCE ratio.
Statistics:
Analysis of micronucleus counts to determine the significance of differences between control and Mexoryl SAB treated groups was carried out by the Mann-Whitney U test.

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
yes
Remarks:
Decrease of PCE/NCE ratio for 1000 mg/kg at 24 h
Vehicle controls validity:
valid
Negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
RESULTS OF RANGE-FINDING STUDY
- Dose range: 50, 320 and 1000 mg/kg
- Clinical signs of toxicity in test animals: no severe toxic events
- Evidence of cytotoxicity in tissue analyzed: not examined

RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay): after 24 h at 1000 mg/kg
- Ratio of PCE/NCE (for Micronucleus assay): 0.52 (males and females) at 24 h
- Appropriateness of dose levels and route: acceptable
- Statistical evaluation: Mann-Whitney U test

Any other information on results incl. tables

Table 1: group means for animals sacrificed at 24 h

 

 

Mean

Mean

Mean

Ratio

Mean %

Group

 

PCE

MN-PCE

MN-NCE

PCE/NCE

MN-PCE

CONTROL

M

1031.4

0.0

0.0

0.83

0.00

CONTROL

F

1004.2

0.0

0.0

0.88

0.00

CONTROL

M+F

1017.8

0.0

0.0

0.86

0.00

 

 

 

 

 

 

 

250 mg/kg

M

1018.4

0.0

0.0

1.06

0.00

250 mg/kg

F

1047.2

0.2

0.0

1.26

0.02

250 mg/kg

M+F

1032.8

0.1

0.0

1.16

0.01

 

 

 

 

 

 

 

500 mg/kg

M

1027.8

0.0

0.0

1.08

0.00

500 mg/kg

F

1023.2

0.0

0.0

1.14

0.00

500 mg/kg

M+F

1025.5

0.0

0.0

1.11

0.00

 

 

 

 

 

 

 

1000 mg/kg

M

1018.2

0.0

0.2

0.60

0.00

1000 mg/kg

F

1036.0

0.2

0.0

0.44

0.02

1000 mg/kg

M+F

1027.1

0.1

0.1

0.52

0.01

 

 

 

 

 

 

 

Mitomycin C

M

1024.2

8.4

0.2

1.23

0.82

Mitomycin C

F

1064.8

12.6

0.6

1.22

1.19

Mitomycin C

M+F

1044.5

10.5

0.4

1.23

1.01

Table 2: group means for animals sacrificed at 48 h

 

 

Mean

Mean

Mean

Ratio

Mean %

Group

 

PCE

MN-PCE

MN-NCE

PCE/NCE

MN-PCE

CONTROL

M

1006.2

0.0

0.0

1.26

0.00

CONTROL

F

1018.4

0.0

0.0

1.44

0.00

CONTROL

M+F

1012.3

0.0

0.0

1.35

0.00

 

 

 

 

 

 

 

250 mg/kg

M

1010.8

0.0

0.0

0.97

0.00

250 mg/kg

F

1034.0

0.0

0.0

0.90

0.00

250 mg/kg

M+F

1022.4

0.0

0.0

0.93

0.00

 

 

 

 

 

 

 

500 mg/kg

M

1011.4

0.0

0.0

1.05

0.00

500 mg/kg

F

1053.0

0.0

0.0

1.06

0.00

500 mg/kg

M+F

1032.2

0.0

0.0

1.06

0.00

 

 

 

 

 

 

 

1000 mg/kg

M

1041.8

0.0

0.0

1.14

0.00

1000 mg/kg

F

1046.6

0.0

0.0

1.27

0.00

1000 mg/kg

M+F

1044.4

0.0

0.0

1.21

0.00

Table 3: group means for animals sacrificed at 72 h

 

 

Mean

Mean

Mean

Ratio

Mean %

Group

 

PCE

MN-PCE

MN-NCE

PCE/NCE

MN-PCE

CONTROL

M

1006.2

0.0

0.0

1.26

0.00

CONTROL

F

1018.4

0.0

0.0

1.44

0.00

CONTROL

M+F

1012.3

0.0

0.0

1.35

0.00

 

 

 

 

 

 

 

250 mg/kg

M

1010.8

0.0

0.0

0.97

0.00

250 mg/kg

F

1034.0

0.0

0.0

0.90

0.00

250 mg/kg

M+F

1022.4

0.0

0.0

0.93

0.00

 

 

 

 

 

 

 

500 mg/kg

M

1011.4

0.0

0.0

1.05

0.00

500 mg/kg

F

1053.0

0.0

0.0

1.06

0.00

500 mg/kg

M+F

1032.2

0.0

0.0

1.06

0.00

 

 

 

 

 

 

 

1000 mg/kg

M

1041.8

0.0

0.0

1.14

0.00

1000 mg/kg

F

1046.6

0.0

0.0

1.27

0.00

1000 mg/kg

M+F

1044.4

0.0

0.0

1.21

0.00

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
Under these test conditions, Mexoryl SAB was found not to be clastogenic in vivo on bone marrow cells of mice.
Executive summary:

In an in vivo micronucleus test similar to OECD guideline 474 and in compliance with GLP, mice were exposed to Mexoryl SAB. In a range finding assay, pairs of male mice were orally exposed to Mexoryl SAB at concentrations of 50, 320 and 1000 mg/kg without any critical sign of toxicity. Then, 5 animals/sex/dose/time of sacrifice were given single dose of 250, 500 and 1000 mg/kg of Mexoryl SAB by oral gavage and were sacrificed at 24, 48 and 72 h after dosing. Then bone marrow cells were harvested, stained with Giemsa and analysed for micronuclei.

Positive controls (mitomycin C at 4 mg/kg intraperitoneally) induced an appropriate increase in the number of polychromatic erythrocytes. Micronuclei were not induced at any tested concentrations and at any time of sacrifice in control and in Meroxyl SAB-treated mice despite a decrease in polychromatic erythrocytes/normochromatic erythrocytes for 1000 mg/kg at 24 h.

Under the test conditions, Mexoryl SAB was found not to be clastogenic in vivo in mice.