Registration Dossier

Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

IN VITRO MUTATION TEST USING MOUSE LYMPHOMA L5178Y CELLS (key and supporting study):

The test item did not demonstrate mutagenic potential in this in vitro cell mutation assay, under the experimental conditions described.

AMES test:

There was no precipitation of the test compound and no toxicity to the bacteria was observed. It was concluded that the test item was not mutagenic.


Link to relevant study records

Referenceopen allclose all

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
13 June 2005 - 9 August 2005
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)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.5300 - In vitro Mammalian Cell Gene Mutation Test
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.17 (Mutagenicity - In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: ICH (1996) Guideline S2A: Genotoxicity: Guidance on Specific Aspects of Regulatory Genotoxicity Tests for Pharmaceuticals. PAB/PCD Notification No. 444.
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: ICH (1998) Guideline S2B: Genotoxicity: A Standard Battery for Genotoxicity Testing of Pharmaceuticals. PMSB/ELD Notification No. 554.
Deviations:
no
GLP compliance:
yes
Type of assay:
in vitro mammalian cell micronucleus test
Specific details on test material used for the study:
Appearance: Clear and colourless liquid
Storage conditions: Room temperature (ca. 20ºC), in the dark
Batch number: 52834
Expiry date: December 2006
Purity: >98%
Target gene:
thymidine
Species / strain / cell type:
mouse lymphoma L5178Y cells
Details on mammalian cell type (if applicable):
CELLS USED
- Suitability of cells: heterozygous at the thymidine kinase locus, TK +/-

MEDIA USED
- Type and identity of media:
R0: RPMI 1640, buffered with 2 mg/mL sodium bicarbonate, supplemented with 2.0 mM L-glutamine and 50 µg/mL gentamicin.
R10p: R0, supplemented with 0.1% v/v Synperonic F68, 1.0 mM sodium pyruvate and HiDHS at 10% v/v.
R30p: R0, supplemented with 0.02% v/v Synperonic F68, 1.0 mM sodium pyruvate and HiDHS at 30% v/v.
- Properly maintained: yes
- Periodically checked for Mycoplasma contamination: yes
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
S9
Test concentrations with justification for top dose:
Concentration preliminary toxicity test: 2, 4.1, 8.1, 16.3, 32.5, 65.1, 130.1, 260.3, 520.5, 1041 µg/mL
Concentration range in the main test: 32.53, 65.06, 130.13, 260.25, 520.5, 1041 µg/mL
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: water
- Justification for choice of solvent/vehicle: the test item was found to be soluble
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
In the absence of S9 mix; solvent: DMSO
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
3-methylcholanthrene
Remarks:
In the presence of S9 mix; solvent: DMSO
Details on test system and experimental conditions:
Exposure period (with metabolic activation): 3 hours
Exposure period (without metabolic activation): 24 hours

Expression time:
2 days

Selection time:
10-14 days

DETERMINATION OF CYTOTOXICITY
- Method: cloning efficiency
Rationale for test conditions:
Data are presented for concentrations tested up to the maximum exposure of 1041 µg/mL (10mM) for freely soluble compounds, in accordance with current guidelines.
Evaluation criteria:
The test agent was regarded as negative if: The Induced mutation frequency (test concentration MF minus mean control MF) for any test concentration was less than the Global Evaluation Factor (126 x 10-6).
If the IMF of any test concentration exceeded the GEF, a linear trend test was applied:
If the linear trend test was negative, the result was regarded as negative.
If the linear trend test was positive, this indicated a positive, biologically relevant response.
Key result
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Key result
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
Preliminary toxicity test (Relative suspension growth):
Concentrations from 2 to 1041 µg/mL:
3 hours exposure :
- without S9 mix:127% to 44%
- with S9 mix: 98% to 89%
24 hours exposure :
- without S9 mix: 93% to 78%
Remarks on result:
other: after 3 hour treatment
Conclusions:
The test item did not demonstrate mutagenic potential in this in vitro cell mutation assay, under the experimental conditions described. The maximum final concentrations assessed for determination of mutant frequency in the 3 hour treatment in the presence and absence of
S9 mix, and also in the 24 hour treatment in the absence of S9 mix were in accordance with current guidelines (1041 µg/mL; 10mM).
Endpoint:
in vitro gene mutation study in mammalian cells
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
7 June 2006 - 19 June 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
In a previous study (Huntingdon Life Sciences report number RIH 498/052850), the test substance did not demonstrate any mutagenic potential, when dosed at a final concentration of 10 mM following a 3 and 24 hour treatment in the absence of S9 mix and a 3 hour treatment in the presence of S9 mix. Following submission of the previous study to the Health and Safety Executive, United Kingdom, it was deemed necessary that a confirmatory test at 3 hours, in the presence of S9 mix would be required. The mutagenic potential of the test item was assessed in this in vitro mammalian cell mutation assay. This test system is based on detection and quantitation of forward mutation in the subline 3.7.2c of mouse lymphoma L5178Y cells, from the heterozygous condition at the thymidine kinase locus (TK+/-) to the thymidine kinase deficient genotype (TK-/-).
Qualifier:
according to guideline
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.5300 - In vitro Mammalian Cell Gene Mutation Test
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.17 (Mutagenicity - In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: ICH (1996) Guideline S2A: Genotoxicity: Guidance on Specific Aspects of Regulatory Genotoxicity Tests for Pharmaceuticals. PAB/PCD Notification No. 444.
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: ICH (1998) Guideline S2B: Genotoxicity: A Standard Battery for Genotoxicity Testing of Pharmaceuticals. PMSB/ELD Notification No. 554.
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of assay:
in vitro mammalian cell micronucleus test
Specific details on test material used for the study:
Appearance: Clear and colourless liquid
Storage conditions: Room temperature (ca. 20 C), in the dark
Batch number: 52834
Expiry date: December 2006
Purity: >98%
Target gene:
thymidine
Species / strain / cell type:
mouse lymphoma L5178Y cells
Details on mammalian cell type (if applicable):
CELLS USED
- Suitability of cells: heterozygous at the thymidine kinase locus, TK +/-

MEDIA USED
- Type and identity of media:
R10p: RPMI 1640, buffered with 2 mg/mL sodium bicarbonate, supplemented with 2.0 mM L-glutamine, 50 µg/mL gentamicin, 0.1% v/v Synperonic F68, 1.0 mM sodium pyruvate and HiDHS at 10% v/v.
R30p: RPMI 1640, buffered with 2 mg/mL sodium bicarbonate, supplemented with 2.0 mM L-glutamine and 50 µg/mL gentamicin, 0.02% v/v Synperonic F68, 1.0 mM sodium pyruvate and HiDHS at 30% v/v.
- Properly maintained: yes
- Periodically checked for Mycoplasma contamination: yes
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with
Metabolic activation system:
S9
Test concentrations with justification for top dose:
73.20, 146.39, 292.78, 585.56, 780.75, 1041 µg/mL
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: water
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
3-methylcholanthrene
Remarks:
In the presence of S9 mix
Details on test system and experimental conditions:
METHOD OF APPLICATION: in suspension
- Cell density at seeding (if applicable): 2.4 x 10^6 cells/mL

DURATION
- Preincubation period: 30 minutes
- Exposure duration: 3 hours
- Expression time (cells in growth medium): 24 and 48 hours
- Fixation time (start of exposure up to fixation or harvest of cells):7 days for viability plates and approximately 10-14 days for mutant plates

SELECTION AGENT (mutation assays):

NUMBER OF REPLICATIONS:

METHODS OF SLIDE PREPARATION AND STAINING TECHNIQUE USED:

NUMBER OF CELLS EVALUATED:

NUMBER OF METAPHASE SPREADS ANALYSED PER DOSE (if in vitro cytogenicity study in mammalian cells):

CRITERIA FOR MICRONUCLEUS IDENTIFICATION:

DETERMINATION OF CYTOTOXICITY
- Method: cloning efficiency
Rationale for test conditions:
Guideline study
See 'Administrative data -Justification for type of information'
Evaluation criteria:
The highest concentration tested was one that allowed the maximum exposure up to 5000 µg/mL or 10 mM for freely soluble compounds, or the limit of toxicity (ie. relative total growth reduced to approximately 10 to 20% of the concurrent solvent control) or the limit of solubility. For a toxic substance, at least 4 analysable concentrations should have been achieved which ideally spanned the toxicity range of 100 to 10% RTG.
Key result
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not determined
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
The positive control, 3-methylcholanthrene, induced an acceptable increase in mutation frequency and an acceptable increase in the number of small colony mutants.
There were no increases in induced mutation frequency that exceeded the Global Evaluation Factor plus the induced mutant frequency of the concurrent solvent control following exposure to the test item up to 1041 µg/mL.
Conclusions:
It was concluded that the test item did not demonstrate mutagenic potential following a 3 hour treatment in the presence of S9 mix in this in vitro cell mutation assay, under the experimental conditions described.
Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
8 May 1987 - 17 May 1987
Reliability:
1 (reliable without restriction)
Qualifier:
according to guideline
Guideline:
other: Method of Ames et al.
Deviations:
not specified
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay
Specific details on test material used for the study:
The test substance Lot No .734242, a clear l iqui d, was stored in the dark at room temperature.
Target gene:
his G 46 in TA 1535 and TA 100
his C 3076 in TA 1537
his D 3052 in TA 98
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A pKM 101
Metabolic activation:
with and without
Metabolic activation system:
Liver from Aroclor-treated rats (S9 mix).
Test concentrations with justification for top dose:
Concentration range in the main test: 33, 100, 333, 1000, 3333 and 10000 µg/plate
Vehicle / solvent:
Solvent: Dimethylsulfoxide
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
2-nitrofluorene
N-ethyl-N-nitro-N-nitrosoguanidine
methylmethanesulfonate
other: 2-Aminoanthracene
Remarks:
With and without metabolic activation
Details on test system and experimental conditions:
DURATION
- Preincubation period: 3 days
- exposure time: 2 days

NUMBER OF REPLICATIONS: 3
Evaluation criteria:
A significant mutagenic response was recorded if there was:
-for S.typhimurium strains TA 1535, TA 1537 and TA 98 and for E.coli, at least a doubling of the mean concurrent vehicle control value at some concentration of the test substances and, for S.typhimurium strain TA 100 a 1.5-fol d increase over the control val ue. If the mean colony count on the vehicle control plates was less than 10 then a value of 10 was assumed for assessment purposes.
-a dose rel ated response, al though at high dose levels this rel ati onship coul d be i nverted because of, for exampl e, (1) toxicity to the bacteri a generally, (2}) specific toxicity tothe mutants and (3) inhibition of foreign compound metabolising enzymes where mutagens require metabolic activation by the liver.
-a reproducible effect in independent tests.
Key result
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Key result
Species / strain:
E. coli WP2 uvr A pKM 101
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
Observations:
Both tests were conducted using the pre-incubation method on agar plates.
Conclusions:
It was concl uded that the test item was not mutagenic in S. typhimurium and E. coli WP2uvrA (pKM101 ) when tested in dimethyl sulphoxide at concentrations ranging between 33 µg and 10000 µg per plate.

Endpoint:
in vitro cytogenicity / micronucleus study
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
an in vitro cytogenicity study in mammalian cells or in vitro micronucleus study does not need to be conducted because adequate data from an in vivo cytogenicity test are available
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

The source substance, 1,3 -butanediol (EC 203 -529 -7) did not induce chromosomal aberrations in a three-generational cytogenic study or, in a dominant lethal assay, the mutagenic indexrevealed no test material trend associated with increasing dose levels. As the source material is considered to be a good structural analogue for the target substance 3 -methyl-1,3 -butandiol (see attached read-across justification in section 13 of this dossier) therefore it is considerd that 3 -methyl-1,3 -butandiol will also be negative in in vivo dominant lethal and cytogenic studies.

Link to relevant study records

Referenceopen allclose all

Endpoint:
in vivo mammalian germ cell study: cytogenicity / chromosome aberration
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH
[Please provide information for all of the points below. Indicate if further information is included as attachment to the same record, or elsewhere in the dataset (insert links in 'Cross-reference' table)]

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
Reading across within the target and source substances is justified, as they are structurally similar and have a common environmental and toxicological fate as well as a common potency of properties.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
[Provide here, if relevant, additional information to that included in the Test material section of the source and target records]

3. ANALOGUE APPROACH JUSTIFICATION
[Summarise here based on available experimental data how these results verify that the read-across is justified]
the full read across justification is available in section 13. Similarity is justified on basis of the representative molecular structure, physico-chemical properties and toxicological profiles.

In particular for mutagenicity, the following genotoxicity studies demonstrate that the read across approach is justified.

In both a bacterial mutagenicity test (Ames) and an in vitro cytogenicity study in mammalian cells 3-methyl-1,3-butanediol did not demonstrate mutagenic potential both in the presence and absence of S-9 mix. These studies were not performed for 1,3-butylene glycol as there was existing published data for an in vivo genotoxicity test in rats (subchronic dietary exposure (24%) over 3 generations) available which showed that 1,3-butylene glycol did not induce chromosomal aberrations or dominant lethal effects in any generation.

Many substances that are active in vitro are only weakly active or inactive in animals and man as they can be detoxified in vivo and excreted without reaching target DNA, although it is possible for some test substances to be activated by metabolic systems in the intact animal. As the in vitro genetic toxicity tests performed on 3-methyl-1,3-butanediol were negative and the in vivo genetic toxicity tests performed on 1,3-butylene glycol data were also negative it is expected that 3-methyl-1,3-butanediol will show no genotoxic potential. We have read-across to the data on 1,3-butylene glycol to fulfil the in vitro gene mutation in mammalian cells end-point for 3-methyl-1,3-butanediol .
Reason / purpose for cross-reference:
read-across: supporting information
Species:
rat
Strain:
Wistar
Sex:
female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Females (if applicable) nulliparous and non-pregnant: [yes/no]
- Age at study initiation: 14—15 weeks
- Weight at study initiation: (P) Males: x-x g; Females: x-x g; (F1) Males: x-x g; Females: x-x g
- Fasting period before study:
- Housing:
- Use of restrainers for preventing ingestion (if dermal): yes/no
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period:
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2°C
- Humidity (%):
- Air changes (per hr):
- Photoperiod (hrs dark / hrs light): artificially illuminated for 12 h each day
Route of administration:
oral: feed
Vehicle:
Diet
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: in the diet
VEHICLE
- Justification for use and choice of vehicle (if other than water): feeding study
- Concentration in vehicle: 0, 5, 10 and 24% of the diet by weight by replacing corn starch and dextro
se of the initail dieatary composition
Duration of treatment / exposure:
Throughout the mating, gestation and lactation phase of the study
Dose / conc.:
5 other: % of the diet by weight
Remarks:
equivalent to 2500 mg/kg bw/d
Dose / conc.:
10 other: % of the diet by weight
Remarks:
equivalent to 5000 mg/kg bw/d
Dose / conc.:
24 other: % of the diet by weight
Remarks:
equivalent to 12000 mg/kg bw/d
No. of animals per sex per dose:
10 males per group - reared from the F1B generation
Control animals:
yes, plain diet
Tissues and cell types examined:
The numbers of implant and/or resorption sites and viable and dead fetuses were recorded
Details of tissue and slide preparation:
N/a
Evaluation criteria:
Mutagenic index
Statistics:
Epstein and Shafner
Sex:
male
Genotoxicity:
negative
Vehicle controls validity:
valid
Additional information on results:
For the dominant lethal test of Fl B generation animals, the performance summary of male rats during the 8-week period is provided in Tables 9-12. All males In all groups sired litters. The percentage of pregnancies as well as the percentage of viable fetuses per implant site were not significantly different between treatment and control groups. Also, the mutagenic index (resorptions as a per­ centage of implant sites) showed no trend with increasing dosages of 1,3-butanediol in the diet.
Conclusions:
The mutagenic index of the dominant lethal assay revealed no test material-associated trends with increasing dose levels.
Executive summary:

In a dominant lethal assay conducted as part of a multi-generational Reproduction and Teratology study with the source substance1,3-butylene glycol (EC 203-529-7), which is considered to be a suitable analogue for the target substance 3 -methyl-1,3 -butanediol (EC 429 -270 -7), the mutagenic index revealed no test material-associated trends with increasing dose levels..

Reading across within the target and source substances is justified, as they are structurally similar and have a common environmental and toxicological fate as well as a common potency of properties.

The justification of the read across is attached in section 13 of the dossier.



Endpoint:
in vivo mammalian germ cell study: cytogenicity / chromosome aberration
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH
[Please provide information for all of the points below. Indicate if further information is included as attachment to the same record, or elsewhere in the dataset (insert links in 'Cross-reference' table)]

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
Reading across within the target and source substances is justified, as they are structurally similar and have a common environmental and toxicological fate as well as a common potency of properties.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
[Provide here, if relevant, additional information to that included in the Test material section of the source and target records]

3. ANALOGUE APPROACH JUSTIFICATION
[Summarise here based on available experimental data how these results verify that the read-across is justified]
the full read across justification is available in section 13. Similarity is justified on basis of the representative molecular structure, physico-chemical properties and toxicological profiles.

In particular for mutagenicity, the following genotoxicity studies demonstrate that the read across approach is justified.

In both a bacterial mutagenicity test (Ames) and an in vitro cytogenicity study in mammalian cells 3-methyl-1,3-butanediol did not demonstrate mutagenic potential both in the presence and absence of S-9 mix. These studies were not performed for 1,3-butylene glycol as there was existing published data for an in vivo genotoxicity test in rats (subchronic dietary exposure (24%) over 3 generations) available which showed that 1,3-butylene glycol did not induce chromosomal aberrations or dominant lethal effects in any generation.

Many substances that are active in vitro are only weakly active or inactive in animals and man as they can be detoxified in vivo and excreted without reaching target DNA, although it is possible for some test substances to be activated by metabolic systems in the intact animal. As the in vitro genetic toxicity tests performed on 3-methyl-1,3-butanediol were negative and the in vivo genetic toxicity tests performed on 1,3-butylene glycol data were also negative it is expected that 3-methyl-1,3-butanediol will show no genotoxic potential. We have read-across to the data on 1,3-butylene glycol to fulfil the in vitro gene mutation in mammalian cells end-point for 3-methyl-1,3-butanediol .
Reason / purpose for cross-reference:
read-across: supporting information
Species:
rat
Strain:
Wistar
Details on species / strain selection:
FDRL-stock
Sex:
female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Females (if applicable) nulliparous and non-pregnant: [yes/no]
- Age at study initiation: 14—15 weeks
- Weight at study initiation: (P) Males: x-x g; Females: x-x g; (F1) Males: x-x g; Females: x-x g
- Fasting period before study:
- Housing: individually
- Use of restrainers for preventing ingestion (if dermal): yes/no
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period:
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2°C
- Humidity (%): not stated
- Air changes (per hr): not stated
- Photoperiod (hrs dark / hrs light): artificially illuminated for 12 h each day
Route of administration:
oral: feed
Vehicle:
Diet
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: in the diet
VEHICLE
- Justification for use and choice of vehicle (if other than water): feeding study
- Concentration in vehicle: 0, 5, 10 and 24% of the diet by weight by replacing corn starch and dextro
se of the initail dieatary composition
Duration of treatment / exposure:
Throughout the mating, gestation and lactation phase of the study
Dose / conc.:
5 other: % of the diet by weight
Remarks:
equivalent to 2500 mg/kg bw/d
Dose / conc.:
10 other: % of the diet by weight
Remarks:
equivalent to 5000 mg/kg bw/d
Dose / conc.:
24 other: % of the diet by weight
Remarks:
equivalent to 12000 mg/kg bw/d
No. of animals per sex per dose:
At least 2 males and 2 females per group - reared from the F1a, F2A and F3A generationS
Control animals:
yes, plain diet
Tissues and cell types examined:
The numbers of implant and/or resorption sites and viable and dead fetuses were recorded
Details of tissue and slide preparation:
N/a
Evaluation criteria:
Aberrant chromosomes from 10--250 metaphase cells per group in each generation were evaluated
Statistics:
Epstein and Shafner
Sex:
male/female
Genotoxicity:
negative
Vehicle controls validity:
valid
Negative controls validity:
not examined
Positive controls validity:
not examined
Additional information on results:
The frequency of occurrence of abnormal cells was found to be within the normal range for FIA, F2A and F3A rats; thus, specific aberrations :are not reported. No specific abnonnalities were consistently observed in any diet group; no dose related effects were noted.
Conclusions:
No significant abnormal incidence of chromosomal aberrations was present in the cytogenetic studies.
Executive summary:

In a three generational cytogenic study conducted as part of a multi-generational Reproduction and Teratology study with the source substance1,3-butylene glycol (EC 203-529-7), which is considered to be a suitable analogue for the target substance 3 -methyl-1,3 -butanediol (EC 429 -270 -7), no significant abnormal incidence of chromosomal aberrations was present in the cytogenetic studies..

Reading across within the target and source substances is justified, as they are structurally similar and have a common environmental and toxicological fate as well as a common potency of properties.

The justification of the read across is attached in section 13 of the dossier.



Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Additional information

Read-across from 1,3-butylene glycol to 3-methyl-1,3-butanediol regarding the endpoints in vivo gene mutation study in mammalian cells and reproductive toxicity – screening study for reproductive/developmental toxicity is justified by the data comparison of the structural and physic-chemical similarity, similar toxicity profiles and similar environmental fate and environmental toxicity.

Justification for classification or non-classification