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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1987
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
A published study containing sufficient details to regard it as reliable for use in hazard assessment. Only basic experimental detail provided in publication but sufficient to judge reliability. Read across justification is contained in overall remarks section.

Data source

Reference
Reference Type:
publication
Title:
Toxicology of diethylene glycol monobutyl ether 3. Genotoxicity evaluation in an in vitro gene mutation assay and an in vivo cytogenic test
Author:
Gollapudi, B.B., et al. (1993).
Year:
1993
Bibliographic source:
J. Am. Coll. Toxicol. 12(2), 155-59

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Principles of method if other than guideline:
According to the method of O'Neill (Mut Res, 45, 91-101 and Mut Res, 45, 103-9 - both 1977)
GLP compliance:
not specified
Remarks:
reported as a GLP compliant study
Type of assay:
mammalian cell gene mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): diethylene glycol monobutyl ether (DGBE)
- Analytical purity: 99.51%
- Impurities (identity and concentrations): peroxides 43ppm
- Lot/batch No.: QP-870323-35-S1

Method

Target gene:
HGPRT locus located on the mammalian X chromosome.
Species / strain
Species / strain / cell type:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Metabolic activation system:
Aroclor induced rat liver S9
Test concentrations with justification for top dose:
1000 to 5000 µg/ml in steps of 1000
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: culture medium
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
no
Remarks:
Culture medium was used to dissolve the test compound
True negative controls:
no
Positive controls:
yes
Positive control substance:
ethylmethanesulphonate
Remarks:
Migrated to IUCLID6: without metabolic activation
Untreated negative controls:
yes
Negative solvent / vehicle controls:
no
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 20-methylcholanthracene. with metabolic activation. DMSO solvent used.
Details on test system and experimental conditions:
METHOD OF APPLICATION: in selection medium Ham's F-12 without hypoxanthine and with 10µM -thioguanine.

DURATION
- Exposure duration: 4hrs at 37C.
- Expression time (cells in growth medium): 8 days prior to plating and mutant selection.

NUMBER OF REPLICATIONS: 2

DETERMINATION OF CYTOTOXICITY
- The cytotoxicity of the test material was assessed by determining the ability of the treated cells to form colonies. The cultures (3 cultures/dose level) were treated with the test chemical or the solvent in the presence and absence of S9 factor. After termination of treatment, cultures were incubated for 7 days to allow colony formation, fixed with methanol and stained with crystal violet. The numberof colonies/dish was counted and the mean colonies/dish/treatment wereexpressed relative to the negative control value.
Evaluation criteria:
no further data
Statistics:
Pairwise comparisons with control (p<0.01, one sided) and by liner and quadratic trend analysis (p<0.25, one sided)

Results and discussion

Test results
Species / strain:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Remarks:
No effects up to the maximum recommended dose for this assay of 5000 µg/ml
Vehicle controls validity:
not specified
Untreated negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1: Results

Assay 1

Assay 1

Treatment

RCSa[%]

mutation frequencyb

RCSa[%]

mutation frequencyb

µg/mL DGBE

S9

Negative control

-

100

1.4

100

0

+

100

0

100

0

1000

-

95.1

7.2

106

0

+

116.8

3.3

107.3

706

2000

-

94.7

3.3

102.7

2.4

+

98.7

0

102.8

1.3

3000

-

93.9

2.9

112.2

5.1

+

114.3

0

98.9

13.9c

4000

-

86.6

0

100

0

+

113.9

0

98

0

5000

-

96.7

0

106.4

0

+

104

0

102.6

5.3

positive control

-

83.8

557.7c

87.7

299.4c

+

94.6

359.2c

98.9

325.4c

a: Relative cell survival = colonies per dish in the treated/colonies per dish in the negative control

b: TG mutants per 10000000 cloable cells

c: significantly (p<= 0.01) different from the negative control

In one of the replicate assays, the 3000 µg/ml dose produced a mutation frequency significantly greater than the concurrent control. No mutations were seen in the current control and if historical values were used for comparison, no significant difference was seen. This result was therefore attributed to a statistical abberation and not treatment related.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative with metabolic activation
negative without metabolic activation

2-(2-butoxyethoxy)ethanol is not cytotoxic in this test system up to the maximum recommended test concentration of 5 mg/ml and does not cause forward mutation up to similar doses.
Executive summary:

In an in vitro forward gene mutation assay at the HGPRT locus of CHO cells, 2 -(2 -butoxyethoxy)ethanol did not elicit a positive response when tested up to the maximum recommended dose of 5000ul/ml with and without S9 metabolic activation.