Registration Dossier

Diss Factsheets

Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1999
Report date:
1999
Reference Type:
secondary source
Title:
SIDS Initial Assessment Report for SIAM 27 - Acid Chlorides (AC) Category
Author:
OECD SIDS
Year:
2008
Bibliographic source:
OECD SIDS

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Pivaloyl chloride
EC Number:
221-921-6
EC Name:
Pivaloyl chloride
Cas Number:
3282-30-2
Molecular formula:
C5H9ClO
IUPAC Name:
2,2-dimethylpropanoyl chloride
Details on test material:
Purity: 99.6%

Method

Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
liver S-9 supernatant of male Aroclor 1254 induced Sprague-Dawley rats
Test concentrations with justification for top dose:
experiment 1 (standard plate test; with and without S-9 mix;
all strains): 0, 20, 100, 500, 2500 and 5000 µg/plate;
experiment 2 (standard plate test; with and without S-9 mix;
all strains): 0, 125, 250, 500, 1000 and 1500 µg/plate;
experiment 3 (preincubation test, with and without S-9; all
strains): 0, 31.25, 62.5, 125, 250 and 500 µg/plate;
experiment 4 (preincubation test, with and without S-9;
TA100): 0, 100, 150, 200, 250 and 300 µg/plate.
Vehicle / solvent:
DMSO
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
other: see freetext
Details on test system and experimental conditions:
System: standard plate test, and preincubation test.
Preincubation of the test solution, bacterial suspension and S-9 mix at 37 °C for 20 minutes before being added to the soft agar.
Incubation: plates were incubated at 37 °C for 48-72 hours in the dark, then the number of colonies was counted.
Replicates: all tests were performed in triplicate.
Concentrations: the concentrations tested varied according to experiment:

Positive controls: N-methyl-N'-nitro-N-nitroso-guanidine (5µg/plate for strains TA100 and TA1535), 4-nitro-o-phenylenediamine (10 µg/plate, strain TA98), 9-aminoacridine (100 µg/plate for strain TA1537), and 2-aminoanthracene (2.5 µg/plate for all strains with S-9) were tested in each experiment. The positive control chemicals were dissolved in DMSO.

EXAMINATION
Precipitation of the test material was recorded (if present). Toxicity was detected by a decrease in the number of revertants, a clearing or diminution of the background lawn or a reduction in the titer.

EVALUATION
The experiment was considered valid if the number of colonies in the negative controls was within the normal range of the historical data for the strain, sterility controls had no evidence of contamination, the positive controls induced a significant increase in the number of revertants and the titer of viable bacteria was > = 10E9/ml.
Evaluation criteria:
A substance was considered mutagenic if it caused a doubling in the spontaneous mutation rate, in at least one strain, and the effect was dose-dependent and reproducible. A test substance was considered non-mutagenic if the number of revertants for all tester strains was within the historical
negative control range under all experimental conditions in 2 experiments carried out independently of each other.

Results and discussion

Test resultsopen allclose all
Species / strain:
other: S.typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
positive
Remarks:
borderline result: weakly positve, result does not fit to other acid chlorides
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
500-1000 µg/plate (standard plate); 250 µg/plate (preincubation)
Vehicle controls validity:
valid
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
500-1000 µg/plate (standard plate); 250 µg/plate (preincubation)
Vehicle controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: strain/cell type: Preincubation test: S. typhimurium TA 100 without metabolic activation

Any other information on results incl. tables

Standard plate test: there was no mutagenic effect of the test material in any of the S. typhimurium or E. coli test strains, neither in the presence nor in the absence of metabolic activation.
Preincubation test:
 except S. typhimurium TA100, there was no mutagenic effect of test material in any of the S. typhimurium or E. coli test strains, neither in the presence nor in the absence of metabolic activation.
In TA 100, a slight increase in the number of revertants was seen in the absence of S-9, but not in the presence of S-9. The increase was dose-related and reached 1.5-fold (compared to vehicle control) at 250 µg/plate in the 3rd experiment., but decreased to 1.3-fold at 500 µg/plate. Therefore, a 4th experiment was conducted using TA100 w/wo S-9. Again, a dose-related increase was seen in the absence of metabolic activation. The control number of revertants was increased by a factor of 2.0 at 300 µg/plate. 


Although the substance showd an 2.0-fold increased in the spontaneous mutation rate in one strain (TA 100) at one concentration (300 µg/plate) in the preincubation test, this finding was not reproducible, as the increase was only 1.5fold at maximum in the other experiment at 250 mg/plate. Furthermore, the absolute numbers of the negative control (101 +/- 1) are rather low compared to the historical control range for this test and strain (PIT, TA 100, vehicle DMSO, no S-9 mix): mean +/- SD: 119 +/-16; min-max: 89-176. This increases the value relative to the control compared to the absolute numbers (201 +/- 10).


 


The test material did not precipitate. All positive controls induced at least a 5-fold increase in mutants. The weakly positive result does not fit with the results of other acid chlorides. Conclusion for acid chlorides on SIAM 27 was: " Bases on all the current available data, the acid chlorides are not expected to be genotoxic".

Applicant's summary and conclusion

Categories Display