Pivaloyl chloride

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Pivanoyl chloride was weakly positive for mutagenicity in an OECD TG 471 study in Salmonella typhimurium TA100 in the absence of metabolic activation at concentrations extending into the toxic range, but negative in all other S. typhimurium test strains and in E. coli uvrA in the standard plate test and in the preincubation test, with or without metabolic activation. Overall, it is considered to be not mutagenic.

Link to relevant study records

Reference

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

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

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.

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

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".

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Pivaloyl chloride (PCl) was tested in the standard plate test and in the preincubation test with and without metabolic activation in S. typhimurium TA98, TA100, TA1535, TA1537 and E. coli WP2 uvrA at doses of 20 - 5000 µg/plate (SPT) and 31.25 - 500 µg/plate (PIT). The test material did not precipitate.

SPT: 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.

PIT: 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. 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 up to 300 µg/plate, but the number of revertants /plate decreased at 500 µg/plate, indicative for cytotoxicity. The control number of revertants was increased by a factor of 2.0 at 300 µg/plate. However, the 2fold increase compared to the rather low control value was observed at only one concentration and not found in the first PIT.

PCl was negative in all other S. typhimurium test strains and in E. coli uvrA, with or without metabolic activation. All positive controls (N-methyl-N'-nitro-N-nitroso-guanidine, 4-nitro-o-phenylenediamine, 9-aminoacridine, and 2-aminoanthracene) induced at least a 5-fold increase in mutants (BASF, 1999a).

Further data are available for other acid chlorides and their respective hydrolysis products, e.g. pivalic acid and HCl, which were negative for mutagenicity in standard bacterial reverse mutation assays. Therefore, based on all the current available data, the acid chlorides are not expected to be genotoxic (Acid Chloride Category, OECD SIDS Initial Assessment Report (2008) for SIAM 27 in Ottawa, CA).

Overall, pivaloyl chloride is considered to be not mutagenic.

Justification for classification or non-classification

No classification suggested for mutagenicity as criteria of regulation 1272/2008/EC are not met.