O-ethylhydroxylamine

Genetic toxicity: in vitro

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions - E.coli or TA 102 not tested - no data on substance purity

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Report date:

1987

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

(TA 102 or E. Coli was not tested, longer incubation period)

Principles of method if other than guideline:

The plate incorporation assay described by Maron and Ames (1983) with minor modifications

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

O-ethylhydroxylamine

EC Number:

402-030-3

EC Name:

O-ethylhydroxylamine

Cas Number:

624-86-2

Molecular formula:

C2 H7 N O

IUPAC Name:

O-ethylhydroxylamine

Details on test material:

- Source: Imperial Chemical Industries PLC
- CTL reference number: Y05460/002/001
- Name of test substance as cited in report: Substance H109360
- Identification of test sample as cited in report: 50% (w/v) aqueous solution (45% Substance H109360 and approximately 5% ethanol)
- Appearance: colourless liquid
- Lot #: EFI-100
- Analytical purity: not specified
- Storage: at room temperature

Method

Target gene:

His operon

Species / strain

Species / strain / cell type:

other: Salmonella typhimurium TA 98, TA 100, TA 1535, TA 1537 and TA 1538

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254 - induced rat liver S-9 fraction mixed with a series of cofactors.

Test concentrations with justification for top dose:

1.6, 8, 40, 200, 1000, 5000 µg/plate

Vehicle / solvent:

DMSO

Controls

Untreated negative controls:

yes

Remarks:

(sterility control)

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

other: (+ S-9): 2-aminoanthracene, 2-AA; (- S-9): Acridine mutagen (ICR191), Daunomycin Hcl (DR), 4-nitro-o-phenylene-diamine (4-NOPD), N-methyl-N'-nitro-N nitrosoguanidine (MNNG)

Remarks:

2-AA (all strains), ICR191 (1537), DR (TA 98), 4-NOPD (TA 1538), MNNG (TA 100 and TA 1535),

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 64-68 hours

NUMBER OF REPLICATIONS: 2 experiments, 3 plates/dose (test substance), 5 plates/dose (negative control), 2 plates/dose (positive and sterility controls)

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth

Evaluation criteria:

- A test item is considered as a mutagen if a biologically relevant increase in the number of revertants exceeding the threshold of twice the colony count of the corresponding solvent control is observed.
- A second criterion for a positive result is the observation of a statistically significant dose-related increase in the number of revertants. In either case, the observed effect should be reproducible.

Statistics:

An assessment of the statistical significance was carried out using a one-tailed Student's t-test. The corresponding probability for each dose level was determined from a t-table using the appropriate degrees of freedom.

Results and discussion

Test results

Test results 1

Species / strain:

other: Salmonella typhimurium TA 98, 100, 1537 and 1538

Metabolic activation:

with and without

Genotoxicity:

negative

Remarks:

(with and without metabolic activation)

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

positive

Remarks:

(with metabolic activation only)

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

No signficant reproducible increases in the number of revertant colonies were present all tester strains in the absence of S9-mix, nor in strains TA 98, TA 100, TA 1537 and TA 1538 in the presence of S9-mix. However, in experiment 1 the test material induced an increase in revertant colony numbers in strain TA 1535 in the presence of S9-mix, reaching a maximum increase at the top dose tested. This response was highly significant, showed some dose-relationship and was reproducible in the second experiment (see table 2). The positive control substance induced expected increase in revertant colonies in the respective strains (see table 1).

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1: Positive Control Data (Ratio of Test Value to Control value). Control; N= 5, Positive control; N= 2

 

		[C] µg/plate	Ratio of Test Value/control value
			TA 1535		TA 1537		TA 1538		TA 98		TA 100
			Exp 1	Exp 2	Exp 1	Exp 2	Exp 1	Exp 2	Exp 1	Exp 2	Exp 1	Exp 2
+ S9	2-AA	2.0	4.4	4.5	10.1	9.0	-	-	-	-	-	-
		1.0	3.4	1.8	5.4	3.9	27.4	33.9	20.0	19.6	3.4	3.9
		0.5	1.9	1.2	2.1	3.0	15.5	14.1	7.2	10.7	2.2	3.0
		0.2	-	-	-	-	4.7	6.9	3.9	4.7	1.2	1.6
- S9	MNNG	5.0	68.3	31.2	-	-	-	-	-	-	-	-
		2.0	5.8	2.5	-	-	-	-	-	-	-	-
		1.0	1.0	0.7	-	-	-	-	-	-	-	-
	ICR 191	2.0	-	-	14.6	11.3	-	-	-	-	-	-
		1.0	-	-	6.9	10.5	-	-	-	-	-	-
		0.5	-	-	4.4	12.3	-	-	-	-	-	-
	4-NOPD	5.0	-	-	-	-	48.3	43.0	-	-	-	-
		2.0	-	-	-	-	19.7	16.6	-	-	-	-
		1.0	-	-	-	-	8.1	10.6	-	-	-	-
	DR	1.0	-	-	-	-	-	-	37.8	26.8	-	-
		0.5	-	-	-	-	-	-	22.7	17.6	-	-
		0.2	-	-	-	-	-	-	10.6	9.4	-	-
	MNNG	5.0	-	-	-	-	-	-	-	-	13.7	7.7
		2.0	-	-	-	-	-	-	-	-	1.9	1.5
		1.0	-	-	-	-	-	-	-	-	0.8	1.1

 

+ S9: In the presence of metabloic activation; - S9: In the absence of metabloic activatio

2- aminoanthracene: 2 -AA; Acridine mutagen: ICR191; Daunomycin Hcl : DR; 4 -nitro-o-phenylene-diamine: 4 -NOPD; N-methyl-N'-nitro-N nitrosoguanidine: MNNG

Table 2 :Test Data (Ratio of Test Value to Control value). Control; N= 5, Test substance: N= 3

 

	[C] µg/plate	Ratio of Test Value/control value
		TA 1535		TA 1537		TA 1538		TA 98		TA 100
		Exp 1	Exp 2	Exp 1	Exp 2	Exp 1	Exp 2	Exp 1	Exp 2	Exp 1	Exp 2
+ S9	5000	2.1	2.2	0.2	0.4	0.5	0.4	0.6	0.4	0.9	1.1
	1000	1.4	1.3	0.4	0.4	0.8	1.0	0.9	0.8	0.9	1.1
	200	1.2	1.1	0.6	0.8	0.8	1.2	1.0	1.1	1.1	1.0
	40	1.2	0.9	1.2	0.8	1.1	0.9	1.1	1.0	1.0	1.0
	8.0	1.0	1.1	1.0	0.7	0.9	0.9	0.8	1.2	1.0	1.0
	1.6	1.2	1.0	1.1	1.0	0.3	1.1	0.8	1.0	0.9	1.0
- S9	5000	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.1	0.8	0.8
	1000	0.8	0.7	0.7	0.5	0.9	0.7	1.7	1.0	1.3	1.1
	200	1.0	1.1	1.1	0.7	1.7	0.8	1.1	1.1	1.2	0.9
	40	0.9	1.1	1.4	1.3	1.1	1.3	1.1	1.2	1.2	1.0
	8.0	0.8	1.0	1.1	1.0	0.9	0.8	0.9	1.0	1.2	1.0
	1.6	1.0	0.8	1.1	0.9	0.9	1.0	1.0	1.2	1.0	1.0

+ S9: In the presence of metabloic activation; - S9: In the absence of metabloic activation;

Applicant's summary and conclusion

Conclusions:

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

Since there was no evidence of mutagenicity in S. typhimurium TA 98, 100, 1537 and 1538 with and without metabolic activation as well as with S. typhimurium TA 1535 without metabolic activation but strain TA 1535 revealed a reproducible increase in revertant colony numbers in the presence of metabolic activation induced by Substance H109360, reaching a maximum increase at the top dose tested, the test substance is considered to be mutagenic in vitro under the conditions of this study.