o-phenylenediamine

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

No reference to OECD guideline. Deviation from OECD guideline with the use of 4-o-Tolylazo-o-toluidine as positive control.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1975

Report date:

1975

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

Only 4 strains of bacteria were used. Strain TA1538 was used and Strain TA98 was not. Positive controls deviate from those recommended in guidelines.

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

o-phenylenediamine

EC Number:

202-430-6

EC Name:

o-phenylenediamine

Cas Number:

95-54-5

Molecular formula:

C6H8N2

IUPAC Name:

benzene-1,2-diamine

Details on test material:

- Purity: 98.3%

Method

Species / strain

Species / strain / cell type:

S. typhimurium, other: strains TA100, TA1535, TA1537, TA1538

Metabolic activation:

with and without

Metabolic activation system:

Phenobarbitol-stimulated rat liver homogenate

Test concentrations with justification for top dose:

1, 10, 50, 100, 250, 500, 750, 1000 micrograms/plate. Test done in duplicate.

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

no

Positive controls:

yes

Positive control substance:

other: with activation-4-o-Tolylazo-o-toluidine, without activation-N-methyl-N'-nitro-N-nitrosoguanidine

Details on test system and experimental conditions:

METHOD:
In the absence of a metabolic activation system, approximately 5x10e8 bacteria were added to 2 mL of top agar (0.6% Difco agar, 0.6% NaCl, 0.050 mM of L-histidine, 0.05 mM of biotin). After the test chemical was added to the top agar, the solution was mixed and poured onto the surface of a minimal agar plate with Vogel-bonner E medium containing 1.5% agar and 2% glucose.

In the presence of the metabolic activation system, the metabolic system (0.25 mL) was added directly to the top agar immediately before it was poured over the minimal agar plate. The plates were incubated at 37°C for 40 hours. The number of histidine-positive revertant colonies on each plate was counted.

NUMBER OF REPLICATIONS: 2

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

with

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

not specified

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium, other: TA1535, TA1537, TA100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Untreated negative controls validity:

valid

Positive controls validity:

valid

Any other information on results incl. tables

Metabolic Activation	Amount of Cmpd per Plate (ug)	TA100 his+ revertants/plate	TA1535 his+ revertants/plate	TA1537 his+ revertants/plate	TA1538 his+ revertants/plate
-	1	85	8	1	5
-	10	82	11	6	5
-	50	86	9	3	4
-	100	79	7	8	7
-	250				11
-	500	90	13	10	10
-	750				9
-	1000	97	9	25	10
+	1	87	11	10	13
+	10	95	9	9	16
+	50	82	10	7	18
+	100	98	10	6	19
+	250				42
+	500	104	10	9	88
+	750				99
+	1000	112	12	10	140
Negative control
-	0	72	11	5	9
+	0	84	11	6	15
4-o-Tolylazo-toluidine
-	25				10
+	25				195
N-methyl-N’-nitro-N-nitrosoguanidine
-	2		600

Applicant's summary and conclusion

Conclusions:

oPDA was mutagenic in strain TA1538 with activation but not mutagenic in this strain without metabolic activation. All other strains were negative for mutagenicity both with and without metabolic activation.

Executive summary:

oPDA was tested in four strains of Salmonella (TA1535, TA1537, TA1538, and TA100). All assays were conducted in the presence or absence of a phenobarbital-stimulated rat liver homogenate activation system. Dose levels tested included 1, 10, 50, 100, 250, 500, 750, and 1000 microgram/plate. oPDA was mutagenic in strain TA1538 with activation but not mutagenic in this strain without metabolic activation. All other strains were negative for mutagenicity both with and without metabolic activation.