Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-02663-0011-0000-1
Chemical Name:	Phenazopyridine hydrochloride
CASRN:	136-40-3
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	051415
Study Result:	Positive

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Table Instructions and Notes:
Studies are indicated to be "Nontoxic" when the observed reductions in relative total growth did not indicate that the maximum tolerated dose was achieved.

Nonactivation Trial: 1 Experiment Call: Negative
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	97	101	81	28	23
			86	105	61	24
			124r	98	86	23
			118	94	63	18
Test Chemical	Phenazopyridine hydrochloride	45	97	87	71	24	19
			103	89	43	14	19
		60	81	75	30	12	26
			74	80	87	39	26
		75	101	68	57	19	16
			119	71	44	12	16
		90	79	46	64	27	27
			95	67	80	28	27
		105	95	19	36	13	21
			74	12	66	30	21
Positive Control	Methyl Methane Sulfonate	15	61	51	193	106	136*
Positive Control			58	36	290	167	136*

Nonactivation Trial: 2 Experiment Call: Equivocal
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	87	117	142	55	55
			82#	92	128	52
			96#	96	157.5	55
			75	96	134	59
Test Chemical	Phenazopyridine hydrochloride	20	54#	48	127.5	78	82
			56#	50	145.5	86	82
		40	68	46	163	80	88*
			51#	45	145.5	96	88*
		60	68	51	154	76	77
			62	49	143	77	77
		80	77	48	176	76
		100	95	23	239	84	90*
			78#	15	225	96	90*
		120

Positive Control	Methyl Methane Sulfonate	15	38#	21	565.5	496	444*
Positive Control			43	26	503	391	444*

Induced S9 Trial: 1 Experiment Call: Rejected
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	57#	99	212	123	119
			33r	71	194	195
			29r	52	208	236
			59	101	202	114
Test Chemical	Phenazopyridine hydrochloride	35	42	36	360	288	273*
			56#	37	436	258	273*
		50	66	33	452	228	231*
			58	30	403	234	231*
		65	47	30	297	213	220*
			48	33	323	227	220*
		80	33	19	266	271	240*
			48	20	303	209	240*
		95	41	14	332	268	269*
			42	15	343	271	269*
		110

Positive Control	3-Methylcholanthrene	2.5	50	53	733	490	516*
Positive Control			49	66	795	543	516*

Induced S9 Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	99	89	98	33	32
			97	107	79	27
			104	105	93	30
			107	99	115	36
Test Chemical	Phenazopyridine hydrochloride	60	96	11	335	116	132*
			70	9	310	147	132*
		70	78	8	241	104	110*
			55	8	193	117	110*
		80	72	8	198	92	113*
			57	8	229	134	113*
		90

Positive Control	3-Methylcholanthrene	2.5	69	53	542	261	282*
Positive Control			65#	53	594	303	282*

Induced S9 Trial: 3 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	83	97	96	39	33
			90	100	74	27
			86	100	82	32
			86	103	86	33
Test Chemical	Phenazopyridine hydrochloride	20	87	23	189	72	74*
			104	44	237	76	74*
		35	80	21	181	75	75*
			78	21	174	74	75*
		50	68	18	186	92	91*
			90	12	243	90	91*
		65	91	12	253	93	84*
			71	13	160	75	84*
		80	72	10	228	106	95*
			75	8	189	85	95*
		95
		110

Positive Control	3-Methylcholanthrene	2.5	52	32	524	336	326*
Positive Control			62	29	588	317	326*

Footnotes:
Asterisks(*) indicate significant responses.
r = rejected value due to quality control criteria
# = reduced sample size because of the loss of one culture dish due to contamination