ABSTRACT

The single dose oral toxicity test revealed an LD50 of above 2000 mg/kg for both sexes.

In the repeat dose study, slight increased salivation was observed in males and females of the 1000 mg/kg/day group, but the frequency was only occasional at one or two times during the administration period. No test substance-related changes were noted in body weights, food consumption, and the findings obtained from hematology tests, blood chemical examination, urinalysis and pathological examination. The NOEL for the repeat dose toxicity is considered to be over 1000 mg/kg/day for both sexes.

2,3-Dibromosuccinic acid was not mutagenic in Salmonella typhimurium TA100, TA98, TA1535, TA1537 and Escherichia coli WP2 uvrA. Neither structural nor numerical chromosomal aberrations were induced in CHL/IU cells up to the concentration going 50% cell growth inhibition or the limit concentration of 10 mM, in the absence or presence of an exogenous metabolic activation system.

SUMMARIZED DATA FROM THE STUDIES

1. Single Dose Oral Toxicity 1)

Purity	:	99.8%
Test species/strain	:	Rat/Crj:CD (SD)
Test method	:	OECD Test Guideline 401
Dosage	:	2000 mg/kg
Number of animals	:	Male, 5; female, 5/group
Vehicle	:	0.5% Sodium Carboxymethyl Cellulose solution
GLP	:	Yes

　Test results:

No abnormal clinical signs were found throughout the observation period. The body weights of all rats increased normally and autopsy revealed no abnormal findings.

LD50: Male, >2000 mg/kg; female, >2000 mg/kg

2. Repeat Dose Toxicity 1)

Purity	:	99.8%
Test species/strain	:	Rat/Crj:CD (SD)
Test method	:	Guidelines for 28-Day Repeat Dose Toxicity Testing for Chemicals (Japan)
Route	:	Oral (gavage)
Dosage	:	0 (vehicle), 20, 140, 1000 mg/kg/day
Number of animals	:	Male, 6; female, 6/group
Vehicle	:	0.5% Sodium Carboxymethyl Cellulose solution
Administration period	:	Male and female, 28 days
Terminal kill	:	Days 29 or 43
GLP	:	Yes

　Test results:

Slight increased salivation was observed in males and females of the 1000 mg/kg/day group, but the frequency was only occasional at one or two times during the administration period. No test substance-related changes were noted in terms of body weights, food consumption, and the findings obtained from hematology tests, blood chemical examination, urinalysis, and pathological examination.

The NOEL for the repeat dose toxicity is considered to be over 1000 mg/kg/day for both sexes.

3. Genetic Toxicity

3-1 Bacterial test 2)

Purity	:	> 98%
Test species/strains	:	S.typhimurium TA100, TA1535, TA98, TA1537 E. coli WP2 uvrA
Test method	:	Guidelines for Screening Mutagenicity Testing of Chemicals (Japan)
Procedures	:	Plate incorporation method
Solvent	:	Acetone
Positive controls	:	-S9, AF-2 (TA100, WP2, TA98), sodium azide (TA1535) and 9-aminoacridine (TA1537) +S9, 2-aminoanthracene (all strains)
Dosage	:	without metabolic activation 0, 156.3, 312.5, 625, 1250, 2500,5000 μg/plate metabolic activation method 0, 312.5, 625, 1250, 2500, 5000 μg/plate
S-9	:	Rat liver, induced with phenobarbital and 5,6-benzoflavone
Plates/test	:	3
Number of replicates	:	2
GLP	:	Yes

　Test results:

Minimum concentration of test substance at which toxicity was observed:

No toxicity was observed up to a concentration of 5000 μg/plate with metabolic activation, while toxicity was observed at a concentration of 5000μg/plate without metabolic activation.

Genetic effects:
S. typhimurium TA100, TA1535, TA 98, TA1537

	+	?	-
with metabolic activation	[ ]	[ ]	[*]
without metabolic activation	[ ]	[ ]	[*]

E. coli WP2 uvrA

with metabolic activation	[ ]	[ ]	[*]
without metabolic activation	[ ]	[ ]	[*]

3-2. Non-bacterial in vitro test (chromosomal aberration test) 2)

Purity	:	≧ 98%
Type of cell used	:	Chinese hamster CHL/IU cells
Test method	:	Guidelines for Screening Mutagenicity Testing of Chemicals (Japan)
Solvent	:	Acetone
Positive controls	:	-S9, Mitomycin C +S9, Cyclophosphamide
Dosage	:	-S9 (continuous treatment): 0, 0.3, 0.7, 1.3 mg/ml -S9 (short-term treatment): 0, 0.7, 1.4, 2.8 mg/ml +S9 (short-term treatment): 0, 0.7, 1.4, 2.8 mg/ml
S-9	:	Rat liver, induced with phenobarbital and 5,6-benzoflavone
Plates/test	:	2
GLP	:	Yes

　Test results:

Lowest concentration producing cytogenetic effects in vitro:

without metabolic activation (continuous treatment ): > 1.3 mg/ml

without metabolic activation (short-term treatment): > 2.8 mg/ml

with metabolic activation (short-term treatment): > 2.8 mg/ml

Genotoxic effects:

	clastogenicity			polyploidy
	+	?	-	+	?	-
without metabolic activation:	[ ]	[ ]	[*]	[ ]	[ ]	[*]
with metabolic activation:	[ ]	[ ]	[*]	[ ]	[ ]	[*]

1)	The tests were performed by the Mitsubishi-Kasei Institute of Toxicological and Environmental Sciences (New name: Mitsubishi Chemical Safety Institute Ltd.), 14 Sunayama, Hasaki-machi, Kashima-gun, Ibaraki 314-02, Japan. Tel +81-479-46-2871 Fax +81-479-46-2874
2)	The tests were performed by the Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano-shi, Kanagawa 257, Japan. Tel +81-463-82-4751 Fax +81-463-82-9627