2H-Benzimidazole-2-thione, 1,3-dihydro-ar-methyl-, sodium salt (1:1)

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vivo

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: sufficient documented and scientifically acceptable

Data source

Reference

Reference Type:

publication

Title:

Toxicokinetic study of 2-mercaptobenzimidazole (MBI) and its methylated derivative (MMBI) in rats treated by repeated oral administration - metabolism and urinary excretion

Author:

Tsuda M, Sakemi K, Ito R, Usami M, Ohno Y

Year:

1997

Bibliographic source:

J Toxicol Sci 22, 348

Materials and methods

Objective of study:

toxicokinetics

Principles of method if other than guideline:

Male Wistar rats were treated with 0.3 mmol/kg of MBI (2-mercaptobenzimidazole) or MMBI (2mercaptomethylbenzimidazole) by gavage for 15 days. 24h-urine samples were collected on day(s) 1, 8 and 15. Urinary amounts of MBI and MMBI, and their metabolites were determined.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

1,3-dihydro-4(or 5)-methyl-2H-benzimidazole-2-thione

EC Number:

258-904-8

EC Name:

1,3-dihydro-4(or 5)-methyl-2H-benzimidazole-2-thione

Cas Number:

53988-10-6

Molecular formula:

C8H8N2S

IUPAC Name:

1,3-dihydro-4(or 5)-methyl-2H-benzimidazole-2-thione

Details on test material:

MMBI (methylated derivative of 2-mercaptobenzimidazole), no further data

Radiolabelling:

no

Test animals

Species:

rat

Strain:

Wistar

Sex:

male

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

not specified

Duration and frequency of treatment / exposure:

15 days

Doses / concentrations

Remarks:

Doses / Concentrations:
0.3 mmol/kg = 49.27 mg

No. of animals per sex per dose / concentration:

no data

Control animals:

not specified

Results and discussion

Preliminary studies:

no data

Metabolite characterisation studies

Metabolites identified:

yes

Details on metabolites:

In the MMBI treatment, the urinary amounts were MMBI < MBI (methylbenzimidazoles) (4 fold in day 1) and this ratio was not changed significantlly in days 8 and 15. The 2 isomeres of MMBI were desulfurized and excreted in different extent.

Any other information on results incl. tables

In the MMBI treatment the, the urinary amounts were MMBI < MBI (4 fold in day 1) and this ratio was not changed significantly in days 8 and 15. The 2 isomers of MMBI were desulfurized and excreted in different extend.

The effective desulfurization in MMBI may be a causal factor for the lack of thyroid toxicity

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): no bioaccumulation potential based on study results

Executive summary:

Wistar male rats were treated with 0.3 mmol/kg of MBI (2-mercaptobenzimidazole) or MMBI (methylated derivative of 2-mercaptobenzimidazole) by gavage for 15 days and collected 24h-urine samples (n=3) in day(s) 1, 8, and 15. Urinary amounts of MBI and MMBI, and their metabolites were determined.

In the MMBI treatment, the urinary amounts were MMBI < MBI (methylbenzimidazoles) (4 fold in day 1) and this ratio was not changed significantlly in days 8 and 15. The 2 isomeres of MMBI were desulfurized and excreted in different extent. The effective desulfurization in MMBI may be a causal factor for the lack of thyroid toxicity