Registration Dossier
Registration Dossier
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EC number: 209-502-6 | CAS number: 583-39-1
Developmental toxicity / teratogenicity
Administrative data
- Endpoint:
- developmental toxicity
- Type of information:
- experimental study
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: A reliable secondary source, summaring 2-mercaptobenzimidazole properties, was used. The used secondary source has been updated on 2012; therefore it covers the most updated literature on the substance.
Data source
Reference
- Reference Type:
- secondary source
- Title:
- The adverse effects of oral 2-mercaptobenzimidazole on pregnant rats and their fetuses.
- Author:
- Yamano T, Noda T, Shimizu M, Morita S.
- Year:
- 1 995
- Bibliographic source:
- PubMed - Fundam Appl Toxicol. 1995 May;25(2):218-23
Materials and methods
Test guideline
- Qualifier:
- no guideline available
- Principles of method if other than guideline:
- It is not specified.
- GLP compliance:
- not specified
Test material
- Reference substance name:
- Benzimidazole-2-thiol
- EC Number:
- 209-502-6
- EC Name:
- Benzimidazole-2-thiol
- Cas Number:
- 583-39-1
- Molecular formula:
- C7H6N2S
- IUPAC Name:
- 1H-benzimidazole-2-thiol
- Test material form:
- solid: particulate/powder
- Remarks:
- migrated information: powder
Constituent 1
Test animals
- Species:
- rat
- Strain:
- Wistar
Administration / exposure
- Route of administration:
- oral: unspecified
- Type of inhalation exposure (if applicable):
- not specified
- Vehicle:
- not specified
- Duration of treatment / exposure:
- Gestation Days 7-17: 0, 3.3, 10, and 30 mg/kg during the period of organogenesis.
Days 7-10, 11-14, or 15-17 of gestation: pregnant rats of three groups were also treated with 60 mg/kg of 2-MBI for 3 or 4 days during specific periods of organogenesis
Results and discussion
Results: maternal animals
Maternal developmental toxicity
- Details on maternal toxic effects:
- Maternal toxic effects:no data
Results (fetuses)
- Details on embryotoxic / teratogenic effects:
- Embryotoxic / teratogenic effects:yes. Remark: delayed ossification, skeletal variations, rudimentary lumbar ribs, kinked ureter and dilated renal pelvis
Effect levels (fetuses)
open allclose all
- Dose descriptor:
- dose level:
- Effect level:
- >= 10 mg/kg bw/day
- Based on:
- test mat.
- Basis for effect level:
- other: teratogenicity
- Dose descriptor:
- dose level:
- Effect level:
- >= 30 mg/kg bw/day
- Based on:
- test mat.
- Basis for effect level:
- other: teratogenicity
- Dose descriptor:
- dose level:
- Effect level:
- >= 60 mg/kg bw/day
- Based on:
- test mat.
- Basis for effect level:
- other: teratogenicity
Fetal abnormalities
- Abnormalities:
- not specified
Overall developmental toxicity
- Developmental effects observed:
- not specified
Any other information on results incl. tables
The effects of oral 2-mercaptobenzimidazole (2-MBI) on pregnant Wistar rats were examined. In a preliminary dosefinding study, pregnant rats treated with 2-MBI over Days 7-17 of gestation showed reduction in maternal thymus weights with compound-related mortality at doses > or = 40 mg/kg. No adverse effects on fetuses were found at doses < or = 40 mg/kg. However, anasarca, cleft palate, and dilated lateral ventricles were present in all fetuses from the only
survivor among the dams treated with 60 mg/kg of 2-MBI. In the teratology study, pregnant rats were treated with 2-MBI at doses of 0, 3.3, 10, and 30 mg/kg during the period of organogenesis (Gestation Days 7-17). In addition, pregnant rats of three groups were also treated with 60 mg/kg of 2-MBI for 3 or 4 days during specific periods of organogenesis (Days 7-10, 11-14, or 15-17 of gestation). Treatment on Gestation Days 7-17 resulted in reduced maternal thymus weights at doses of > or = 3.3 mg/kg. In addition to reduced fetal weights, visceral variations (kinked ureter and dilated renal pelvis) and delayed ossification were seen in the fetuses at doses > or = 10 mg/kg, and skeletal variations (rudimentary lumbar ribs) were seen at 30 mg/kg. In the fetuses from the dams treated with 60 mg/kg of 2-MBI,rudimentary lumbar ribs were seen mainly in the group treated on Days 7-10 of gestation, whereas kinked ureter and dilated renal pelvis were evident mainly in the group treated on Gestation Days 15-17
Applicant's summary and conclusion
- Conclusions:
- According to Directive 67/548/EEC and to Regulation (EC) n. 1272/2008, the substance should be classified for teratogenicity.
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