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Diss Factsheets
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EC number: 200-252-3 | CAS number: 56-04-2
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Endpoint summary
Administrative data
Link to relevant study record(s)
- Endpoint:
- basic toxicokinetics in vivo
- Type of information:
- experimental study
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- test procedure in accordance with generally accepted scientific standards and described in sufficient detail
- Objective of study:
- other: accumulation in thyroid
- Qualifier:
- no guideline available
- GLP compliance:
- not specified
- Radiolabelling:
- yes
- Remarks:
- 35-S
- Species:
- rat
- Strain:
- Sprague-Dawley
- Sex:
- male
- Details on test animals or test system and environmental conditions:
- Commercial diet 41B, iodine content 2ug/g, tap-water ad lib.
- Route of administration:
- oral: drinking water
- Vehicle:
- other: alkaline saline (pH 8.0)
- Details on exposure:
- Methylthiouracil was adminístered in 0.2 ml alkaline saline
- Duration and frequency of treatment / exposure:
- After 8 hr all animals were killed
- Dose / conc.:
- 170 other: ug
- No. of animals per sex per dose / concentration:
- Four
- Control animals:
- no
- Details on study design:
- 35S labelled antithyroid drugs were administered in 1.2 umoles to normal rats. Thin-layer chromatography of the solutions immediately before injection demonstrated no significant breakdown. All animals were killed 8 hours afterinjection and the blood obtained by cardiac puncture into a heparinized syringe while under light ether anasthesia. The thyroids were quickly removed, dissected free of fat, weighed (wet weight) on a toriosn balance and homogenized in 0.5 ml of ice-cold distilled water in pyrex ground glass homogenizers. 0.1 ml of plasma and thyroid homogenates were transferred into liquid scintillation vials and analyzed with a scintillator. Aliquits of thyroid homogenates and plasma were analyzed using thin-layer chromatography and radiochromatogram.
- Details on distribution in tissues:
- Methylthiouracil is accumulated in thyroid gland. Thyroid:plasma ratio is 8.2 after 8 hours after substance administration.
- Metabolites identified:
- not measured
- Conclusions:
- Methylthiouracil was shown to accumulate in thyroid gland.
Reference
Table 1. Thyroid accumulation of 35S-labelled methylthiouracil to rats.
Drug | Dose (ug) | Total 35S activity/g thyroid or ml plasma | Actual drug or sulphate nmoles /thyroid |
|||||
35S - Methylthiouracil |
nmoles/g thyroid | nmoles/g plasma | Thyroid plasma 35S ratio | Sulphate | Drug | Plasma drug level nmoles/ml |
Drug thyroid:plasma ratio |
|
170 | 66.1±6.3 | 1.63±0.18 | 43.1±5.6 | 14,5±2.2 | 9.9±0.9 | 1.2 | 8.2 |
Description of key information
Methylthiouracil was accumulated in thyroid gland. Thyroid:plasma ratio was 8.2 after 8 hours after substance administration.
Key value for chemical safety assessment
- Bioaccumulation potential:
- high bioaccumulation potential
Additional information
Methylthiouracil is a thionamide anti-thyroid drug, which has been used in the treatment of hyperthyroidism.
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