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Registration Dossier
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EC number: 202-311-9 | CAS number: 94-18-8
Basic toxicokinetics
Administrative data
- Endpoint:
- basic toxicokinetics in vitro / ex vivo
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Data is from peer reviewed journal
Data source
Reference
- Reference Type:
- publication
- Title:
- Metabolism of Parabens (4-Hydroxybenzoic Acid Esters) by Hepatic Esterases and UDP Glucuronosyltransferases in Man
- Author:
- Suzanne Abbas, Jacques Magdalou, Helene greige-gerges et al
- Year:
- 2 010
- Bibliographic source:
- Drug Metab. Pharmacokinet. 25 (6): 568–577 (2010)
Materials and methods
- Objective of study:
- metabolism
Test guideline
- Qualifier:
- according to guideline
- Guideline:
- other:
- Principles of method if other than guideline:
- Details of guidelines not mentioned in the publication
- GLP compliance:
- not specified
Test material
- Reference substance name:
- Benzyl 4-hydroxybenzoate
- EC Number:
- 202-311-9
- EC Name:
- Benzyl 4-hydroxybenzoate
- Cas Number:
- 94-18-8
- Molecular formula:
- C14H12O3
- IUPAC Name:
- benzyl 4-hydroxybenzoate
- Test material form:
- solid: particulate/powder
- Remarks:
- migrated information: powder
- Details on test material:
- CAS No: 94-18-8
Chemical Name: Benzyl 4-hydroxybenzoate (Synonym: benzyl paraben)
Nature of chemical: Organic
Constituent 1
- Radiolabelling:
- no
Test animals
- Species:
- other: Human liver microsomes (pool of 21 livers from men and women)
- Strain:
- not specified
- Sex:
- not specified
- Details on test animals or test system and environmental conditions:
- Not applicable considering in-vitro study
Administration / exposure
- Details on exposure:
- The hydrolysis and glucuronidation of benzyl paraben were investigated in human liver microsomes.
Calibration curves were constructed by plotting the paraben/standard paraben area ratio against the concentration of paraben in mg/mL, and the linear relationships were evaluated by regression analysis with the least-squares method. The equations were drawn from eight concentrations and the experiments were repeated six times. The lower limits of detection was 550 ng/ml for benzylparaben. - Duration and frequency of treatment / exposure:
- 24 hr
Doses / concentrations
- Remarks:
- Doses / Concentrations:
100 µg benzylparaben
- No. of animals per sex per dose / concentration:
- Not applicable considering in-vitro study
- Control animals:
- no
Results and discussion
Main ADME resultsopen allclose all
- Type:
- absorption
- Results:
- Details not available
- Type:
- distribution
- Results:
- Details not available
- Type:
- metabolism
- Results:
- The hydrolysis of parabens in human liver microsomes occurred more rapidly than in plasma, and the rate decreased as a function of the chain length. The hydrolysis rate followed first-order kinetics.
- Type:
- excretion
- Results:
- Not applicable
Metabolite characterisation studies
- Metabolites identified:
- yes
- Details on metabolites:
- benzylparaben-4 O-glucuronide.
Any other information on results incl. tables
Metabolism: The hydrolysis of parabens in human liver microsomes occurred more rapidly than in plasma, and the rate decreased as a function of the chain length. The hydrolysis rate followed first-order kinetics, thus allowing the determination of hydrolysis rate constants and half-lives. The benzylparaben was hydrolyzed at an intermediate rate, with a half-life of 43 min. The results indicated the formation of a benzylparaben-4 O-glucuronide.
Possible metabolic route of parabens in attached as a figure.
Applicant's summary and conclusion
- Conclusions:
- Interpretation of results (migrated information): low bioaccumulation potential based on study results
This study shows that parabens are extensively metabolized in human liver microsomes by the combined action of esterases and UGT [UDP-glucuronosyltransferase] (UGT) of families 1A and 2B. This active biotransformation is likely to prevent the accumulation of these molecules in man and thus prevent their possible toxicity. - Executive summary:
In an in-vitro study conducted with Benzyl 4-hydroxybenzoate (Synonym: benzyl paraben) using human liver microsomes,the hydrolysis of the paraben occurred more rapidly than in plasma. The hydrolysis rate followed first-order kinetics, thus allowing the determination of hydrolysis rate constants and half-lives. The benzyl paraben had a half-life of 43 min. Benzyl paraben is metabolized to benzylparaben-4 O-glucuronide.This active biotransformation is likely to prevent the accumulation of these molecules in man and thus prevent their possible toxicity.
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