Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

additional toxicological information
Type of information:
experimental study
Adequacy of study:
key study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP, non-guideline study. Available as a publised report. Acceptable with restrictions.

Data source

Reference Type:
Differential effects of phthalate esters on transciptional activities via human estrogen receptors α and ß, and androgen receptor
Takeuchi S, Iida M, Kobayashi S, Jin K, Matsuda T, Kojima H
Bibliographic source:
Toxicology 210, 223-233

Materials and methods

Type of study / information:
Estrogenic and androgenic activity of diisobutyl phthalate.
Principles of method if other than guideline:
Highly sensitive gene reporter assays used to determine the endocrine disrupting potential of the test substance via a number of different routes.

Plasmids were prepared as per Kojima et al. 2003, 2004
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Diisobutyl phthalate
EC Number:
EC Name:
Diisobutyl phthalate
Cas Number:
Molecular formula:
1,2-bis(2-methylpropyl) benzene-1,2-dicarboxylate
Details on test material:
Purity: >99.0%
Source: Wako Pure Chemical Industriues, Ltd.

Results and discussion

Any other information on results incl. tables

Diisobutyl phthalate was observed to have the following effects (> 20% inhibitory effect with 10^-5 M DIBP)

Agonistic activity via ERα [REC20 = 6.1*10^-6 M]

Antagonsitic activity via ERß [RIC20 = 6.2*10^-6 M]

Antiandrogenic activities in hAR-transactivation assay

Negative results were observed for:

Agonistic activity via ERß

Antagonsitic activity via ERα

Androgenic activity in AR assay

Cytotoxicity or suppression of ß-Gal activity

Applicant's summary and conclusion

Diisobutyl phthalate was found to exhibit ERα-estrogenic activity and antiandrogenic activity.
Executive summary:

In a non-GLP, non-guideline study Diisobutyl phthalate was found to was found to exhibit ERα-estrogenic activity and antiandrogenic activity.