Bis(4-methylbenzoyl)peroxide

Endpoint summary

Description of key information

Specific data are not available on the toxicokinetics, metabolism and distribution of the test substance.  Evidence of absorption and distribution of the test substance can only be inferred indirectly from the available repeated oral gavage study in rats. The test substance contained ~72% of the test article.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Absorption rate - oral (%):

10

Absorption rate - dermal (%):

10

Absorption rate - inhalation (%):

100

Additional information

Specific data are not available on the toxicokinetics, metabolism, distribution and elimination of the test substance.

 

The peroxide is a poorly water soluble (23 ug/L) low molecular weight substance with a relatively high log Pow value of 4.7. Any lipophilic compound may be taken up by micellar solubilization but this mechanism may be of particular importance for highly lipophilic compounds (log P>4), particularly those that are poorly soluble in water (< 1mg/L) that would otherwise be poorly absorbed.

Oral

The test substance as tested in a 28 -day repeated dose oral toxicity study in rats contained ~72% of the test article. Evidence of absorption and distribution of the test item can only be inferred indirectly from this repeated oral gavage study.

Di-(4-Methylbenzoyl)-peroxid (INTEROX-PMBP) was administered daily to SPF-bred Wistar rats. The test article, prepared in PEG 400, was administered to 7-week old rats [(HanIbm: WIST (SPF)] of both sexes for 28 days at doses of 0 (vehicle only), 50, 200 and 1000 mg/kg body weight. The presence of PEG 400 as the vehicle in the oral gavage formulation could have improved the test substance’s absorption from the digestive tract due to greater chances of emulsification. Despite this, there were no toxicologically or statistically significant health effects on the body weights, food consumption, hematological, clinical biochemical and urinalysis parameters, and absolute or relative organ weights. There was no evidence of any treatment-related macroscopic or microscopic findings. Based upon the results obtained in this study, the "no-adverse-effect-level" of Di-(4 -Methylbenzoyl)-peroxid (INTEROX-PMBP) is1000 mg/kg body weight for male and female rats when administered orally by gavage for a period of 28 days. Thus, Di-(4 -Methylbenzoyl)-peroxid (INTEROX-PMBP) appears to be either poorly absorbed and/or efficiently metabolized/eliminated by rats.

 

Dermal

Acute dermal toxicity in rats revealed LD50 > 2000 mg/kg b.w. without systemic effects. The test item is neither an irritant to the rat skin nor a sensitizer to the guinea pig skin suggesting poor uptake and systemic effects. Based on the physical properties (low molecular weight; poor water solubility; log P = 4.7; low vapor pressure, 0.0012 Pa at 25 degrees C), the test substance is expected to have a relatively low dermal absorption rate. The absorption rate was assumed to be 10% for long term systemic DNEL calculations.

 

Inhalation

The test substance is a paste. Additionally, due to the low vapor pressure (0.0112 Pa at 25^oC), inhalation is not expected to be a major route of exposure.

Key values to be used in IUCLID for chemical safety assessment are as follows:

Absorption rate –oral (%): 100

Absorption rate –dermal (%): 10

Absorption rate –inhalation (%): 100