Reaction mass of 1-phenyloctadecane-1,3-dione and phenylicosane-1,3-dione

Endpoint summary

Description of key information

Short description of key information on bioaccumulation potential result: 
The available experimental data in animals show limited evidence of oral absorption, systemic distribution and metabolization of the test substance since no systemic effects were reported in rodents following acute or repeated exposures and the only noteworthy change in dogs treated for 90 days consisted in a slight increase in liver weight with no apparent histopathological correlation. No systemic effects were observed when the test substance was dermally applied in the acute dermal toxicity study. No indication on the test substance excretion was obtained.

Additional information

No specific toxicokinetic (TK) study using Rhodiastab 55P has been performed. Therefore, the assessment of absorption, distribution, metabolism and excretion of the reaction mass of Stearoylbenzoylmethane and Palmitoylbenzoylmethane is based on the physico-chemical properties of the test substance and on the results of the available toxicity studies.

 

Physico-chemistry data:

The test substance is a solid (powder), poorly soluble in water (< 1 mg/L), and with a very low vapour pressure (1.8 E-05 Pa at 25 °C). Its relative density is 1.095. The distribution of particle sizes indicates that 53% of the particles was lower than 100 µm (inhalable fraction) and less than 1% of particles was lower than 10 µm (respirable fraction). The boiling point of the test substance was determined to be 377.5°C at 98.4 kPa. The log Pow was determined to be above 6, which indicates a low potential of dermal / percutaneous absorption.

 

Absorption:

Oral route:

There was no mortality or evidence of systemic toxicity in rats in the acute oral toxicity study at the dose of 5000 mg/kg bw and in the 28-day toxicity study up to the dose of 10000 mg/kg bw. There were also no signs of systemic toxicity in the combined carcinogenicity/reproductive rat toxicity study at the in-diet dose of 100 ppm and in the in vivo micronucleus test in mice treated once up to the dose of 2500 mg/kg bw.

In contrast, in the 90-day dog toxicity study, a slight increase in absolute liver weight was observed at the 2 highest doses (450 and 1350 mg/kg). This can be considered as an indication of absorption of the test substance following oral administration although these changes were not considered to be adverse since they were not correlated with any histopathological changes.

 

Dermal route:

There was no mortality or evidence of systemic toxicity in the acute dermal toxicity study in rats at the dose of 2000 mg/kg bw. There were neither any signs of toxicity or sensitisation effects after cutaneous exposure on the mouse ears in the LLNA assay.

 

Distribution:

No specific toxicological effects were observed in the acute and/or repeated dose toxicity studies in rodents. However, the slight increase in liver weight in the 90-day dog toxicity study (with no histopathological correlation), support a systemic distribution of the test substance.

 

Metabolism:

No specific toxicological effects indicative of metabolic alteration were observed in the acute and/or repeated dose toxicity studies in rodents.

The slight increase in liver weight noted in the 90-day dog study could be indicative of increase metabolic activity, although there was no apparent histopathological correlation.

The outcome of the in vitro mutagenicity tests (bacterial reverse mutation assay, mouse lymphoma assay and chromosome aberration in human lymphocytes) was not affected by the presence of metabolic activation. The tests showed no mutagenic or clastogenic effects in the presence or in the absence of exogenous liver S9 metabolization system.

 

Excretion:

No data are available with regards to the test substance excretion.