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Description of key information

No toxicokinetic studies are available with INB. The toxicokinetics of INB was assessed based on physico-chemical data, the toxicological profile and literature data.

The molecular weight, water solubility, octanol/water partition coefficient and QSAR predictions favours oral absorption, whereas dermal and inhalative absorption is considered to be very low. High dose effects in repeated dose studies further demonstrate that systemic distribution takes place. With the log P value of 6.1 – 6.4, INB is highly lipophilic and thus will tend to concentrate in adipose tissue. After oral take up and intestinal absorption it is assumed that INB will be hydrolysed by cleavage of the ester bond and then further metabolized. The results of the repeated dose oral toxicity study in the rat do suggest that enhanced hepatic metabolism does take place.  

Key value for chemical safety assessment

Additional information

TEST MATERIAL: BENZOIC ACID ISONONYLESTER

The test material is a Benzoic acid ester. The material is a colourless liquid with a vapour pressure value that suggests that there is unlikely to be significant inhalation of the material. The high log oil/water partition coefficient suggests that the test material should easily cross biological membranes.

Absorption: The results of the repeated dose oral toxicity study in the rat shows evidence of systemic toxicity which indicates some degree of absorption of test material. The lack of significant effects at a high dose level on an acute oral toxicity study in the rat does suggest that the degree of toxicity may be limited by the rate of absorption of test material. The rate of absorption is facilitated by the high log oil/water partition coefficient but may be limited by the low water solubility of the test material. The lack of toxicity observed in both an acute dermal and acute inhalation toxicity study in the rat suggests that enhanced absorption does not occur via the dermal or inhalation route of exposure.

Distribution: The result of the repeated dose oral toxicity study in the rat shows that some systemic distribution does take place. The high log oil/water partition coefficient does suggest that the test material has the capacity to accumulate in body fat.

Metabolism: The results of the repeated dose oral toxicity study in the rat do suggest that enhanced hepatic metabolism does take place. The purpose of this metabolism is to increase the water-solubility of the test material prior to excretion. The results of the in vitro genotoxicity assays suggest that genotoxicity is neither enhanced nor diminished in the presence of S9 metabolising system.

Excretion: The results of the repeated dose oral toxicity study in the rat show that the kidney is a potential route of test material excretion, following hepatic metabolism.