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Description of key information

N-(3-Aminopropyl)-imidazole is considered to be favourable for GIT absorption and to be systemically available. However, there are no indications for a potential to accumulate.

Key value for chemical safety assessment

Additional information

There are no studies available for the determination of toxicokinetics or dermal absorption.

N-(3-Aminopropyl)-imidazole, CAS 5036-48-6 (API) is a liquid substance with a molecular weight of 125.1 g/mol and a vapour pressure of 0.0012 hPa at 20°C. It is miscible with water at room temperature in any ratio and the log Pow is -0.57 at 23°C and pH 10.8.

Because of its physico-chemical properties (log Pow between -1 and 4 and a MW < 500 g/mol), API is favourable for GIT absorption. Due to its low VP of 0.0012 hPa, the saturated vapour concentration is about 0.006 mg/L and exposure by vapour is rather unlikely. There is no information concerning dermal penetration, but the substance is corrosive to the skin (1986: RL2).

Evidence for systemic availability of API comes from a repeated dose toxicity study in rats: In the oral 28-day study (1999; RL1), transient mild hypoproteinemia (significant reduced total protein and albumin levels only in males) was found in the high dose group of 1000 mg/kg bw/d. In the oral 90 -d study (2019; RL1) incrased liver weights in the high dose females (1000 mg/kg bw/d) as well as some changes in clinical chemistry in both sexes indicated a changed liver cell metabolism. However, the local irritation of the mucosa of the stomach/forestomach in the high dose group was considered to be the main effect of API after 90 days of administration.

In the acute oral study, rats showed clinical signs and the LD50 was 1780 mg/kg bw (1986; RL2). The effects observed in the rats, which died (dark red stomach, small and large intestines with bloody contents), are considered to be caused mainly by the corrosivity of the substance (GHS EU: Skin Corr. Cat. 1B) and are therefore no indicators of specific organ toxicity after single exposure.

Studies on mutagenicity in vitro (Ames-Test, in vitro CA, HPRT) were negative, i.e. there is no indication of a reactivity of API or its metabolites under the test conditions.

The results of the RDT studies in rats do not indicate a potential of API for accumulation. Therefore, excretion via the urine is most likely. This is supported by the log Pow value of -0.57.