2-piperidinoethanol

Endpoint summary

Description of key information

The molecular weight and the high water solubility favour absorption after oral uptake of the substance. The substance may pass through aqueous pores or be carried through the epithelial barrier by the bulk passage of water. With regard to absorption after inhalation, the target substance is likely to dissolve in the mucus of the upper respiratory tract due to its high water solubility, but absorption is still possible and must be assumed via upper mucosa. Because of the low vapor pressure the inhalation portion will be very low.

Due to the corrosivity a dermal uptake of 100% is expected for the undiluted substance. The log Pow of 0.62 points to a poor uptake through the skin at non-corrosive concentrations. Excretion is assumed to take place mainly via urine after potential phase II metabolism has taken place.

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Additional information

1.        Chemical and physico-chemical description of the substance

The target substance (CAS 3040-44-6) belongs to the chemical class of heterocyclic amines.Thenitrogen atomin the ring carries a hydroxyethyl group.

Description of the physico-chemical properties:

- physical state (20°C): liquid

- vapour pressure (20°C): 0.217 hPa

- molecular weight: 129.2 g/mol

- log Pow (25°C): 0.62

- water solubility: miscible with water

2.        Toxicokinetic assessment

No experimental data on absorption, metabolism and distribution are available for the substance. Therefore, the toxicokinetic behavior was evaluated based on the structure and the physico-chemical properties of the substance as well as data from experimental in vivo toxicity studies.

2.1.  Absorption:

Due to its small molecular weight of 129.2 g/mol, the target substance is assumed to be easily soluble in gastrointestinal fluids. As the substance is ionizable, it will not readily diffuse across biological membranes. The molecular weight and the high water solubility favour absorption after oral uptake of the substance. The substance may pass through aqueous pores or be carried through the epithelial barrier by the bulk passage of water. The log Pow of 0.62 is also favourable for a passive absorption.

According to Kollig et al. (1993), Boethling & Mackay (2000) and Harris (1990), 2-piperidinoethanol (CAS 3040-44-6) is generally resistant to hydrolysis because it does not contain any labile functional groups. Therefore, no study on hydrolysis was performed and it is assumed, that the parent compound is not hydrolysed in the gastrointestinal tract.

In the acute oral toxicity study available for the substance, a LD50 of 110 mg/kg was deduced. Severe clinical signs were observed starting at the testing dose 100 mg/kg body weight. The systemic toxicity revealed that absorption has occurred. The gross pathological findings (hemorrhagic enteritis, thickened forefront of the forestomach) could be attributed to the corrosive potential of the substance.

However, apart from that, no specific data concerning oral absorption of the test substance are available. Therefore, as a worst case an oral absorption of 100 % is assumed.

With regard to absorption after inhalation, the target substance is likely to dissolve in the mucus of the upper respiratory tract due to its high water solubility, but absorption is still possible and must be assumed via upper mucosa. However, due to the low vapor pressure the inhalation portion will be very low.

In an inhalation hazard test no severe clinical effects were observed besides local effects like snout wiping and nasal secretion most likely caused by the corrosivity of the substance.

Due to the lack of data as a worst case 100 % absorption after inhalation is assumed as well.

The log Pow suggests that the substance is not likely to be sufficiently lipophilic to cross the stratum corneum despite the small molecular weight. Therefore, dermal absorption is likely to be low at non-corrosive concentrations.

In an in vivo dermal toxicity study the substance caused severe clinical and local irritating to corrosive effects. The LD50 was determined to lie inbetween 1000 and 2000 mg/kg body weight. The systemic toxicity is assumed to be mainly caused by the skin damage and consequently enabled skin penetration.

On the basis of this study and the implications from structure, PC data and a skin corrosion test which led to the classification for skin corrosivity cat. 1B, a dermal uptake of 100 % is expected for the undiluted substance. At non-corrosive concentrations, where the skin barrier is not destroyed, dermal uptake however will be low.

2.2.  Distribution and accumulative potential:

The physico-chemical information point to a wide distribution of the substance. Due to the high water solubility and good distribution an accumulation is assumed to be unlikely.

2.3.  Metabolism and Excretion:

With regard to metabolism, no information is available.

As suggested by the small molecular weight of the target substance, excretion is assumed to take place mainly via urine after potential phase II metabolism has taken place.

Boethling R and Mackay D (2000). Handbook of Property Estimation Methods for Chemicals. CRC Press, Boca Raton, FL, USA.

Harris JC (1990). Rate of hydrolysis. in: Lyman WJ et al., Handbook of chemical property estimation methods, 3rd edition, ACS Washington.

Kollig, HP et al. (1993). Environmental fate constants for organic chemicals under consideration for EPA's hazardous waste identification projects. EPA/600/R-93/132