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Administrative data

Link to relevant study record(s)

Description of key information

The octanol/water partition coefficient of the different constituents of 2,2'-Isopropylidenebis(p-phenyleneoxy)diethanol were comprised between 2.5 and 4. The log Kow of the main constituent was 2.86. The molecular weight of 316 g.mol-1are favourable for absorption. The water solubility of 2,2'-Isopropylidenebis(p-phenyleneoxy)diethanol is moderate (111.8 mg/L). In general, a compound needs to be dissolved before it can be taken up from the gastro-intestinal tract after oral administration. Potential for ionization may result in impaired uptake since compounds need to pass the lipid membranes in the gastrointestinal wall. For risk assessment purposes the oral absorption of 2,2'-Isopropylidenebis(p-phenyleneoxy)diethanol is set at 50% as a worst case assumption. The results of the toxicity studies do not provide reasons to deviate from this proposed oral absorption factor.

Absorbed 2,2'-Isopropylidenebis(p-phenyleneoxy)diethanol might undergo biotransformation. Because of the moderate molecular weight, the conjugates will either be excreted via the bile or the urine.

As 2,2'-Isopropylidenebis(p-phenyleneoxy)diethanol is considered as a clear yellowish waxy solid with white lump i.e. (sort of suspension, liquid), no particle size was determined. In addition, the vapour pressure of the test substance at 20°C was very low (3.1x10-7 Pa). However, for risk assessment purposes the inhalation absorption of 2,2'-Isopropylidenebis(p-phenyleneoxy)diethanol is set at 100% as a worst case assumption.

 

2,2'-Isopropylidenebis(p-phenyleneoxy)diethanol being a waxy solid with a moderate water solubility (111.8 mg/L) has the potential for dermal absorption. Its molecular weight (316) and log Pow (2.5 to 4) are indicative to be moderately favorable for dermal uptake. However, the criteria for 10% dermal absorption as given in the Reach Guidance on information requirements and chemical safety assessment (MW>500 and -1<log Pow >4) are not met, and therefore 100% dermal absorption of 2,2'-Isopropylidenebis(p-phenyleneoxy)diethanol should be considered for risk assessment purposes. It is, however, generally accepted that dermal absorption is not higher compared to oral absorption. The 100% dermal absorption derived from physical/chemical properties of the substance should therefore be considered as a non-realistic assumption, and for risk assessment purposes a lower dermal absorption of 50% might be considered more appropriate.

 

Based on the present available data, no additional conclusions can be drawn on the distribution, metabolism and excretion of 2,2'-Isopropylidenebis(p-phenyleneoxy)diethanol after dermal or oral absorption or inhalation.

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential
Absorption rate - oral (%):
50
Absorption rate - dermal (%):
50
Absorption rate - inhalation (%):
100

Additional information