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Administrative data

Link to relevant study record(s)

Description of key information

Key value for chemical safety assessment

Absorption rate - oral (%):
50
Absorption rate - dermal (%):
50
Absorption rate - inhalation (%):
100

Additional information

The octanol/water partition coefficient of 1,1-isopropylidenebis(p-phenyleneoxy)dipropan-2-ol, being 3.3 to 3.6, and the molecular weight of 344.44 are favourable for absorption. The water solubility of 1,1-isopropylidenebis(p-phenyleneoxy)dipropan-2-ol is moderate (109 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 1,1-isopropylidenebis(p-phenyleneoxy)dipropan-2-ol 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 1,1-isopropylidenebis(p-phenyleneoxy)dipropan-2-ol might undergo biotransformation. Because of the moderate molecular weight of 1,1-isopropylidenebis(p-phenyleneoxy)dipropan-2-ol, the conjugates will either be excreted via the bile or the urine.

 

Based on the particle size of 1,1-isopropylidenebis(p-phenyleneoxy)dipropan-2-ol, particles < 100µm which have the potential to be inhaled, are present in a small amount (4.48%). Particles will predominantly settle in the nasopharyngeal region (particles with aerodynamic diameter > 1-5 µm); the particles are too large to reach the tracheobronchial or pulmonary region (no particles < 5 µm). Part of the deposits in the nasopharyngeal region will be coughed or sneezed out of the body, or swallowed, while the moderate water solubility of 1,1-isopropylidenebis(p-phenyleneoxy)dipropan-2-ol (0.109 g/L) indicates that a part will dissolve into the mucus lining of the respiratory tract. Next to the moderate water solubility, the log Pow > 0 (3.3 to 3.6) furthermore indicates a limited potential for absorption directly across the respiratory tract epithelium. However for a risk assessment purposes the inhalation absorption of 1,1-isopropylidenebis(p-phenyleneoxy)dipropan-2-ol is set at 100% as a worst case assumption to be compliant to ECHA guidance.

 

 

1,1-isopropylidenebis(p-phenyleneoxy)dipropan-2-ol, being a solid with a moderate water solubility (0.109 g/L) has the potential for dermal absorption. Its molecular weight (344.44) and log Pow (3.3 to 3.6) are indicative to be moderately favarouble 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 1,1-isopropylidenebis(p-phenyleneoxy)dipropan-2-ol 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 1,1-isopropylidenebis(p-phenyleneoxy)dipropan-2-ol after dermal absorption.