Liposome—water and octanol—water partitioning of alcohol ethoxylates

✍ Scribed by Markus T. Muuller; Alexander J.B. Zehnder; Beate I. Escher

• Book ID: 102202456
• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 125 KB
• Volume: 18
• Category: Article
• ISSN: 0730-7268
• DOI: 10.1002/etc.5620181011

✦ Synopsis

Liposome-water partitioning coefficients, (K lipw s), were determined for eight pure alcohol ethoxylates using equilibrium dialysis and ultracentrifugation. Both methods yielded statistically indistinguishable results. The experimentally determined log K lipw s were compared with log K ow values estimated with the fragment method using different literature sources for the fragment constants. Fragments of log K lipw were calculated for the ethoxy group (EO) and the -CH 2 -units from the experimentally determined data. An additional -CH 2 -unit causes an average increase of log K lipw by 0.45, and an additional EO causes an average decrease of log K lipw by Ϫ0.12. With these fragments, the quality of log K lipw estimations can be improved significantly as compared to simple linear regression of log K lipw versus log K ow . The K lipw values calculated according to the new fragment method for pure compounds and for commercial mixtures are shown to be adequate descriptors for quantitative structure-activity relationships of bioaccumulation, toxicity, and sorption to natural organic material.