Partitioning of moderately hydrophobic endocrine disruptors between water and synthetic membrane vesicles

Jung Hwan Kwon, Howard M. Liljestrand, Lynn E. Katz

Research output: Contribution to journalArticlepeer-review

58 Citations (Scopus)


The partition coefficient between water and lipid membrane vesicles (K lipw) has been used as an alternative to the 1-octanol-water partition coefficient (Kow) between water and organic solvent, because it more closely represents actual biological membranes. Despite theoretical differences, log Klipw correlates well with log K ow for conventional nonpolar organic pollutants. In the present study, Klipw values of 11 structurally diverse endocrine-disrupting chemicals (EDCs) were measured for three different types of lipid membrane vesicles from dipalmitoylphosphatidylcholine (DPPC), DPPC/cholesterol, and palmitoyloleoylphosphatidylcholine. Correlation analyses were conducted to evaluate the effects of hydrophobicity, molar liquid volume (MLV), and polar surface area (PSA) for 20 EDCs, including nine from a previous study. Correlations that include MLV and PSA reduce the predicted value of log K lipw, suggesting that lipid membranes are less favorable than 1-octanol for a hydrophobic solute because of the higher molar volume and higher hydrogen-bonding potential. These results suggested that Kow alone has limited potential for estimating Klipw and that additional descriptors are required. In addition, Klipw values vary by as much as two orders of magnitude because of the changes in membrane fluidity and the amount of cholesterol in the lipid bilayer. Therefore, lipid components should be chosen carefully to evaluate the bioconcentration of these compounds.

Original languageEnglish
Pages (from-to)1984-1992
Number of pages9
JournalEnvironmental Toxicology and Chemistry
Issue number8
Publication statusPublished - 2006 Aug
Externally publishedYes


  • Bioconcentration
  • Endocrine disrupters
  • Lipid bilayer
  • Partitioning

ASJC Scopus subject areas

  • Environmental Chemistry
  • Health, Toxicology and Mutagenesis


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