title: Comparison of lipid membrane-water partitioning with various organic solvent-water partitions of neutral species and ionic species: Uniqueness of cerasome as a model for the stratum corneum in partition processes.
abstract: Lipid membrane-water partitions (e.g., immobilized artificial membrane systems where the lipid membrane is a neutral phospholipid monolayer bound to gel beads) were compared to various organic solvent-water partitions using linear free energy relationships. To this end, we also measured the retention factors of 36 compounds (including neutral and ionic species) from water to liposomes made up of 3-sn-phosphatidylcholine and 3-sn-phosphatidyl-l-serine (80:20, mol/mol), employing liposome electrokinetic chromatography in this work. The results show that lipid membranes exhibit a considerably different chemical environment from those of organic solvents. For both neutral species and ionic species, partitions into the more polar hydroxylic solvents are chemically closer to partition into the lipid membrane as compared to partitions into the less polar hydroxylic solvents and into aprotic solvents. This means that solutes partition into the polar parts of lipid membranes, regardless of whether they are charged or not. In addition, cerasome (i.e., liposome composed mainly of stratum corneum lipids) was compared with regular phospholipid liposomes as a possible model for human stratum corneum in partitions. It was found that the cerasome-water partition exhibits a better chemical similarity to skin permeation. This is probably due to the unique structures of ceramides that occur in cerasome and in the stratum corneum lipid domain. We further show that membranes in membrane-water partitions exhibit very different properties.
authors.affiliation: Department of Pharmaceutical Technology, Friedrich-Schiller-Universität Jena, Jena 07743, Germany; Department of Pharmacy, The Third Hospital of Wuhan, Wuhan 430060, China.
authors.forename: Keda
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Department of Pharmaceutical Technology, Friedrich-Schiller-Universität Jena, Jena 07743, Germany.
authors.forename: Alfred
authors.initials: A
authors.lastname: Fahr
authors.affiliation: Department of Chemistry, University College London, London WC1H 0AJ, UK. Electronic address: m.h.abraham@ucl.ac.uk.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Abraham
authors.affiliation: Department of Chemistry, University of North Texas, 1155 Union Circle Drive #305070, Denton, TX 76203, USA.
authors.forename: William E
authors.initials: WE
authors.lastname: Acree
authors.affiliation: Center of Skin Science, Faculty of Life Sciences, University of Bradford, Bradford BD7 1DP, UK.
authors.forename: Desmond J
authors.initials: DJ
authors.lastname: Tobin
authors.affiliation: Bradford School of Pharmacy, Faculty of Life Sciences, University of Bradford, Bradford BD7 1DP, UK. Electronic address: X.Liu18@bradford.ac.uk.
authors.forename: Xiangli
authors.initials: X
authors.lastname: Liu
mesh_terms: D006624:Hippocampus / Q000378:metabolism*; D006801:Humans; D007477:Ions / Q000378:metabolism*; D008081:Liposomes / Q000378:metabolism; D008563:Membrane Lipids / Q000378:metabolism*; D008567:Membranes, Artificial; D009930:Organic Chemicals / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D012869:Skin Absorption / Q000502:physiology; D012996:Solutions / Q000378:metabolism; D012997:Solvents / Q000378:metabolism*; D014867:Water / Q000378:metabolism*
chemical_list: D007477:Ions; D008081:Liposomes; D008563:Membrane Lipids; D008567:Membranes, Artificial; D009930:Organic Chemicals; D010713:Phosphatidylcholines; D010743:Phospholipids; D012996:Solutions; D012997:Solvents; D014867:Water
keywords: Ionic species; LEKC; LFER; Liposomes; Partition; Physicochemical properties