Cholesterol‐containing phosphatidylcholine liposomes: Characterization and use as dispersed phase in electrokinetic capillary chromatography

Wiedmer, Susanne Κ.; Jussila, Minttu S.; Holopainen, Juha M.; Alakoskela, Juha-Matti; Kinnunen, Paavo K.J.; Riekkola, Marja‐Liisa

doi:10.1002/1615-9314(20020501)25:7<427::aid-jssc427>3.0.co;2-#

Cited by 46 publications

(20 citation statements)

References 35 publications

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“…These data further allow a comparison of the penetration of pregnanolone into monolayers consisting of different lipids. Using this method for different film compositions, it was shown previously that the results on the penetration of estradiol and testosterone into monolayers agree qualitatively with those obtained for steroid association to liposomes assessed by capillary electrophoresis (Wiedmer et al, 2002).…”

Section: Methodssupporting

confidence: 74%

Dipole Potential and Head-Group Spacing Are Determinants for the Membrane Partitioning of Pregnanolone

Alakoskela¹,

Söderlund²,

Holopainen³

et al. 2004

Mol Pharmacol

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The membrane interactions of pregnanolone, an intravenous general anesthetic steroid, were characterized using fluorescence spectroscopy and monolayer technique. di-8-ANEPPS [4-[2-[6-(dioctylamino)-2-naphthalenyl]ethenyl]-1-(3-sulfopropyl)-pyridinium], a membrane dipole potential (⌿)-sensitive probe, revealed pregnanolone to decrease ⌿ similarly as reported previously for other anesthetics. The decrement in ⌿ was approximately 16 and 10 mV in dipalmitoylphosphatidylcholine (DPPC) and DPPC/cholesterol (90:10, mol/mol) vesicles, respectively. Diphenylhexatriene anisotropy indicated pregnanolone to have a negligible effect on the acyl chain order. In contrast, substantial changes were observed for the fluorescent dye Prodan, thus suggesting pregnanolone to reside in the interfacial region of lipid bilayers. Langmuir balance studies indicated increased association of pregnanolone to DPPC monolayers containing cholesterol or 6-ketocholestanol at surface pressures Ͼ 20 mN/m as well as to monolayers of the unsaturated 1-palmitoyl-2-oleoylphosphatidylcholine. In the same surface pressure range, the addition of phloretin, which decreases ⌿, reduced the penetration of pregnanolone into the monolayers. These results suggest that membrane partitioning of pregnanolone is influenced by the spacing of the phosphocholine head groups as well as by membrane dipole potential. The latter can be explained in terms of electrostatic dipole-dipole interactions between pregnanolone and the membrane lipids with their associated water molecules. Considering the universal nature of these interactions, they are likely to affect membrane partitioning of most, if not all, weakly amphiphilic drugs.Pregnanolone (Fig. 1) is a steroid-based progesterone metabolite that is used as an intravenous general anesthetic (Hering et al., 1996). Because of its low solubility into water, it is administered in an oil-in-water emulsion (eltanolone). Hydrophobicity of compounds is directly linked to their membrane partitioning, and thus, pregnanolone can be expected to favor association with lipid bilayers. However, as far as we are aware, no studies on pregnanolone-lipid interactions have been reported. Other general anesthetics such as isoflurane and halothane have been shown to interact with lipid membranes (Cafiso, 1998). Although many different modes of action have been suggested, the exact mechanism of action of general anesthetics has remained unresolved. The proposed mechanisms include interactions between anesthetics and proteins, interactions between anesthetics and lipids, and effects of anesthetics on the lipid-protein interface (Makriyannis et al., 1990;Ueda et al., 1994). Cantor (1997) suggested a mechanism linking the membrane lateral-pressure profile to the action of membrane proteins. The importance of nonspecific interactions mediated by the amino acid residues in the lipid-water-protein interface was highlighted in a recent molecular-dynamics simulation of the effects of an anesthetic on gramicidin channels in membranes (Tang and Xu,...

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Section: Methodssupporting

confidence: 74%

Dipole Potential and Head-Group Spacing Are Determinants for the Membrane Partitioning of Pregnanolone

Alakoskela¹,

Söderlund²,

Holopainen³

et al. 2004

Mol Pharmacol

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“…Furthermore, chloramphenicol has multiple chloride substituents, which have been observed to increase the interaction between lipid membranes and analytes [30]. As shown before [31,32], the addition of cholesterol to the liposomes slightly reduced the interaction between all the charged compounds and the liposomes reducing the log k value; cholesterol inhibits the movement of the acyl chains in the lipid bilayer which makes the bilayer more rigid [33].…”

Section: Separation Of the Model Compounds By Liposome Electrokineticmentioning

confidence: 87%

Effect of ionic liquids on the interaction between liposomes and common wastewater pollutants investigated by capillary electrophoresis

Ruokonen

Duša

Lokajová

et al. 2015

Journal of Chromatography A

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“…Their results showed that the presence of cholesterol slightly increased the liposomal diameter, and signicant differences in selectivity between the steroids and the liposomal membranes were achieved through the addition of cholesterol. 186 Alternatively, liposomes have been used as coating materials in CE in order to mimic biological cell membranes, since cell membranes are mainly composed of phospholipids and cholesterol, and the interaction between the liposomes and the analytes has been studied. 185,187 As an example, Hautala and collaborators showed the coating of silica capillaries with anionic liposomes comprising POPC, bovine brain PS, and cholesterol, and evaluated the coating effectiveness by examining the interactions of steroids with the coated capillaries.…”

Section: Analytical Sciencementioning

confidence: 99%

Cholesterol – a biological compound as a building block in bionanotechnology

et al. 2013

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Cholesterol is a molecule with many tasks in nature but also a long history in science. This feature article highlights the contribution of this small compound to bionanotechnology. We discuss relevant chemical aspects in this context followed by an overview of its self-assembly capabilities both as a free molecule and when conjugated to a polymer. Further, cholesterol in the context of liposomes is reviewed and its impact ranging from biosensing to drug delivery is outlined. Cholesterol is and will be an indispensable player in bionanotechnology, contributing to the progress of this potent field of research.

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Cholesterol‐containing phosphatidylcholine liposomes: Characterization and use as dispersed phase in electrokinetic capillary chromatography

Cited by 46 publications

References 35 publications

Dipole Potential and Head-Group Spacing Are Determinants for the Membrane Partitioning of Pregnanolone

Dipole Potential and Head-Group Spacing Are Determinants for the Membrane Partitioning of Pregnanolone

Effect of ionic liquids on the interaction between liposomes and common wastewater pollutants investigated by capillary electrophoresis

Cholesterol – a biological compound as a building block in bionanotechnology

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