Phosphatidylcholine vesicle solubilization by glucosidic non-ionic surfactants: a turbidity and x-ray diffraction study

Beugin, Sophie; Grabielle-Madelmont, Cécile; Paternostre, Maı̈té; Ollivon, Michel; Lesieur, Sylviane

doi:10.1007/bfb0115239

Cited by 13 publications

(27 citation statements)

References 11 publications

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“…This transformation is realized during the intermediate domain 1. Indeed, Beugin et al (1995) visualized this structural transformation for OG/Lip ratios, which are comparable to ours.…”

Section: Partition Coefficientssupporting

confidence: 86%

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Partition coefficient of a surfactant between aggregates and solution: application to the micelle-vesicle transition of egg phosphatidylcholine and octyl beta-D-glucopyranoside

Paternostre¹,

Meyer²,

Grabielle-Madelmont³

et al. 1995

Biophysical Journal

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The mechanism of the solubilization of egg phosphatidylcholine containing 10% (M/M) of egg phosphatidic acid unilamellar vesicles by the nonionic detergent, octyl beta-D-glucopyranoside, has been investigated at both molecular and supramolecular levels by using fluorescence and turbidity measurements. In the lamellar region of the transition, the solubilization process has been shown to be first a function of the initial size before reaching an equilibrium aggregation state at the end of this region (the onset of the micellization process). The analysis during the solubilization process of the evolution of both the fluorescence energy transfer between N-(7-nitro-2,1,3-benzoxadiazol-4-yl)-phosphatidylethanolamine (NBD-PE) and N-(lissamine rhodamine B sulfonyl)-phosphatidylethanolamine (Rho-PE) and the fluorescence of 6-dodecanoyl-2-dimethylaminoaphtalene (Laurdan) has allowed us to determine the evolution of the detergent partitioning between the aqueous and the lipidic phases, i.e., the evolution of the molar fraction of OG in the aggregates (XOG/Lip) with its monomeric detergent concentration in equilibrium ([OG]H2O), throughout the vesicle-to-micelle transition without isolating the aqueous medium from the aggregates. The curve described by XOG/Lip versus [OG]H2O shows that the partition coefficient of OG is changing throughout the solubilization process. From this curve, which tends to a value of 1/(critical micellar concentration), five different domains have been delimited: two in the lamellar part of the transition (for 0 < [OG]H2O < 15.6 mM), one in the micellization part, and finally two in the pure micellar region (for 16.5 < [OG]H2O < 21 mM). The first domain in the lamellar part of the transition is characterized by a continuous variation of the partition coefficient. In the second domain, a linear relation relates XOG/Lip and [OG]H2O, indicating the existence of a biphasic domain for which the detergent presents a constant partition coefficient of 18.2 M-1. From the onset to the end of the solubilization process (domain 3), the evolution of (XOG/Lip) with [OG]H2O can be fitted by a model corresponding to the coexistence of detergent-saturated lamellar phase with lipid-saturated mixed micelles, both in equilibrium with an aqueous phase, i.e., a three-phase domain. The micellar region is characterized first by a small two-phase domain (domain 4) with a constant partition coefficient of 21 M-1, followed by a one-phase mixed-micellar domain for which XOG/Lip no longer linearly depends on [OG]H2O. The results are discussed in terms of a phase diagram.

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“…This transformation is realized during the intermediate domain 1. Indeed, Beugin et al (1995) visualized this structural transformation for OG/Lip ratios, which are comparable to ours.…”

Section: Partition Coefficientssupporting

confidence: 86%

“…Our data can be compared with small-angle x-ray scattering (SAXS) data obtained by Beugin et al (1995) on EPC/OG system. The experiments have been performed on concentrated multilayers of EPC (about 700 mM) with increasing concentrations of OG.…”

Section: Partition Coefficientsmentioning

confidence: 99%

Partition coefficient of a surfactant between aggregates and solution: application to the micelle-vesicle transition of egg phosphatidylcholine and octyl beta-D-glucopyranoside

Paternostre¹,

Meyer²,

Grabielle-Madelmont³

et al. 1995

Biophysical Journal

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“…All these points indicate drastic changes in the morphology and/or interactions of the aggregates formed during the solubilization process, or they could result from phase separation phenomena. As previously shown, ,,,,, they are closely connected to domains of existence of different structures encountered in the corresponding lipid−surfactant(s)−buffer phase diagram. In particular, by analogy with DPPC−OG and PC−OG 11 systems, the last point (VII) specific to a large decrease in aggregate turbidity, also called point C, coincides with the complete transformation of vesicles into mixed micelles.…”

Section: Resultsmentioning

confidence: 57%

“…The principle of this process rests on the solubilizing potential reduction of the surface-active agent DM by enzymatic hydrolysis of its polar head group. This is similar to the usual vesicle reconstitution procedures which consist of removing the solubilizing surfactant (detergent) from lipid(s)−detergent mixed micelles. − In this regard, the most detailed information is mainly restricted to the egg phosphatidylcholine (EPC)−octyl β- d -glucopyranoside (OG) system. − …”

Section: Introductionmentioning

confidence: 99%

Phase Behavior of Mixed Aqueous Dispersions of DPPC and Dodecyl Glycosides: Aggregation States Implicated in the Micelle-to-Vesicle Transition

et al. 1998

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The aggregation behavior of dipalmitoylphosphatidylcholine (DPPC) mixed with dodecyl β-d-glucopyranoside (DG) and/or dodecyl β-d-maltoside (DM) was studied in excess buffer. From high-performance liquid chromatography on a gel exclusion column and quasi-elastic light scattering, ultrasonic irradiation of DPPC−DG mixtures yields closed unilamellar vesicles for DG-to-DPPC molar ratios smaller than 1.8, above which some discoid structures are seen by cryofracture electron microscopy. Solubilization by DM of pure DPPC and DPPC−DG vesicles was followed at 37 °C. Turbidity recordings reveal seven significant break points corresponding to the limits separating distinct aggregation states and corresponding to a precise partitioning of DM between lipid aggregates and buffer. Three of these limits coincide with the boundaries of four distinct phase domains revealed by SAXS performed on more concentrated samples over the same composition range. At 37 °C, with increasing DM-to-DPPC ratios, (1) fully hydrated lamellar structures, (2) coexisting lamellar and micellar assemblies, (3) mixed micelles separating from the aqueous phase, and (4) isotropic micellar solutions successively appear. The sequence of these phases is sensitive to temperature variations; bilayer formation is favored by heating. Domain 3 is attributed to a cloud point phenomenon occurring in the micellar region at temperatures higher than 30 or 34 °C, with or without DG, respectively.

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“…While scattering is usually detected at an angle θ to the incident wave, turbidity it is detected by the reduction in the transmitted light at θ=0°. Thus, turbidity can be used to monitor the evolution of particle size or shape through changes in the light scattering properties or the optical density of vesicle suspensions (Beugin et al, 1995;Rachkauskas, 2014;Zerkoune et al, 2016). So, these techniques had been used to follow the fusion of liposomes into cochleates on the addition of divalent cations (Düzgüneş & Ohki, 1977;Portis et al, 1979;Wilschut et al, 1980).…”

Section: Turbiditymentioning

confidence: 99%

Cochleate drug delivery systems: An approach to their characterization

Lipa-Castro

Legrand

Barratt

2021

International Journal of Pharmaceutics

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Cochleate systems formed from phospholipids have very useful properties as drug delivery systems with sustained release capabilities, which are able to improve bioavailability and efficacy, reduce toxicity and increase the shelf-life of encapsulated molecules. These nanometric or micrometric structures are usually obtained after interaction of negatively charged liposomes with a positively charged bridging agent. Many different methods are now available to prepare cochleates and there are also numerous techniques that can be used to characterize them, some of which can be easily applied while others require more sophisticated equipment or analysis. The present review describes the important features of this drug delivery system; including their structural properties and potential applications, as well as a brief account of methods for their preparation and an extensive description of the techniques used for their characterization. This information could guide formulators in their choice of methods of characterization that would be best suited to their needs in terms of time, precision and technological difficulty.

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Phosphatidylcholine vesicle solubilization by glucosidic non-ionic surfactants: a turbidity and x-ray diffraction study

Cited by 13 publications

References 11 publications

Partition coefficient of a surfactant between aggregates and solution: application to the micelle-vesicle transition of egg phosphatidylcholine and octyl beta-D-glucopyranoside

Partition coefficient of a surfactant between aggregates and solution: application to the micelle-vesicle transition of egg phosphatidylcholine and octyl beta-D-glucopyranoside

Phase Behavior of Mixed Aqueous Dispersions of DPPC and Dodecyl Glycosides: Aggregation States Implicated in the Micelle-to-Vesicle Transition

Cochleate drug delivery systems: An approach to their characterization

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