Temperature dependence of the interaction of cholate and deoxycholate with fluid model membranes and their solubilization into mixed micelles

Hildebrand, Annegret; Beyer, Katja; Neubert, Reinhard H.H.; Garidel, Patrick; Blume, Alfred

doi:10.1016/j.colsurfb.2003.08.001

Cited by 64 publications

(80 citation statements)

References 29 publications

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“…The phase diagrams for the vesicle-to-micelle transition in water ( Figure 7) are characterised by non-linear phase boundaries with a decrease of the phase boundaries at low lipid concentration [59,62,75,81]. This is not observed to such an extent for the lipid to bile salt systems dispersed in 100 mM NaCl.…”

Section: Total Detergent Concentration D T / Mmmentioning

confidence: 87%

“…At 30 °C a continuous change in the reaction heat from -400 μJ to -100 μJ is observed, whereas at 60 °C a continuous change in the reaction heat from -900 μJ to -200 μJ is detected [59]. The model used for the calculation of the partition coefficient P and the heat of transfer ΔH T of detergent molecules from water to lipid vesicles takes into account electrostatic effects.…”

Section: Investigation Of Detergent Water To Membrane Partitioning Bymentioning

confidence: 99%

“…This is in agreement with the phase rule approximation, which predicts that the reaction enthalpies are constant over the whole coexistence range. [59,72,73]. The morphology of the formed aggregates depends on the chemical structure of the components, however, the composition of the mixed aggregates is given by the effective (index e) detergent to lipid ratio R e # according to:…”

Section: Increase Of Detergent Concentrationmentioning

confidence: 99%

“…Higher P av values and larger ΔG av T are obtained in 100 mM NaCl compared to pure water. The intrinsic partition coefficient should be unaffected by changing the ionic strength, due to the fact that charge screening effects at infinite dilution of the bile salt in the lipid phase is strongly reduced (for more details see [41,56,59,62]). …”

Section: Influence Of Ionic Strengthmentioning

confidence: 99%

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Membranolytic Activity of Bile Salts: Influence of Biological Membrane Properties and Composition

et al. 2007

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Abstract:The two main steps of the membranolytic activity of detergents: 1) the partitioning of detergent molecules in the membrane and 2) the solubilisation of the membrane are systematically investigated. The interactions of two bile salt molecules, sodium cholate (NaC) and sodium deoxycholate (NaDC) with biological phospholipid model membranes are considered. The membranolytic activity is analysed as a function of the hydrophobicity of the bile salt, ionic strength, temperature, membrane phase properties, membrane surface charge and composition of the acyl chains of the lipids. The results are derived from calorimetric measurements (ITC, isothermal titration calorimetry). A thermodynamic model is described, taking into consideration electrostatic interactions, which is used for the calculation of the partition coefficient as well as to derive the complete thermodynamic parameters describing the interaction of detergents with biological membranes (change in enthalpy, change in free energy, change in entropy etc). The solubilisation properties are described in a so-called vesicle-to-micelle phase transition diagram. The obtained results are supplemented and confirmed by data obtained from other biophysical techniques (DSC differential scanning calorimetry, DLS dynamic light scattering, SANS small angle neutron scattering).

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Section: Total Detergent Concentration D T / Mmmentioning

confidence: 87%

Section: Investigation Of Detergent Water To Membrane Partitioning Bymentioning

confidence: 99%

Section: Increase Of Detergent Concentrationmentioning

confidence: 99%

Section: Influence Of Ionic Strengthmentioning

confidence: 99%

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Membranolytic Activity of Bile Salts: Influence of Biological Membrane Properties and Composition

et al. 2007

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“…Therefore, proliposomes would be a potential vehicle to help improve the oral absorption of hydrophobic drugs. The underlying mechanism allowing proliposomes to improve oral absorption might be partially explained by the presence of bile salts, which can www.nature.com/aps Chu C et al Acta Pharmacologica Sinica npg interact with phospholipids in the gastrointestinal tract to form mixed micelles for vehicles/mesophases to increase the solubility of hydrophobic drugs [20,21] . Expanding on our previous work [5] , novel proliposomes (a polyphase dispersed system containing trace micelles and emulsions) loaded with dehydrosilymarin were prepared.…”

Section: Introductionmentioning

confidence: 99%

Proliposomes for oral delivery of dehydrosilymarin: preparation and evaluation in vitro and in vivo

Chu

Tong

et al. 2011

Acta Pharmacol Sin

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Aim: To formulate proliposomes with a polyphase dispersed system composed of soybean phospholipids, cholesterol, isopropyl myristate and sodium cholate to improve the oral bioavailability of dehydrosilymarin, an oxidized form of herbal drug silymarin. Methods: Dehydrosilymarin was synthesized from air oxidation of silymarin in the presence of pyridine, and proliposomes were prepared by a film dispersion-freeze drying method. Morphological characterization of proliposomes was observed using a transmission electron microscope. Particle size and encapsulation efficiency of proliposomes were measured. The in vitro release of dehydrosilymarin from suspension and proliposomes was evaluated. The oral bioavailability of dehydrosilymarin suspension and proliposomes was investigated in rabbits. Results: The proliposomes prepared under the optimum conditions were spherical and smooth with a mean particle size in the range of 7 to 50 nm. Encapsulation efficiency was 81.59%±0.24%. The in vitro accumulative release percent of dehydrosilymarinloaded proliposomes was stable, which was slow in pH 1.2, and increased continuously in pH 6.8, and finally reached 86.41% at 12 h. After oral administration in rabbits, the relative bioavailability of proliposomes versus suspension in rabbits was 228.85%. Conclusion: Proliposomes may be a useful vehicle for oral delivery of dehydrosilymarin, a drug poorly soluble in water.

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Biomaterial Approaches for Understanding and Overcoming Immunological Barriers to Effective Oral Vaccinations

Frizzell

Woodrow

2020

Adv Funct Materials

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Oral vaccines have the potential to reduce cost, improve compliance, and induce immunity at mucosal surfaces that are the first line of defense against infection. The gastrointestinal tract is highly evolved to efficiently digest and absorb nutrients without eliciting aberrant inflammation. However, these functions also limit the efficacy of immunization by the oral route. While mechanisms responsible for the development of tolerance to fed antigens are being illuminated, the application of materials with precise physiochemical properties and immunomodulatory potential may accelerate understanding of immunity within the gastrointestinal tract. Insight into these immunological mechanisms can inform the design of next‐generation oral vaccines to harness critical functions to elicit immunity. Here, material strategies for oral vaccines and their dual function in understanding and overcoming immunological barriers associated with oral immunization are discussed.

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Temperature dependence of the interaction of cholate and deoxycholate with fluid model membranes and their solubilization into mixed micelles

Cited by 64 publications

References 29 publications

Membranolytic Activity of Bile Salts: Influence of Biological Membrane Properties and Composition

Membranolytic Activity of Bile Salts: Influence of Biological Membrane Properties and Composition

Proliposomes for oral delivery of dehydrosilymarin: preparation and evaluation in vitro and in vivo

Biomaterial Approaches for Understanding and Overcoming Immunological Barriers to Effective Oral Vaccinations

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