A Study of the Emulsified Microemulsion by SAXS, Cryo‐TEM, SD‐NMR, and Electrical Conductivity

Lutz, Rachel; Aserin, Abraham; Wachtel, Ellen; Ben‐Shoshan, Einav; Danino, Dganit; Garti, Nissim

doi:10.1080/01932690701525452

Cited by 26 publications

(24 citation statements)

References 26 publications

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“…Emulsified microemulsions have a similar structure to W/O/W emulsions but the oil droplets contain W/O microemulsions (or reverse micelles), rather than water droplets (Lutz et al 2007). In this case, a W/O microemulsion solution is formed by dispersing water-and oil-soluble surfactant in an oil phase.…”

Section: Emulsified Microemulsions and Cubosomesmentioning

confidence: 99%

Particle Characteristics and Their Impact on Physicochemical Properties of Delivery Systems

McClements¹

2014

Nanoparticle- And Microparticle-Based Delivery Systems

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Section: Emulsified Microemulsions and Cubosomesmentioning

confidence: 99%

Particle Characteristics and Their Impact on Physicochemical Properties of Delivery Systems

McClements¹

2014

Nanoparticle- And Microparticle-Based Delivery Systems

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“…Analytical approaches to determine DSDs of multiple emulsions are for example light scattering, CARSmicroscopy [1], Cryo-SEM and -TEM [2][3][4][5], and pulsed-field-gradient NMR (PFG-NMR) [6][7][8]. The latter has the advantage of being completely non-destructive and independent of optical properties of the emulsion (e.g., opaqueness).…”

Section: Introductionmentioning

confidence: 99%

PFG‐NMR on W₁/O/W₂‐emulsions: Evidence for molecular exchange between water phases

Guan¹,

Hailu²,

Guthausen³

et al. 2010

Euro J Lipid Sci & Tech

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A major question in the investigation of multiple emulsions of WOW-type is that of stability and ripening, which is often reflected in the droplet-size distribution (DSD). The DSD is an important parameter for judging product properties. Instability in multiple emulsions is often linked to molecular exchange between inner and outer water phases (W 1 , W 2 ), which has to be taken into account. For example, coalescence phenomena and Ostwald ripening affect microscopic and/or macroscopic stability and therefore the multi-dispersity of an emulsion. This is especially important as the inner compartment can act for encapsulating active agents. NMR investigations on emulsions are mainly based on the analysis of diffusion properties of molecules in the different compartments. For determination of the DSD of the inner and outer droplets, it is crucial to know the physical effects influencing the NMR-signal. Depending on these effects, the NMR data are analyzed by different models, depending for example on the occurrence and time scale of molecular exchange between the phases. They are shown to yield correct DSDs. Evidence for the effect of diffusion between phases is given by using the phenomenon of driven diffusion, which allows a direct detection of the exchange by NMR. The exchange is confirmed by confocal laser scanning microscopy.

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“…For these reasons, attempts are made to measure droplet size distributions in multiple emulsions after the critical second emulsification step in order to assure targeted product properties. However, only few measurement techniques are described in the literature in this context [17][18][19][20]. Conventional measurement techniques for emulsions of the simple type (O/W or W/O), such as the well-established laser light diffraction, cannot be applied due to the impossibility to dilute the inner W 1 droplets.…”

Section: Introductionmentioning

confidence: 99%

“…Optical microscopic methods are limited to droplet sizes of .1 mm for light [18] or .750 nm (pixel size = 150 nm) for confocal fluorescence microscopy [22]. On the other hand, samples are extremely difficult to prepare for cryo-scanning electron microscopy (SEM) or -transmission electron microscopy (TEM) [19,20] with respect to samplespecific representation. Microscopic methods also lack in applicability for distribution measurements as only a limited number of droplets is usually observed.…”

Section: Introductionmentioning

confidence: 99%

Preparation of W₁/O/W₂ emulsions and droplet size distribution measurements by pulsed‐field gradient nuclear magnetic resonance (PFG‐NMR) technique

Wolf

Hecht

Schuchmann

et al. 2009

Euro J Lipid Sci & Tech

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manyMultiple emulsions of W 1 /O/W 2 type are of major interest in life sciences, offering possibilities for the encapsulation of water-soluble active agents. In food science, they are also applied for fat reduction. The droplet size distributions of the inner and outer emulsions are of main importance as they influence the rheological and sensorial properties, the release kinetics, as well as the structural and microbial stability. However, the determination of the inner and outer droplet size distributions is a major challenge, as conventional measurement techniques cannot be applied. Pulsed-field gradient nuclear magnetic resonance (PFG-NMR) is well known as a non-destructive tool for droplet size determination, especially in simple emulsions. In this work, double emulsions of the W 1 /O/W 2 type were prepared with polyglycerol-polyricinoleate (PGPR) and polyoxyethylen-20-sorbitan monolaurate (Tween 20) as emulsifiers by means of rotor-stator emulsification machines. PFG-NMR was applied for measurements of the inner phase (W 1 ) droplet size distribution as well as for the characterization of the O phase. The W 1 values were compared with results from laser light diffraction of simple emulsions (W 1 /O type) and were found to be consistent within the experimental errors, if restricted diffusion in the outer water phase (W 2 ) and additional effects are considered.

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A Study of the Emulsified Microemulsion by SAXS, Cryo‐TEM, SD‐NMR, and Electrical Conductivity

Cited by 26 publications

References 26 publications

Particle Characteristics and Their Impact on Physicochemical Properties of Delivery Systems

Particle Characteristics and Their Impact on Physicochemical Properties of Delivery Systems

PFG‐NMR on W₁/O/W₂‐emulsions: Evidence for molecular exchange between water phases

Preparation of W₁/O/W₂ emulsions and droplet size distribution measurements by pulsed‐field gradient nuclear magnetic resonance (PFG‐NMR) technique

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A Study of the Emulsified Microemulsion by SAXS, Cryo‐TEM, SD‐NMR, and Electrical Conductivity

Cited by 26 publications

References 26 publications

Particle Characteristics and Their Impact on Physicochemical Properties of Delivery Systems

Particle Characteristics and Their Impact on Physicochemical Properties of Delivery Systems

PFG‐NMR on W1/O/W2‐emulsions: Evidence for molecular exchange between water phases

Preparation of W1/O/W2 emulsions and droplet size distribution measurements by pulsed‐field gradient nuclear magnetic resonance (PFG‐NMR) technique

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PFG‐NMR on W₁/O/W₂‐emulsions: Evidence for molecular exchange between water phases

Preparation of W₁/O/W₂ emulsions and droplet size distribution measurements by pulsed‐field gradient nuclear magnetic resonance (PFG‐NMR) technique