Micelles solubilization into

The secondary solubilization of electrolytes, namely, their solubilization into water solubilized in the micelle, has been widely investigated [125-127]. 

Thus, in contrast to previous in vivo models, this in vitro model provides the possibility of dissociating experimentally two important processes of the intestinal carotenoid absorption cellular uptake and secretion. Under conditions mimicking the postprandial state (TC OA supplementation), differentiated Caco-2 cells were able (1) to take up carotenoids at the apical side and to incorporate them into CM and (2) to secrete them at the basolateral side, associated with CM fractions. In this model, no attempt has yet been made to reproduce the in vivo physiochemical conditions occurring in the intestinal lumen, such as carotenoid release from the food matrix and solubilization into mixed lipid micelles. Carotenoids were delivered to Caco-2 cells in aqueous suspension with Tween 40 (During et al., 2002). Using this cell culture system in conjunction with an in vitro... 

One of the most important characteristics of micelles is their ability to enclose all kinds of substances. Capture of these compounds in micelles is generally driven by hydrophobic, electrostatic and hydrogen-bonding interactions. The dynamics of solubilization into micelles are similar to those observed for entrance and exit of individual surfactant molecules, but the micelle-bound substrate will experience a reaction environment different from bulk water, leading to kinetic medium effects308. Hence, micelles are able to catalyse or inhibit reactions. The catalytic effect on unimolecular reactions can be attributed exclusively to the local medium effect. For more complicated bimolecular or higher-order reactions, the rate of the reaction is affected by an additional parameter the local concentrations of the reacting species in or at the micelle. 

The Winsor II microemulsion is the configuration that has attracted most attention in solvent extraction from aqueous feeds, as it does not affect the structure of the aqueous phase the organic extracting phase, on the other hand, is now a W/0 microemulsion instead of a single phase. The main reason for the interest in W/0 microemulsions is that the presence of the aqueous microphase in the extracting phase may enhance the extraction of hydrophilic solutes by solubilizing them in the reverse micellar cores. However, this is not always the case and it seems to vary with the characteristics of the system and the type of solute. Furthermore, in many instances the mechanism of extraction enhancement is not simply solubilization into the reverse micellar cores. Four solubilization sites are possible in a reverse micelle, as illustrated in Fig. 15.6 [19]. An important point is that the term solubilization does not apply only to solute transfer into the reverse micelle cores, but also to insertion into the micellar boundary region called the palisade. The problem faced by researchers is that the exact location of the solute in the microemulsion phase is difficult to determine with most of the available analytical tools, and thus it has to be inferred. 

Since ANS was not solubilized into fluorocarbon micelles, the existence of mixed micelles formed by the fluorocarbon and hydrocarbon surfactants can be discussed. 

Figure 1 shows the change in fluorescence intensity of ANS in the aqueous surfactant solution. In the case of the hydrocarbon surfactant, the fluorescence intensity of ANS was proportional to the surfactant concentration above the CMC. Since the fluorescence intensity of ANS had a constant value below the CMC, the inflection point appeared at the CMC. The surfactant concentration at the inflection pojnt nearly coincided with the CMC of 6ED and SDS( the CMC was 6x10 mole/1 for 6ED and 8.5x10 mole/1 for SDS). These findings indicate that ANS is solubilized into the hydrocarbon surfactant micelles. Further, above the CMC, the fluorescence intensity of ANS in 6ED solution was about ten-fold larger than in SDS solution. Since both ANS and SDS are anionic, the lower solubility of ANS in SDS micelles is probably due to the electric... 

O, the surface charge density of the micelle and At, a constant of the system. For simplification, it is assumed that the surface charge density of the micelle does not change appreciably when the alcohol molecules are solubilized into the micelle. Then the equation for the micelle formation may be written as... 

Ru(bpy)2 + containing long alkyl groups at the bpy ring (5 RuC12B2+) was solubilized into micells, where the Ru complex group is located at the interface. 

The photoinduced charge separation between N-alkyl-N -methyl-4,4 -dipyridinium dichloride (CnMV2+ Cn = dodecyl, tetradecyl, hexadecyl, and octadecyl) and Ru(bpy)j + was also strongly affected by the presence of CTAC micells 21 . Upon reduction by Ru(bpy)j +, the viologen aquires hydrophobic properties leading to solubilization into micells (Eq. (13)). The subsequent recombination reaction is retarded by the positive surface of the micell. This decreases the rate constant of the back electron transfer at least by 500. 

Use of reverse micelles in synthetic chemistry to improve the rate and the yield of reactions seems likely to be a fruitful area of research in the future. In addition to catalysis, several other applications of reverse micelles can be cited. Just as nonpolar dirt is solubilized in aqueous micelles, so, too, polar dirt that would be unaffected by nonpolar solvents may be solubilized into reverse micelles. This plays an important role in the dry cleaning of clothing. Motor oils are also formulated to contain reverse micelles to solubilize oxidation products in the oil that might be corrosive to engine parts. 

Movement into a micelle can also be observed in some cases. The photoreduction of an amphiphilic viologen (for example, methyl viologen modified by attachment of a long chain, lipophilic C- 2 fragment), by Ru2+ occurs mainly in the aqueous phase surrounding a micelle, but the hydrophilic reduced product is reasily solubilized into a cationic micelle, eq. 87 ... 

Drug is soluble in neither oil nor water however, it can be retained at the interface of an emulsion. Thus, if a liposomal preparation can be made in which the drug resides in the lipid bilayer, or if it can be solubilized into micelles by an appropriate detergent, an emulsion can probably be made wherein the drug resides at the interface. 

Sugioka, H., and Y. Moroi. 1998. Micelle formation of sodium cholate and solubilization into the micelle. Biochim. Biophy. Actd394 99-110. 

When using an alcohol/surfactant solution to modify the density of DNAPLs, several processes occur simultaneously (Figure 2). Perhaps the most important process is alcohol partitioning, where alcohol which is initially solubilized in surfactant micelles partitions into the DNAPL,... 

A solute (additive) can be located in reverse micelles in different solubilization sites in the water core, in the interfacial region or in the bulk solvent. Solubilization into the water cores increases the inner volume at constant interfacial area, resulting in radial growth. If the micelle is too small to receive a solute molecule without deformation, e.g., at low water content, a segregation occurs between small free molecules and the large objects which are covered with surfactant (Chatenay et al., 1987 Encinas and Lissi, 1986 Pileni et al., 1985). 

The results of surfactant-dependency on protein trahsfer indicate that protein extraction reverse micelles not only provide a hydrophilic droplet in a non-aqueous solvent to facilitate protein partition, but also make proteins sufficiently hydrophobic to solubilize into an organic solvent by coating the protein surface. Consequently, we suggest that proteins in the aqueous phase are extracted through the formation of an interfacial complex, a surfactant-coated protein and that the hydrophobic property dominates the extraction efficiency of the proteins, as seen in Figure 14.4. The unsaturated or branched alkyl chain may contribute to the formation of a soluble protein-surfactant complex into a non-aqueous solvent. 

This review will focus on a variety of photochemical reactions which have been studied in micellar solutions, and will show how the micelle affects the outcome of these reactions. Photochemical reactions can be altered by solubilization into micellar solutions, such that the products or the relative yield of products can change relative to homogeneous solution. Furthermore, an increase or decrease in the dynamics or the efficiencies of photochemical reactions may also occur upon solubilization in micelles. 

Again, an examination of water solubilization into micelles in various solvents helps explain the differences for this surfactant and AOT. The uptake of water into 0.1 M Cn-14 EO5 was found to increase as ACN decreased from 10 (decane) to 5 (pentane). We do not expect that this increase would continue all the way to ethane. However, we do find that the optimal ACN for water uptake into this surfactant is less than 8, the value for AOT. The lower ACN for Ci 1-14 EO5 versus AOT could be a factor in the explanation of their different behavior in ethane. 

The 2-monoglycerides and fatty acids are packaged into micelles (solubilized by bile salts) and absorbed into intestinal epithelial cells, where they are reconverted to triacylglycerols. 

C 2 Ci6) hydrocarbon "tail" to promote solubilization into the micelle. Tlie chelating... 

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