A review on fundamental concepts that are pertinent to understanding surfactants. It also describes self-assembled aggregate structures of surfactants. [on SciFinder(R)]

A review. First the definition of microemulsions is referred. The differences between microemulsions, emulsions and nanoemulsions are demonstrated. A simple presentation of the mechanism of microemulsion stability is then given., followed by a discussion of microstructures, a characterization of microemulsions,and a brief description of their phase behavior. After that, applications of. microemulsions are discussed, with a focus on the important topic of solubilization of bioactives. Obviously the description of this application was not meant to be all-inclusive. Rather, it was delved into selected microemulsion systems which mainly were investigated in the authors' lab. [on SciFinder(R)]

A review. Microemulsions are considered excellent delivery vehicles for bioactives, food additives and food supplements. They offer the advantages of spontaneous formation, ease of manuf., thermodn. stability, very low viscosity and Newtonian properties, full transparency (clear solns.) and improved solubilization capacities of bioactive materials. This chapter explores some of the new trends in microemulsion research, including many carried out in our lab, through anal. of some representative studies. The solubilization of different food additives such as flavoring agents, aromas, antioxidants, and colorants, as well as peptides and nutraceuticals, in various microemulsion compns. and microstructures are reviewed. [on SciFinder(R)]

A review on two major activities of emulsifiers on cocoa butter and chocolate: rheol. and polymorphism. It discusses the effects of emulsifiers on viscosity and bloom. [on SciFinder(R)]

The present work investigates a system composed of a ternary reversed hexagonal mesophase (HII) loaded with a lipase for modulating drug delivery capabilities of the system. Thermomyces lanuginosa lipase was solubilized into HII mesophase for the benefits of continuing lipolysis of the lipids, consequently disordering and decompg. the hexagonal mesophase and thereby enhancing the diffusion of the encapsulated drug. A single transition from the HII structure to a random micellar phase was detected during the lipolysis. In the first lipolysis stage the hexagonal system (glycerol monooleate, tricaprylin, and water) preserved its symmetry within ca. 200 min. During this step about 40-60% molar of the lipids were hydrolyzed, and a gradual shrinking of the HII cylinders (decrease of 8 \AA in lattice parameter) was detected. In the second lipolysis stage, the HII mesophase gradually disintegrated (faster rate) and the release of a model drug (sodium diclofenac) was significantly enhanced, which was assumed to be lipolysis rate-controlled. After about 15 h the HII mesophase was disintegrated into two dispersed immiscible phases. The release obeyed two-step Higuchi kinetics with two consecutive linear correlations of the drug release. [on SciFinder(R)]

A review provides better understanding of the stabilizing mechanisms and pathways and a better control of the release patterns from double emulsions. It discusses the different approaches such as stability considerations, instability pathways, release and transport phenomenon. [on SciFinder(R)]

In this review the authors present recent progress on lyotropic liq. crystals (LLC) as delivery vehicles for cosmetoceuticals, nutraceuticals, and drugs. LLC were known for decades and their potential as delivery vehicles is well recognized. Yet, the 2 major mesophases, reverse hexagonal (HII) and bicontinuous cubic (primitive, gyroid, and diamond), are relatively hard gels with very slow release kinetics of the bioactives. In recent years a discontinuous cubic micellar mesophase (QL) was characterized and studied, showing significant potential as a delivery vehicle. In addn., the HII mesophase formed could be much more fluid and produced at room temp. Recent studies concd. on establishing methods to evaluate solubilization capacity and relationship between the diam. and length of the cylinders and the nature of the solubilizates. Special attention was given to finding methods to target the vehicles to the lumen and to trigger the release of the bioactives. This review summarizes the efforts of the authors' group along with work by numerous other scientists in this area. All these efforts suggest that the lyotropic mesophases and the corresponding dispersed soft particles (cubosomes, hexosomes, micellosomes) are now more than ever ready to become drug delivery vehicles for transport across the skin and the gut. [on SciFinder(R)]

A review. Neurotrophic factors, such as the brain-derived neurotrophic factor (BDNF), are essential for the development and survival of human neurons. Their encapsulation in carrier lipid systems is anticipated to overcome the problems resulting from the pharmacokinetics of peptides in the cerebral circulation. Lipid nanocarriers contg. an omega-3 polyunsatd. fatty acid [eicosapentaenoic acid] (EPA), showing neuroprotective effects, should trigger the BDNF activity. The purpose of this study is to design and characterize self-assembled lipid systems suitable for encapsulation and potentiation of neurotrophic peptide activity and study of multicompartment liq. cryst. formulations in vitro on a human neuronal cell line expressing BDNF receptors. Sterically stabilized nanodispersed lipid systems are prepd. from a PEGylated (polyethylene glycol) liq. cryst. phase in excess water. Such lipid nanovectors, derived by self-assembly, are of ongoing interest thanks to their biocompatible compns. and the relatively low energy input required for their manuf. The latter is an essential factor for the encapsulation of fragile and temp.-sensitive peptide mols. Having induced the differentiation of a human neuroblastoma cell line SH-SY5Y, as a model of neurodegeneration, we examine in vitro the expression of the TrkB brain receptor of neurotrophins and the cytotoxicity of the designed multicompartment lipid nanocarriers to neuronal cells. [on SciFinder(R)]

The NMR chromatog. method is applied to a class of mols. with similar phys. properties. We correlate the sepn. ability of microemulsions to the phys. properties of the analyzed mols. Flavor and aroma compds. are very widespread. Compositional anal. is in many cases tedious. Any new method of anal. is always useful and challenging. Here we show a new application to a class of fragrance mols., with only a moderate variation in their chem. and phys. characteristics. Up to 11 selected compds. in one mixt. are resolved in one spectrum by NMR chromatog., despite the similarity of the compds. The differences between O/W and W/O microemulsions and their resoln. mechanism as applied to fragrance mols. are explained in terms of hydrophilicity and lipophilicity and effective crit. packing parameters of the microemulsions. The obsd. diffusion rates are shown to correlate with solvation parameters. These results can be used to est. the diffusion rates of mols. to be sepd., allowing selection of the microemulsion or NMR chromatog. solvent appropriate for each specific application. [on SciFinder(R)]

A review. The development of techniques for the characterization of the nanostructure of lyotropic liq. cryst. systems were crucial in enabling increased understanding of fundamental properties and efficacy in technol. applications. Provided is a review of a no. of commonly used and emerging nanocharacterization techniques, with a view to providing a resource for academic and industrial researchers joining the field. [on SciFinder(R)]

A review. There is an increasing tendency towards the development of food, cosmetic and pharmaceutical products contg. only natural ingredients. Many proteins and polysaccharides extd. from nature can be used as functional ingredients to form colloidal systems suitable for use in industrial products. These colloidal systems can be fabricated using a variety of physicochem. and processing approaches. This chapter focuses on the fabrication and properties of sub-micron to micron-sized colloidal particles, formed by controlled aggregation/complexation of mixed biopolymer systems. The processes used to fabricate these particles include treatments of globular protein and/or polysaccharide solns. at select temps., pH, ionic strengths, and/or solvent qualities. Potential applications of the biopolymer colloidal particles are discussed. [on SciFinder(R)]

A review. During the last twenty years dendrimers have attracted wide interest as potential therapeutics. These novel macromols. differ in many ways from traditional polymers. Dendrimers are globular, possessing a core mol. to which layers of branched monomers are attached. The no. of layers is described by so-called generations. The structure of dendrimers results in plenty of terminal surface groups and empty internal cavities. Both these features are important when considering dendrimers for biomedical applications. Moreover, precise methods of synthesis enable the tailoring of dendrimers to specific purposes. In this concise review, a few examples of the part dendrimers play in anti-cancer therapies will be presented. It is worth stressing that these examples of pharma applications of dendrimers do not include all areas of study that are presently being conducted, and that each year produce new ways to use dendrimers in medicine. [on SciFinder(R)]