Effect of Dialkyl Ammonium Cationic Surfactants on the Microfluidity of Membranes Containing Raft Domains.

It has been reported that a lot of receptors localize in lipid raft domains and that the microfluidity of these domains regulates the activation of these receptors. In this study, we focused on the lipid raft and in order to evaluate the physicochemical effects of surfactants on microfluidity of lipid membranes, we used liposomes comprising of egg-yolk L-α-phosphatidylcholine, egg-yolk sphingomyelin, and cholesterol as a model of cell membranes containing raft domains. The microfluidity of the domains was characterized by fluorescence spectrometry using 1,6-diphenyl-1,3,5-hexatriene and 2-dimethylamino-6-lauroylnaphthalene.

Viscosity stability of O/W emulsion containing α-gel through an ionic-complex system.

Although many active ingredients are used in cosmetic products for moisturizing and whitening the skin, they are often electrolytes, and the stabilities of oil in water (O/W) type emulsion formulae containing electrolytes are generally difficult to control. To solve this problem, formulae containing an α-crystalline phase (α-gel) consisting of water, higher alcohols, and anionic surfactants such as sodium N-stearoyl-N-methyl-taurate (SMT) have been developed. However, in spite of their excellent salt tolerance, these formulae have poor viscosity stability under non-electrolyte conditions, and the viscosity decreases over time.

Development of novel multifunctional cosmetic raw materials and their applications. IV. The effect of structure of polyoxyethylene/polyoxypropylene derivative on the self-organizing structures of surfactants.

In this study, the effect of a random copolymer of polyoxyethylene (POE, 38 mol)/polyoxypropylene (POP, 10 mol) pentaerythrytol tetramethyl ether [PEPTME (38/10)], which is unable to form a self-organizing structure on account of its bulkiness, on the microemulsion phase was examined. The phase diagram of the liquid paraffin - nonionic surfactant+PEPTME (38/10) - water system was compared with that of polyoxyethylene (POE)/polyoxypropylene (POP) dimethyl ether (EPDME) system which has a straight-chain structure. In the previous study, the authors reported that a special droplet type microemulsion (highly concentrated microemulsion) was formed, when EPDME was distributed in the hydrophilic moiety of a surfactant in a lamellar liquid crystalline phase.

Development of novel cosmetic base using sterol surfactant. II. Solubilizing of sparingly soluble ultraviolet ray absorbers.

Previous studies have reported that O/W emulsion prepared using a surfactant with phytosterol as the hydrophobic moiety exhibited unique morphology; a lamellar structure was present on the surface of the emulsified particles. It is suggested that such a unique self-organized structure was due to the large and bulky planar structure of the sterol. On the other hand, sparingly soluble compounds including ultraviolet ray absorbers and medicines (e.

A narrow bicontinuous microemulsion domain in mixed polymeric silicone systems.

We have prepared a viscous bicontinuous microemulsion consisting of water / [20 wt% POE-GIS + 30 wt% PEPTME + 47.5 wt% POE/POP-PDMS + 2.5 wt% OA)] / DMPS system.

Development of novel cosmetic base using sterol surfactant. I. Preparation of novel emulsified particles with sterol surfactant+.

We have developed various kinds of ultrafine emulsifying methods using random copolymer of polyoxyethylene (POE)/polyoxypropylene (POP) dimethyl ether [EPDME]. Among ultrafine emulsions made by these methods, it was revealed that an O/W type emulsion, which had prepared with EPDME, sterol surfactant, and polar oils, had a unique structure that had a lamellar structure on the surface of emulsified particles. To clarify the character of the particles and the mechanism of the emulsification, investigation using small angle X-ray scattering (SAXS) measurement and the phase diagram of the emulsion system was done.

Formation and characterization of microemulsions containing polymeric silicone.

We have prepared microemulsions consisting of water/[40 wt % polyoxyethylene (20 mol) glycerin isostearate (abbreviated as POE-GIS) + 60 wt % random copolymer of polyoxyethylene (POE, 38 mol)/polyoxypropylene (POP, 10 mol) pentaerythritol tetramethyl ether {abbreviated as PEPTME (38/10)}]/[polyoxyethylene (POE, 19 mol)/polyoxypropylene (POP, 19 mol) polydimethylsiloxane copolymer (abbreviated as POE/POP-PDMS)] and water/[40 wt % POE-GIS + 60 wt % PEPTME (38/10)]/[95 wt % POE/POP-PDMS + 5 wt % oleic acid (abbreviated as OA)] systems and characterized them with optical observation, rheometry, and freeze-fracture transmission electron microscopy (FF-TEM) images. Bicontinuous and droplet-type O/W (oil-in-water) microemulsions are formed depending on the volume fraction of water. The bicontinuous structure observed in the oil-rich region, upon successive dilution with water, is transformed into a droplet-type microemulsion without phase separation.