Importance of micellar kinetics in relation to technological processes.

The association of many classes of surface-active molecules into micellar aggregates is a well-known phenomenon. Micelles are in dynamic equilibrium, constantly disintegrating and reforming. This relaxation process is characterized by the slow micellar relaxation time constant, tau(2), which is directly related to the micellar stability.

Self-assembled Gemini surfactant film-mediated dispersion stability.

The force-distance curves of 12-2-12 and 12-4-12 Gemini quaternary ammonium bromide surfactants on mica and silica surfaces obtained by atomic force microscopy (AFM) were correlated with the structure of the adsorption layer. The critical micelle concentration was measured in the presence or absence of electrolyte. The electrolyte effect (the decrease of CMC) is significantly more pronounced for Gemini than for single-chain surfactants.

Effect of degree, type, and position of unsaturation on the pKa of long-chain fatty acids.

Titration of a series of C(18) fatty acids yields pK(a) values that decrease with an increasing degree of unsaturation in the fatty acid chain. The pK(a) values of stearic, elaidic, oleic, linoleic, and linolenic acids were studied and compared to values of area per molecule in a spread monolayer of these acids. The decrease in pK(a) was found to relate to melting point temperature and area per molecule in the spread fatty acid monolayer.

Improved drug delivery using microemulsions: rationale, recent progress, and new horizons.

Microemulsions are excellent candidates as potential drug delivery systems because of their improved drug solubilization, long shelf life, and ease of preparation and administration. The formulation of microemulsions for pharmaceutical use requires a thorough understanding of the properties, uses, and limitations of microemulsions. Three distinct microemulsions--oil external, water external, and middle phase--can be used for drug delivery, depending upon the type of drug and the site of action.