[Show abstract][Hide abstract] ABSTRACT: The influence of polyols as cosurfactants (propylene glycol PG; glycerol G) and short chain alcohol as a cosolvent (ethanol EtOH) on the formation and solubilization capacity of the systems: hexadecane/monoacylglycerols (MAG)/polyol/water:EtOH, at 60 °C, was investigated. Electrical conductivity measurement, and the DSC method were applied to determine the structure and type of microemulsions formed. The dimension of the droplets was characterized by DLS. It has been stated that concentration of EtOH has a strong influence on the shape and extend the microemulsion areas and helps to avoid rigid structures such as gels, precipitates, and liquid crystals. It was found that, depending on the concentration of five-component systems, it was possible to obtain fully diluted microemulsions with dispersed particles size distribution ranging from 5 to 30 nm. Studied systems are changing the w/o structure into a bicontinuous system. The results of electrical conductivity showed that the electrical percolation threshold is dependent on the hydration of polar head groups in the whole system and the less rigid interfacial film due to the intercalation of ethanol. In addition, the surfactant/alcohol/polyol can strongly bind water in the inner phase so that it freezes below -10 °C and acts in part as 'bound' water. In the systems containing more than 50 mass% of polyols, with respect to the water, the all the water was non-freezable. Propylene glycol and glycerol are cryoprotectants protecting biological systems from massive ice crystallization, since they lower the freezing point of water.
Journal of Surfactants and Detergents 01/2015; 18:97-106. · 1.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Biocompatible microemulsions composed of Peceol(®), lecithin, ethanol and water developed for encapsulation of hydrophilic drugs were investigated. The binary mixture Peceol(®)/ethanol was studied first. It was shown that the addition of ethanol to pure Peceol(®) has a significant fluidifying and disordering effect on the Peceol(®) supramolecular structure with an enhancement in water solubilization. That water solubilization capacity was improved by adding lecithin as a third component. It was then demonstrated that the ethanol/lecithin weight ratio played an important role in determining the optimal composition in term of water solubilization efficiency, a necessary property for a nutraceutical or pharmaceutical application. The optimal ethanol/lecithin weight ratio in the Peceol(®) rich region was found to be 40/60. Combination different techniques such as SAXS, fluorimetry, rheology and conductivity, we analyzed the water uptake within the microemulsion taking into account the partitioning of ethanol between polar and apolar domains. This ethanol distribution quantified along a water dilution line has a major effect on microemulsion properties.
International Journal of Pharmaceutics 07/2014; · 3.99 Impact Factor
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