Behind the Alkyl Polyglucoside-based structures: Lamellar liquid crystalline and lamellar gel phases in different emulsion systems

Abstract

Surfactants play an important role in the development of colloidal delivery systems for cosmetics and pharmaceutical ingredients. Alkyl Polyglucosides (APGs) show peculiar physicochemical behaviour, which affects their interfacial properties. For example, the phase behaviour of APG/water systems is only slightly influenced by temperature. Hence, no temperature-dependent phase inversion occurs in APG-containing emulsions. They may form thermotropic liquid crystalline phases on heating, and lyotropic liquid crystalline phases on addition of a solvent. In lyotropic liquid crystals, increasing alkyl chain length leads to destabilization of the hexagonal phase in favour of the lamellar one, which is interesting for pharmaceutical systems. The addition of fatty alcohol to APG/water mixtures leads to the appearance of different lamellar phases. Characteristics of APG-mediated systems will be discussed in this chapter.