The phase diagram of the binary system composed of octyl-beta-D-glucopyranoside and water was investigated and the phase boundaries were determined. Polarising optical microscopy was used to define the different phases, proton and deuterium NMR experiments to define the region of existence of the different phases and to obtain information on axiality and head group solvation. DSC experiments were performed to determine the thermal transitions from solid to thermotropic liquid crystals for octyl-beta-D-gluco-pyranoside, the related alkylglucosides or maltosides, and to gain information on the role played by sugar units in the thermodynamics of such phase transitions

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The interaction of neutral and anionic phospholipid liposomes, used as cell models, with cationic liposomes formulated with 1,2-dimyristoyl-sn-glicero-3-phosphocholine and stereomeric cationic gemini surfactants was investigated by differential scanning calorimetry, fluorescence experiments and dynamic laser light scattering. This study was aimed at rationalizing the different biological features shown by liposomes based on different gemini stereoisomers observed in previous investigations. In fact, to correlate the observed biological activity of liposomes with the molecular structure of their components is critical for a rational and systematic approach to the design of new carriers for drug delivery. The obtained results show that the different stereochemistry of the gemini surfactant controls the interaction and the extent of fusion with different cell models.

The physicochemical features of mixed cationic liposomes formulated with 1,2-dimyristoyl-sn-glycero-3-phosphatidylcoline and one of three stereomeric cationic gemini surfactants were investigated by differential scanning calorimetry, fluorescence, TEM and dynamic laser light scattering. Actually, it was shown that the different stereochemistry of these gemini can strongly influence their capability of condensing and transfecting a plasmid DNA and of delivering a photosensitizer. The results obtained in this investigation show that the stereochemistry of liposome components and their percentage in the formulation may have dramatic effects on the organization of the lipid bilayer and hence on the morphological and physicochemical features of vesicles, thus being highly relevant to the biological features evaluated previously

A polymer-surfactant complex (OTAPA) was prepared by titration of aqueous poly(sodium acrylate) with stoichiometric amounts of octadecyltrimethylammonium chloride. The resulting product is not water-soluble and does not dissolve in most polar and nonpolar, liquids. OTAPA has peculiar thermal behaviour and interesting structural properties. It has a high melting temperature and decomposes around 350 degreesC. According to preliminary X-ray findings, the complex is formed by an arrangement of alkyl chains around the polymer skeleton, packed into a layered structure. The complex forms an elastic gel in ethylene glycol, and, to a much lesser extent, in glycerol or tetrahydrofuran, but is hardly water-soluble. Indeed, the occurrence of micelle-assisted dissolution and the precipitation of OTAPA from such mixtures, upon dilution with water, have been observed. Applications of OTAPA as a hydrophobic modifier of surfaces can be considered

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