Nonionic-anionic mixed surfactants cubic mesophases. Part I: Structural chaotropic and kosmotropic effect.

We prepared and investigated cubic bicontinuous (V) phase from mixtures of nonionic monoolein (GMO) and anionic oleyl lactate (OL) surfactants in the presence of ethanol and water. The isotropic region and the composition of the V phase in the pseudoternary phase diagram vary with the nature of the hydrophilic headgroups and their charge. We examined three anionic species, acidic (HOL), partially neutralized (OL), and totally ionized (NaOL) forms.

In vitro permeation of diclofenac salts from lyotropic liquid crystalline systems.

In this paper we examined feasible correlations between the structure of different lyotropic mesophases and transdermal administration of three diclofenac derivatives with varying degrees of kosmotropic or chaotropic properties, solubilized within the mesophases. It was found that the most chaotropic derivative of diclofenac diethyl amine (DEA-DFC) interacted with the polar heads of glycerol monooleate (GMO), thus expanding the water-lipid interface of the lamellar and cubic mesophases. This effect was detected by an increase in the lattice parameter of both mesophases, enhanced elastic properties, and increased solid-like response of the systems in the presence of DEA.

Solubilization of hydrophobic guest molecules in the monoolein discontinuous QL cubic mesophase and its soft nanoparticles.

Hydrophobic bioactive guest molecules were solubilized in the discontinuous cubic mesophase (QL) of monoolein. Their effects on the mesophase structure and thermal behavior, and on the formation of soft nanoparticles upon dispersion of the bulk mesophase were studied. Four additives were analyzed.

Effect of sodium diclofenac loads on mesophase components and structure.

We studied the effect of a model electrolytic drug on intermolecular interactions, conformational changes, and phase transitions in structured discontinuous cubic QL lyotropic liquid crystals. These changes were due to competition with hydration of the lipid headgroups. Structural changes of the phase induced by solubilization loads of sodium diclofenac (Na-DFC) were investigated by directly observing the water, ethanol, and Na-DFC components of the resulting phases using 2H and 23Na NMR.