lipidwater

Lipidwater is a colloidal system in which lipid-based phases are dispersed in an aqueous phase. It is not a single chemical compound but a class of mixtures that includes oil-in-water emulsions, lipid vesicles, and micellar systems formed from amphiphilic lipids and stabilizers.

Formation occurs when lipids are dispersed in water with energy input or with emulsifiers, proteins, or surfactants. Droplet or vesicle sizes vary, from nanometer-scale microemulsions to larger macroemulsions. Interfacial tension is reduced by surfactants, enabling kinetic stability through electrostatic or steric repulsion.

Properties depend on lipid type, surfactant, ionic strength, temperature, and pH. Lipidwater systems may demonstrate creaming or sedimentation if densities differ, and they can undergo phase transitions that reorganize lipid assemblies. The rheology of these systems can range from predominantly liquid to gel-like, depending on composition and concentration.

Applications span food, cosmetics, and pharmaceuticals, where lipidwater emulsions carry fats, vitamins, or hydrophobic drugs. In biology, lipidwater interfaces are central to cell membranes, lipoprotein particles, and drug delivery vehicles such as liposomes. They also serve as model systems for studying membrane mechanics and the behavior of amphiphilic molecules in aqueous environments.

Characterization employs dynamic light scattering, electron microscopy, cryo-electron microscopy, zeta potential measurements, and rheology. Safety and regulatory considerations depend on the lipids and additives used; many lipids common to food and pharma have established guidelines, but formulations require stability and compatibility evaluation.