SelfEmulsifying

SelfEmulsifying refers to a system or formulation that has the inherent ability to form an emulsion upon contact with a liquid, typically water, without the need for external high-energy mixing. These systems are composed of active ingredients, surfactants, and co-surfactants or co-solvents. The key to their self-emulsifying property lies in the specific selection and ratio of these components.

When these components are dispersed in a suitable solvent, they form a thermodynamically stable liquid lipid phase. Upon dilution with water, the surfactants and co-solvents spontaneously rearrange at the oil-water interface, reducing interfacial tension significantly. This reduction in tension, coupled with the solubility of the components, allows the dispersed oil phase to break down into fine droplets, forming a stable oil-in-water or water-in-oil emulsion.

The droplet size of the resulting emulsion is generally very small, ranging from nanometers to a few micrometers, which enhances the surface area available for absorption. This characteristic makes self-emulsifying drug delivery systems (SEDDS) and self-microemulsifying drug delivery systems (SMEDDS) particularly useful for improving the oral bioavailability of poorly soluble drugs. By presenting the drug in a pre-dissolved state within the lipid matrix, absorption from the gastrointestinal tract can be facilitated. These formulations are also employed in topical and parenteral applications.