Review on Self Nano Emulsifying Drug Delivery System
SEDDS (Self Emulsifying Drug Delivery System) have been broadly classified based on the basis of droplet size obtained after dispersion. If the droplet size of dispersion is in range of 100-250 nm then the SEDDS are termed as SMEDDS (Self Micro Emulsifying Drug Delivery System) while those having droplet size below 100 nm are called SNEDDS (Self Nano Emulsifying Drug Delivery System). Selection of lipid, surfactant and co-surfactant is done based on solubility of drug in lipid, surfactant and co-solvent. A ternary phase diagram of the three components is plotted by keeping oil, surfactant and co-surfactant on three different axis. Based on the clarity of dispersion, emulsification time and droplet size, the entire plot is divided into four regions namely phase separation, SEDDS, SMEDDS and SNEDDS. Self-emulsification is a phenomenon that occurs spontaneously during the formation of SEDDS. It occurs when entropy change that favours dispersion is greater than energy required to increase the surface area of emulsion. Physical adsorption of L-SEDDS (Liquid- Self Emulsifying Drug Delivery System) on the solid carriers is one of the simplest technique of solidification. In this process, L-SEDDS are added on solid carrier and mixed either via physical blending with hand or motor pestle on lab scale or via use of blenders.