Self Emulsifying Drug Delivery System, A Novel Approach In Drug Delivery: A Review

Lipid formulations for oral administration of drugs generally consist of a drug dissolved in a blend of two or more excipients, which may be triglyceride oils, Partial glycerides, Surfactants or co-surfactants. The primary mechanism of action, which leads to improved bioavailability, is usually avoidance, or partial avoidance, of the slow dissolution process, which limits the bioavailability of hydrophobic drugs from solid dosage forms. Ideally the formulation allows the drug to remain in a dissolved state throughout its transit through the gastrointestinal tract. The availability of the drug for absorption can be enhanced by presentation of the drug as a solubilizer within a colloidal dispersion. This objective can be achieved by formulation of the drug in a self-emulsifying system or alternatively by taking advantage of the natural process of triglyceride digestion. In practice ‘Lipid’ formulations range from pure oils, at one extreme, to blends which contain a substantial proportion of hydrophilic surfactants or co solvents.