Recent Approaches in Self Emulsifying Drug Delivery System

Self emulsifying is a topic of current interest for overcoming the formulation difficulties of drugs with poor aqueous solubility. SEDDS are isotropic mixture of oil, surfactant and co-surfactant with a unique ability to form fine oil-inwater (o/w) emulsions or micro emulsions upon mild agitation in the gastrointestinal tract which present the drug in a solubilized form, and the small size of formed droplet provides a large interfacial surface area for drug absorption. It is a promising strategy to improve the rate and extent of oral absorption. The SEDDS were characterized for robustness to dilution, globule size, polydispersity index and zeta potential. INTRODUCTION: Oral route is the most easiest and convenient way of non-invasive administration. Approximately 40% of new chemical entities exhibit poor aqueous solubility and present a major challenge to modern drug delivery. A rate limiting step for absorption of these drugs is often their Solubilization in the GIT. These drugs are classified in class II drug by Biopharmaceutical classification system (BCS), drugs with poor aqueous solubility and high permeability. Different formulation approaches like micronization, solid dispersion, and complexation with cyclodextrin have come up . Indeed in some cases these approaches have been successful but they often many have disadvantages. The main problem with micronization is chemical /thermal stability; many drugs may degrade and lose bioactivity when they are micronized by conventional method. For solid dispersion the amount of carrier use is often large, and thus if the dose of active ingredient is high, the tablets or capsules formed will be large in volume and difficult to swallow. Moreover, since the carriers used are usually expensive and freeze drying or spray –drying methods requires particular facilities and processes leading to high production cost.” Though traditional solvent method can be adopted instead, it is difficult to deal with co-precipitation with high viscosity. Complexation with cyclodextrin technique is not application for drug substances which are not soluble in both aqueous and organic solvents. Realization that the oral bioavailability of poorly water soluble drugs may be enhanced when coadministered with meal rich in fat has led to increasing recent interest in the formulation of poorly water soluble drugs in lipids. Lipid based drug delivery have gained considerable interest after the commercial success of Sandimmiune Neoral (Cyclosporin A) , Forovase (Saquinavir), Norvir (Rotonavir) .