SELF-MICRO EMULSIFYING DRUG DELIVERY SYSTEMS (SMEDDS): A REVIEW ON PHYSICO-CHEMICAL AND BIOPHARMACEUTICAL ASPECTS

Abstract

Nearly 40% of new drug candidates exhibit low solubility in water, which is a challenge in development of optimum oral solid dosage form in terms of formulation design and bioavailability of new pharmaceutical products. Many strategies have been used to overcome these problems either by means of modifying the solubility or maintaining the drug in dissolved form throughout gastric transit time. Much attention has focused on lipid solutions, emulsions and emulsion pre-concentrates, which can be prepared as physically stable formulations suitable for encapsulation of such poorly soluble drugs. Recently, self-micro emulsifying drug delivery systems (SMEDDS) especially have attracted increasing interest primarily because  these are physically stable, easy to manufacture, can be filled in soft gelatin capsules and then will generate a drug containing micro-emulsion with a large surface area upon dispersion in the gastrointestinal tract. The emulsions will further facilitate the absorption of the drug due via intestinal lymphatic pathway and by partitioning of drug into the aqueous phase of intestinal fluids. In the present review, an overview of SMEDDS as a key technology for formulating lipophilic drugs and various factors that potentially affect the oral bioavailability of such drugs are presented. Keywords: Low solubility, Oral bioavailability, Self-micro emulsion, Intestinal lymphatic pathway.Â