SMEDDS: A NOVEL APPROACH FOR LIPOPHILIC DRUGS

The oral delivery of lipophilic drugs presents a major challenge because of the low aqueous solubility and less bioavailability. Self-micro emulsifying drug delivery systems (SMEDDSs) have gained exposure for their ability to increase solubility and bioavailability. SMEDDS, which are isotropic mixtures of oils, surfactants, solvents and co-solvents/surfactants, can be used for the design of formulations in order to improve the oral absorption of highly lipophilic drug compounds. SMEDDS can be orally administered in soft or hard gelatin capsules and form fine relatively stable oil-in-water (o/w) emulsions upon aqueous dilution owing to the gentle agitation of the gastrointestinal fluids. The efficiency of oral absorption of the drug compound from the SMEDDS depends on many formulation-related parameters, such as surfactant concentration, oil/surfactant ratio, polarity of the emulsion, droplet size and charge, all of which in essence determine the self-emulsification ability. Thus, only very specific pharmaceutical excipient combinations will lead to efficient self-microemulsifying systems. The fact that almost 40% of the new drug compounds are hydrophobic in nature implies that studies with SMEDDS will continue, and more drug compounds formulated as SMEDDS will reach the pharmaceutical market in the future. Further this review highlights various components of SMEDDS. This review gives an overview of SMEDDS as a promising approach to effectively tackle the problems of poorly soluble molecules.