Co-solvents

Various strategies have been widely investigated to enhance the solubility of poorly soluble drugs. These strategies increase the clinical efficacy when the drug is administered orally. Around 40% of novel chemical entities show evidence of poor aqueous solubility and their bioavailability becomes low. Thus to overcome this problem new technologies are applied. This new technologies improve the solubility of those drugs whose water solubility is poor. This new technology is known as SEDDS. Self-emulsifying drug delivery systems (SEDDS), 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. It can be orally administered in soft or hard gelatin capsules. This formulation enhanced bioavailability due to increase the solubility of drug and minimizes the gastric irritation.

Oral route is the easiest and most convenient route for drug administration.  The major problem in oral drug formulations is low and erratic bioavailability, which mainly results from poor aqueous solubility. This may lead to high inter and intra subject variability, lack of dose proportionality. It is estimated that 40% of active substances are poorly water soluble. The solubility of such drugs is increased by formulating self emulsifying drug delivery system (SEDDS). Self emulsifying drug delivery systems have gained exposure for their ability to increase solubility and bioavailability of poorly water soluble drugs. SEDDS are isotropic mixtures of oil, surfactants, solvents and co-solvents/surfactants, which emulsify to produce fine oil-in-water emulsions upon gentle agitation. SEDDS typically produce emulsions with a droplet size between 100–300 nm. Solid SEDDSs are being developed from liquid/semisolid SEDDS mainly by adsorption on solid carriers, spray drying, lyophilization, melt extrusion, and nanoparticle technology. This review focuses on newer approaches for development of SEDDS and Solid SEDDS.