Nearly 40% of new drug candidates exhibit low solubility in water, which
leads to poor oral bioavailability, high intra- and inter-subject
variability and lack of dose proportionality. Modification of the
physicochemical properties, such as salt formation and particle size
reduction of the compound may be one approach to improve the dissolution
rate of the drug. However, these methods have their own limitations. In
recent years, much attention has focused on lipid based formulations to
improve the oral bioavailability of poorly water soluble drugs. In fact,
the most popular approach is the incorporation of the drug compound into
inert lipid vehicles such as oils, surfactant dispersions,
self-emulsifying formulations, emulsions and liposomes with particular
emphasis on self-microemulsifying drug delivery systems (SMEDDS).