Microemulsions as potential drug delivery systems: a review

By many estimates, up to 40 percent of new chemical entities discovered by the pharmaceutical industry are poorly soluble or lipophilic compounds. Solubilization of hydrophobic drugs with low aqueous solubility has been a major area of interest in recent years. Various solubilization techniques involve the use of co-solvents and surfactants along with pH adjustments. Applications of microemulsions have also drawn attention in the field of solubilization techniques. Microemulsions are optically isotropic and thermodynamically stable systems consisting of water, oil, a surfactant, and a co-surfactant and are known to enhance the bioavailability of drugs via topical and systemic routes. The objective of this review is to present briefly the possible applications of these novel systems of microemulsions. Most studies reported in the literature have investigated microemulsions intended for dermatological application because of the wider range of potential excipients.