Thermal Reversible Microemulsion for Oral Delivery of Poorly Water-Soluble Drugs

There have been many attempts to improve absorption and bioavailability of poorly watersoluble drugs [1-3]. One of attractive systems is microemulsions which are composed of fine oil-in-water droplets in aqueous medium [4-8]. When such a formulation is released into the lumen of the gut, it disperses to form a fine emulsion, so that the drug remains in liquid state in the gut avoiding dissolution step that frequently limits the rate of absorption of liphophilic drugs [9]. The smaller sizes of droplets will have a larger interfacial surface areas per unit volume and correspondingly large free energy contribution from the liquid-liquid interfacial tension [10].