Solubility enhancers for oral drug delivery

With recent progress in high throughput screening of potential therapeutic agents, the number of poorly water-soluble drug candidates has risen sharply and formulating for poorly water-soluble compounds for oral delivery now presents one of the most frequent and greatest challenges to scientists in the pharmaceutical industry. Many new drugs and potential therapeutic compounds under investigation possess high lipophilicity, poor water solubility, and low oral bioavailability. Furthermore, development of improved oral dosage forms for currently marketed drugs can also enhance their therapeutic value. Oral delivery systems designed for poorly water-soluble drugs include micelles with surfactants, microemulsions, self-emulsifying/microemulsifying drug delivery systems (SEDDS/SMEDDS), solid dispersions, microspheres and cyclodextrin inclusion complexes. These delivery systems have been shown to enhance oral bioavailability and therapeutic effects of poorly water-soluble drugs mainly by improving the poor solubility. As a consequence of extensive research, various oral delivery systems for poorly water-soluble agents are being developed in clinical phases worldwide. New formulation technologies and multidisciplinary expertise may lead to development of advanced and effective oral drug delivery systems applicable to a wide range of poorly water-soluble drugs in the near future.