Polymeric micelles for oral drug delivery: Why and how

The oral delivery of drugs is regarded as the optimal means for achieving therapeutic effects owing to increased patient compliance. Unfortunately, the oral delivery route is beset with problems such as gastrointestinal (GI) destruction of labile molecules, low levels of macromolecular absorption, etc. To reduce the impact of digestive enzymes and to ensure the absorption of bioactive agents in an unaltered form, molecules may be incorporated into microparticulate carriers. Many approaches to achieve the oral absorption of a wide variety of drugs are currently under investigation. Among the different polymer-based drug delivery systems, polymeric micelles represent a promising delivery vehicle especially intended for poorly water-soluble pharmaceutical active ingredients in order to improve their oral bioavailability. Recent findings of a dextran-based polymeric micelle study for solubilization of a highly lipophilic drug, cyclosporin A (CsA), will be discussed.