Innovative strategies for the oral delivery of drugs and peptides.

Conventional forms of administration for nonabsorbable drugs and peptides often rely on parenteral injection, because the intestinal epithelium represents a major barrier to the oral absorption of these therapeutic agents. Recently, a number of innovative drug-delivery approaches have been developed, including entrapment within small vesicles and passage through the space between adjacent intestinal cells. This article reviews some of the most promising techniques currently available for oral delivery and their possible practical applications for the delivery of vaccines and drugs for the treatment of clinical conditions that require frequent, chronic parenteral administration.