Polymeric carriers for oral uptake of microparticulates

Delivery of vaccine antigens by the oral route is plagued with challenges. Much of the research has focused on the development of microparticles as an tigen carriers to the gastrointestinal (GIT) mucosa. Polymers, either natur al or synthetic, have been the class of compounds most often investigated f or their ability to form microparticles containing antigen. A great deal of research has been performed using model microparticles composed of polysty rene. From this work it has become clear that microparticles are taken up a nd translocated across the GIT epithelium. Antigen carrying microparticles generated from both hydrophobic and hydrophilic polymers are able to induce significant immune responses after oral immunization. Although very little systematic work on the effects of the physicochemical properties of the po lymer composing the microparticles has been done, enough is known to conclu de that the surface of the polymeric microparticle can be decisive in deter mining the overall uptake of the microparticles. Charge and the hydrophobic /hydrophilic balance of the polymer are important physicochemical character istics that determine the value of the polymer as a microparticulate carrie r. This review examines the properties of polymeric matrices that make them viable candidates as oral vaccine delivery vehicles. (C) 1998 Elsevier Sci ence B.V. All rights reserved.