Polymeric nano- and microparticles for the oral delivery of peptides and peptidomimetics

Due to recent advances, numerous bioactive peptides are now available in la rge quantities. Administering these substances by the oral route appears as a formidable challenge due to their insufficient stability in the gastroin testinal tract and their poor absorption pattern. Several approaches have b een investigated to improve their oral bioavailability. Among them, the use of polymeric particulate delivery systems (microparticles and nanoparticle s) represents a promising concept. Encapsulating or incorporating peptides in particles should at least protect these substances against degradation a nd, in some cases, also enhance their absorption. The aim of this paper is to review the principal studies where peptide-loaded particles were adminis tered by the oral route. The preparation methods and in vitro trials are pr esented and in vivo results are discussed with emphasis placed on the pepti de blood levels reached or on the biological effects observed. Whether or n ot intact particles can be taken up and translocated to the systemic circul ation is not the aim of this review. (C) 1998 Published by Elsevier Science B.V. All rights reserved.