title: Self-emulsifying drug delivery systems in oral (poly)peptide drug delivery.
abstract: BACKGROUND
  Oral administration of most therapeutic peptides and proteins is mainly restricted due to the enzymatic and absorption membrane barrier of the GI tract. In order to overcome these barriers, various technologies have been explored. Among them, self-emulsifying drug delivery systems (SEDDS) received considerable attention as potential carriers to facilitate oral peptide and protein delivery in recent years.
  
  
  METHODS
  This review article intends to summarize physiological barriers which limit the bioavailability of orally administrated peptide and protein drugs. Furthermore, the potential of SEDDS to protect incorporated peptides and proteins towards peptidases and proteases and to penetrate the mucus layer is reviewed. Their permeation-enhancing properties and their ability to release the drug in a controlled way are described. Moreover, this review covers the results of in vivo studies providing evidence for this promising approach.
  
  
  CONCLUSIONS
  As SEDDS can: i) provide a protective effect towards a presystemic metabolism; ii) efficiently permeate the intestinal mucus gel layer in order to reach the absorption membrane; and iii) be produced in a very simple and cost-effective manner, they are a promising tool for oral peptide and protein drug delivery.
authors.affiliation: a Leopold - Franzens University Innsbruck, Institut of Pharmacy, Center for Chemistry and Biomedicine, Department of Pharmaceutical Technology , Innrain 80/82, Innsbruck, Austria +43 512 507 58601 ; +43 512 507 58699 ; andreas.bernkop@uibk.ac.at.
authors.forename: Gintare
authors.initials: G
authors.lastname: Leonaviciute
authors.affiliation: a Leopold - Franzens University Innsbruck, Institut of Pharmacy, Center for Chemistry and Biomedicine, Department of Pharmaceutical Technology , Innrain 80/82, Innsbruck, Austria +43 512 507 58601 ; +43 512 507 58699 ; andreas.bernkop@uibk.ac.at.
authors.forename: Andreas
authors.initials: A
authors.lastname: Bernkop-Schnürch
mesh_terms: D000284:Administration, Oral; D001682:Biological Availability; D016503:Drug Delivery Systems; D004655:Emulsions; D041981:Gastrointestinal Tract / Q000378:metabolism; D006801:Humans; D010455:Peptides / Q000008:administration & dosage*; D011506:Proteins / Q000008:administration & dosage*
chemical_list: D004655:Emulsions; D010455:Peptides; D011506:Proteins
keywords: absorption barrier; controlled release; oral bioavailability; peptidases/proteases; peptides; permeation; self-emulsifying drug delivery system