Published in: Journal of Controlled Release (2007), vol.118, iss.3, pp.294-302 Status: Postprint (Author’s version) Helodermin-loaded nanoparticles: Characterization and transport across an in vitro model of the follicle-associated epithelium

M cells represent a potential portal for oral delivery of peptides and proteins due to their high endocytosis abilities. An in vitro model of human FAE (co-cultures) was used to evaluate the influence of M cells on the transport of free and encapsulated helodermin- a model peptide- across the intestinal epithelium. M cells enhanced transport of intact helodermin (18-fold, Papp = 3 x 10-6 cm s-1). As pegylation increased nanoparticle transport by M cells, helodermin was encapsulated in 200 nm nanoparticles containing PEG-b-PLA:PLGA 1:1. Stability of the selected formulation was demonstrated in simulated gastric and intestinal fluids. M cells increased the transport of helodermin encapsulated in these nanoparticles by a factor of 415, as compared to Caco-2 cells. Transport of free and encapsulated helodermin occurred most probably by endocytosis. In conclusion, M cells improved helodermin transport across the intestinal epithelium, confirming their high potential for oral delivery of peptides