According to aspects illustrated herein, there is provided an agent that transiently disrupts claudin-1 within tight junctions. The agent includes a peptide having at least 40% polar, uncharged amino acid residues and a self-assembled β-sheet secondary structure. According to aspects illustrated herein, there is also provided a transepithelial drug and vaccine formulations, as well as isolated peptides, pharmaceutical compositions, and transdermal delivery devices. Also described herein are methods of disrupting epithelial barrier and methods of administering the transepithelial formulations described herein.