Non-invasive strategies for protein drug delivery: Oral, transdermal, and pulmonary

Proteins are the building blocks of human life which involve physiological processes such as growth, development, metabolism, and reproduction. Despite its role in various biological processes, recently, the protein’s function has been evolving as a promising therapy. The use of protein and peptide as therapeutic agents has several advantages upon small-molecule drugs, such as high specific interaction with its target that is less likely to elicit immune response. Currently, hundreds of protein drugs are available in the market, and this number is expected to increase each year. Consequently, the growth of protein therapeutics requires several improved strategies for drugdelivery processes. Generally, protein and peptide drugsare administrated parenterally by conventional injections due to its poor oral bioavailability and limited permeability across epithelial cells in the gastrointestinal tract. However, a high frequency of injections results in decreased patient compliance because of the pain and skin wound. Therefore, a lot of research has been conducted in order to study the non-parenteral route of protein and peptide drug.In this review, we discuss recent findings for non-parenteral administration of protein drugs,for instance, oral, transdermal, and pulmonary route. The recent advancements in protein drugdelivery make the non-parenteral route a promising method for protein drugdelivery because of the ease of use among patients.